THE LOCATION, HAZARD ASSESSMENT AND SEALING OF
 UNSAFE MINE OPENINGS IN THE CENTRAL
 WITWATERSRAND GOLD MINING BASIN
 Gregory John Heath
 A dissertation submitted to the Faculty of Engineering and the
 Built Environment, University of the Witwatersrand, in fulfilment of
 the requirements for the degree of Master of Science in
 Engineering by research only
 Johannesburg, 2009
ii
iii
 ABSTRACT
 One of the most unfortunate legacies of more than 100 years of mining in the Central Witwatersrand
 Mining Basin is the presence of many unsafe mine related openings such as shafts and subsidences
 that are present in the southern part of the city of Johannesburg. Using available mine plans and
 knowledge of the manner in which these holes were formed, a search was undertaken and a total of
 244 openings were located.
 A literature survey revealed that perimeter walls, concrete seals and plugs have most often been used
 to prevent human access to these unsafe mine openings. Locally mine openings have most often
 been backfilled with available materials though concrete plugs or seals, walls and fences have also
 commonly been used. In order to assess which holes should be considered for sealing, a simple ?hole
 risk rating system? was developed, which considered the depth of the hole and its proximity to
 settlements or thoroughfares. During a Department of Minerals and Energy project led by the author,
 it was concluded that concrete plugs were probably the most effective method of sealing such unsafe
 mine openings. Eighty holes were thus sealed using unreinforced, concrete plugs. Polyurethane
 Foam (PUF) has been used as an alternative method to seal mine openings in the United States for
 nearly 25 years and was used here to seal two abandoned mine openings. This method requires
 minimal design, engineering supervision and offers a quick, simple, cost effective and environmentally
 friendly method of sealing such openings.
 The documentation of the mine openings, the openings plugged, the methods of plugging and the
 locations of the plugged holes ia a valuable practical and historical record. The plugging of many
 holes is a significant contribution to public safety.
iv
 Dedicated to my wife Lindy and children Jessica, Rachel and Jonathan
v
 ACKNOWLEDGEMENTS
 The Department of Minerals and Energy is hereby acknowledged for their foresight in identifying the
 risk that unsafe mine openings pose to the inhabitants of southern Johannesburg and allowing the
 author this opportunity to document this problem. Additionally, my project assistant, Mr. Donald
 Molapo, is thanked for his tireless assistance in locating these mine openings.
vi
 CONTENTS
 DECLARATION............................................................................... ERROR! BOOKMARK NOT DEFINED.
 ABSTRACT ........................................................................................................................... III
 ACKNOWLEDGEMENTS.......................................................................................................... V
 1 INTRODUCTION ...........................................................................................................1
 1.1 Scope of the mine openings study ...............................................................................1
 1.2 Possible closure methods...........................................................................................12
 1.3 Context of Dissertation ..............................................................................................14
 2 IDENTIFICATION OF MINE OPENINGS ......................................................................16
 2.1 Introduction and review of available information.....................................................16
 2.2 Literature Study .........................................................................................................17
 2.3 Review of mine plans .................................................................................................19
 2.4 Background to exploitation of the gold reefs ............................................................22
 2.5 LIDAR Survey .............................................................................................................27
 2.6 Field Verification ........................................................................................................29
 2.6.1 Safety Rating criteria .......................................................................................................... 31
 2.7 Summary ....................................................................................................................33
 3 THE UNSAFE MINE OPENINGS IN THE CENTRAL WITWATERSRAND MINING
 BASIN.........................................................................................................................34
 3.1 Introduction ...............................................................................................................34
 3.2 The number and nature of the mine openings identified ..........................................34
 3.3 Hazardous nature of the mine openings....................................................................43
 3.3.1 Depth factor....................................................................................................................... 43
 3.3.2 Mine openings proximity factor............................................................................................ 44
 3.3.3 Results of the hole rating .................................................................................................... 46
 3.4 Summary ....................................................................................................................46
 4 COMMON METHODS OF CLOSING MINE OPENINGS...................................................48
 4.1 Literature Survey .......................................................................................................48
 4.1.1 Seals ................................................................................................................................. 49
 4.1.2 Plugs ................................................................................................................................. 51
 4.2 Legal requirements ....................................................................................................62
 4.3 Typical Methods Observed in the Central Witwatersrand Mining Basin....................64
 4.3.1 Seals ................................................................................................................................. 65
 4.3.2 Fences and Walls............................................................................................................... 67
 4.3.3 Plugs ................................................................................................................................. 67
 4.3.4 Backfilling .......................................................................................................................... 68
 4.3.5 Mine openings considered for sealing................................................................................... 69
 4.3.6 Conclusions........................................................................................................................ 70
 5 CASE STUDIES OF SELECTED METHODS OF CLOSING MINE OPENINGS IN THE
 CENTRAL WITWATERSRAND BASIN...........................................................................72
 5.1 Introduction ...............................................................................................................72
 5.2 Case Study 1: Polyurethane Foam (PUF) Plugs .........................................................72
 5.2.1 PUF Test Hole 1: ERPM 19A ................................................................................................ 72
 5.2.2 PUF Test Hole 2: Mine Opening S&J 15B.............................................................................. 80
 5.3 Case Study 2: Concrete Plugs ....................................................................................84
 5.3.1 Methodology ...................................................................................................................... 86
 5.3.2 Results............................................................................................................................... 89
vii
 5.4 Comparison between PUF and concrete plugs...........................................................94
 5.5 Insertion of landmarks...............................................................................................96
 5.6 Summary ....................................................................................................................97
 6 CONCLUSIONS ...........................................................................................................98
 7 REFERENCES ............................................................................................................100
viii
 LIST OF FIGURES
 Figure 1.1 Local inhabitant dangerously close to two abandoned mine shafts, Johannesburg.
 Each of these openings is believed to be approximately 500m deep........................................ 2
 Figure 1.2 Map showing the Witwatersrand Geological Basin (Pretorious, 1986)................................ 4
 Figure 1.3 Witwatersrand Mining Basins (Council for Geoscience, 2004) ........................................... 5
 Figure 1.4 . Stratigraphic Column of the Witwatersarnd Supergroup showing the position of the
 reefs, Norman and Whitfield (2006)...................................................................................... 6
 Figure 1.5 Typical examples of types of openings found in the study area ........................................ 7
 Figure 1.6 Steel framework within an abandoned, vertical mine shaft (Rand Leases Mine,
 Roodepoort)........................................................................................................................ 8
 Figure 1.7 Typical example of an abandoned inclined mine shaft, Ekurhuleni .................................... 8
 Figure 1.8. Surface ?sinkhole? development above an abandoned stope (Brink, 1983) ...................... 10
 Figure 1.9 Collapse into stope in central Johannesburg (Bell et al, 2000) ........................................ 11
 Figure 1.10. Dip section showing High risk zone (Zone V) in the stope outcrop region (Barker,
 1998)................................................................................................................................ 12
 Figure 1.11: Uncontrolled backfilling, Boksburg (circa 2004) .......................................................... 15
 Figure 2.1: Stages in the location of abandoned mine shafts (Anon, 1976) ..................................... 17
 Figure 2.2: System to rate the hazard level of each opening (Nemai, 2001).................................... 19
 Figure 2.3. Mine properties with available mine plans, Central Mining Basin (DME, Pretoria) ............ 20
 Figure 2.4. Original mine positions (Scott, 1995)........................................................................... 21
 Figure 2.5. Original surface workings, Langlaagte, Southern Johannesburg .................................... 23
 Figure 2.6. Exploitation of surface outcrop by early miners (Albrecht, 2006) ................................... 23
 Figure 2.7. Cross section showing gold reefs that were exploited at Simmer and Jack Gold Mine
 (Scott, 1995)..................................................................................................................... 25
 Figure 2.8. Cross section through Crown Mines property (Scott, 1995) ........................................... 26
 Figure 2.9: Production of LIDAR imagery (ALS, 2005) ................................................................... 28
 Figure 2.10. Resolution elevation relationship of LIDAR imagery (ALS, 2005).................................. 28
 Figure 2.11: Example of information field sheet (Council for Geoscience, 2004) .............................. 30
 Figure 3.1. Central Basin Mine Openings....................................................................................... 37
 Figure 3.2. Central Basin Mine Openings....................................................................................... 38
 Figure 3.3. Relationship between mine openings and major reefs .................................................. 39
 Figure 3.4. Size range of mine openings ....................................................................................... 39
 Figure 3.5. Largest subsidence in study area, ERPM 17, Ekurhuleni ................................................ 41
 Figure 3.6. ERPM24x, collapse of a slimes dam into an underlying mine opening, Ekurhuleni ........... 41
 Figure 3.7: S & J 15, the old Primrose No.9 shaft, one of the largest known ................................... 42
 Figure 3.8. Aerial extent of growth of S&J 15................................................................................ 42
 Figure 3.9. Typical depths of mine openings ................................................................................. 44
 Figure 3.10. Proximity between mine openings and settlements/ infrastructure............................... 45
 Figure 3.11. Informal settlement situated close to dangerous mine opening ................................... 45
 Figure 3.12: Simplified grouping of hazardous mine openings ........................................................ 47
 Figure 4.1: Typical concrete cap (Healy and Head, 1984) .............................................................. 50
 Figure 4.2: Potential mechanism of failure below a shaft covered by a cap ..................................... 51
 Figure 4.3: Polyurethane plug (U.S National Park Service, 1992).................................................... 53
 Figure 4.4: Expanded, rigid PUF (Council for Geoscience, 2004)..................................................... 53
 Figure 4.5 PUF, the effect of density on compressive strength (Dunham, 2004)............................. 55
 Figure 4.6 Graphical depiction showing variation in Polyurethane Foam plug thickness in
 relation to shortest mine dimension .................................................................................... 59
ix
 Figure 4.7: Truncated concrete pyramid with polyurethane support (Dunham, 2004) ...................... 61
 Figure 4.8. ?Balloon? technique for consolidating old mine workings (Parry-Davies, 1992) ............... 61
 Figure 4.9. Building restrictions on undermined land (Government Mining Engineer, 1965).............. 64
 Figure 4.10: Mine opening (S & J 8) sealed with a metal grate and barbed wire fencing,
 Johannesburg.................................................................................................................... 66
 Figure 4.11: Typical shaft sealed with concrete seal (Crown Mine 8 Shaft A, Johannesburg) ............ 66
 Figure 4.12. Access attempt through reinforced concrete seal, Kleinfontein Mine (Ekurhuleni) ....... 67
 Figure 4.13. Access attempts through perimeter wall in Mine Opening Roode 5, Johannesburg........ 68
 Figure 5.1: Locality plan of Holes sealed with PUF, Ekurhuleni ....................................................... 73
 Figure 5.2 Hole 19A, Ekurhuleni ................................................................................................... 73
 Figure 5.3: Geological cross section of Hole 19A (Council for Geoscience, 2005) ............................. 75
 Figure 5.4: Base of plug being lowered into position ..................................................................... 76
 Figure 5.5: Thin stream of foam mixture being delivered from the applicator nozzle........................ 77
 Figure 5.6: Layers of expanding foam .......................................................................................... 78
 Figure 5.7: Placing covering material over PUF filled shaft ............................................................. 78
 Figure 5.8. Location of S & J 15 B, Ekurhuleni............................................................................... 81
 Figure 5.9. S & J 15B: PUF plug being created in mine shaft.......................................................... 83
 Figure 5.10. S & J 15B: Gravel load being placed on PUF plug ....................................................... 83
 Figure 5.11. Field test: Hole S & J 15B, Ekurhuleni (Council for Geoscience, 2008).......................... 85
 Figure 5.12 Determination of plug thickness for a vertical shaft (Council for Geoscience 2007) ........ 88
 Figure 5.13. Determination of plug thicknesses for an inclined shaft (Council for Geoscience,
 2007)................................................................................................................................ 88
 Figure 5.14. Sacrificial formwork, suspended by steel cables from steel girders, prior to the
 casting of the primary slab................................................................................................. 89
 Figure 5.15. Investigation and sealing solution for ERPM 17, Ekurhuleni ......................................... 93
 Figure 5.16. Concrete plugs installed in S&J 15 and S&J 15A, Ekurhuleni........................................ 94
 Figure 5.17. Typical landmark placed on sealing of a mine opening................................................ 97
x
 LIST OF TABLES
 Table 2.1. Abandoned hole saftey rating (Nemai, 2001) ................................................................ 18
 Table 2.2. Central Basin Mine plans (Council for Geoscience, 2005)................................................ 22
 Table 2.3. Mine Opening Hazard Rating System ............................................................................ 32
 Table 3.1. Central Basin Mine Openings........................................................................................ 36
 Table 3.2. Type of mine openings and gold reefs .......................................................................... 36
 Table 3.3. Measured depths of some shafts in the Central Basin (Council for Geoscience, 2004) ...... 43
 Table 4.1: Recommended design for concrete slabs (Healy and Head, 1984).................................. 51
 Table 4.2: List of standard tests conducted on PUF samples (U.S Bureau of Mines, 1992) ............... 56
 Table 4.3: Polyurethane Foam Design Plug Thickness (Colorado Mined Land Reclamation
 Division, 1989) .................................................................................................................. 58
 Table 4.4. Table showing split between vertical and inclined mine openings ................................... 70
 Table 4.5. Observed methods used to seal abandoned mine openings in the Central Mining
 Basin ................................................................................................................................ 71
 Table 5.1. Concrete plug dimensions ............................................................................................ 90
 Table 5.2. Typical depths of concrete plugs .................................................................................. 90
 Table 6.1. Summary of mine openings (Council for Geoscience, 2007) ........................................... 99
 APPENDIX A: RAND WATER PIPELINE ACCIDENT
 APPENDIX B: CENTRAL WITWATERSRAND MINING LAND STUDYRISK ANALYSIS
 APPENDIX C: MAPS SHOWING UNSAFE MINE OPENINGS
 APPENDIX D MINE PLANS REVIEWED
 APPENDIX E: OPENINGS DERIVED FROM MINE PLANS
 APPENDIX F: TOTAL LIST OF MINE OPENINGS
 APPENDIX G: PHOTOGRAPHIC RECORD OF MINE OPENINGS
 APPENDIX H: HISTORICAL METHODS USED TO SEAL MINE OPENINGS
 APPENDIX I: SRK CONCRETE PLUG DESIGN
 APPENDIX J: MATERIAL QUANTITIES FOR INSTALLING CONCRETE PLUGS IN
 CENTRAL BASIN MINE OPENINGS
1
 1 INTRODUCTION
 The extraction of gold from the Witwatersrand gold reefs has been carried out more or less
 continuously since the 1880?s to produce a 100km elongated mining belt situated south of the
 Johannesburg central business district, South Africa.
 Initially the outcropping reefs were exploited at surface and as techniques improved, extraction of
 deeper reserves was targeted. Openings, such as shafts, raizes, winzes and other excavations were
 created for the various underground activities associated with mining. Available records show that
 some 43 500t of gold have been produced to date from the area south of central Johannesburg
 (Wilson and Annhaeusser, 1998) which has resulted in the development of large, east west striking,
 tabular underground mining voids that intersect the surface in this area. As the attention of the
 various mining houses turned to deeper mining opportunities, scant thought was given to, nor
 required for rehabilitating the disturbance caused by the efforts of the previous mining. This resulted
 in a highly disturbed landscape consisting of dangerous, abandoned mine openings of various sizes,
 depths and origins. The collapse at surface of the near surface mining void also produced numerous
 mine related openings.
 Figure 1.1 shows a young boy blissfully unaware of the danger posed by two deep, abandoned shafts
 in the Tudor area, Johannesburg, whose depths have been estimated at nearly 500m. Additionally,
 these two openings appear to have been initially sealed (with concrete) by the original mine owner,
 but have been subsequently opened by persons wanting to illegally access the shaft, and materials
 therein, below. Their actions have created a substantial risk for persons, such as this young boy,
 living nearby. The risk posed by such openings was further, dramatically illustrated during the course
 of this study when a young woman, who was inspecting a pipeline, fell 20m down a narrow (0,5m)
 subsidence (Makause Informal Settlement, Germiston) that had developed above an old stope
 (Appendix A).
 1.1 Scope of the mine openings study
 The Witwatersrand ?Mining? Basin, has developed as a result of exploitation of the gold rich horizons
 deposited in the Witwatersrand ?Geological? Basin (Figure 1.2), a former sedimentary basin that
 existed 2750 million years ago (Viljoen and Reimold, 1999). This elongated mining belt can be
 subdivided into three goldfields (Figure 1.3), namely the Central, Eastern and Western goldfields,
2
 though the latter is also typically subdivided, from a mining point of view, into the Western and Far
 Western goldfield. From a mining perspective, each of these areas, is referred to as a mining basin
 and each of which is:
 a. Geologically separate (Scott, 1996) i.e the reefs are not continuous, but can be
 broken into sections by either tectonic breaks or regions of lower payability, which
 are referred to as ?Gaps? and which separate these basins (Johnson, 2006).
 b. Geohydrologically separate (Scott, 1996) i.e the water levels in the mine voids of
 each of the basins are independent with no natural connections.
 For the purposes of the current research only the Central Mining Basin is considered here.
 Figure 1.1 Local inhabitant dangerously close to two abandoned mine shafts, Johannesburg.
 Each of these openings is believed to be approximately 500m deep.
 This study of the Central Witwatersrand Mining Basin was undertaken to:
 1. form a comprehensive record of the openings that are present within this Mining
 Basin
3
 2. consider various methods that have been previously used to seal such mine openings
 3. determine the safety risk that each hole presents to local inhabitants
 4. document existing methods used to seal these openings
 5. investigate the merits of using Polyurethane Foam (PUF) to seal a number of these
 openings
 6. document the use of concrete plugs to seal a substantial number of these openings.
 Particular reference is made to a Council for Geoscience (CGS) project, led by the
 author, to seal a number of mine openings on behalf of the Department of Minerals
 and Energy (DME) during the period 2006-2007.
 The Central Mining Basin of the Witwatersrand Goldfield is defined:
 a. by the lateral extent of the strike, as well as the dip, of the gold bearing reefs of the
 Central Rand Group (Witwatersrand Supergroup). These rocks form an east - west
 ?belt? that runs for approximately 38km through southern, central Johannesburg. The
 surface outcrops of these reefs lie immediately south of Main Reef Road, also known
 as the R29, and form the northern boundary of the study area.
 b. by an unmined strip of land that forms the eastern boundary which is known as the
 ?Boksburg Gap? (Scott, 1996), separates the Eastern Mining Basin from the Central
 Mining Basin. It was not mined because of (apparently) very poor gold grades.
 c. on its western side by the ?Witpoortjie Gap? (Antrobus, 1986), where a series of major
 faults (Roodepoort Fault and Doornkop Fault) have produced a horst block which
 separates the gold reefs of the Western Mining Basin from the Central Mining Basin,
 situated immediately east of Randfontein.
 d. by the southern extent of the nine original farms on which the first gold mines were
 established, approximately 9 km south of the outcrop of the northernmost reefs.
 The Central Mining Basin lies across three municipal boundaries namely; Ekurhuleni (Germiston/
 Boksburg/ Springs), Johannesburg and Mogale City (Randfontein).
Figure 1.2 Map showing the Witwatersrand Geological Basin (Pretorious, 1986)
5
 Figure 1.3 Witwatersrand Mining Basins (Council for Geoscience, 2004)
6
 The location of unsafe, mine related holes is largely related to the exploitation of gold bearing reefs in
 the Central Mining Basin. These reefs consist essentially of thin (<2m thick) layers of gold bearing
 conglomerate. While many reefs are known in the Witwatersrand Supergroup in this area only the
 reefs in the Central Rand Group have proven to be gold bearing and hence of exploitable interest
 (Norman and Whitfield, 2006). At least 10 gold bearing reefs have been mined in the Central Basin
 with the Main Reef (including the Main Reef Leader and South Reefs), Bird and Kimberley reefs
 (which consists of four reefs) being the most important, Figure 1.4.
 Figure 1.4 . Stratigraphic Column of the Witwatersarnd Supergroup showing the position of
 the reefs, Norman and Whitfield (2006)
7
 The prime aim of this project was to identify as many as possible surface openings related to ?mining?
 activities (Figure 1.5). Openings produced by construction, building activities or dolomite related
 sinkholes are not related to mining activities and hence are not considered here.
 Figure 1.5 Typical examples of types of openings found in the study area
 (Council for Geoscience, 2004)
 In essence, for the purposes of this project, the mine openings i.e holes that were identified during
 this study, were produced by:
 1. The sinking of a shaft (Figure 1.6), which is defined as a hole excavated to conduct
 underground mining operations. Typically shafts are used to provide access for
 mining personnel and equipment, ore extraction and/ or for ventilation. They vary
 greatly in shape (square, rectangular or circular) and extend to great depths
 (>2000m). They may be supported with some type of framework (wood or steel) and
 a form of headgear, for lifting purposes is typically placed over the shaft. In most
 cases they are vertical although inclined shafts are also common (Figure 1.7), into
 which access by foot, rail or vehicle is possible. Some of these incline shafts were also
 commonly used for ventilation purposes to allow air to enter or exit the mine
 workings below. ?Shaft? is used here to describe all of the above types of structures.
8
 Figure 1.6 Steel framework within an abandoned, vertical mine shaft (Rand Leases Mine, Roodepoort)
 Figure 1.7 Typical example of an abandoned inclined mine shaft, Ekurhuleni
 2. Collapse at surface caused by the subsurface mining void i.e. a subsidence. In some
 areas linear type failures, along strike, are present which have been caused by the
 failure of underlying stopes. Hill (1981) has stated that during the 1970?s collapse
9
 into old mine workings was ?not uncommon? with at least 12 such events having being
 recorded. He is of the opinion that this type of collapsing of the backfilled void could
 continue indefinitely as the underlying support weakens. Additionally the records of
 subsidence have often not been kept and as stated by Bell et al (2000) there is no
 confidence as to whether, or to what degree, settlement has taken place. Brink
 (1983) has recognized four categories of this type of mine related subsidence in the
 Central Witwatersrand, namely:
 a. Sinkholes (Figure 1.8). In these cases, material i.e backfill that has been
 deliberately placed in the near surface outcrop of shallow stopes to seal
 these voids is progressively washed downwards by infiltrating surface water.
 By a process of backward erosion a sinkhole develops at surface. This form
 of subsidence can also be exacerbated by a) the removal of pillars b) the
 removal of adjacent reefs c) the deterioration of timber props and waste
 packs (Bell et al, 2000) etc. Bell et al (2000) report that the sides of
 outcropping stopes can also collapse into the workings below leading to, in
 some cases in the Johannesburg area, huge subsidences Figure 1.9.
 Sinkholes, in terms of karstic or dolomitic origin, were not considered in this
 study.
 b. Subsidence accompanying cavern development.
 c. Tension fracture related subsidences. From 1903 to 1930 the Government
 Mining Engineer reported numerous surface cracks in this area due to
 undermining (Hill, 1981). Hill (1981) states that surface cracks produced as a
 result of the northwards and downwards settling of the rock mass overlying
 shallow undermining is a feature of the pre-1920 era. At the time of the
 writing of his article, Hill concluded that, with very few cracks visible (most
 would have probably been backfilled with soil) there was no expectation of
 their development today and hence they are discussed no further in this
 document.
 d. ?Normal? stope closure related subsidence. Such openings are found along
 strike of the outcropping reefs and if large enough may be rectangular in
 shape. This is a process that is related to the forces of gravity, percolating
 waters, rotting of timber supports etc. It thus is a process that has little or no
 time limit.
10
 Figure 1.8. Surface ?sinkhole? development above an abandoned stope (Brink, 1983)
 Where a ?hole? has been created at surface, ??subsidence? is used here to describe any
 or all of the above type of features.
 Bell et al (1989) have also defined the causes of mining related subsidence as being
 typically caused by:
 a) Collapse between pillars.
 b) The collapsing of the pillars themselves. They record that where the strength
 of the pillars is exceeded large subsidence zones may result.
 c) Failure of the pillar roof or floor.
 3. A mining related surface excavation such as a pit, quarry, borrow pit or trench.
 Stacey and Bakker (1992) have identified a number of factors that may have an influence on the
 stability of the surface overlying shallow underground mine workings, which are listed below:
 o Dip of reefs
 o Stoping width
 o Extent of mining
 o Number of reefs mined
11
 o Separation of reef
 o Competence of rocks
 o Support
 o Time elapsed since mining
 Figure 1.9 Collapse into stope in central Johannesburg (Bell et al, 2000)
 While this dissertation is essentially concerned with existing mine openings, cognisance has to be
 taken of areas that are considered susceptible to subsidence formation. Barker (1993) has utilised
 mine plans of mined out areas in the central Johannesburg area and the dip of the ore body to
 develop a subsidence risk analysis. He has defined five levels of subsidence risk of which Level V is
 the highest and refers to the ?near surface zone (<50 to 0mBS), including the outcrop zone (Figure
 1.10), where sinkhole failures that extend to the surface may occur? (Barker, 1993). The northern
 edges of the undermined areas (Appendix B), where the stopes intersect the surface, are defined as
 the most susceptible to subsidence formation. Colouring has been added, by the author, in order to
 differentiate these zones. Bell et al (1989) however do caution that such thematic maps which
 attempt to depict varying levels of risk ?cannot be interpreted too literally? as they only represent
12
 information available at the time of compilation i.e they are almost immediately out of date especially
 if mining is still continuing.
 Figure 1.10. Dip section showing High risk zone (Zone V) in the stope outcrop region (Barker,
 1998)
 1.2 Possible closure methods
 Mining, by definition, involves the excavation of the earth to extract water, ores or minerals. The
 resultant effect is almost always a hole in the ground. However, historically, when the purpose of the
 mining had come to an end, the mine and its shafts and other associated openings were typically
 abandoned by the mine operators, with little effort put into rehabilitation. This has been common
 practice throughout the world. In the United States for example, 9 934 mine openings have been
 reported (U.S National Parks, 1992).
 Closure of these holes has obviously not been a major priority for mine operators and guidelines were
 not available for a long time in many countries for this to be undertaken to a suitable, uniform
 standard. Gallagher et al (1978) report that historically in the United Kingdom, the most common
 practice to close an old shaft involved a) jamming a large tree against the shaft sides and backfilling
13
 b) building a wooden platform 3-15m below surface and backfilling. This often failed as the platform
 rotted away. In most instances, any readily available materials are typically used for closure, normally
 to complete the task as quickly and cheaply as possible, in a weak attempt to address issues of
 safety. Local examples exist, where materials such as builders? rubble and or waste rock have
 typically been dumped into these holes in a random uncontrolled fashion (Figure 1.11).
 In some circumstances, authorities (Nova Scotia, 1997) have recommended the use of blasting to
 seal an opening with broken rock.
 The ?Best Practices in Mine Reclamation? issued by the Colorado Division of Minerals and Geology
 (2002) recommend, when considering the best approach to safeguarding a mine opening, that the
 following factors be considered:
 1. The life span. Is a temporary or a permanent solution required?
 2. The degree of hazard elimination. Is total or partial elimination of the hazard
 required?
 3. Maintenance requirements. Will the measure be subject to vandalism or
 environmental degradation?
 4. Construction safety. What degree of risk will there be for construction
 workers? Obviously the longer time spent in a hole by the workers increases
 risks of accidents.
 5. Environmental concerns. What fauna and flora will be disturbed when closing
 the hole? Can water enter (or exit) the hole?
 6. Design concerns. The design is obviously dependant on the in situ conditions
 which may affect the feasibility of the design.
 7. Cost. The measures to be considered are obviously dependent on the
 financial resources available to undertake the task.
 In considering possible methods to close abandoned mine openings during this study the following
 assumptions have been made, namely that the measures :
 i. form a permanent barrier to human access. ?Permanent? for the purposes of this
 study is taken as meaning >50 years.
 ii. should not result in environmental deterioration i.e the materials used should be
 compatible with the local environment in which they are placed,
14
 iii. be cost effective,
 iv. be properly engineered solutions. Thus methods such as blasting to collapse the area
 around holes will not be considered, as the strength and stability of the material in
 the hole cannot be verified.
 In the aforementioned DME project (Council for Geoscience, 2007) various options to seal unsafe
 mine openings in the Witwatersrand Mining Basin were considered before a preferred method was
 selected. This preferred method was used to seal the majority of the holes. The approaches used
 during that project are discussed below.
 1.3 Context of Dissertation
 The presence of many unsafe, abandoned mine openings in the Central Witwatersrand Mining Basin
 poses a significant risk to the residents of this area. Records of varying quality are scattered between
 the offices of various mining houses (whose ownership changes on a regular basis), mining
 institutions and the Department of Minerals and Energy. The persons with institutional knowledge of
 these mine openings are also disappearing due to retirement or resignation. Many of the records too,
 of which only single copies are available, have not been transferred to digital formats which poses a
 risk that such information could easily be lost forever. It is in this context that this dissertation aims to
 document, locate and produce a substantial, reliable and authoritative record of these unsafe,
 abandoned mine openings which will be of both technical and historical value. A review of local and
 international practices to seal such openings will also be undertaken.
15
 Figure 1.11: Uncontrolled backfilling, Boksburg (circa 2004)
16
 2 IDENTIFICATION OF MINE OPENINGS
 2.1 Introduction and review of available information
 The wide variety of activities associated with mining operations in the Witwatersrand Mining Basins
 has left behind a wide range of surface openings, as briefly defined above. The activities, use of the
 land and the responsibility surrounding these openings has also changed, resulting in a mixture of
 land-uses that often hide the presence of these holes. Similarly, the records of these holes have
 either been lost, as the mines ceased operating, or in the case of the very old mines, may never have
 been recorded. In many cases these openings are hidden by newer structures, vegetation or
 obscured by informal settlements. Only rarely are distinctive features such as a headgear left behind.
 Being essentially subsurface features, their location is thus a difficult task. Having experienced similar
 problems regarding locating abandoned shafts in the United Kingdom, the U.K. Department of the
 Environment (Anon, 1976) recommended that a four stage cyclical process be followed (Figure 2.1)
 that involves:
 Stage I. The gathering of all available local information from old mine maps,
 air photos, published data etc. as well as field inspection
 Stage II. The study of mining journals, local mining history and original
 documents
 Stage III. The commissioning of specialized methods such as aerial
 photography in the area where the abandoned mine shafts are
 expected. In their approach geophysical surveys are also used to
 detect underground voids. Similarly geochemical surveys may detect
 chemical traces from the mined out areas. These exercises should be
 undertaken while simultaneously conducting field verification
 exercises.
 Stage IV Field proving involving excavation, probing and drilling.
17
 Figure 2.1: Stages in the location of abandoned mine shafts (Anon, 1976)
 2.2 Literature Study
 Prior to this study a number of studies had been carried out which are briefly summarized below:
 ? Scott, 1995. This report was commissioned by the Water Research
 Commission (WRC) to investigate the inflow rate and water quality if the gold
 mines of the Central and East Rand Basins were allowed to flood. Scott
 provides a thorough overview of the gold reefs that were extracted at
 surface.
 ? Dept. Mineral and Energy Affairs, 1996. This report, an internal investigation
 by Frank Barradas, identified a number of openings (25) in the Far Eastern
 Mining Basin.
 ? Nemai, 2001. This investigation was carried out on behalf of East Rand
 Proprietary Mines (ERPM) and the Interdepartmental Committee of State
 Departments (IC) to identify openings in the central mining basin area. A
 total of 102 openings were identified by way of contacting interested and
 affected parties. No systematic ground or aerial surveys were undertaken.
 Openings were named according to the mine property on which they were
18
 found. Each hole was rated in terms of the safety hazard it presented. All the
 openings were plotted on a GIS system. Nemai also devised a system to rate
 the threat to human safety posed by these surface openings (?Hazard Level?),
 Table 2.1.
 Table 2.1. Abandoned hole saftey rating (Nemai, 2001)
 Hazard rating Safety condition
 Very little hazard Typically fenced and hole covered
 Slightly hazardous Hole is typically not completely covered but is
 fenced
 Hazardous Site is typically not covered but is fenced
 Very Hazardous Site is typically not covered, is poorly fenced and
 is deep
 Extremely Hazardous Holing?s safety should be attended to as the
 holing is neither covered nor fenced and is deep.
 Using this rating system Nemai (2001) was able to determine the most
 hazardous holes. ?Thirty four? (Classes 4 and 5) holes (Figure 2.2) were
 considered to represent a ?considerable threat? to pedestrians in the area. It was
 recommended that the safety hazard presented by the openings be addressed as
 a matter of urgency. The defining criteria in this system were essentially based
 on whether the hole was covered or not (not defined) and the state of any
 surrounding fencing. Passing reference was given to the depth of the hole,
 though this was not defined.
 ? Dept. Minerals and Energyy, 2004. An openings database was compiled by A.
 Aukamp of the DME using the same openings collected in the Nemai report. No
 new openings were added.
19
 Figure 2.2: System to rate the hazard level of each opening (Nemai, 2001)
 2.3 Review of mine plans
 In order to locate the positions of the original mine shafts the original mine plans had to be located.
 Mine plans, believed to be probably the last remaining copies, were located in the DME (Pretoria)
 offices. These mine plans, belonging to 21 mine properties, show the position of officially excavated
 shafts in the Witwatersrand Central Mining Basin, Figure 2.3. According to Scott (1995) however a
 number of other mines also existed in this area, Figure 2.4. These mine boundaries have changed
 significantly over the 120 years of mining in this area, from the nine original mine properties to
 approximately 21 at the peak of mining (1950?s), to four today. This of course has created some
 confusion in determining the number of mine shafts present due to the risk of double counting shafts
 recorded on different plans covering the same area. Barker (1992) also states that these mine plans
 often lacked essential near surface information leading to uncertainty as to whether near surface
 areas have been mined. From the available plans the positions of the mine shafts were extracted by
 scanning the mine plans into a digital format (JPEG) and then ?placing? (i.e geo-referencing) these
 images onto topographic maps within a Geographic Information System (Appendix B). The positions
 of the shafts could then be reasonably accurately determined from within the geographic co-ordinate
 system. In a parallel study, to locate shafts that could be used for measuring water table depths in
 this basin, Shango (2005) catalogued a total of 236 mine plans from 23 mines, Table 2.2.
 Hazard level (Nemai, 2001))
 0
 5
 10
 15
 20
 25
 30
 35
 1 2 3 4 5
 Hazard Level
 102 Openings
20
 Figure 2.3. Mine properties with available mine plans, Central Mining Basin (DME, Pretoria)
21
 Figure 2.4. Original mine positions (Scott, 1995)
22
 Table 2.2. Central Basin Mine plans (Council for Geoscience, 2005)
 2.4 Background to exploitation of the gold reefs
 In the Central Mining Basin the gold reefs strike east west from Boksburg to Randfontein over a
 distance of approximately 48km. Their southwards dip generally varies from steep near surface (50-
 90?) and becoming flatter at depth. These reefs outcrop south of the N12 Highway (Main Reef Road),
 also known as the R29. The early city of Johannesburg developed immediately north of these areas
 so that this major road did not have to cross these dangerous areas. All gold mining activities in this
 basin thus occurred south of this road except for the Rietfontein Mine. This mine developed in a small
 outlier (produced by faulting) of gold reefs that occurs approximately 10km north of the major reefs.
 This knowledge of the gold mining area guided the area in which the mine opening survey was
 conducted.
 Perusal of the mine plans mentioned above helped to identify the positions of the original mine shafts
 i.e officially excavated holes. The position of other surface holes, such as subsidences, that also
 developed as a result of mining activities had to be undertaken via other means. Specific attention
 was given to searching the areas where they were most likely to develop, i.e at the surface or near
 surface intersection of the mined out gold reefs with the ground surface.
23
 The initial exploitation of the gold reefs started in 1886 on the farm Langlaagte by the
 removal of the surface outcrop, Figure 2.5. These reefs could be traced for several kilometres
 which led to President Paul Kruger proclaiming nine farms in this area as public gold diggings
 (Wilson and Annhaeusser, 1998). Extraction began by open cutting of the reef which, with
 the use of simple equipment, was only feasible to a depth of 60ft (20m), Figure 2.6.
 Figure 2.5. Original surface workings, Langlaagte, Southern Johannesburg
 Figure 2.6. Exploitation of surface outcrop by early miners (Albrecht, 2006)
 The specific nature of the reefs in this area had a major influence on the manner in which
 exploitation took place. Four major reefs running approximately parallel to each other are
24
 present in the study area, Figure 3.1, Figure 3.2. A number of other reefs in the immediate
 vicinity and parallel to these, which, with available information cannot be easily separated,
 are joined together to create three simple groups. These consist of:
 1. The Main Reef group. Within this group the Main Reef varies from 1-6m thick and
 has been mined on DRD and ERPM Mines but was essentially barren in terms of gold
 (Scott, 1995). This reef is cut off in the eastern part of the basin by the South Reef.
 The Main Reef Leader was sought after for its high gold values, but being generally
 thin (0-2m thick) an adequate stope thickness required for access by miners was not
 possible and thus was often mined with the adjacent Main Reef. The South Reef is
 the third reef in this group and is generally more visible in the western portion of the
 Basin. It is 0,5-3m thick and is situated 15-60m stratigraphically above the Main Reef
 i.e. it outcrops a similar distance south of the Main Reef except in the central portion
 where they are only 10m apart and even in places cuts off the other reefs in this
 group.
 2. Bird Reef. This reef is traceable across the whole Basin but is broken into at least six
 pieces in the central part of the Basin. These reefs are thin being less than 0,5m
 thick.
 3. Kimberley Reef. Consists of four reefs that are laterally extensive across the middle
 part of the whole Basin.
 4. Elsburg Reef. These reefs are upto 100m thick and can be located on the ridges from
 Mondeor to Elsburg in the southern, central portion of the Basin. Surface gold mining
 thus took place along these ridges.
 As seen below, the exploitation of the reefs immediately south of Main Reef Road on the Simmer and
 Jack property eventually resulted in the creation of a large opencast mine, Figure 2.7. This was later
 followed by small incline shafts on the reef itself (Jeppe, 1943). More than 120 small mines were
 believed to have been in operation during this initial period (Wilson and Annhaeusser, 1998). In the
 Central Rand area these reefs were opened along a line of approximately 48km (Scott, 1995). Due to
 the variability of the reef and its gradient, these inclines were limited in their usefulness and small
 vertical shafts were soon sunk. As these mining areas were small, many of these inclines and small
 vertical shafts were excavated. By 1898 ?deep level mining? (> 6000ft) had begun and deep shafts
 were installed. In the Central Mining Basin, the reefs typically have a steep dip near surface and then
 flatten out at depth, which resulted in the deep shafts being placed 300-520m south of the outcrop to
 intersect them at depth. A second line of shafts was later created, approximately 1100m south of the
 outcrop to intersect the reef at even greater depth, Figure 2.8. Due to economic considerations the
 larger shafts were typically placed 10 600 ft (approx. 3200m) apart, along strike. Ventilation shafts
25
 were typically placed in the centre of the mine property. Where the average dip was shallow the
 ventilation shafts were placed closer to the reefs and further apart where the dip was steeper (Jeppe,
 1943).
 Figure 2.7. Cross section showing gold reefs that were exploited at Simmer and Jack Gold
 Mine (Scott, 1995)
26
 Figure 2.8. Cross section through Crown Mines property (Scott, 1995)
27
 2.5 LIDAR Survey
 The most obvious methods of locating holes in the ground are either by undertaking a survey on foot
 or by use of aerial photography. The former method is severely limited by the size of the terrain and
 access to it. Considering that the project area is approximately 150 000ha in extent it clearly was not
 an option to do a foot survey. The latter method, on the other hand, is limited by the availaibility of
 aerial photographs, and by the presence of vegetation and structures that prevent a clear line of sight
 of the ground surface. Additionally, reviewing of large scale photography requires a ?keen eye? and
 systematic approach to be able to locate these features amongst hundreds of aerial photogrpahs. A
 search, amongst local municipalities and survey companies, for suitable aerial photographs of the
 study was undertaken. Only 1: 30 000 imagery was available, which proved to be unsuitable for this
 purpose. In undertaking a similar exercise on the East Rand, Cameron Clarke (1986) found that
 similar aerial photography (1: 30 000 monochromatic) was useful for identifying open excavations,
 but could not be used for surface subsidences in the outcrop workings of the Witwatersrand strata.
 As no aerial photographs of a suitable scale could be located, an attempt was made to use the LIDAR
 (Light Detection and Ranging) aerial photographic survey which had been conducted by the Council
 for Geoscience on behalf of the Department of Minerals and Energy during the period April to June
 2005 (Council for Geoscience, 2005). In the process, imagery is produced utilizing laser and optical
 systems to produce a three dimensional picture of the ground surface. An infrared laserbeam is
 reflected off an optical dish and directed at the ground surface from an aerial platform such as an
 aircraft. The laser beam is able to penetrate through the covering vegetation to the ground surface
 below giving the ground height below the vegetation cover. To ensure accuracy, laser pulse readings
 are taken approximately every 0,25m along the flight path. The position of the aircraft is recorded via
 onboard Global Positioning Systems (GPS), which are linked with equivalent earth based GPS
 systems, Figure 2.9. The inertial movements of the aircraft are also recorded. Suitable cameras are
 also used to produce accompanying photographic imagery.
 The laser data is then used to produce digital contour elevation maps which are superimposed onto
 the aerial photographs. The vertical accuracy is dependant on the height at which the aerial survey is
 flown, Figure 2.10, which in the case of the data supplied, was an altitude of 1000m giving a vertical
 accuracy of 0,1m and a scale of 1: 5000. The use of laser data allows ?depth? to be added to
 standard imagery as the laser beam penetrated to the shaft or subsidence cavity. Once the digital
 data have been downloaded a list of the mine ?features? is produced, and the features then verified in
 the field. At the scale at which the system operated, the results proved to be ineffective for the
 location of mine openings, and the method was not considered further.
28
 Figure 2.9: Production of LIDAR imagery (ALS, 2005)
 Figure 2.10. Resolution elevation relationship of LIDAR imagery (ALS, 2005)
29
 2.6 Field Verification
 Based on the information gained from available literature and mine plans field verification of the
 positions of identified holes was then undertaken.
 Once an opening was located in the field its GPS co-ordinates (WGS 84 system) and characteristics
 were recorded, (Appendix C). A standard field sheet was used, Figure 2.11. The details that were
 recorded included:
 o The location of the hole (x and y co-ordinates)
 o The size of the hole
 o The safety hazard rating
 The header and locality information was transferred to a GIS system so that the positions of the
 openings could be plotted. The hole names used were derived from the earlier mentioned Nemai
 report (Nemai, 2001). These names are usually loosely linked to the original mine property names eg.
 ERPM (East Rand Proprietary Mine), S&J (Simmer and Jack Mine) etc. It was decided, for purposes of
 continuity (and to avoid confusion), to maintain and add to this system.
 The photographs of each opening observed are stored in Appendix 2.
 Each opening was classified into one of the following four simple categories of openings, namely:
 a. Shaft
 b. Subsidence
 c. Mine related excavation
 d. Underground mine related structure
 Each opening was rated, using the system described below, in terms of the safety hazard it
 presented.
30
 Figure 2.11: Example of information field sheet (Council for Geoscience, 2004)
31
 2.6.1 Safety Rating criteria
 In order to be able to assess which holes would require sealing the risk that each hole represented (in
 terms of safety) had to be determined. Two criteria were considered as being relevant in determining
 the risk posed by each hole:
 ? Depth of the hole i.e. the deeper the hole, the greater the likelihood of
 injury. Beyond a certain depth death is considered almost inevitable. The
 depths of two of the shafts, namely 1728,8m and 2105m at DRD and ERPM
 respectively, illustrate how deep some of these shafts are. This factor, which
 represents the hazard or danger posed by each hole, was given a score out
 of five (increasing score with depth). The size of the hole was considered to
 have an insignificant influence on the injury caused.
 ? Proximity of the hole to human settlements i.e the closer the hole to a local
 settlement or thoroughfare, the greater the risk that that hole creates i.e
 scale 1-5. A distance of 1000m was generally taken as the threshold distance
 about which this factor was considered relevant. Inclined holes required
 special consideration because, even though there was no danger posed in
 terms of falling from height, there were additional dangers posed because of
 easy access to the underground mine workings (refer Figure 1.7) which
 opened up other dangers, namely; falls of ground, gas, drowning and getting
 lost underground. These openings were treated as extremely hazardous.
 These two factors were then added together, giving a score out of 10 (Table
 2.3.
32
 Table 2.3. Mine Opening Hazard Rating System
 Hazard rating Description Remarks
 1 Sealed Adequately These openings had been sealed prior to this
 project and currently pose no danger.
 2 Slightly hazardous Small settlement or shallow surface opening or
 trench. Depth < 1,5m. Minor injuries
 possible.
 3 Hazardous Surface opening 1,5-3m deep. Minor injuries
 probable.
 4 Very hazardous Surface opening is 3-10m deep. Serious injuries
 probable though probably non fatal.
 5 Extremely hazardous Surface opening > 10m deep, serious injuries
 likely and probably fatal.
 Inclined holes: fatal injuries due to fall of ground,
 gas, drowning, getting lost.
 Proximity
 Rating
 Description
 1
 Opening is in a vacant field (> 1000m from any settlement or thoroughfare),
 area frequented by few people.
 3
 Opening is <1000m from a human settlement or thoroughfare. Area
 occasionally frequented by passers by.
 5
 Opening within or close to an urban settlement or where the holing
 threatens a road or walkway.
 Overall Risk Rating
 1-3 Hole shallow or far away from settlements i.e insignificant threat
 Low
 4-5
 Hole either a) deep (>10m) and far away (>1000m) or b) close but shallow
 (<3m) or c) moderately deep (3-10m) and reasonably far away (>1000m)
 Moderate 6-7
 Hole either a) hole deep (>10m) but far away (>1000m) or b) moderately
 deep (3-10m) and reasonably close to settlements (<1000m)
 High 8-10 Hole deep (>10m) and close to settlements (<1000m)
33
 2.7 Summary
 The location of unsafe mine openings in the Central Witwatersrand Mining Basin in this dissertation
 was based on a) a literature survey b) developing an understanding of the relationship between the
 gold reefs and the mine openings. Available LIDAR surveys were unfortunately not at a scale to be of
 any effective use. All holes were systematically documented and recorded on a GIS system. A simple
 safety risk rating system was developed to be able to assess the risk to local inhabitants that each
 hole poses.
34
 3 THE UNSAFE MINE OPENINGS IN THE CENTRAL WITWATERSRAND MINING BASIN
 Waltham et al (2005), state that where a hazard impinges upon human activity it involves a degree of
 risk. The hazard being considered in this study, namely deep mine openings, being situated in and
 adjacent to many residential communities in the southern Johannesburg area, pose a significant
 threat to the residents of these communities.
 3.1 Introduction
 The unsafe nature of these mine openings is illustrated by a number of historical as well as recent
 examples:
 ? A hole developed next to a building in the Motortown area, central
 Johannesburg, which swallowed three cars (Stacey and Bell, 1999)
 ? A Rand Water employee was seriously injured when she fell 20m down a 1m
 diameter hole (Appendix A) while inspecting a water pipeline in Germiston,
 February 2006
 ? the sudden development of a subsidence in Makause informal settlement
 (Germiston), above the reef outcrop which led to the death of a woman,
 circa October 2007.
 3.2 The number and nature of the mine openings identified
 The determination of the number of mine openings in the Central Witwatersrand Basin was based on
 the collation of:
 ? holes formally/ intentionally excavated and whose positions were officially
 recorded i.e mine shafts
 ? the holes formally/ intentionally excavated but whose positions were not
 officially recorded, i.e such as box holes and ventilation holes, and
 ? holes that developed as a result of collapse of the reef outcrop i.e
 subsidences.
35
 In his survey of the available mine plans (236) for the Central Mining Basin, Shango (Council for
 Geoscience, 2005) initially identified 402 officially recorded shafts (Appendix E). However a number
 of factors place doubt on the accuracy of this total, namely:
 ? many of the mines were sold and resold over the years resulting in
 duplication of shafts on plans
 ? poor record keeping by the mine owners
 ? missing maps
 ? the use of shaft names that were not unique i.e No.1 Shaft, Shaft 1 etc.
 ? as underground plans were also reviewed, it is possible that subvertical shaft
 positions (which obviously do not daylight) were also recorded.
 After a process of checking, verification (where possible) and elimination, a substantially lower total
 of mine plan shafts was arrived at, i.e 221. This total was then used as a guide i.e a theoretical total
 of what to expect in the field.
 With the use of available mine plans and an understanding of the nature of the gold reefs in the
 central Johannesburg area, 244 mine openings were eventually located, Table 3.1, whose positions
 are shown in Figure 3.1 and 3.2. A larger version of these maps is shown in Appendix C where they
 have been plotted both on topographic maps and aerial photographs. The number of mine shafts
 located (170), represents 76,9% of the theoretical total (221). Most of the mine openings (69,6%)
 found in this basin were shafts, while a significant number were subsidences. Hill (1981) mentions the
 occurrence of a further 10 subsidence events in the Johannesburg city area. However as their
 positions could not be verified they are not included in this total. Only a few openings, defined as
 excavations and underground structures, were located and were hence not considered significant in
 this study.
 Most of the mine openings (68%), were found along the strike of the northernmost group of reefs i.e
 the Main Reef Leader, Main Reef and South Reefs, Figure 3.3. A similar number of mine openings
 were scattered along each of the Bird Reef group and the Kimberley Reef group. No mine openings
 were along the Elsburg reefs during this study.
36
 Table 3.1. Central Basin Mine Openings
 Type of Openings Number Percentage
 Shafts 170 69,6
 Subsidence 60 24,5
 Structure 7 2,8
 Excavation 7 2,8
 Total 244 100
 The Main Reef group of reefs is dominated by shafts however a significant proportion (34%) of mine
 openings found here are subsidences, Table 3.2 . This is significantly higher than that found along the
 Bird Reef (7%) and Kimberley Reef (2,7%) groups situated further south. This high percentage of
 subsidences present along the Main Reef group can perhaps be attributed to the manner in which
 gold from the surface outcrop was initially exploited via many small claims. By the time the search for
 gold moved further south, primary mining groups had probably been established who would, by then,
 have realised that appropriately placed vertical shafts offered greater potential for the exploitation of
 gold, rather than down dip mining by winzes and incline shafts. Hill (1981) indicated that the down
 dip mining era largely came to an end by the late 1920?s.
 Table 3.2. Type of mine openings and gold reefs
 Mine Opening Main Reef Bird Reef Kimberley Reef
 Shafts 99 36 35
 Subsidences 57 3 1
 Structures 2 3 0
 Excavations 8 0 0
 Percentage Total
 Openings
 68% 17.2% 14.7%
37
 Figure 3.1. Central Basin Mine Openings
38
 Figure 3.2. Central Basin Mine Openings
39
 Figure 3.3. Relationship between mine openings and major reefs
 The range of the largest dimension of the mine openings in the Central Witwatersrand Mining Basin
 varies from 1-85m with an average of 6,22m, Figure 3.4. For the most part the largest dimension of
 these openings is <10m which is typical of the shafts that make up the majority of the holes that
 were encountered.
 SIZE RANGE OF MINE OPENINGS
 0
 10
 20
 30
 40
 50
 60
 70
 80
 90
 0 50 100 150 200 250
 HOLE
 H
 O
 L
 E
 S
 IZ
 E
 (m
 )
 ERPM 17
 S&j 15
 ERPM 24
 Figure 3.4. Size range of mine openings
 Relationship between Mine Openings and
 Gold Reefs
 0
 10
 20
 30
 40
 50
 60
 70
 80
 90
 100
 110
 Main Reef Bird Reef Kimberley Reef
 Reef
 No. of Openings
 Shafts
 Subsidence
 Structures
 Excavations
40
 The largest mine opening encountered in the study area was ERPM 17, Ekurhuleni (Figure 3.5), which
 is an old stope outcrop of the Main Reef into which substantial surface material has fallen,
 approximately 35 700m?. The initial dimensions of this hole would probably have been the
 intersection of the underground void i.e the stoping width (1-2m), with the surface. Continued
 collapse into the void below probably led to extension of this hole along strike. Subsequent transport
 of surface materials by water and gravity over a period of approximately 100 years have resulted in a
 hole 85m by 22m by 28m.
 Similarly ERPM 24X (Figure 3.6) on the former Waverly Gold Mine, Ekurhuleni, visually provides a
 visible record of the volume of material that has collapsed into the void below. This hole is situated
 underneath a slimes dump into which the dump has fallen leaving a hole in the overlying material wth
 a circular dimension of approximately 20m i.e a volume of approximately 4000m?. This hole is
 situated on the Main Reef oucrop. During the course of this project the former mining rights holders,
 Centurion Gold, attempted to backfill an adjacent hole, < 10m away, using additional slimes. Within a
 year the volume of material used to fill this hole (approximately 1500m?) had already subsided
 leaving it exposed again.
 Besides its size, approximately 27 000m?, S&J15 (Figure 3.7) on the former Primrose Gold Mine
 property also illustrates how quickly subsidence can occur. Up until 1999 this area was a working gold
 mine, with a working headgear positioned over an inclined shaft. Yet by 23 October 2002, the date of
 a site visit by L. Croukamp (pers. com), a massive subsidence was present which presumably had
 developed sometime within this period i.e three years. This appears to be indicative of the illegal
 removal of steel supports from the abandoned shaft which led to collapse of the hanging wall and
 eventually surface collapse, Figure 5.16.
41
 Figure 3.5. Largest subsidence in study area, ERPM 17, Ekurhuleni
 Figure 3.6. ERPM24x, collapse of a slimes dam into an underlying mine opening, Ekurhuleni
42
 Figure 3.7: S & J 15, the old Primrose No.9 shaft, one of the largest known
 subsidences in the study area
 Figure 3.8. Aerial extent of growth of S&J 15
43
 3.3 Hazardous nature of the mine openings
 In order to prioritize which of these hazardous mine openings required closure, each hole was rated
 according to two simple criteria, namely a) depth and b) distance from settlements or thoroughfares,
 as explained in Chapter 2.
 3.3.1 Depth factor
 From their mine shaft survey of the mine plans stored in the Pretoria offices of DME, Shweitzer and
 Arnold (Council for Geoscience, 2006) recorded at least 34 shafts with depths >500m below the collar
 elevation (mbC), Appendix C . The deepest shaft depth recorded from this data source was the
 South Deep Shaft at the former Simmer and Jack Mine with a vertical depth of 1991mbc. This was
 not the ?longest? shaft depth recorded, however, with the P8 Incline Shaft of Crown Mines having a
 length of 2066.88m. Not all these shafts could be located in the field. The depths of the shafts that
 were found and which could be related to the mine plans are shown in Table 3.3 which indicates a
 range of depths of up to 990.5mbc. The actual depths of these shafts could not be confirmed in the
 field due to obvious safety limitations. The deepest subsidence observed was that surrounding the
 Primrose No. 9 Shaft with a depth of approximately 35m, Figure 3.7.
 During this study, the exact depth of each mine opening was considered to be only of limited interest,
 as anything deeper than 10m was considered to be extremely hazardous and certain to result in a
 fatality. Thus exact depths were not recorded. The percentage of these very deep holes compared to
 the shallower categories of holes (defined earlier in Table 2.3) is shown in Figure 3.9 with the
 majority of the holes (74,5%) being greater than 10m deep.
 Table 3.3. Measured depths of some shafts in the Central Basin (Council for Geoscience,
 2004)
 No. of
 Shafts CGS Shaft Names DME Shaft Names Depth (mbc)
 1 Private 2 Langlaagte East Deep Shaft 457.2
 2 Rudd Shaft Rudd Shaft 448.6
 3 S&J 15 Rose Deep 4 990.5
 4 S&J 16A Rose Deep 5 217.6
 5 Knights Shaft Rose Deep No. 1 438.9
 6 Rose Deep no 2 Rose Deep no 2 517.2
44
 Typical depths of Mine Openings
 0
 10
 20
 30
 40
 50
 60
 70
 80
 <1,5m 1,5-3m 3m-10m >10m
 Hole Depth Categories
 %
 Figure 3.9. Typical depths of mine openings
 3.3.2 Mine openings proximity factor
 The distance between each hole and the nearest settlement, infrastructure, road or well used path
 was measured to determine what risk each hole poses to anyone living nearby.
 In general the majority of the 244 holes in this basin were found within 100m (average 59,8m) of
 such settlements (Figure 3.10). At least 11% of the holes were found surrounded by such settlements
 i.e people were living around the collars of such openings (Figure 3.11). While some of these
 openings had been permanently sealed and hence posed little or no danger, others only had
 temporary barricades (such as barbed wire fences etc.), indicating that perhaps people were not
 aware of the danger posed by such mine openings. At least eight holes (ERPM 32-38, Appendix D)
 were found in the small loop of land that separates Main Reef Road and the N3 Highway, former
 Geldenhuys Mine (Figure 3.2). On a much smaller scale, Hole R61 was located within a metre of a
 major footpath that leads from the Meadowlands Men?s Hostel (Soweto) to Main Reef Road, a
 thoroughfare that is more than likely used at night. The arbitrary 1000m which was initially chosen
 as being the dividing line between ?near? and ?far? proved to be too coarse when used in this Basin.
45
 PROXIMITY BETWEEN OPENINGS AND SETTLEMENTS/INFRASTRUCTURE
 0
 50
 100
 150
 200
 250
 300
 350
 400
 450
 0 50 100 150 200 250 300
 NO. OF MINE OPENINGS
 D
 IS
 T
 A
 N
 C
 E
 (m
 )
 Figure 3.10. Proximity between mine openings and settlements/ infrastructure
 Figure 3.11. Informal settlement situated close to dangerous mine opening
 (Balmoral Vertical), Balmoral Informal Settlement, Ekurhuleni
46
 3.3.3 Results of the hole rating
 Of the 244 mine openings located (Table 3.1), 151 were found to be open and unsafe (61,8%) while
 the remaining 93 had some type of access prevention (concrete slab, plug etc.) and hence were
 rated as not hazardous. These holes were classified as ?Sealed adequately?, exampes of which are City
 Deep 4 and Crown Mine 8 (Appendix 8). Of these 151 open, unsafe openings, 97 (64,2%) were
 identified (Figure 3.12), as posing a ?high? risk i.e being deep and close to local settlements (Table
 2.3). Such an example is shown in the Balmoral Informal Settlement (Ekurhuleni), which has
 developed within 10m of, and irrespective of, such a dangerous hole (?Balmoral Vertical?) (Figure
 3.11). A further 48 (31,7%) were considered to have a moderate risk i.e moderately deep and
 relatively close to settlements. The remaining 4% were considered to pose a ?low? risk i.e because
 they were shallow and/ or far from settlements and were not considered any further.
 Using this system as a guideline, 49 high risk (50,5%) and 31 moderate risk holes (64,5%) were
 selected for closure, a total of 80. This resulted (Figure 3.12) in a reduction in risk due to the sealing
 of these medium and high risk openings. Prior to closure, the majority of the holes were considered
 to be a ?high? risk (64,2%) which after sealing reduced the number of high risk unsafe holes to 48
 (29%). Similarly the holes with a medium risk (31,7%) were reduced to 18 i.e 11,9 %. Consequently
 the number of holes with a low risk risk increased because of the addition of the 80 newly sealed
 holes.
 A number of ?high risk? mine openings could not be considered for closure during the DME Project
 because they were not ?abandoned? mine openings, i.e an existing mine owner had been identified
 whose legal responsibility it was to close those holes. Additionally, other high risk openings were
 identified later in the DME project, and were only then added to the high risk total, by which time
 construction tenders had already been issued. Hence it was too late to include closure of these holes
 in the DME project and they will more than likely be closed in the near future.
 3.4 Summary
 This dissertation has documented the position of 244 unsafe, abandoned mine openings in the central
 mining area of Johannesburg. The majority of these openings are <10m wide but being deep and
 close to local settlements they can be considered danagerous and pose a substantial danger to local
 inhabitants.
47
 Figure 3.12: Simplified grouping of hazardous mine openings
 Central Basin Mine Openings Safety Ranking
 0
 20
 40
 60
 80
 100
 120
 140
 160
 Total Low Medium High
 Mine Openings Hazard Levels
 No. of Openings
 Post - Closure
 Pre- Closure
48
 4 COMMON METHODS OF CLOSING MINE OPENINGS
 ?Once a shaft has been sunk, it is impossible to restore the earth to its? original condition? (U.S Dept.
 Agriculture, 1981). While this comment probably refers to attempts to restore mine areas to their
 original, pristine conditions a survey of methods used internationally, and those observed locally in
 the Central Witwatersrand Mining Basin, to seal mine openings was undertaken.
 4.1 Literature Survey
 In their ?Best Practices in Abandoned Mine Reclamation? the Colorado Division of Minerals and
 Geology (2002) have noted that typically three types of closure methods are commonly used, namely:
 i. Barriers - these methods are designed to discourage access and to keep
 persons away from the hazard. They are appropriate particularly when the
 opening is too large for other alternatives or when restricted access is
 required. Thus fences or grates are placed around or across the opening.
 These methods are necessary if access is required for various types of fauna
 (bats, birds, insects) or for ventilation purposes.
 ii. Seals (or caps) - these methods prevent entry to the mine opening by placing
 panels or slabs across or on top of the opening. They should be of sufficient
 weight that substantial effort is required (such as heavy construction
 equipment) to remove them.
 iii. Plugs - these methods eliminate the hazard altogether by filling all or part of
 the hole. The holes are thus backfilled completely with available materials or a
 concrete plug/ cap placed within a portion of the hole.
 The Nova Scotia Department of Resources (1997), states that the effective life of the selected closure
 method must be considered. They consider methods such as fences, screens and grates to be of a
 temporary nature even though they may last up to 20 years (with suitable maintenance). The biggest
 failing with these methods is that they do not prevent deliberate or even accidental entry into mine
 openings. They define long term measures as being methods that ?seal and prevent entry?.. but still
 preserve the general condition of the opening?. They define ?long term? as being methods that are
 expected to last for 30 to 50 years. Methods such as pre-cast or cast in place concrete caps,
 monolithic concrete caps and/ or native rock or concrete bulkheads are considered to fall into this
 category. Regular inspections and maintenance are still required. Permanent measures, such as
 backfilling and closure through blasting, are considered to be methods that permanently close off the
49
 opening and which will not require further inspection or maintenance.
 Differences in definition are apparent above where the Nova Scotia Department considers backfilling
 to be a ?seal? and the Colorado Division of Minerals and Geology regarding this method as a ?plug?. For
 the purposes of definition during this study, measures such as the use of a monolithic mass of
 concrete (or other similar material) placed in or near the top of a hole will be termed a ?plug?.
 As stated in Chapter 1 of this dissertation, only long term and permanent measures will be considered
 here and temporary methods are excluded. Similarly, only properly engineered methods are being
 considered where the surrounding conditions have been analysed, the method used has been
 properly calculated, and a reliable estimate of its effect can be determined.
 4.1.1 Seals
 Probably the most common form of seal used is the concrete cap where entry is prevented by the
 installation of concrete slabs or panels, precast or cast in situ, on top of the collar of the opening,
 (Figure 4.1).
 The intention of this method is to create a long term to permanent method of preventing access that
 will require substantial effort, to remove. This is an efficient method, especially where numerous
 holes are located close to one another. Furthermore the panels can be designed and placed relatively
 easy without anyone having to enter the hole for any length of time, which has safety implications.
 A number of sources1 2 3 have shown that in general this method involves:
 o Excavating the top of the opening down to solid or competent bedrock to
 create solid footings for the panels.
 o Using either pre cast slabs or casting in situ slabs to cover the hole. Healy
 and Head (1984) specifically recommended that the dimensions of these
 slabs should be at least twice the diameter of the shaft and the slabs should
 not be less than 0,45m thick, (Table 4.1). The beam should be placed
 1
 Healy and Head, 1984
 2
 Nova Scotia, 1997
 3
 Colorado National Park Service, 1992
50
 symmetrically about the hole. These specifications are influenced by the
 nature of the local ground conditions. A minimum width of 6? (0,15m) for the
 steel beams has also been recommended (Colorado National Parks Service,
 1992).
 Figure 4.1: Typical concrete cap (Healy and Head, 1984)
 o Placing steel beams to carry the panels or inserting reinforcing steel, along
 with the necessary formwork, if the concrete is cast in situ. These steel
 beams should be coated with epoxy resin or bituminuous tar to prevent
 corrosion which could lead to failure. The steel beams should be placed
 perpendicular to the direction of the concrete panels.
 o Placing backfill, generally unspecified, over the panels to prevent the ingress
 of water. However where the panels are < 2,5m from the surface, complete
 covering with backfill is not considered necessary (Colorado National Parks
 Service, 1992). Mounding of the backfill may assist the drainage of surface
 water away from the opening.
 o If the cap is then covered by backfill the shaft position should be marked to
 indicate that there is a shaft below.
 This method does require the use of a qualified structural engineer to oversee all aspects of the
 design.
 The use of this method is limited by the hole diameter that panels are able to span. The delivery of
51
 materials or the precast panels may also be limited by road access. Concern has also been expressed
 by Healy and Head (1984) that water infiltration around the edges of the panels may in time lead to
 their subsidence and failure, Figure 4.2.
 Table 4.1: Recommended design for concrete slabs (Healy and Head, 1984)
 Shaft Diameter Slab Thickness Slab Size Minimum Reinforcement
 Up to 1,8m 4,2m x x4,2m
 1,8 - 2,7m 6,4m x 6,4m
 200mm centres
 2,7 ? 3,6m
 Minimum 450mm
 8,2m x 8,2m 250mm centres
 Figure 4.2: Potential mechanism of failure below a shaft covered by a cap
 (Healy and Head, 1984)
 4.1.2 Plugs
 Two types of plugs are reviewed below.
 Concrete plugs
 In the Isle of Man, the local authorities (Isle of Man, 1986) had identified 160 abandoned mine
 openings in their region. The preferred methods of treatment for abandoned shafts was to place an in
 situ reinforced concrete cap or plug over the shaft and then to cover it with soil and return it to its
 original condition. Where it was not possible to construct a shaft cap, such as limitations due to
 access, a suitable steel fence, with signage, was used.
52
 A variation of the ?plug? method has been used in the south Limburg region of The Netherlands where
 35 shafts had to be closed, circa 1971 (Schilp, 1971). The method chosen involved using two
 concrete plugs. The lower one was placed at the level of the highest underground station and
 supported by the floor. The shaft was then filled with clastic material, filler stones or debris. An upper
 concrete plug was placed at the surface.
 Where mined out stopes intersect the surface, outcrops have been plugged using concrete before
 covering them with compacted backfill (Stacey, 1986). This approach involves excavating the stopes
 along strike until competent material in the stope walls is exposed. The concrete is then placed to
 form a base for the overlying backfill. The backfill layer is compacted between the stope walls, which
 results in a ?stabilising ground arch?. This method is probably only suitable for dipping (>30?) to
 vertically dipping stopes.
 Polyurethane plugs
 In dealing with the 9934 abandoned mine openings in the United States National Parks (U.S National
 Park Service, 1992) rigid Polyurethane Foams (PUF) have been used in some circumstances as an
 alternative method for the quick sealing of mine openings, (Figure 4.3). During the period 1987 to
 1989 approximately 15% of abandoned mine openings holes closed in Colorado were sealed using
 this method (Rushworth et al, 1989). The advantages of creating PUF plugs, is that the PUF is highly
 portable, is easily and quickly applied with only minimal site preparation required. It also has low
 costs of design and implementation.
 Essentially the foam is produced by the mixing of two components, an isocyanate (Component A) and
 a polyol resin (Component B) which is then pored or placed on top of a lightweight formwork
 (cardboard, plywood etc). A rapid exothermic reaction occurs within 15-45s, generating a rigid foam
 that expands to fill all voids and cracks and which bonds with the sidewall of the host rock. An
 expansion of 20-30 times typically occurs within 190-240s, Figure 4.4. Once this stage is reached the
 following layer of foam can be placed. The hole is then filled with successive layers to within 0,5m of
 the surface before covering with soil to prevent breakdown due to UV light and damage due to
 vandalsim. The soil layer also creates an arching layer that reduces the effective load by transferring
 it to the sidewalls.
53
 Figure 4.3: Polyurethane plug (U.S National Park Service, 1992)
 Figure 4.4: Expanded, rigid PUF (Council for Geoscience, 2004)
54
 The strengths of Polyurethane Foams are directly related to their density. They can be manufactured
 to produce densities that range from 12,81-961 kg/m? with a 400x increase in strength over this
 density range, Figure 4.5. While denser foams are able to produce plugs that are significantly
 stronger, perhaps similar to that of that of concrete they do though expand less, requiring more
 chemicals and hence cost more.The U.S National Park Service has thus chosen a foam density of 32
 kg/m?, which produces a compressive strength of approximately 240 kPa, as being the optimum,
 most cost effective density for the closing of mine openings. The density of this type of foam is
 approximately 1,3% that of concrete. This appears to have been accepted as the norm for this type
 of application. While higher foam densities can be achieved by varying the chemical nature of the two
 components used, the denser foams obviously expand less, require larger volumes of the raw
 materials and hence lead to increased costs.
 PUF is tan-white to buff in colour, has no vesicles and forms a smooth bulbous surface on setting. It
 is a polyurethane, isocyanate based on a Polyol resin system. The typical product used is 4,4? ?
 Diphenylmethane diisocyanate. It is water based with no chlorofluorocarbons. It has a 6-9 month
 shelf life if stored at > 60?F. If the PUF darkens during production, becomes smooth and glassy,
 friable or brittle, the correct density has not been achieved and is probably caused by excess ?A?
 component. If however it lightens during production, becomes mottled, blowholes or pinholes
 develop, then excess ?B? component is present. If it is slow to rise and has a poor cell structure, if the
 equipment clogs and is slow in curing, then the materials have spoiled.
55
 Relationship Between Compressive Strength and Density of PUF
 10
 100
 1000
 10000
 100000
 12.8 16.0 32.0 64.1 96.1 160.0 320.0 641.0 961.0
 Density (kg.m3)
 C
 o
 m
 p
 r
 e
 s
 s
 iv
 e
 S
 tr
 e
 n
 g
 th
 (k
 P
 a
 )
 Compressive Strength
 Compressive Strength =12.77D
 1.416
 Figure 4.5 PUF, the effect of density on compressive strength (Dunham, 2004)4
 4
 Graph converted from Imperial Units
56
 A distinct property of Polyurethane Foams is that closed foam cells are produced during the chemical
 reaction process. This property inhibits the uptake of water which is particularly important when used
 in areas where subzero temperatures can be expected. If complete and proper mixing of the two
 components has taken place the product should contain almost 100% closed cells (Rushworth et al,
 1989). Incomplete mixng however can lead to some open cells and hence ?weakening? of the final
 product. Generally this type of PUF has a compressive strength of 172-241kPa, and a tensile strength
 of 172-448kPa, Rushworth et al (1989).
 The following standard tests were conducted on 32kg/m? PUF samples by the U.S Bureau of Mines
 (1992),Table 4.2.
 Table 4.2: List of standard tests conducted on PUF samples (U.S Bureau of Mines, 1992)
 Test
 ASTM
 standard
 Specimen Size Result
 Density
 ASTM
 D 1622
 Variable
 9,03-11,93
 (kg.m?)
 Compressive Strength
 and modulus
 ASTM
 D 1621
 50,8mm x 50,8mm x 25.4
 42,75-55,16 kPa
 399,9-579,2 kpa
 Tensile Strength
 and modulus
 ASTM
 D 1623
 50,8mm x 50,8mm x 25.4
 42,75-114,5 kPa
 1951-4709
 Shear strength
 and modulus
 ASTM
 C 273
 304,8 x 50,8 x 25,4
 59,98-63,43 kPa
 806,7-992,8
 Polyurethane Foams are best used in small to medium sized holes where the width of openings varies
 from 0,9-3m. The design plug thickness varies according to the length of the shortest dimension of
 the opening and the depth at which the plug is placed, Table 4.3, Figure 4.6.
 Note:
 o the larger the opening the thicker the plug required to span the opening. For
 example, using the same depth of formwork (eg. 7,0m), the PUF plug
 thickness varies from 2m for a 0,9m hole to 5,9m for a 3m hole.
 o for any given shaft dimension the plug thickness increases with the depth of
 the formwork to carry the increased volume of backfill. Thus for a hole
57
 dimension of 1,8m, the plug thickness varies from 2,1m if placed at 2,7m
 depth to 6,4m if placed at 12,8m depth.
 o It appears that PUF plugs have to be at least as thick as they are wide, thus
 for a 0,9m wide opening a 0,8m thick plug is required while for a 3m wide
 opening a plug of at least 4,3m would be required.
 The following general procedure for closing holes with PUF has been generally recommended:
 i. a lightweight frame (consisting of re-bar, planks etc) is fixed across the hole
 opening, at a specified depth, and mesh/ tarp/ plastic placed across it. This
 forms a platform onto which the liquid PUF is poured.
 ii. The two components are mixed at a 1:1 ratio and stirred in a container. The
 reaction then occurs resulting in creation and expansion of the foam.
 iii. The mixture is then poured into the hole to create a layer. No foreign
 materials should be added to the PUF layer. For larger applications a spray
 pump can be used and the hoses attached to drums of chemicals mounted
 on a small truck. This system should be self-cleaning and adjustable to alter
 mixtures as necessary.
 iv. Closure then takes place in lifts of 0,5m allowing suitable time for hardening
 of each layer. The foam should be tack free before applying the next lift. All
 voids must be filled. A standard table of foam thickness requirements is
 normally used (Table 4.3).
 To reduce the risk of fire during installation, a small fire extinguisher should
 be available. Lifts should not cut into pre-existing foam i.e the underlying
 layer should be relatively hard before applying the next layer. It is
 recommended that the process take place slow enough such that the
 exothermic reaction is controlled. Thermocouples may be used to monitor
 temperature.
 There should be no running water as PUF will react preferentially with water.
 It therefore should not be applied during rain unless protected by a cover.
 The foam therefore cannot be placed in wet conditions. The foam should not
 take on water as it could freeze and thaw and reduce the structural integrity.
58
 Table 4.3: Polyurethane Foam Design Plug Thickness (Colorado Mined Land Reclamation Division,
 1989)
59
 PUF Plug Thickness (m)
 0
 1
 2
 3
 4
 5
 6
 7
 8
 9
 10
 1
 .5
 2
 .4
 3
 .4
 4
 .3
 5
 .2
 6
 .1 7
 7
 .9
 8
 .8
 9
 .8
 1
 0
 .7
 1
 1
 .6
 1
 2
 .5
 Depth to form (m)
 P
 lu
 g
 th
 ic
 k
 n
 e
 s
 s
 (m
 )
 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3
 Figure 4.6 Graphical depiction showing variation in Polyurethane Foam plug thickness in relation to shortest mine dimension
 (Colorado Mined Land Reclamation Division, 1989)
60
 v. Density tests can be taken at any time during application by filling a
 container. Typical density should be 32.0 kg/m? ?8%, minimum of 29.63
 kg/m?. If the results are not acceptable then corrective action must be
 initiated.
 vi. Tensile strength tests using three samples (0,00163 m?) can be taken.
 vii. An access pipe/ ventilation pipe or drainage pipe may be added if needed.
 PUF, being inert, does not react to acids or acid mine drainage and is extremely resistant to chemical
 degradation (Rushworth et al, 1989). It is thus environmentally friendly and can be discarded in
 standard sanitary landfills. PUF however decays when exposed to Ultra Violet light (sunlight) and is
 flammable at > 398?C, although a flame retardant can be added.
 PUF plugs should not be used within 200ft (60m) of heavy vehicular traffic and no vehicular traffic
 should be allowed to drive over them.
 The use of PUF as an alternative to conventional types of formwork (wood etc.) has been advocated
 by Dunham (2004), Figure 4.7, where a layer of PUF is inserted across the mine opening before
 successive layers of concrete are placed.
 A procedure in South Africa developed by Parry-Davies (1992), but never implemented, was what he
 referred to as the ?Balloon Technique? for the consolidation of old mine workings. He designed (and
 patented) this technique for the sealing of dangerous mine workings where man access was not
 possible. Essentially he recommended that:
 i. boreholes be drilled to intercept an open stope (Figure 4.8),
 ii. large (2,5m diameter), cubical polyethelene ?balloons? be inserted into the
 stopes through these holes and then inflated.
 iii. once these balloons had sealed the open slope, polyurethane foam could
 then be inserted into them to form a lightweight, stiff barrier. The role of the
 balloon was to provide a type of formwork onto which the foam could be
 placed. The expansion of the foam (typically 30 times) would then press
 against the stope walls to form a stronger barrier for the placing of concrete.
 iv. Place successively a few layers of lightweight, fibrous concrete, in lifts of 0,5-
 1m, which would not load the polyurethane layer excessively. Once these
 layers had bonded to the stope sidewalls to form a strong plug, conventional
61
 concrete could be placed (and/or backfill) to fill the hole.
 Figure 4.7: Truncated concrete pyramid with polyurethane support (Dunham, 2004)
 Figure 4.8. ?Balloon? technique for consolidating old mine workings (Parry-Davies, 1992)
62
 The Grand Junction office of the U.S Department of Energy reports (1998) that a similar technique
 has been used in that area where weather balloons are placed down abandoned mine shafts
 (maximum diameter of 3m) as the temporary formwork before PUF is placed in layers to form the
 permanent seal.
 4.2 Legal requirements
 The mining industry in South Africa has over the last 100 years made a significant contribution to the
 economy, but has also had a huge, often negative, impact on local communities and the environment.
 As a result of this laws have had to be enacted to ensure that this impact does not result in lasting
 damage, particularly to the environment. Parties responsible for such damage have had to be
 identified, standards set and recommendations made regarding prevention and rehabilitation.
 Mining in South Africa is now governed by the Minerals and Petroleum Resources Development Act
 (MPRDA) which became operational on the 1 May 2004. This Act replaces the Mines and Works Act
 (1911) and the Minerals Act of 1991. In essence the primary purpose of the Act is to provide
 ?equitable access to and the sustainable development of the nation?s mineral and petroleum
 resources? (Edward Nathan and Friedland, 2005). Section 1 of this Act defines a mining operation as
 ?any operation relating to the act of mining and and matters directly incidental thereto?.
 Regulation 5.6.1 of this Act states that, ?If in the opinion of the Regional Director the conditions of or
 the circumstances,?., in undermined ground, and of dangerous slimes dams, waste dumps, ash
 dumps, shafts, holes, trenches or excavations of whatever nature, made in the course of prospecting
 or mining operations, whether abandoned or being worked, are dangerous to life or health of
 persons, property or public traffic, he may order that it be safeguarded to his satisfaction by the
 owner or manager of the mine or works?. In the more recent version of this Act (Section 46 of the
 MPRDA, 2004) if the owner (permit holder) cannot be traced, has died or is in liquidation, the liability
 then rests with the State to make these holes safe.
 Prior to the issuing of the above Act, the Department of Minerals and Energy (DME) had already
 issued guidelines (Dept. Minerals and Energy, 1991) for the treatment and sealing of disused shafts
 and outcrops in the Gauteng region, namely Regulation 5.6.1 of the Minerals Act (1991). While these
 are general guidelines applicable for the closing of any shaft they ?may with the permission of the
 Regional Director, be adapted to suit each individual shaft?. Essentially these guidelines state that:
 o the positions of these shafts have to be surveyed
63
 o competent persons have to be appointed to take charge of the safety and
 health of the site workers
 o if a mining title holder will retain responsibility for the shaft, security fences,
 steel grills, reinforced slabs or even backfilling (with permission from the
 Regional Director) may be used to seal the shaft
 o if there will be no-one present to retain responsibility for the shaft, then a
 system consisting of two slabs can be used for near vertical shafts (dip >40?)
 and any appropriate ad hoc design for near horizontal shafts/ adits.
 The 1991 DME Guidelines recommends the following method for closing of shafts:
 o For near vertical shafts the insertion of lower and upper heavily reinforced
 slabs, using high strength concrete, are required.
 o These slabs have to be attached to the surrounding rock by a hitch which
 must be excavated at least 1m into the solid rock of the side walls and
 pinned to the surrounding rock.
 o After the lower slab is constructed, granular inorganic fill (such as mine sand,
 stone, rubble or similar materials) has to be placed to cover the shaft and
 compacted.
 o The upper slab, has to be placed at least 3m above the lower slab and it may
 not receive any support from the underlying fill.
 o The upper slab should be able to support a minimum pressure of 2000kg.m
 -2
 from the overlying material.
 o This upper slab has to exceed the diameter of the shaft in all directions and
 should have the name of the shaft inscribed on it.
 o Suitable precautions are required to prevent water entering above the lower
 slab.
 o Shafts still being used for ventilation purposes by other mines may be not be
 sealed.
 o Both a plan and section, showing the design and method used have to be
 signed by an engineer.
 o The concrete mixing and placing also have to be supervised by an engineer,
 with the concrete cubes having to be sent for testing.
 o According to these regulations, once the shaft sealing has been completed to
64
 the satisfaction of the DME the land may be used for commercial and light
 industrial uses providing no foundations are placed on such sealed shafts.
 Besides the hazard posed by unsafe shafts the DME has also issued regulations regarding
 building on shallow undermined land which poses a risk of subsidence and settlement.
 Essentially these restrictions limit the height of the structure according to the depth of the
 undermined stope, Figure 4.9. Where undermining is less than 90m below surface no surface
 structures are allowed. As depth of mining increases successively more storeys are allowed.
 Where mining is deeper than 240m there are no building restrictions as mining is not believed
 to have any surface effects. This system was derived from observation of undermined areas
 by the Government Mining Engineer in the Witwatersrand areas who observed that
 substantial cracks had developed after mining where undermining was less than 800 feet
 below surface.
 Figure 4.9. Building restrictions on undermined land (Government Mining Engineer, 1965)
 4.3 Typical Methods Observed in the Central Witwatersrand Mining Basin
 Various methods to close mine openings were observed in the study area. Typical methods used
 included:
 i. Concrete slabs,
65
 ii. steel grates,
 iii. perimeter walls and fencing,
 iv. corrugated iron sheets and
 v. backfilling.
 The methods used to seal existing sealed mine openings in the Central Basin are shown in Appendix
 H.
 4.3.1 Seals
 Steel gratings consisting of a lattice of steel mesh and/or closely spaced steel bars have been used to
 seal access to mine shafts in the study area. This steel however appears to be in great demand as
 scrap and was only rarely found in its original place, Figure 4.10. Similarly, corrugated iron sheets
 fixed to the top of the shaft have also been used. This system of sealing shafts apprears to have only
 been suitable for smaller holes unless a shaft frame was still present onto which the iron sheets could
 be attached. Occasionally these iron sheets were found to be corroded or bent, allowing human
 access into the shafts.
 Concrete seals, where a layer of concrete was placed across the top of the shaft, were also commonly
 found, (Figure 4.11). No information could generally be found regarding the nature or age of such
 seals. However, in general, most observed seals seem not to have been tampered with. This can
 probably be ascribed the effort required to remove the reinforcing from the concrete matrix. There
 were exceptions however such as at the Kleinfontein Mine (outside the study area), Ekurhuleni,
 where evidence was seen (Figure 4.12) that the concrete layer covering the shaft was removed by
 force, the reinforcing bar cut and access to the shaft gained.
66
 Figure 4.10: Mine opening (S & J 8) sealed with a metal grate and barbed wire fencing,
 Johannesburg
 Figure 4.11: Typical shaft sealed with concrete seal (Crown Mine 8 Shaft A, Johannesburg)
67
 Figure 4.12. Access attempt through reinforced concrete seal, Kleinfontein Mine (Ekurhuleni)
 4.3.2 Fences and Walls
 Brick walls have also been used to create perimeter walls to prevent access to many shafts (Figure
 4.13). These are typically 1.8m to 3m high and most are still fully intact. A few have however
 deteriorated due to cracking etc of the structures and holes have also been found in some of these
 walls.
 Fencing, like corrugated iron, was observed to be one of the least effective measures of preventing
 human access to unsafe holes. Several holes which were previously fenced are now largely accessible
 as the materials (wire, poles etc.) have been stolen.
 4.3.3 Plugs
 Concrete plugs have been the most common method observed for sealing mine shafts, which is what
 one would expect, as this would be in fulfilment of the Government Mining Engineer?s recommended
 method of sealing shafts. These plugs have largely proven to be durable with most of them still
 intact. It was observed on occasions, that attempts had been made to remove the reinforcing steel
 from within the plugs, while elsewhere the steel was commonly removed from the side walls of the
 shafts. This practice is obviously highly dangerous considering the depths of these shafts. (>100m
 deep). No attempt was made by the author, by way of a drill etc., to determine the thickness of the
 plugs used and thus no information is at hand regarding the range of concrete thicknesses used for
 these plugs.
68
 4.3.4 Backfilling
 Backfilling of the mine openings has also been widely used in the study area. This method is probably
 the historical default method chosen by most persons faced with having to seal a mine opening,
 particularly if required to do so when the mine or shaft is at the end of its economic life cycle5. In its
 simplest form any hard rock and/ or soil material in the vicinity of the opening is utilized. Stacey
 (1983) reports finding loose, sandy gravel and ash fill in a backfilled reef outcrop in the Cleveland
 area, central Johannesburg. In some cases more effort using this method is attempted as in the
 mined out Main Reefs in the Cleveland area (central Johannesburg) where the archives of the
 Government Mining Engineer?s Department show that waste rock was (hand?) packed into the empty
 stopes after mining to prevent collapse of the hangingwall (Stacey and Bell, 1999). Control over
 compaction during backfilling is generally difficult due to access difficulties for men and equipment.
 Great reliance is then placed on the roughness of the shaft and jamming effect obtained from
 dumping the material. Thus it is not clear, as no tests are possible, whether the material has collected
 at the bottom of the hole or somewhere higher in the shaft. A number of mine shafts were observed
 being sealed in this manner during the period of this study eg. Mine Opening R61, ERPM 1-6. On
 occasions the mine owner had to add material on a later occasion to these holes, particularly R61,
 because settlement had already taken place.
 Figure 4.13. Access attempts through perimeter wall in Mine Opening Roode 5, Johannesburg
 5
 Unofficial discussions, and personal observations, with at least two mine officials on two different active mines
 during the period of this dissertation, indicate that this is common practice in the Johannesburg area
69
 The inefficacy of this method to cover (seal?) underlying mine voids was illustrated by two collapses
 that occurred during February 2005 and October 2006 which resulted in severe injuries for one
 woman and a fatality another. In the first instance a woman inspecting a water pipeline fell 20m
 through a small collapse (1m diameter), Mine Opening ERPM 57, that had developed in thick fill
 (approx. 20m) placed over shallow underlying stopes. It is understood that the fill material had been
 placed in this area some 50 years previously. This is seen in Figure 2.7 which illustrates a typical
 profile in this area in the former Simmer and Jack Mine property in the vicinity of this collapse. The
 depth of this vertical hole in the backfill was estimated at 20m before the underlying, steeply dipping
 stopes were encountered. In the second instance, sudden unexpected collapse in fill material placed
 in shallow underlying stopes in the Makuse Informal Settlement, Ekurhuleni, resulted in the death of a
 young woman 6.
 Not only does backfilled material get eroded and deposited in the underlying stopes, the mine
 opening (shaft or subsidence) also frequently acts as a receptacle for surrounding materials which
 under the influence of gravity, and presumably aided by rainwater, transports the surficial materials
 into the underlying void. The ability of even a small opening (9-12m?) to ?swallow? large volumes of
 surface material is illustrated by Mine Opening ERPM 17 which was on inspection identified as a
 backfilled stope. The collapse consisted of a 50m long by 20m wide subsidence into an opening
 approximately 15m below surface, Figure 3.5. The volume of material that had subsided into this void
 up until present (a 40-50 year period) is estimated at approximately 4500m?.
 On occasion dynamic compaction of the surface fill has also been undertaken to densify this fill
 material, as undertaken in the Cleveland area and reported by Stacey (1983). This stabilisation work
 was carried out to allow development of the site, and no deterioration of the surface has been
 reported to date.
 4.3.5 Mine openings considered for sealing
 Of the 80 mine openings in the Central Witwatersrand Mining Basin that were considered to be
 sufficiently dangerous to warrant sealing:
 ? 20 (25%) were vertical mine openings and 60 (75%) were inclined, Table
 4.4.
 ? Of the vertical openings, 11 (55%) were found with pre-existing concrete
 linings while the remaining openings were unlined (45%).
 6
 Mine opening ERPM 65
70
 ? In the inclined mine openings however, only 6 (10%) were lined while the
 overwhelming majority (90%) were unlined. This is probably a reflection that
 most of the inclined mine openings were instances where the gold reef
 outcrop intersected the surface, and access was possible for initial, small
 scale, informal mining via inclined holes. The larger, formal, high production
 mines would more than likely have installed concrete linings because of the
 large volumes of men and materials that would have used these access
 points.
 Table 4.4. Table showing split between vertical and inclined mine openings
 Lined 11
 Vertical
 mine
 opening
 20
 Unlined 9
 Lined 6
 Incline
 mine
 opening
 60
 UnLined 54
 4.3.6 Conclusions
 Historically, as per the limited requirements of former times, cost effective methods were most
 commonly used to seal mine shafts when the use of that underground opening had come to an end.
 The most basic methods such as fences and walls have over time proved to be largely ineffective,
 with backfilling of shafts appearing to have been the most popular and most convenient method used
 (Table 4.5). Properly installed concrete plugs or seals were observed to be still fulfilling their function
 of preventing access to the underground workings. Only approximately 16% of the observed holes in
 the Central Mining Basin appear to have met the DME 1991 Guideline.
71
 Table 4.5. Observed methods used to seal abandoned mine openings in the Central Mining Basin
 Method Used No. of holes Percentage
 Wall 7 7.5
 Backfill 48 51.6
 Slab 19 20.4
 Fence 4 4.3
 Plug7 8 15 16.1
 Total 93
 100
 7
 Information supplied by John Cruise, 2004, Ground Stabilization and Rhabilitation of Contracts Undertaken by John
 Cruise Mining (PTY) Ltd,
 8
 Nemai, 2001
72
 5 CASE STUDIES OF SELECTED METHODS OF CLOSING MINE OPENINGS IN THE
 CENTRAL WITWATERSRAND BASIN
 5.1 Introduction
 As stated in the Introduction to this dissertation, the author on behalf of the Council for Geoscience
 was requested by the Dept. Minerals and Energy to seal the most dangerous, abandoned mine
 openings identified in the Central Witwatersrand Mining Basin. While that is an ongoing program
 some of the methods used in that project to seal a number of those holes are discussed here.
 As Polyurethane Foam has been widely used to seal mine openings in the United States it made sense
 to test its efficacy under South African conditions. In this application however it appears to be largely
 unknown in South Africa and therefore has not been used by local contractors. Mass concrete on the
 other hand, being a known quantity, with strength and relative ease of application, has proven to be
 a popular choice for the construction of plugs. In the abovementioned project, concrete plugs offered
 a ?permanent? solution to sealing mine openings in this area. They were thus proposed as the
 preferred method in that project.
 The value of both of these methods is discussed below.
 5.2 Case Study 1: Polyurethane Foam (PUF) Plugs
 The effectiveness of Polyurethane Foam as a potential method to seal mine openings was tested on
 two abandoned mine openings in the Ekurhuleni area. The first consisted of a shallow abandoned soil
 lined ventilation hole (ERPM 19A) and the second consisted of a concrete lined mine shaft (ERPM
 16A).
 5.2.1 PUF Test Hole 1: ERPM 19A
 This test was undertaken on the 19/5/2004 at a small abandoned ventilation shaft (Hole 19A)
 situated in the Balmoral informal settlement, Ekurhuleni, Figure 5.1 and Figure 5.2, as an urgent
 solution was required to eradicate this communuity hazard. PUF was considered because of its proven
 relaibaility in the United States where its efficacy, reliability and ease of installation had already been
 proven.
 This shaft is rectangular in shape being 2,6m (long), 1,7m (wide) and 11m (deep),Figure 5.3. It has
 the following profile consisting of an overlying layer of loose to moderately dense fill (3,2m deep),
 followed by a 2,4m thick layer of moderately hard, weathered quartzite before slightly weathered,
73
 hard rock quartzite is encountered at a depth of 5,6m.
 Figure 5.1: Locality plan of Holes sealed with PUF, Ekurhuleni
 Figure 5.2 Hole 19A, Ekurhuleni
 Hole
 19A
 Balmoral Informal Settlement
74
 Methodology
 The depth of the base of the plug and hence the required foam thickness, was chosen according to
 prescribed standards used in the United States (CMRLD, 1989) which was then adapted from imperial
 to metric units, Table 4.3. While the recommendations of this standard are independent of the nature
 of the sidewalls it was decided that the relatively hard, moderately weathered quartzite layer (depth
 5,6m) would provide suitably good bonding characteristics in which to place the foam plug for this
 first field trial. Accordingly, with the hole having a shortest dimension (of the opening) of 1,7m and
 the base of the plug being placed at 5,6m, a vertical height of foam of 3,53m was required. This
 standard is not recommended for openings having a shortest dimension of larger than 3,5m and
 where the plug has to be placed at a depth of greater than approximately 14m.
 A layer of wire mesh (5mm thick strands), covered by a sheet of thin (20 micron) plastic was lowered
 by ropes to the appropriate depth to form the base of the plug (Figure 5.4). PUF was then produced
 on surface using a mechanical mixer with an applicator nozzle system which was supplied by the
 contractor (McArthur?s Packaging). As far as could be ascertained this was the only known portable
 system available for hire in the Witwatersrand area This system was chosen so that the foam could
 be mixed consistently, delivered quickly and placed accurately.
75
 Figure 5.3: Geological cross section of Hole 19A (Council for Geoscience, 2005)
76
 Figure 5.4: Base of plug being lowered into position
 The two components (the isocyanate and polyol resin) were mixed at a ratio of 1:1
 respectively using an initial mix temperature of 60? C. This resulted in a ?cream time? of 15-
 20s at which point it was then discharged through the applicator nozzle, at a delivery rate of
 3,2kg/min, into the hole, Figure 5.5. ?Cream time? is taken as the reaction time of the two
 components which results in the mixture changing from a clear liquid to an opaque, creamy
 or viscous mixture.
 The foam mixture was initially sprayed on to the formwork, close to the sidewalls, so that a
 rigid bond would form and the platform could become self supporting. Approximately 45-50s
 after mixing, the ?creamy? mixture expanded (30-32 times) and hardened to form a rigid,
 impermeable foam. The foam was applied in layers with each layer bonding with the sidewall
 (Figure 5.6) until the required thickness of foam plug was attained. The hole was then
 backfilled with an overlying protective layer of soil and a survey peg installed. According to
 the foam manufacturer, who observed this hole being filled with PUF, the foam attains its
 maximum strength after 24 hours.
77
 Figure 5.5: Thin stream of foam mixture being delivered from the applicator nozzle
 Results
 Before the initial foam layer could bond with the sidewalls, the base of the formwork slipped
 0,5m to a depth of 6,1m. According to the foam thickness required as stated in the U.S
 specifications (Table 4.3), the plug thickness required had to be adjusted to 4,7m for a hole
 of these dimensions. A theoretical volume 20,77 m? of PUF was thus required to create a
 plug of this thickness at this depth. According to the contractor?s records however, 800 kg of
 chemicals (components A and B) were used which should theoretically have generated
 26,6 m? of rigid foam, at a density of 30 kg/m? which indicates that the PUF did not foam to
 the expected volume.
 Once the upper layer of the foam had set reasonably hard in the hole/ shaft it was then
 backfilled with soil (Figure 5.7) so that it could be protected from potentially damaging
 sunlight and from curious residents who may have wanted to take samples of the foam. The
 time taken for this whole process was approximately 6 hours. A survey peg was also installed,
 so that any settlement could be monitored which to date (3 years) indicates that no
 noticeable settlement nor deterioration of the foam has taken place.
78
 Figure 5.6: Layers of expanding foam
 Figure 5.7: Placing covering material over PUF filled shaft
79
 Analysis
 During the process of placing the foam it soon became apparent that:
 ? the rate of the delivery by this mechanical system was low. As this
 equipment did not allow for adjustment of the flow rate it was then decided
 to use a simple manual mixing system whereby equal amounts of each
 component were decanted into a mixing bucket and the reaction allowed to
 take place. Buckets of this mixture (approx. 10 l) were then poured into the
 hole. This resulted in a rapid increase in the rate of foam being placed.
 ? the expected rate of foam expansion was not being achieved with the
 mechanical mixer. This, the contractor believed
 9
 was due to the foam
 mixture cooling excessively after being discharged from the nozzle but
 before landing on the plug floor (4-6m below). Thus an incomplete reaction
 was taking place and hence the foam was not expanding as expected and
 hence more chemicals were required. The contractor attempted to adjust the
 temperature of the reaction, to produce a longer ?creaming time?, however
 this seemed to have little effect.
 Substantially more chemicals were used during this trial due to:
 i. the foam mixture falling between the formwork base and the sidewalls and
 hence being lost. It was quickly realised that a base with a larger degree of
 overlap with the sidewalls would probably eliminate any future gaps through
 which the foam mixture could fall.
 ii. the mixture from the mechanical mixer cooling excessively before being
 placed, hence expanding insufficiently and thus requiring greater volumes of
 mixture.
 iii. the plug being placed at a lower depth than theoretically required.
 According to the recommended standards for an opening of these
 dimensions (Table 4.3) the base of the plug could theoretically have been
 placed at a depth of 2,59m with a plug thickness of 1,95m, the volume
 required being 8,62 m?. This would have resulted in the entire plug being
 placed in the moderately loose fill layer. However, this was the first such use
 of this foam and thus a conservative approach was taken and the plug
 placed deeper down so that there would be solid wall rock onto which the
 9
 C. McArthur, pers.comm.
80
 foam could bind. This obviously resulted in a far greater amount of foam
 being required, and consequently greater cost. While no specific
 recommendations are stipulated in the U.S standard it is presumed that
 selection of the depth to place the plug is based on an evaluation of the wall
 rock conditions. It is quite likely that further testing would show that the
 foam is suitable for a range of wall rock conditions.
 While a direct comparison with other methods (backfilling with available materials or inserting a
 concrete plug) to fill this shaft has not been undertaken, the following should be borne in mind when
 compared with traditional methods:
 i. no detailed engineering designs were necessary, which resulted in time and
 cost savings.
 ii. no large volumes of fill materials were necessary, which would have required
 heavy equipment to transport and place these materials, if available.
 Backfilling would have required the whole shaft (11m) to be filled, which
 could be substantial if deep shafts are present.
 iii. no person was required to enter the opening which would be necessary if a
 concrete plug had to be fixed at some depth below surface.
 iv. concrete plugs and the bringing in of materials would require substantial site
 preparations.
 v. traditional methods would take days per hole as opposed to hours, which
 was demonstrated here.
 5.2.2 PUF Test Hole 2: Mine Opening S&J 15B
 Mine Opening S&J 15B is an abandoned, vertical, rectangular, concrete lined shaft, whose dimensions
 measure 3,5m long by 1,5m wide. The shaft is estimated at >1000m deep. It is situated on the
 former Rose Deep Mine property, Ekurhuleni (Figure 5.8).
81
 Figure 5.8. Location of S & J 15 B, Ekurhuleni
 This site was selected to test whether the Polyurethane Foam could be used as a mine plug,
 that;
 ? would be a cost effective alternative to concrete plugs
 ? forms an effective bond with the concrete lining of the mine shaft
 ? could be placed by relatively unskilled labour
 ? could be placed without a formal plug design normally produced by an
 engineer
 ? could be placed quicker than that of concrete plugs.
 The previous users of this shaft had placed a 2,5m concrete wall around its perimeter and
 presumably a seal on top of this wall. At the time that the author found the shaft in the field
 (circa mid 2006) however, no surface seal was present leaving the shaft vulnerable to entry
 and hence a major hazard. Thus, despite the shaft entrance not being level with the ground
 surface this shaft was taken as being typical of many such similar shafts which when sealed
 and covered, tend to be forgotten about. This raises the possibility that someone may
 unknowingly build on top of such a plug. The load thus chosen to test the plug?s capabilities
 was taken as needing to be able to carry at least the load of a portion of a house.
 Main Reef Road
82
 Methodology
 The test was carried out as follows:
 1. Wire mesh was mounted onto a light timber frame, covered with thin, standard,
 plastic sheeting and lowered into the concrete lined shaft. It was suspended 9m
 below the top of the shaft by nylon ropes tied to the four corners.
 2. The PUF was produced on site by mixing the two components, namely the Polyol
 and the Resin, in standard 20l buckets. This was undertaken at a 1:1 ratio as per
 the manufacturer?s specifications to produce a foam with a density of
 approximately 30 kg/m?. As the reaction began to take place (after
 approximately 40s) this mixture was then poured onto the suspended plastic
 sheet and timber frame. The recommended plug thickness to seal a shaft, Table
 4.3, having a minimum dimension of 1,5m, is 4,2m. The actual plug thickness
 created, for testing purposes, was 2m.
 3. The first PUF pours did not expand as expected i.e did not achieve a theoretical
 30x expansion. It was then observed that the PUF chemicals being used had
 significantly exceeded their expiry date, by more than 12 months. According to
 specifications published by a PUF manufacturer in the United States, PUF
 chemicals have a limited shelf life (Foamconcepts.com). New chemicals were
 then purchased, which when mixed produced the expected expansion and a plug
 2m thick was achieved.
 4. It was initially hoped to use water to load the foam plug but a watertight seal
 could not be achieved so concrete gravel (19mm) was used instead. A front end
 loader was used to place the stone in the shaft (Figure 5.10). Care had to be
 taken when placing the gravel with the front end loader not to drop it from
 height and cause damage to the foam which is vulnerable too puncturing. A thin
 layer of gravel was thus initially hand placed before using the front end loader.
 5. Measured amounts of gravel were then continually added to induce failure.
 However even after the loading of a total of 36m? of gravel i.e a layer 2,8m thick
 and weighing 80tonnes, it was decided that the test be halted as failure had still
 not taken place.
 6. As the PUF was only being used here on a test basis, the Consulting Engineer felt
 it prudent to seal this shaft with a 1,5m thick concrete plug which was placed in
 the upper portion of the shaft.
83
 Figure 5.9. S & J 15B: PUF plug being created in mine shaft
 Figure 5.10. S & J 15B: Gravel load being placed on PUF plug
84
 Results and conclusions
 The initial intention of this field test of the bearing strength of the PUF was to test various thicknesses
 of PUF plugs to failure. An initial plug thickness of 2m (Figure 5.11) was thus chosen which was
 based on the dimensions of the hole. Such a plug thickness is substantially thinner than the Colorado
 Division of Mines and Geology (2002) recommended PUF plug thickness (5,5m) for a shaft of these
 dimensions (3,5m x 1,5m). After loading the plug with 57 tonnes of gravel however, failure was not
 achieved. Therefore it would appear, that even such a PUF plug is able to carry a significant load
 perhaps equivalent to that of a house.
 Plug dimensions: 3,5m (L1) x 1,5m (W1)
 Plug area: 5.25m
 2
 Load Mass: 5,25 x 5,5m x 2000kN/m? = 577,50 kN
 Overburden Pressure = 577,5/5.25m
 2
 = 110 kPa
 5.3 Case Study 2: Concrete Plugs
 While reinforced concrete perimeter walls and concrete seals were considered as acceptable
 measures to seal mine openings, the former do not eliminate the hazard entirely and the latter are
 limited by the size of hole that they are able to span. Concrete plugs were thus considered as being
 the most suitable method that would eliminate the hazard altogether, irrespective of the size of the
 hole, as well as provide a ?permanent? i.e a 50 year design life, solution.
85
 Figure 5.11. Field test: Hole S & J 15B, Ekurhuleni (Council for Geoscience, 2008)
86
 5.3.1 Methodology
 A generic plug design, with only three slight variations, was produced by SRK Consulting (Dept.
 Minerals & Energy, 2007) that could be used in any hole irrespective of its shape (Figures 1-3,
 Appendix I). The bearing capacity of this plug design was based on the shear strength of the bond
 between the sidewalls and the concrete plug. There was thus no need to excavate slots in the
 sidewalls nor attach steel dowels which are susceptible to chemical attack in the long term. The
 thickness of the concrete plugs was determined as at least 1x the minimum width of the shaft though
 the contractor frequently used a thickness of 2x the minimum shaft width. SRK Consulting indicate
 that, in their experience, such designs are capable of bearing 15MPa of water pressure. They assume
 that unlined shafts would have a lower unconfined compressive strength (in soils) of 1MPa and
 obviously higher in unlined rock sided tunnels. A typical example using their assumptions indicates
 that the expected load on the plugs will be well within this limit:
 Typical plug dimensions: 5m (L1) x 2m (W1)
 Assume Overburden thickness: 10m (H1)
 Overburden volume = 100m?
 Overburden Mass = 100 m? x 1600kg/ m? = 160 000kg
 Overburden Force = 160 000kg x 10m.s
 -2
 = 1 600 000 N
 Overburden Pressure = 1 600 000N/10m
 2
 = 160 000N.m
 -2
 ~ 0,2 MPa
 Slight variations in the plug design were produced to allow for the inclination of the shaft i.e. vertical
 or inclined. Where a concrete lining was present, the lining of the shaft was scabbled to increase the
 roughness so that a firmer bond between the plug and lining could be produced. The roughness
 recommended by SRK was to create undulations 20mm deep and a spacing of 200mm. An important
 factor to be considered was whether the shaft lining had sufficient strength to carry the load imposed
 by the concrete plug.
 Where a lining was absent the base of the plug was set well within competent bedrock, which in most
 of this basin is quartzite. These sides too were barred to remove any loose blocks and to increase the
 shear resistance of the sidewalls. For inclined shafts, whose inclination usually varied between 30?
 and 45?, a single design could be used irrespective of the presence of a lining, with the base of the
 plug being placed in competent rock.
 This general design consisted of a plug of 20MPa concrete that was placed on a sacrificial formwork
87
 at depth. This formwork consisited of a wooden platform that was suspended via steel cables from
 steel girders placed across the top of the opening. A 300mm primary, reinforced (10mm diameter
 steel at 200mm centres with two layers of Ref.617 mesh), slab was then cast onto the suspended
 formwork, Figure 5.12 , to provide a safe platform for the workers. Once this had achieved adequate
 strength (typically 24 hours), a secondary, thicker (600mm), similarly reinforced slab was then cast
 and allowed to cure for 48 hours. The insertion of these two reinforced slabs allowed for the creation
 of sufficient bearing capacity to carry the load of the successive layers (up to 3m) as they too in turn
 were allowed to cure. The wet concrete was delivered to the work surface via a chute. The main plug
 was then placed in 1m lifts until the design thickness had been achieved. A similar design was used
 for inclined shafts, Figure 5.13.
 Available backfill material was then placed on top of the plug to fill each hole as well as to provide
 secondary protection for the concrete plug. The top of the backfill was domed to lead water away
 from the hole. Ingress water, which could erode the contact between the plug and the shaft wall, is
 probably the single biggest agent that could threaten the integrity of the plug.
88
 Figure 5.12 Determination of plug thickness for a vertical shaft (Council for Geoscience 2007)
 Figure 5.13. Determination of plug thicknesses for an inclined shaft (Council for Geoscience,
 2007)
89
 Figure 5.14. Sacrificial formwork, suspended by steel cables from steel girders, prior to the
 casting of the primary slab
 5.3.2 Results
 In general the dimensions of the holes, whether vertical or inclined, that were considered for sealing
 were of a similar size, Table 5.1, with an overall range of the smallest dimension (W1 or W2) being
 from 4.1m to 3.15m. The average plug size, in both vertical and inclined holes, was therefore also
 similar i.e 2,9m long. The plug thickness was not affected by; a) the presence of a lining or b) the
 hole inclination. The only factor affecting plug thickness was the smaller dimension i.e L1 or W1.
 The effect of the presence of a lining is reflected in the depth at which the plugs were placed. While
 the average depth, for both vertical and inclined openings, at which the plugs were placed is largely
 similar i.e 3.01m compared to 5.59m, the vertical openings (Table 5.2) show that those unlined had
 to be placed at greater depth, 4.09m compared to 2.72m, in order to find competent rock. In the
 inclined shafts however this relationship is not so obvious largely because two of the openings S&J 15
 and S&J15A, were placed significantly deeper than the average i.e 32 and 33m respectively. The
 former hole was the largest hole encountered in the project area into which a substantial amount of
 overburden material had drained. The throat was thus found at considerable depth below surface i.e
 32m. The latter hole represents an access shaft to S&J15 and the contractor decided to place the
 plug at a similar depth.
90
 Table 5.1. Concrete plug dimensions
 Vertical mine openings
 Average
 shortest
 dimension
 (L1), m
 Average
 widest
 dimension
 (W1), m
 Average
 backfill
 thickness
 (H1), m
 Average
 plug
 thickness
 (D1), m
 Average plug volume, m?
 2.44 4.43 3.01 2.9 53.1
 Range of
 shortest
 dimension
 (L1), m
 Range of
 longest
 dimension
 (W1), m
 Range of
 backfill
 thickness
 (H1), m
 Range in
 plug
 thickness
 (D1), m
 Range of concrete volume
 (m?)
 1.4-10.2 1-4.7 0-6.3 1.8-5.2 9-144
 Inclined Mine openings
 Average
 shortest
 dimension
 (L2), m
 Average
 widest
 dimension
 (W2), m
 Average
 backfill
 thickness
 (H2), m
 Average
 plug
 thickness
 (D2), m
 Average plug volume, m?
 3.15 4.1 5.59 2.9 42.27
 Range of
 shortest
 dimension
 (L2), m
 Range of
 longest
 dimnsion
 (W2), m
 Range of
 backfill
 thickness
 (H2), m
 Range in
 plug
 thickness
 (D2), m
 Range of concrete volume
 (m?)
 1.5-12 1.8-9 1.5-33 0.5-6.3 4-110
 Table 5.2. Typical depths of concrete plugs
 Type of Opening
 Total Overburden
 thickness (m)
 No.
 Openings
 Average Overburden (m)
 Vertical Lined 29.9 11 2.72
 Vertical UnLined 36.8 9 4.09
 Inclined Lined 78.5 6 13.08
 Inclined Unlined 182.65 54 3.38
91
 The average time taken to close each hole, was typically 12 calendar days. The activities making up
 this period of time consisted of:
 ? prepare hole. Loose soils and other materials (tree trunks etc.) were
 removed from the perimeter of the hole collar. In cases such as ERPM 60, a
 crane with a grab bucket had to be used to remove waste that had been
 dumped in the hole and which covered the throat. Initial cleaning of the sides
 of the hole had to be undertaken to establish the competent bedrock contact.
 Typical duration 1-2 days.
 ? install formwork. Two steel girders (such as railway tracks) were placed
 across the hole with at least four steel cables attached. Workers suitably
 attached to safety harnesses were then lowered to the level where the first
 slab could be installed. Scabbling of the concrete or rock sides, depending on
 the presence of a lining, was then undertaken. The wooden, sacrificial
 formwork was then lowered to this level.
 ? install slabs. A grid of rebar steel was then created, a chute lowered to pour
 the concrete (25MPa) and the first slab, 200mm thick, left to set. After 48
 hours, once the first slab had hardened sufficiently, the rebar grid for the
 second slab was placed. The concrete for this slab, 600mm thick, was then
 poured and allowed to set. Typical duration 2-4 days. On all the vertical
 shafts a vertical pipe to surface was installed so that future monitoring of
 water levels in the shafts could take place.
 ? install mass concrete plug. Once the second slab had set sufficiently and was
 able to provide sufficient carrying capacity the mass concrete was poured in
 1m lifts with 24 hours curing time between lifts. This process took between 1
 and 6 days.
 ? Backfill remainder of hole. During the DME project the Conractor chose to
 complete the plug creation process for all the holes requiring closure before
 backfilling all of the holes together. The time taken for this process therefore
 could not be included in the collective time taken to close these holes.
 ? place landmark. Similarly the placing of the landmarks was undertaken long
 after the creation of the plugs and the backfilling operations.
 This methodology was used for the closing of all these holes. Two holes, ERPM 17 and S & J 15/15A
 require special mention however, largely because of the size of the holes that were closed.
92
 ERPM 17
 As stated earlier (Section 4.3.3) and shown in Figure 3.5, ERPM 17 developed into a very large hole
 by virtue of the overlying materials subsiding into the shallow outcrop of the gold reefs. Locating the
 throat so that the plug could be inserted proved to be difficult due to a layer of unknown thickness of
 overlying materials which had fallen from the sidewalls of this large elongate subsidence. This created
 a safety risk for the labourers who were tasked with finding the throat which was situated somewhere
 below their feet at the base of this 28m deep hole.
 After many futile attempts the Contractor then used a portable soil auger at the base of this hole to
 drill eight 6m long probe holes. The intention of this approach was to find either an empty stope or a
 stope filled with backfilled materials. Even after considerable effort these abandoned stopes could not
 be located and hence the concrete plugs could not be placed.
 As the throats of the subsidence were somewhere in the approximately 1700m
 2
 floor, a change to the
 plug design was required. Three soilcrete plugs, covering areas of up to 150m
 2
 , each 2m thick, were
 placed at the base of the subsidence. The soilcrete was produced using a dry mix consisting of
 cement (3%) and non plastic soils. As this mix was placed it was wetted to a moisture content
 (optimum) of 15%.
 Five layers, each 2m thick, were then placed over the soilcrete consisting of alternating sheets of
 Grade 5 Bidim and compacted soil. This was undertaken to create a 10m thick impermeable layer that
 covered the whole base of the subsidence. The top 18m of the subsidence was then backfilled and
 compacted, using a heavy duty drum roller, before a landmark was placed on top.
93
 Figure 5.15. Investigation and sealing solution for ERPM 17, Ekurhuleni
94
 S & J 15 and 15A
 As described earlier S & J 15 (Section 3.2) was one of the largest holes located in the study area
 (Figure 3.7) with an estimated volume of 27000m? and a depth of 30m. During preparation of a
 sealing solution an adjacent incline hole, S&J 15A, was discovered. It was then realised that S&J 15
 was draining into a break in the Armco lining of S&J 15A.
 A concrete plug was then placed in competent rock of S & J 15A to seal this shaft, which had a
 volume of 36 m?, at a depth of 35m below surface, Figure 5.16. S&J15 was then entered from the
 surface and a further plug of 108 m? placed at its base. The shaft and hole were then both backfilled
 to surface.
 Figure 5.16. Concrete plugs installed in S&J 15 and S&J 15A, Ekurhuleni
 5.4 Comparison between PUF and concrete plugs
 The casting of concrete plugs is probably the most conventional method of permanently sealing mine
 openings in South Africa today. Steel grids and fences are generally not considered because of the
 risk of theft, and walls are easily broken. In order to conform with mining regulations however this
 method requires that a number of onerous conditions be adhered to. The use of PUF plugs however
 offers the ability to close these openings in a much simpler manner, with a minimal time of persons
95
 entering the mine opening, or even no requirement for entry.
 Advantages of PUF:
 ? No detailed design or engineers needed. This proven technology from the
 United States has accompanying tables of required foam thicknesses, based
 on readily available 32kgm
 -3
 density PUF, that guide the creation of PUF
 plugs to the required standard. The recommendations in these tables appear
 to be conservative, based on the the two tests conducted.
 ? Cost effective: PUF cost is R1200/m? (2007 prices). No cleaning of wall sides
 is needed so minimal labour is required. Components of foam can be hand
 mixed. Only additional materials required are rope, plastic sheeting and
 standard chicken mesh to create the formwork on which to cast the PUF.
 ? Environmentally friendly; being inert it has no deleterious impact on the
 environment
 ? Short and easy installation time with minimal equipment needed. Typically
 one day needed per hole, though accessibility for transporting chemical
 components, and cleaning away of vegetation may lead to delays. In many
 instances labourers would not need to enter the mine opening, which
 reduces the risk of injury or fatality.
 ? Ideal for remote locations, as components of the foam can be carried to site
 by local labour.
 ? Limited quality control needed.
 ? The PUF could also be considered as a base for a concrete plug which would
 avoid the insertion of the two lower concrete slabs in the concrete plug
 method, and hence speed up construction. A hybrid approach could thus be
 considered.
 Disadvantages of PUF:
 ? Technology not familiar to local contractors
 ? If not covered by soil is susceptible to UV deterioration.
 ? As it is not very hard it is susceptible to being damaged by vandals but this
 can be overcome by covering it with an overburden layer.
 ? Based on the U.S specifications the size of the hole is limited to 3,3m
96
 (shortest dimension) for this density of PUF though with a greater density it
 could be considered for closing larger holes.
 Advantages of Concrete Plugs
 ? Plugs are proven technology which can be designed to whatever design
 criteria are required.
 ? Engineer certified
 ? Has more than adequate hardness which prevents most vandalism.
 ? Cost effective materials in urban environments where readymix concete is
 readily available. Can also be produced on site even in remote locations.
 Typical cost is R650/m?, 2007 average prices.
 Disadvantages of Concrete Plugs
 ? Needs to be engineer designed and certified
 ? Needs certified contractors
 ? Substantial preparation of site needed to ensure that the concrete keys into
 the sidewalls. This creates a substantial safety risk as labourers are in the
 hole for a number of days. Compliance with safety regulations requires
 monitoring.
 ? Total cost per cubic meter of plug cast includes:
 ? Concrete
 ? Labour
 ? Hole preparation
 ? Engineers design
 ? Engineer?s supervision
 ? Use of safety officer
 ? Checking engineer?s monitoring
 5.5 Insertion of landmarks
 Once an unsafe mine opening has been sealed and covered with soil, its position is easily and quickly
 and inevitably forgotten about. This could pose a risk for current and future users of this land. The
97
 insertion of an immovable, concrete landmark was thus proposed by the author to permanently mark
 the position of such openings. Servitudes showing the positions of these landmarks were then created
 and submitted to the Surveyor General of South Africa for recording on the Title Deeds of these sites.
 This landmark consists of a 2,5ton, 30MPa strength concrete block, approximately 1,85mm high and
 0,9mm wide which is placed on top of the domed surface of the newly sealed mine opening, Figure
 5.17. It thus is sufficiently hard and heavy to ensure that criminal attempts to remove it or deface it
 will be very difficult. It is hoped that this will ensure longevity. A graphical depiction of a mining
 headgear is recessed onto the side of the landmark to indicate to all persons, irrespective of their
 reading capabilities, that some sort of mine hole is beneath this monument. The official hole number
 is also enscribed as well as reference to the Dept. Minerals and Energy. Thus should any person
 require further details regarding this hole it can be traced to the Department.
 Figure 5.17. Typical landmark placed on sealing of a mine opening
 5.6 Summary
 The use of concrete plugs as seen in case studies used in this dissertation shows the efficacy of using
 this method to permanently seal unsafe mine openings. Polyurethane Foam plugs, widely used in the
 United States, were used for the first time in South Africa and were shown to offer a cost effective,
 ?low technology? approach to sealing such openings.
98
 6 CONCLUSIONS
 1. The legacy of more than 100 years of mining in the Central Witwatersrand Mining Basin is the
 presence of many unsafe, abandoned mine related openings such as shafts and subsidences.
 2. Using available mine plans and knowledge of the manner in which these holes were created a
 total of 244 openings was located, Table 6.1. The majority of these openings located were
 shafts (69,6%) and subsidences (24,5%).
 3. The majority of these openings were found along the Main Reef/ South Reef/ Main Reef
 Leader group of reefs (68%).
 4. Typically the openings found range in size from 1-72m with an average of 6,22m. Two of the
 largest holes were found to to be growing in size, with surface material being transported
 into the mining void below.
 5. A literature survey of methods used elsewhere in the world was conducted which revealed
 that perimeter walls, concrete seals and plugs were often used. A survey of methods used in
 the study area revealed that most often holes were merely backfilled with available materials.
 Concrete plugs or seals were also commonly used and occasionally walls and fences were
 found (which were often in disrepair).
 6. In order to assess which holes should be considered for sealing a simple hole risk rating
 system was developed which considered the depth of the hole and its proximity to
 settlements or thoroughfares. Of these open unsafe holes 64,2% were considered to pose a
 high risk and a further 31,7% to pose a moderate risk. This system was used as a guideline
 for planning the sealing of a number of these holes.
 7. During a Department of Minerals and Energy project led by the author it was concluded that
 concrete plugs were probably the most effective method of sealing such unsafe mine
 openings as they offered complete sealing of the hole for a design life of at least 50 years.
 8. Eighty holes were thus sealed using unreinforced, concrete plugs. The average plug size was
 2,9m thick, using a guideline of one to two times the thickness of the minimum dimension of
 the hole. A total of 3544,5 m? of 20MPa concrete was used to seal these holes.
 9. Once the plug had been placed and the hole backfilled with soil, a 2,5ton concrete landmark
 was used to mark the position of the shaft.
 10. Polyurethane Foam (PUF) has been used as an alternative method to seal mine openings in
 the United States for nearly 25 years. After some simple laboratory tests the PUF was used to
 seal two abandoned mine openings. To date (nearly 3 years) these PUF holes have proved to
 be as effective as the concrete plugs. Furthermore, sealing of such holes using PUF requires
 minimal design and engineering supervision and as a result offers a quick, simple cost
 effective and environmentally friendly method of sealing such openings.
99
 11. The documentation of the mine openings, the openings plugged, the methods of plugging
 and the locations of the plugged holes in this dissertation represents a valuable record for
 future reference.
 Table 6.1. Summary of mine openings (Council for Geoscience, 2007)
 Number of Openings 244
 All sealed 173
 Previously sealed 93
 Sealed by CGS 80
 Unsealed Openings 71
 Dangerous 46
 Less dangerous 25
100
 7 REFERENCES
 Albrecht, D., 2006. Indepth Video Production Photo Collection
 Anon, 1976. Reclamation of Derelict Land: Procedure for locating abandoned mine shafts.
 Department of the Environment, London, U.K.
 Antrobus, E. S. A., 1986. Witwatersrand Gold - 100 Years. The Geological Society of South
 Africa, pp79, Johannesburg.
 Aukamp, A., 2004. Database. Dept. Minerals and Energy, internal report. Johannesburg
 office.
 African Environmental Development, 2001. A quantification of water volumes recharging the
 central Rand mine void, associated with direct ingress from surface water sources. EAD report
 dated 17/9/2001, Johannesburg.
 Badenhorst, G.P., 1986. Legal Aspects on the Undermining of Structures and the use of
 Undermined Ground. SANGORM Syp., Johannesburg.
 Barker, O.B., 1992. A phased approach to the optimal utilisation of undermined ground in the
 Central Rand-Wits Basin. Sym. Construction over mined Areas, Pretoria.
 Barker, O.B., 1993. Surface Rights, Mining Rights, and Geoetchnical Data collection and
 analysis and Land Hazard Mapping in Relation to the Optimal Use of Deproclaimed ?Mining
 Land? in the Germiston Area, Vol.1, City Engineer?s Dept., Germiston City Council (now
 Ekurhuleni).
 Bell, F. G.,1988. Land Development. State-of-the-art in the Location of Old Mine Shafts.
 International Association of Engineering Geology Bulletin, No.37, Paris.
101
 Bell, F. G., Culshaw, M.G., Cripps, J.C., Stacey, T. R., 1989. Investigation and Treatment of
 Certain Abandoned Mine Workings, Proc. Int. Conf. on Surface Crown Pillar Evaluation for
 Active and Abandoned Metal Mines, Timmins, Ontario, Canada, 15-17 November 1989,
 CANMET/CIM?Ontario Ministry of Northern Development and Mines, pp 155-168.
 Bell, F. G., Stacey, T. R., Genske, D.D., 2000. Mining Subsidence and its Effect on the
 Environment: Some Differing Exampes, J. Env. Geology, Vol. 40, pp 135-152
 Brink, A.B.A., 1979. Engineering Geology of South Africa, Vol.1, p103, Building Publications,
 Pretoria.
 Cameron-Clarke, I. S., 1986. The Distribution and Nature of Surface Features Related to
 Shallow Undermining on the East Rand, SANGORM Symposium., Johannesburg.
 Charney, F.A., Matheson, G.M., and Sieben, A.K. 1992. Design Procedures for Rigid
 Polyurethane Foam Mine Closures, U.S. Bureau of Mines, U.S. Dept. Interior, U.S.
 Cole, K., 1987. Building over Shallow Abandoned Mines, Ground Engineering Vol 20, pp14-30.
 Colorado Mined Land Reclamation Division, 1989 General Bid Specifications, Inactive Mine
 Reclamation Program, Supplement 1, Dept. Natural Resources, State of Colorado, U.S.
 Colorado Division of Minerals and Geology, 2002. Best Practices in Abandoned Mine Land
 Reclamation, Dept. Natural Resources, Colorado (United States).
 Council for Geoscience, 2005. Prevention of Water Ingress into the Witwatersrand Mining
 Basins, Progress Report No.?,, CGS Report no. 2005-0162, Pretoria.
 Council for Geoscience, 2007. Sealing of Unsafe, Abandoned Mine Openings in the Central
 Witwatersrand Mining Basin, CGS Report no. 2007-0073. , Pretoria.
 Council for Geoscience, 2008. Vela VKE, Polyurethane foam (PUF): Evaluation of its Suitability
102
 for use in Sealing Abandoned Mine Openings, Report to Council for Geoscience (CGS), CGS
 Report No. 0193 , Pretoria.
 Department of Minerals and Energy, 1991. A Guideline for the Treatment and Permanent
 Sealing of Disused Mine Shafts and Outcrops Mined to Surface in the Gauteng Region, The
 Minerals Act 1991, Regulation 5.6.1 South Africa.
 Department of Minerals and Energy, 1996. Internal report, F. Barradas, Pretoria.
 Dunham, D., P., E. 2004. Use of polyurethane Foam (PUF) as the underform for concrete
 mine shaft caps, National Association of Abandoned Mine Lands Conference (NAAMLP),
 Flagstaff, U.S.
 Gallagher, C.P., Henshaw, A.C., Money, M.S., Tarling, D.H., 1978. The Location of Abandoned
 Mine Shafts in Rural and Urban Environments. Bulletin of the International Association of
 Engineering Geology Bulletin, No.18, pp179-185, Paris.
 Department of Minerals and Energy Affairs. Government Mining Engineer Memorandum on
 Undermining, GME no. 7/4/71/1, Pretoria.
 Hill, F. G., 1981. The Stability of the Strata Overlying the Mined-out areas of the Central
 Witwatersrand, Jour.SAIMM, Johannesburg.
 Healy, P.R., Head, J.M., 1984. Construction over Abandoned Mine Workings, Construction
 Industry research & information Association (CIRIA), Dept. Environment, UK.
 Jeppe, C., B., 1943. Gold Mining in the Witwatersrand, Vol.1, Chamber of Mines, Todd,
 London, pp163
 Johnson, M. R., Anhaeusser, C. R., Thomas, R. J.(Eds), 2006. The Geology of South Africa,
 Joint publication by the Geological Society of South Africa, Johannesburg/Council for
 Geoscience, p161, Pretoria.
103
 Nemai Consulting, 2001. Findings of the holings investigation in the area from ERPM Mine to
 Geldenhuys Interchange. Internal report to ERPM by Nemai Consulting dated October 2001,
 Johannesburg.
 Norman N. and Whitfield G., 2006. Geological Journeys, A Traveller?s Guide to South Africa?s
 Rocks and Landforms, Struik, Cape Town.
 Nova Scotia, 1997.Abandoned Mine Openings Hazards and Remediation Handbook,
 Department of Natural Resources,Information Series ME 23, pp11, 22, Nova Scotia, Canada.
 Parry-Davies, R., 1992. Consolidation of Old Mine Workings, Symp. On Construction Over
 Mined Areas, Pretoria.
 Pretorious D.A., 1986.The Witwatersrand Basin, surface and subsurface geology and
 structure (Map) in Mineral Deposits of Southern Africa, I: (C. R Annhauesser and S. Maske,
 eds): Geological Society of South Africa, back pocket.
 Rison, 2001. Geological and Geohydrological Control on the Groundwater Ingress into the
 Central Rand Basin, Johannesburg.
 Rushworth, P., Bucknam, D., Scriven, D., 1989 Shaft Closures using Polyurethane Foam,
 Proc. Symposium on Evolution of Abandoned Mine Technologies, Wyoming.
 Schilp, J.P.,1971. Geologie en Mijnbouw, Vol. 50, pp225-236.
 Scott, R., 1995. Flooding of Central and East Rand Gold Mines: an investigation into controls
 over the inflow rate, water quality and the predicted impacts of flooded mines. Water
 Research Commission report no. 486/1/95
 Schweitzer, J., Arnold, V., 2006 Shango Final Report: Controlled Decanting: Central Rand
 Goldfield Quantification of the Geohydrol ogical Environment
104
 Stacey, T. R., 1983. Stabilising Undermined Sites, Case Studies Illustrate the Sophistication of
 Modern Techniques, March 1983, S.A Construction World,pp64-75, Johannesburg
 Stacey, T. R., 1985. Undermined Road Re-opened, March 1985, S.A Construction World,
 pp75,76, Johannesburg
 Stacey, T.R., 1986. Interaction of Underground Mining and Surface Development in a Central
 City Environment, in Rock Engineering and Excavation in an Urban Environment, Hong Kong,
 Inst. Min. Metall., 1986, pp 397-404.
 Stacey, T.R., Bell. F. G., 1999. The influence of subsidence on planning and development in
 Johannesburg, South Africa. Env. & Eng. Geoscience, vol. 4, 1999, 373-388.
 Stacey, T.R. and Bakker, D., 1992. The Erection or Construction of Buildings and Other
 Structures on Undermined Ground. Construction over Mined Areas (COMA), Pretoria, May
 1992. S.Afr. Instn Civil Engineers, pp282-288.
 U.S Dept. of Agriculture, 1981. Treatment of Abandoned Mine Shafts and Adits. Agricultural
 Engineering Note 1, pp 1-1, Soil Conservation Service.
 U.S Dept. Energy, 1998. When is a balloon more than a balloon, Gran Junction Perspective,
 Vol.4, Grand Jucntion, Colorado, U.S
 U.S National Park Service, 1992. Handbook for the Remediation of Abandoned Mine Lands,
 Land Resources Division, Colorado.
 Van Deventer, J., 2002. Executive summary of the Nemai and Fourie reports, internal Dept.
 Minerals and Energy Report, Pretoria.
 Vela VKE, 2007. Prevention of Access into Abandoned Mine Openings Phase 1 Project
 Completion Report, Report for Council for Geoscience, Pretoria
105
 Vela VKE, 2008. Prevention of Access into Abandoned Mine Openings Phase 2 Project
 Completion Report, Report for Council for Geoscience, Pretoria
 Viljoen, M.J., and Reimold, W.U., 1999. An Introduction to South Africa?s Geological and
 Mining Heritage, pp 27, Mintek, Johannesburg.
 Waltham, T., Bell, F., Culshaw, M., 2005. Sinkholes and Subsidence. Karst and cavernous
 Rocks in Engineering and Construction, Praxis, Chichester, pp205
 Wilson M.G.C. and Anhaeusser C. R. (eds), 1998. The Mineral Resources of South Africa,
 Council for Geoscience, pp294-350.
APPENDIX A:
 RAND WATER PIPELINE ACCIDENT
INITIAL REPORT
 ON ABANDONED MINE OPENING ACCIDENT
 G.HEATH, 18/3/2005
 BACKGROUND
 A woman, Patricia Nzimande was reported, in the local media, to be seriously injured after falling
 down an abandoned mine ?shaft? (Figure 1) situated in Ekurhuleni. This incident took place at
 approximately 10am on the 17/3/05. This woman was undertaking pipeline inspection duties on
 behalf of Rand Water.
 Figure 1: Ekurhuleni, small subsidence into which a woman fell on the 17/3/2005.
 SITE REPORT
 This hole is situated in the proclaimed mine lands 100m south of Main Reef Road (R29), Ekurhuleni
 (Figure 2). It is approximately 0,5m x 0,5m wide and 20m deep and is hidden in long grass in this
 open piece of veld. This hole is a few metres from a well worn footpath.
 While the hole is narrow at the surface (0,5m) it widens immediately underground. At a depth of 20m
 the hole inclination changes from vertical to steeply inclined where, the original stopes are
 encountered, and continues for at least another 50m.
This area was a former open cast mining operation, overlying mining stopes, that has been backfilled
 with a variety of materials. It appears that it was formed by the loosening and collapse into the
 underlying void of these unconsolidated materials. This process appears to have occurred by a
 process of backwards collapse until the void reached the surface. It is thus by definition a
 ?subsidence? and not a ?shaft?.
 Figure 2: Location of accident hole plus location of other known abandoned mining
 holesholes.
 Accident holeGeldenhuys
 Interchange
APPENDIX B:
 CENTRAL WITWATERSRAND MINING LANDS
 STUDY RISK ANALYSIS MAPS
 (BARKER, 1993)
 See attached CD
APPENDIX C:
 MAPS SHOWING UNSAFE MINE OPENINGS
 See attached CD
APPENDIX D:
 MINE PLANS REVIEWED
No. of
 Mines
 Names of
 Mines
 No. of
 plans
 scanned
 Names/ Description of
 plans
 1 City Deep 2
 i). General Surface Plan,
 ii). General Underground plan
 2
 Consolidated
 Main Reef
 Mines and
 Estate Ltd
 3
 i). General Surface Plan,
 ii). General Underground plan (Main
 Reef and Main Reef Leader),
 iiii). General Underground plan (South
 Reef)
 3
 Croesus Gold
 mining Co.
 1959 Ltd
 2 i). 2 Surface Plans
 4
 Crown Gold
 Mines
 1
 5
 Durban
 Roodepoort
 Deep Ltd
 6
 i). General Surface Plan,
 ii). 4 Underground plans of the south
 reef and
 iii). Block No.2 of South Leader
 6
 East Rand
 Proprietary
 Mines
 6
 i). General Surface Plan,
 ii). Surface plan and
 iii). 4 Underground plans
 7
 Herbbard Gold
 Mining Co. Ltd
 1 i). Reclamation Plan (South Reef)
 8
 Jumpers Gold
 Mining Co. Ltd
 2
 i). Plan of Underground Workings and
 ii). Underground plan
 9
 Knights Deep
 Ltd
 3
 i). Surface plan - Section between
 West and Glenluce,
 ii). General Underground plan of
 Simmer and Jack East Ltd and iii).
 Underground plan
 10
 Langlaagte
 Estate and
 Gold Mining
 Co. Ltd
 6
 i).Two Surface plans
 ii). Four Underground plans
 11
 Mayfair Gold
 Mining Co. Ltd
 5
 i). Five Underground Plans (Farm
 Langlaagte No. 224 IQ)
No. of
 Mines
 Names of
 Mines
 No. of
 plans
 scanned
 Names/ Description of
 plans
 12
 New Boksburg
 Gold Mine
 1
 13
 Rand Leases
 Gold Mining
 Co. Ltd
 8
 i). Surface Plan (South Reef, Main Reef
 Leader, Main Reef),
 ii). Surface plan,
 iii). Government Surface plan,
 iv). Underground Plan- Vogelsfontein
 231 IQ,
 v). Undgerground Plan - Rand Leases
 D3 Hall OR,
 vi). Underground Plan - RL MA D3,
 vii). Underground Plan of the Kimberly
 Reef,
 viii). Underground Plan of the Main
 Reef
 14
 Robinson Deep
 Ltd
 5
 i). 2 General Surface Plans (Turfontein
 Nos. 100&96.IR. Booysen Estate No.
 98 .IR. and Klipriversberg No. 106 IR.
 and Birkenruth No.95 ? IR. District of
 Johannesburg),
 ii). General Surface Plan,
 iii). General Surface plan of Turfontein
 No. 21 and Booysen No. 20 Estate and
 iv). General surface plan of the Turf
 Mines
 15
 Rose Deep
 Ltd
 1
 16
 Simmer and
 Jack
 12
 i). 7 General Surface Plans ( Sheets
 D3,C3,D4,C4,B6,B4,F3, ii). Simmer
 Deep Ltd General surface plan and iii).
 2 Underground plans of Simmer Deep
 Ltd
 17
 South
 Roodepoort
 MR
 1
 18
 Stanhope Gold
 Mining Co. Ltd
 5
 i). General surface plan,
 ii). 2 Surface plans,
 iii). Surface plan of the South Reef
 Plan and iv). Surface plan of the Main
 Reef leader
 19
 Star Gold
 Mining Co. Ltd
 4
 i). 3 Surface Plans and
 ii). Reclamation plan of the Main Reef
 Leader and Main Reef
No. of
 Mines
 Names of
 Mines
 No. of
 plans
 scanned
 Names/ Description of
 plans
 20
 Village Main
 Reef Gold
 Mining Co. Ltd
 4
 i). Surface plan- Anti-pollution plan,
 ii). 2 General surface plans and
 iii). General Underground plan
 21 Wilford Pty Ltd 1
APPENDIX E:
 MINE OPENINGS DERIVED FROM MINE
 PLANS
Mine
 No. of
 shafts
 per
 mine
 Shaft Name Y-Coord X-Coord
 1 No.2 Shaft -26.21070285540 28.09415643040
 2 No. 4 Shaft -26.23274432960 28.06782308850
 3 No.2 A Incline Shaft -26.22020648000 28.09997138970
 4
 East Shaft
 (Henry Nourse)
 -26.20894892300 28.09929616400
 5
 Central Shaft
 (Henry Nourse)
 -26.20933478850 28.09434393620
 6
 Henry Nourse
 West Shaft
 -26.20983721750 28.08909814630
 7
 No.3 Shaft
 (Nourse Shaft)
 -26.21103285510 28.09228641750
 8
 No.2 Shaft
 (Nourse Decline)
 -26.21172764270 28.09612153020
 9 West Incline Shaft -26.21323335070 28.08855810690
 10 No.4A Incline Shaft -26.21216421760 28.08250596300
 11 No.2 Shaft -26.22090683170 28.07065629660
 12 No.1 Shaft (N) -26.21666907350 28.10103510670
 13 No.3 Shaft (N) -26.21686590410 28.09688114910
 14 No.3A Incline Shaft -26.22101043600 28.09104830960
 15 East Incline Shaft -26.21141009230 28.10199874500
 16 Mo. 1A Incline Shaft -26.21733996100 28.10745483400
 City Deep
 17 No.4 Incline Shaft -26.21415185950 28.09936454150
 1 A Shaft -26.19722190100 27.91529053650
 2 5 Shaft Vertical -26.19992153550 27.92216753020
 3 Aurora Vertical Shaft -26.19081254280 27.92463136260
 4 Aurora Shaft Incline -26.19021956340 27.92510467080
 5 4 Compound Shaft -26.19874437100 27.93157409340
 6 New Unified Incline -26.19323997130 27.93375569390
 7
 Old West
 Incline Shaft)
 -26.19644181400 27.93943188690
 8 No.2 Incline Shaft -26.19693703460 27.94052049590
 9 No.3 Vertical Shaft -26.20751284460 27.94278624010
 10 Central Incline Shaf -26.19812863200 27.94770776940
 11 East Incline Shaft -26.20000214380 27.95461544040
 12 Incline Shaft -26.20404547190 27.92864408370
 13 No.2A Incline Shaft -26.20559323510 27.93607157650
 14 No.3A Incline Shaft -26.20769724870 27.94226631800
 15 3BW Incline Shaft -26.22059152410 27.93773650240
 16 3BE Incline Shaft -26.22072167740 27.93808868170
 Consolidated
 Main Reef Mines
 and Estate Ltd
 17 3C Incline Shaft -26.22869892270 27.93405010320
Mine
 No. of
 shafts
 per
 mine
 Shaft Name Y-Coord X-Coord
 1 Croesus Shaft -26.20464811900 27.97058431890
 2 West Shaft -26.20660150670 27.97382854950
 3 Air Shaft -26.20736066850 27.97136605660
 4 Central Shaft -26.20770313320 27.97696678830
 5 Main Shaft -26.20916444320 27.97474593390
 6 Bird Winze -26.21223667620 27.96508766580
 Croesus Gold
 ining Co.
 1959 Ltd
 7 Est Deep -26.20886501000 27.96965825870
 1 No.17 Shaft -26.22382296700 27.96404441390
 2 N0.16 Shaft -26.23423684530 27.98101599250
 3 Shaft -26.22789553730 27.99839499720
 4 No.15 Shaft -26.23082021420 27.99738065840
 5 N0.2 Shaft -26.21889259780 28.02854774020
 6 No.5 Shaft -26.22088469730 28.01608605110
 7 No.7 Shaft -26.21692263280 28.00168981210
 Crown Gold
 Mines
 8 No.14 Shaft -26.23823367050 28.01185394640
 1 N0.2A Shaft -26.16657774420 27.86364169760
 2 N0.4 Shaft -26.17355448880 27.84348097150
 3 No.5 Shaft -26.18035875760 27.86019217970
 4 Shaft -26.17666284560 27.86318681610
 5 N0. 8 Shaft -26.18265211830 27.85410814000
 6 No.6 Shaft -26.18286598790 27.83502010650
 7
 No.3 W. Incline
 Shaft
 -26.18558523570 27.83460044470
 8 No.6A Shaft -26.18615444610 27.83744549040
 9 2 W. Incline -26.18117557680 27.84701092200
 10 A. Shaft -26.16901393240 27.87768015460
 11 Evelyn Shaft -26.16432447330 27.85810966530
 12 Wilford No.2 Shaft -26.16452925320 27.85512419030
 13 No.2 Shaft -26.16441069640 27.86300282660
 14 No.1 Wilford -26.16502503600 27.84986350310
 15 Princess Shaft -26.16545615160 27.84784803800
 16 No.3 Shaft -26.16704050110 27.84397123170
 17 N0.4 Shaft -26.16756861760 27.84274255240
 18 No.6 Shaft -26.16602737960 27.84064086420
 19 No.7 Shaft -26.16685727700 27.83817272780
 20 Shafta -26.17254692420 27.82642914090
 21 Shaftb -26.17303192910 27.82569624450
 22 Shaftc -26.17308581860 27.82337899850
 23 Shaftd -26.17339837730 27.82455378840
 24 Shafte -26.17601740420 27.82357300050
 25 Shaftf -26.17375404760 27.82531901840
 26 Shaftg -26.17167391520 27.82498490390
 27 Monza Liza Adit -26.17504739420 27.83510318530
 28 Circular Shaft -26.17603895990 27.86292630360
 29 Shafth -26.17055301490 27.86972068420
 Durban
 Roodepoort Deep
 Ltd
 30 5 Shaft -26.18029514800 27.86244453200
Mine
 No. of
 shafts
 per
 mine
 Shaft Name Y-Coord X-Coord
 31 8 Shaft -26.18191183120 27.85694996460
 32 9 Shaft -26.18495119570 27.83602900590
 33 Bird Reef Adit -26.17744978550 27.82373359110
 34 7 Shaft -26.18612490770 27.87284196070
 35 5A Shaft -26.18408936610 27.86273424070
 1 West Vertical Shaft -26.21316556010 28.21841390680
 2 Angelo Shaft -26.20486539870 28.22964807870
 3
 Central Vertical
 Shaft
 -26.22588217940 28.21537180110
 4 Commet Deep Shaft -26.21679060730 28.22378777870
 5 Hercules Shaft -26.22204094200 28.23377499620
 6 Cinderella Shaft -26.22433796340 28.24262528450
 7 South East Shaft -26.24322758650 28.24304222290
 8
 Cinderella East
 Shaft
 -26.22839920750 28.26239269610
 9 Ventilation Shaft -26.23383887970 28.26914359790
 10 No.2 Shaft -26.24419776160 28.29158056680
 11 Shaft -26.20842287270 28.23959058220
 12 Agnes Shaft -26.20840451580 28.24036157060
 13 Shaft -26.20905802030 28.24133081320
 14 Shaft -26.20865233350 28.24053779650
 15 Shaft -26.20924342470 28.24110685940
 16 Shaft -26.20966563260 28.23990264890
 17 Shaft -26.20961203050 28.24193512120
 18 Shaft -26.20948353250 28.24305489010
 19 Cason Shaft -26.20975521410 28.24506129560
 20 Shaft -26.21057760170 28.24573682830
 21 Shaft -26.21070242840 28.24567441500
 22 Shaft -26.21233178390 28.25386598320
 23 Shaft -26.21282374790 28.25357961610
 24 Shaft -26.21302567350 28.25440200370
 25 No.1 Incline Shaft -26.21280539110 28.25498575210
 26 Shaft -26.21361676460 28.25581915380
 27 Blue Sky Incline -26.21416783770 28.25768678140
 28 Shaft -26.21291957080 28.25645320000
 29 No.3 Incline -26.21611807120 28.26127591600
 30 Shaft -26.21622821240 28.26137137170
 31 Shaft -26.21623555520 28.26070318180
 32 No.4 Incline Shaft -26.21777900050 28.26367589280
 33 Shaft -26.21568081070 28.26193162330
 34 Shaft -26.21523290310 28.26190225230
 35 Shaft -26.21795963210 28.26700803120
 36 No.5 Shaft -26.21890317510 28.26539262690
 37 Shaft -26.22023808640 28.26756497850
 38 No.1 South Shaft -26.21301475830 28.25505250340
 39 Blue Sky Main Inclin -26.21435340840 28.25778751240
 East Rand
 Proprietary Mines
 40 South West Ventilati -26.21451975850 28.18777696730
Mine
 No. of
 shafts
 per
 mine
 Shaft Name Y-Coord X-Coord
 1 Herbbard Shaft -26.21140442970 27.97979853090
 Hebbard Gold
 Mining Co. Ltd
 2
 Herbbard Junior
 Shaft
 -26.21048446220 27.98344308630
 1 West Vertical Shaft -26.20601472970 28.11450489140
 2 East Vertical Shaft -26.20477321660 28.11912906400
 Jumpers Gold
 Mining Co. Ltd
 3 East Incline Shaft -26.20344874360 28.12080554170
 Knights Deep Ltd
 The Knights mine plans could not be geo-referenced. The boundaries on the plans
 do not fit anywhere on the Lease boundary map.
 1 East Shaft -26.20526004590 27.97497075900
 2 West Deep -26.20761076770 27.96045661850
 3 West Incline Shaft -26.20382634940 27.96721266340
 4 Old Incline -26.20518420830 27.97171264240
 5 East Deep -26.20999206050 27.96826785860
 Langlaagte
 Estate and Gold
 Mining Co. Ltd
 6 Star Shaft -26.20437491260 27.96207263770
 1 Estate Shaft -26.21285013800 28.00653402430
 2 Vernon Shaft -26.21383127420 28.00905929770
 3 Marcus Shaft -26.21420638870 28.00171482370
 4 Robinson Shaft -26.21427991910 28.00660711560
 5 New Main Shaft -26.21506768150 28.00676317550
 6 Shaft -26.21327898900 28.00314412800
 7 Shaft -26.21328436660 28.00346239370
 8 Shaft -26.21327887930 28.00356665310
 9 Shaft -26.21296752760 27.99779726490
 Mayfair Gold
 Mining Co. Ltd
 10 Shaft -26.21260536330 27.99737693470
 1 Shaft -26.22387729530 28.27476691170
 2 Shaft -26.22446554210 28.27556104490
 3 Shaft -26.22225961640 28.27263451680
 4 Ventilation Shaft -26.23306658050 28.28910753060
 New Boksburg
 Gold Mine
 5 No.2 Shaft -26.23110225450 28.30023535380
 1 No 6 Shaft -26.18390453960 27.91100168750
 2 No 7 Shaft -26.18584318720 27.91736882520
 3 No 1 Shaft -26.17556202510 27.88107283380
 4 No 2 Shaft -26.17813246390 27.88441020690
 5 No 3 Shaft -26.17980257890 27.88813522250
 6 No 5 Shaft -26.18292400170 27.90452430970
 7 No 9 Shaft -26.18532921480 27.89076996300
 8 No 10 Shaft -26.18541751570 27.89636628180
 9 KR.2 Shaft -26.20027464340 27.89754362800
 10 Aurora West Shaft -26.17872402400 27.92438846290
 11 Rast Shaft -26.19164745160 27.95414390370
 Rand Leases
 Gold Mining Co.
 Ltd
 12 RL 11 Shaft -26.18994028010 27.89830256580
Mine
 No. of
 shafts
 per
 mine
 Shaft Name Y-Coord X-Coord
 1 No.1 Shaft -26.22115031060 28.03798586490
 2 Chris Shaft -26.22942416380 28.03278869870Robinson Deep
 Ltd
 3 Turf Shaft -26.22765340870 28.05071095380
 1 No.5 Shaft -26.20362506190 28.15605690550
 2 No.4 Shaft -26.20366436080 28.15647322790
 3 No.3 Shaft -26.19886281490 28.15833983690
 4
 No.1 Shaft Rose
 Deep
 -26.19659419170 28.17144988790
 Rose Deep Ltd
 5 Hammond Shaft -26.20407398800 28.16515003400
 1 North vertical Shaft -26.20628162020 28.13782695070
 2 No.1 Shaft -26.20784277160 28.13938810210
 3 No.3 Shaft -26.20590991750 28.14615309160
 4 No.2 Shaft -26.21037035010 28.13708354520
 5 Rhodes Shaft -26.21572286920 28.14001999670
 6 Catlin Shaft -26.22074085590 28.12162071220
 7 Milner Shaft -26.21416171780 28.14778858350
 8 Rudd Shaft -26.21367850430 28.15403318920
 9 South Deep Shat -26.22850944270 28.18770573850
 10 West Sub-Vert Shaft -26.23594349710 28.16841808440
 11 Milner Shaft -26.21393766810 28.14190958210
 12 Howard Shaft -26.21920344490 28.13011563180
 13 South Deep Shaft -26.22812129270 28.14194818750
 Simmer and Jack
 14 Incline Shaft -26.20035615830 28.14833394130
 1 Ventilation Shaft -26.21718967080 27.75777993440
 2 No.2 Shaft -26.21831671400 27.76898274290
 South
 Roodepoort
 MR 3 No.1 Shaft -26.21793351930 27.77682696290
 1 No 6 Shaft -26.20530514640 28.12612851550
 2 No 5 Shaft -26.20515439140 28.12906823830
 3 Diagonal Shaft -26.20476114070 28.13296381280
 4 Geldenhuis Shaft -26.20848190280 28.13126647860
 5 West Shaft -26.20912768580 28.12459691420
 6 Main Shaft -26.20732880920 28.12713299390
 7 East Shaft -26.20748585920 28.13207329250
 Stanhope Gold
 Mining Co. Ltd
 8 Vertical Shaft -26.20601035440 28.12261467840
 Star Gold Mining
 Co. Ltd
 These plans could not be geo-referenced because the boundaries on the plans do
 not fit to the Lease boundaries.
Mine
 No. of
 shafts
 per
 mine
 Shaft Name Y-Coord X-Coord
 1 N0.4 B. Incline Shaft -26.21203107900 28.08310106590
 2 No.1 Shaft -26.21475345770 28.05242858630
 3 Worcester no.2 -26.20984241510 28.03262654260
 4 Mynpacht Shaft -26.21014944330 28.06835659060
 5 West Shaft -26.21013927550 28.07078635850
 6 No.3 Shaft -26.20966138840 28.08288910380
 7 No.4 Shaft -26.21175900780 28.08285182180
 8 No.2 Vertical -26.21241991550 28.05243583240
 9 Ferreira East -26.21372749600 28.04009414350
 10 Wolhuter East -26.21350380410 28.07605599590
 11 No.2 Shaft Chris -26.21835012170 28.03273230950
 12 No.1 Shaft Turf -26.21926827500 28.05225586210
 13 No.2 Shaft Turf -26.21923777160 28.04674389180
 14 No.1 Shaft Chris -26.22031555960 28.03658489310
 15 Charlton Incline -26.20999989800 28.06332621600
 Village Main Reef
 Gold Mining Co.
 Ltd
 16 Ferreira Shaft -26.21346780140 28.04030159240
 1 No.5 Incline -26.16526388450 27.84824208830
 2 Incline Shaft -26.16774101210 27.83722188760
 3 N0.7 Incline -26.16743670550 27.83854141270
 4 Wilford No.1 Shaft -26.16570312920 27.84993898900
 5 Shaft -26.16580996020 27.84790272480
 6 Shaft -26.16481287060 27.85502544120
 7 Evel.. Shaft -26.16481287060 27.85876485110
 8 No.4 Vertical shaft -26.16877727310 27.83290785620
 9 Shaft -26.17088411060 27.83780557350
 Wilford Pty Ltd
 10 Pars Shaft -26.19781991290 28.20579573120
APPENDIX F:
 TOTAL LIST OF MINE OPENINGS
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 1 A006 ERPM Ekhurleni -26.20146 28.2146 10 9 30 90 Shaft
 Old shaft
 closed by
 municipality
 (according to
 old
 mineworkers)
 + big sinkhole
 closed
 1 5 6 Low
 2
 Wilford
 No.1 Shaft
 No. 1
 Wilford
 DRD Johannesburg -26.16582 27.85073 7/7/2006 5 5 100 25 Shaft Shaft closed 0 5 5 Low
 3 A002
 No original
 opening
 name
 ERPM Ekhurleni -26.20015 28.22045 1.5 1.5 0.5 2.25 Subsidence
 Shaft
 backfilled.
 Method of
 closure
 unknown.
 1 5 6 Low
 4 A004
 No original
 opening
 name
 ERPM Ekhurleni -26.19998 28.22118 10 6 30 60 Subsidence
 Big sinkhole
 closed. Shack
 on top of it;
 identified by
 local people.
 Probably
 closed by
 Chestnut
 Projects
 1 5 6 Low
 5 A010
 No original
 opening
 name
 ERPM Ekhurleni -26.19434 28.2183 3 2 2 6 Subsidence
 Disturbed land
 with holes.
 Mine related
 ruins on hill.
 1 5 6 Low
 6
 Angelo
 Deep Shaft
 Angelo Deep
 Shaft
 ERPM Ekurhuleni -26.21819 28.22573 14/6/2006 6 3 100 18 Shaft
 Shaft closed on
 13/6/7
 according to
 scrab metal
 collector in the
 area. Method
 of closure
 unknown
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 7
 Angelo
 Ventilation
 Shaft
 Angelo
 Ventilation
 shaft
 ERPM Ekurhuleni -26.21419 28.21943 14/6/2006 5 2 100 10 Shaft Ventilation
 Shaft closed on
 13/6/7
 according to
 scrab metal
 collector in the
 area. Method
 of closure
 unknown
 0 5 5 Low
 8 B54 Shaft
 Cinderella
 West Saft
 ERPM Ekhurleni -26.22465 28.24666 11.5 5.8 100 66.7 Shaft
 Shaft enclosed
 in a wall. Steel
 grate on top of
 the wall
 5 5 10 High
 9
 Balmoral
 Hole no.1
 ERPM Ekhurleni -26.19964 28.20828 20/3/2006 8 8 0 64 Subsidence Hole
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 10
 Balmoral
 no.2
 Verical
 Shaft
 ERPM Ekhurleni -26.19975 28.20801 20/3/2006 2 2 0 4 shaft vertical
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 11
 Balmoral
 Verical
 Shaft
 ERPM Ekhurleni -26.19987 28.20528 20/3/2006 8 3 0 24 shaft vertical
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 12
 Benrose
 Shaft
 Worhuter
 Shaft
 City
 Deep
 Johannesburg -26.21313 28.07632 ###### 2 2 100 4 shaft
 Shaft enclosed
 in a wall. Shaft
 completely
 inaccessible
 0 5 5 Low
 13 Chris Shaft Chris Shaft
 Village
 Main
 Johannesburg -26.22045 28.03654 1/8/2006 0 0 100 0 shaft vertical Shaft closed 0 5 5 Low
 14
 City Deep
 no.1 Shaft
 City Deep
 No.3 Vertical
 City
 Deep
 Johannesburg -26.21909 28.07692 13 8 100 104 shaft
 Shaft enclosed
 in a large brick
 structure.
 5 5 10 High
 15
 City Deep
 no.2 Shaft
 City Deep
 No.4 Shaft
 City
 Deep
 Johannesburg -26.23366 28.07122 14 9 100 126 shaft
 Shaft closed.
 Closure
 method
 unknown.
 Headgear has
 not been
 removed
 0 5 5 Low
 16
 City Deep
 no.3 Shaft
 City Deep
 No.2 Shaft
 City
 Deep
 Johannesburg -26.22225 28.06918 15 10 100 150 shaft
 Shaft lie open
 in factories'
 area. A lot of
 human traffic
 in the area.
 5 5 10 High
 17
 City Deep
 no.4 Shaft
 City Deep
 No.5 Shaft
 City
 Deep
 Johannesburg -26.2285 28.10435 16 11 100 176 shaft
 shaft sealed
 with a concrete
 slab
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 18
 City Deep
 no.5 Shaft
 Worcester
 N0.1 Shaft
 City
 Deep
 Johannesburg -26.21315 28.05231 27/9/2006 8 6 100 48 shaft vertical
 Shaft closed.
 Closure
 method
 unknown.
 Headgear has
 not been
 removed.
 0 5 5 Low
 19
 Clement
 Shaft
 Clement
 Shaft
 Simmer
 and
 Jack
 Ekhurleni -26.21111 28.15917 22/11/2005 5 4 100 20 shaft
 Shaft closed.
 Closure
 method
 unknown.
 0 5 5 Low
 20
 CMR - R
 67B
 CMR Johannesburg -26.1897 27.925 2/8/2006 5 4 100 20 shaft Incline
 Shaft had been
 backfilled.
 Shaft opening
 again
 5 5 10 High
 21 CMR - R67
 Aurora
 Vertical
 Consolid
 ated
 Main
 Reef
 Johannesburg -26.18814 27.9229 25/10/2005 5 2 100 10 shaft vertical
 Shaft enclosed
 in a concrete
 wall
 5 5 10 High
 22
 CMR
 Central
 Shaft
 CMR Central
 shaft
 CMR Johannesburg -26.19784 27.94419 2/8/2006 4 4 100 16 shaft Incline
 Shaft had been
 closed, but is
 re-opening.
 Shaft by a
 busy dirt road.
 5 5 10 High
 23
 CMR East
 Shaft
 East Incline
 Shaft
 Consolid
 ated
 Main
 Reef
 Johannesburg -26.19975 27.95457 25/10/2005 4 2 100 8 shaft Incline
 No safety
 measures.
 Shaft behind
 shopping mall
 5 5 10 High
 24
 CMR no.10
 Shaft
 CMR No.10
 shaft
 Consolid
 ated
 Main
 Reef
 Johannesburg -26.20623 27.94393 25/10/2005 5 4.5 100 22.5 shaft
 Shaft backfilled
 by Iprop.
 0 5 5 Low
 25
 CMR no.2
 Shaft
 CMR No. 2
 shaft
 Consolid
 ated
 Main
 Reef
 Johannesburg -26.19663 27.94033 2/8/2006 5 4 100 20 shaft Incline
 Shaft sealed
 with a concrete
 slab
 0 5 5 Low
 26
 CMR no.4
 Shaft
 No.4
 Compound
 Shaft
 Consolid
 ated
 Main
 Reef
 Johannesburg -26.1983 27.93119 25/10/2005 6 4 100 24 shaft
 Shaft backfilled
 by Iprop.
 0 5 5 Low
 27
 CMR no.8
 Shaft
 CMR No. 8
 shaft
 Consolid
 ated
 Main
 Reef
 Johannesburg -26.19819 27.9215 25/10/2005 5 5 100 25 shaft
 Shaft backfilled
 by Iprop.
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 28
 CMR Old
 West Shaft
 Old West
 Shaft
 CMR Johannesburg -26.19574 27.93787 2/8/2006 3 3 100 9 shaft vertical
 Shaft enclosed
 in a wall
 structure
 appears to
 have been
 pluged at 10m
 below surface
 5 5 10 High
 29
 CMR Old
 West Shaft
 B
 CMR Johannesburg -26.19654 27.93844 2/8/2006 4 4 100 16 shaft vertical
 Shaft enclosed
 in a concrete
 wall.
 5 5 10 High
 30 CMR- R66
 Randleases
 No.7 Incline
 DRD Johannesburg -26.18621 27.9169 5/9/2005 8 8 100 64 shaft Incline
 No safety
 measures.
 5 5 10 High
 31
 Crown
 Mine 12
 Ventilation
 Crown Mine
 12
 Ventilation
 Crown
 Gold
 Mines
 Johannesburg -26.21938 27.98324 ###### 7 6 100 42 shaft Ventilation
 Shaft enclosed
 in a large brick
 structure.
 0 5 5 Low
 32
 Crown
 Mine no.1
 Shaft
 Crown Mine
 No. 6 shaft
 Crown
 Gold
 Mines
 Johannesburg -26.21828 28.00522 23/11/2004 10 3 100 30 shaft vertical
 Shaft enclosed
 in a brick wall.
 Wall is no
 longer intact.
 5 5 10 High
 33
 Crown
 Mine no.10
 Shaft
 Crown Mine
 No. 18 West
 shaft
 Crown
 Gold
 Mines
 Johannesburg -26.21952 27.95508 ###### 5 3.5 100 1750 shaft
 Shaft sealed
 with a concrete
 slab.
 0 5 5 Low
 34
 Crown
 Mine no.11
 Shaft
 Crown Mine
 No.16
 Ventilation
 shaft
 Crown
 Gold
 Mines
 Johannesburg -26.23772 27.98187 ###### 4.8 2.6 100 12.48 shaft Ventilation
 Shaft sealed
 with a slab.
 0 5 5 Low
 35
 Crown
 Mine no.12
 Crown
 Gold
 Mines
 Johannesburg -26.134638 27.581388 30/11/2004 5 3.5 100 17.5 shaft Incline
 No safety
 measures.
 Water in shaft
 5 5 10 High
 36
 Crown
 Mine no.12
 Incline
 Shaft
 Crown Mine
 12 Incline
 Crown
 Gold
 Mines
 Johannesburg -26.21934 27.98571 7 4 3 28 shaft Incline
 Shaft
 backfilled.
 Shaft not
 completely
 closed though.
 Drums in shaft.
 3 5 8 Low
 37
 Crown
 Mine no.13
 Shaft
 Crown Mine
 No. 8 shaft
 Crown
 Gold
 Mines
 Johannesburg -26.21525 27.99817 ###### 5 5 100 25 shaft vertical
 Shaft enclosed
 in a wall. Wall
 no longer
 intact
 5 5 10 High
 38
 Crown
 Mine no.14
 Shaft
 Crown Mine
 No. 10
 Incline shaft
 Crown
 Gold
 Mines
 Johannesburg -26.21256 27.9953 ###### 4 4 100 16 shaft Incline
 Shaft
 backfilled.
 White drum
 with shaft
 name on shaft
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 position
 39
 Crown
 Mine no.15
 Shaft
 Crown Mine
 no.7 shaft
 Crown
 Gold
 Mines
 Johannesburg -26.21568 27.99978 ###### 5 4 100 20 shaft
 Shaft area
 developed. The
 exact position
 of shaft could
 not be
 determined.
 0 5 5 Low
 40
 Crown
 Mine no.16
 Shaft
 Crown
 Gold
 Mines
 Johannesburg -26.21768 28.02324 ###### 6 5 100 30 shaft
 Grating ontop
 of shaft. Shaft
 headgear not
 removed
 0 5 5 Low
 41
 Crown
 Mine no.17
 Shaft
 Crown Mine
 no. 14 shaft
 Crown
 Gold
 Mines
 Johannesburg -26.23829 28.01644 25/10/2005 5 4 100 20 shaft vertical
 Shaft most
 probably safe.
 Shaft is being
 used by Gold
 Reef City.
 0 5 5 Low
 42
 Crown
 Mine no.17
 Ventilation
 Shaft
 Crown Mine
 17Ventilation
 Crown
 Gold
 Mines
 Johannesburg -26.21938 27.98324 25/10/2006 6 5 100 30 shaft Ventilation
 Shaft sealed.
 Building in
 which shaft is
 enclosed is
 being used for
 educational
 purposes
 0 5 5 Low
 43
 Crown
 Mine no.17
 Vertical
 Shaft
 Crown Mine
 17Vertical
 Crown
 Gold
 Mines
 Johannesburg -26.22751 27.96301 25/10/2005 7 5 100 35 shaft vertical
 Shaft sealed.
 Water
 monitoring
 shaft.
 0 5 5 Low
 44
 Crown
 Mine no.2
 Shaft
 Crown Mine
 No. 18
 Ventilation
 shaft
 Crown
 Gold
 Mines
 Johannesburg -26.23088 27.998 23/11/2004 5 5 100 25 shaft
 Enclosed in a
 large brick
 structure.
 0 5 5 Low
 45
 Crown
 Mine no.3
 Shaft
 Crown
 Gold
 Mines
 Johannesburg -26.21200 27.9936 ###### 1.5 1 50 1.5 shaft
 Opening
 backfilled.
 Exact closure
 method
 unknown.
 0 5 5 Low
 46
 Crown
 Mine no.4
 Crown
 Gold
 Mines
 Johannesburg -26.21216 27.99395 E4:F5 1 1 20 1 Subsidence
 Opening
 backfilled.
 Exact closure
 method
 unknown.
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 47
 Crown
 Mine no.5
 Shaft
 Crown Mine
 No. 1 shaft
 Crown
 Gold
 Mines
 Johannesburg -26.21678 28.02422 23/11/2004 5 4 100 20 Shaft
 Grating ontop
 of shaft. Shaft
 headgear not
 removed
 0 5 5 Low
 48
 Crown
 Mine no.6
 Shaft
 Crown Mine
 No. 5 shaft
 Crown
 Gold
 Mines
 Johannesburg -26.22164 28.01472 23/11/2004 5 5 100 25 Shaft Shaft capped. 0 5 5 Low
 49
 Crown
 Mine no.7
 Shaft
 Crown Mine
 No.3 shaft
 Crown
 Gold
 Mines
 Johannesburg -26.21973 28.01247 23/11/2004 2 1 6 2 Shaft vertical
 Trench, partly
 filled.
 3 5 8 Medium
 50
 Crown
 Mine no.8
 Shaft
 Crown Mine
 No. 16
 Vertical
 shaft
 Crown
 Gold
 Mines
 Johannesburg -26.237223 27.981945 30/11/2004 3 2 100 6 Shaft
 Shaft sealed
 with a concrete
 slab
 0 5 5 Low
 51
 DRD 3
 Vertical
 DRD No.3
 Vertical
 shaft
 DRD Johannesburg -26.17041 27.85696 7/7/2006 6 3 100 18 Shaft vertical
 Shaft enclosed
 in a wall
 5 5 10 High
 52
 DRD
 Bitcom
 Incline
 Shaft
 DRD Bitcom
 Incline shaft
 DRD Johannesburg -26.17386 27.82492 13/7/2006 6 4 100 24 Shaft Incline
 Shaft
 backfilled by
 DRD
 0 5 5 Low
 53
 DRD
 Bitcom
 Shaft
 DRD Bitcom
 Shaft
 DRD Johannesburg -26.16753 27.83722 29/5/2006 6 3 100 18 Shaft Incline
 No safety
 measures
 5 5 10 High
 54
 DRD
 Bitcom
 Ventilation
 Shaft
 DRD Bitcom
 Ventilation
 shaft
 DRD Johannesburg -26.17216 27.82568 13/7/2006 6 5 100 30 Shaft Ventilation
 Shaft
 backfilled by
 DRD
 0 5 5 Low
 55 DRD Hole DRD Johannesburg -26.17221 27.84963 2/9/2005 16 16 8 256 Shaft vertical
 No safety
 measures.
 3 5 8 Medium
 56
 DRD Hope
 Shaft
 DRD Hope
 shaft
 DRD Mogale -26.17052 27.82738 13/7/2006 5 4 100 20 Shaft Incline
 Shaft
 backfilled by
 DRD
 0 5 5 Low
 57
 DRD
 Monaliza
 Shaft
 DRD
 Monaliza
 shaft
 DRD Mogale -26.17542 27.83504 13/7/2006 6 4 100 24 Shaft Incline
 Shaft
 backfilled by
 DRD
 0 5 5 Low
 58
 DRD no.1
 Shaft
 DRD
 Greatbrittan
 incline shaft
 DRD Johannesburg -26.18696 27.871 ###### 4 4 100 16 Shaft
 Shaft backfilled
 by DRD.
 0 5 5 Low
 59
 DRD no.1
 Vertical
 Shaft
 DRD No. 1
 Vertical
 shaft
 DRD Johannesburg -26.17112 27.86973 3 2 100 6 Shaft vertical
 Shaft backfilled
 by DRD.
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 60
 DRD no.2
 Vertical
 Shaft
 DRD No. 2
 Vertical
 shaft
 DRD Johannesburg -26.17041 27.86156 7/7/2006 5 4 100 20 Shaft vertical
 Shaft backfilled
 by DRD.
 0 5 5 Low
 61
 DRD no.3
 Shaft
 DRD No. 07
 Shaft
 DRD Johannesburg -26.18796 27.87208 ###### 2.5 0.9 20 2.25 Shaft
 Shaft
 backfilled.
 Exact closure
 method
 unknown
 0 5 5 Low
 62 DRD no.4
 DRD Open
 pit shaft
 DRD Johannesburg -26.188897 27.87751 ###### 5 5 100 25 Shaft Incline
 No safety
 measures.
 5 5 10 High
 63
 DRD no.4
 Ventilation
 Shaft
 DRD No.04
 Ventilation
 shaft
 DRD Johannesburg -26.17054 27.83786 2/8/2005 4 2 100 8 Shaft
 Shaft enclosed
 in a wall. Shaft
 is, however,
 accessible.
 5 5 10 High
 64
 DRD no.4
 Vertical
 Shaft
 Princess
 Ventilation
 Shaft
 DRD Johannesburg -26.17309 27.84303 2/9/2005 3 2 100 6 Shaft Incline
 Shaft enclosed
 in a wall. Shaft
 wall can be
 seen from R41
 (in the south)
 5 5 10 High
 65
 DRD no.5
 Shaft
 DRD N0.5
 shaft
 DRD Johannesburg -26.18056 27.86229 5/7/2006 4 4 100 16 Shaft vertical
 Shaft sealed.
 Shaft breather
 pipe can be
 seeing on shaft
 position.
 0 5 5 Low
 66 DRD no.7
 DRD No. 6
 shaft
 DRD Johannesburg -26.18247 27.83665 ###### 12.6 4.3 100 54.18 Shaft
 Shaft sealed
 with a concrete
 slab.
 0 5 5 Low
 67 DRD no.8
 DRD No. 9
 shaft
 DRD Johannesburg -26.18368 27.83652 ###### 13.3 5 100 66.5 Shaft Incline
 No. 9 shaft,
 Steel grate.,
 headgear
 removed
 0 5 5 Low
 68 DRD no.9
 Circular
 Shaft
 DRD Johannesburg -26.17618 27.86343 26/11/2004 5 5 100 25 Shaft Incline
 Shaft safe.
 Security guard
 on site at all
 times.headgear
 still on shaft.
 Alarm shaft
 5 5 10 High
 69
 DRD Tinkla
 Shaft
 DRD Tinkla
 shaft
 DRD Johannesburg -26.16661 27.86349 5/7/2006 5 4 100 20 Shaft vertical
 Shaft
 backfilled by
 DRD
 0 5 5 Low
 70 DRD2 DRD Johannesburg -26.18696 dd ###### 2 1 20 2 Subsidence
 No safaety
 measures -
 mine air exits
 here
 3 5 8 Medium
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 71
 East
 Memorials
 Shaft
 LL Proprietry
 Incline shaft
 Lanlaagt
 e
 Johannesburg -26.21289 27.98916 ###### 4 4 100 16 Shaft Incline
 Shaft closed
 with slab. Slab
 chipped open.
 5 5 10 Low
 72 ERPM 58
 Centurio
 n
 Ekhurleni -26.19312 28.16559 ###### 2 1 80 2 Subsidence
 Fenced off.
 Opening on
 shallow
 undermined
 land. Woman
 fell into this
 opening and
 died
 0 5 5 Low
 73 ERPM 59
 Centurio
 n Gold
 Mines
 Ekhurleni -26.19532 28.15842 18/7/2007 1.5 5 5 Excavation vertical
 No safety
 measures in
 place around
 the opening
 0 5 5 Low
 74 ERPM 60 ERPM Ekhurleni -26.2014 28.21982 13/11/2006 9 9 1 81 Subsidence
 Opening
 occurred
 beneath a
 shack. The
 shack was
 damaged, but
 there were not
 casualties.
 Opening on
 shallow
 undermined
 land.
 1 5 6 Low
 75 ERPM 63
 Centurio
 n
 Ekhurleni -26.19304 28.16464 ###### 0 0 0 0 Subsidence
 Subsidence
 occuring.
 Shack built on
 this subsiding
 ground. Small
 opening
 developed in
 one of the
 Shack rooms.
 Subsidence
 occuring on
 shallow
 undermined
 land
 0 5 5 Low
 76 ERPM.32X
 Centurio
 n
 Ekhurleni -26.19439 28.16088 ###### 1.5 1.5 0 2.25 Subsidence
 Subsidence
 occurring on
 shallow
 undermined
 land
 1 5 6 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 77 ERPM1 Shaft ERPM Ekhurleni -26.21223 28.25382 ###### 7 4 10 28 Shaft
 Shafts
 backfilled by
 ERPM after
 discussions
 with CGS
 0 5 5 Low
 78 ERPM12 ERPM Ekhurleni -26.20674 28.23377 ###### 5.5 5.5 100 30.25 Shaft
 Wire mesh
 over shaft
 opening.
 5 5 10 High
 79 ERPM13 ERPM Ekhurleni -26.2053 28.22732 ###### 5 5 100 25 Shaft
 Shaft enclosed
 in a wall. Wall
 still intact
 5 5 10 High
 80 ERPM14 ERPM Ekhurleni -26.2053 28.22732 ###### 7.1 5.7 100 40.47 Shaft
 Shaft enclosed
 in a wall. Wall
 no longer
 intact
 5 5 10 High
 81 ERPM15 Angelo Shaft ERPM Ekhurleni -26.2053 28.22732 ###### 6.3 4.3 100 27.09 Shaft
 Shaft partly
 covered with
 logs
 5 5 10 High
 82 ERPM16 ERPM Ekhurleni -26.2032 28.22013 ###### 4 3 50 12 Shaft
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 83 ERPM17 ERPM Ekhurleni -26.19809 28.20993 16/11/2004 72 26 17 1872 Subsidence
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 84 ERPM18 ERPM Ekhurleni -26.19769 28.2095 16/11/2004 13 10 40 130 Subsidence
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 85 ERPM18A ERPM Ekhurleni -26.1975 28.20918 27/3/2006 3 3 50 9 Subsidence
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 86 ERPM19A ERPM Ekhurleni -26.19725 28.20983 16/11/2004 2.5 1.7 11 4.25 Shaft
 Shaft closed by
 CGS. Shaft
 plugged with a
 PUF plug and
 backfilled
 0 5 5 Low
 87 ERPM2 Shaft ERPM Ekhurleni -26.21262 28.25377 ###### 5 5 10 25 Shaft
 Shafts
 backfilled by
 ERPM after
 discussions
 with CGS
 0 5 5 Low
 88 ERPM20 ERPM Ekhurleni -26.19747 28.20712 14/1/2005 7 5 6 35 Subsidence
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 89
 ERPM21
 Shaft
 ERPM Ekhurleni -26.19272 28.1969 ###### 3 3 5 9 Shaft
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 90 ERPM22 ERPM Ekhurleni -26.19015 28.19442 ###### 1 2 1 2 Subsidence
 Subsidence
 backfilled.
 Exact closure
 method
 unknown
 0 5 5 Low
 91 ERPM23 ERPM Ekhurleni -26.18995 28.19274 ###### 0,5 0.5 2 0.5 Subsidence
 Subsidence
 backfilled.
 small openings
 developing.
 0 5 5 Low
 92 ERPM24
 Centurio
 n
 Ekhurleni -26.19025 28.18303 ###### 30 20 6 600 Subsidence
 No safety
 measures. An
 open hole at
 Cedar Dump. A
 water ingress
 point
 3 5 8 Medium
 93 ERPM24X
 Centurio
 n
 Ekhurleni -26.19034 28.18321 ###### 20 30 30 600 Subsidence
 No safety
 measures. An
 open hole at
 Cedar Dump. A
 water ingress
 point
 5 5 10 High
 94 ERPM25
 Centurio
 n
 Ekhurleni -26.18906 28.18069 ###### 2 2 4 4 Subsidence
 No safety
 measures. An
 open hole at
 Cedar Dump. A
 water ingress
 point
 3 5 8 Medium
 95 ERPM26
 Centurio
 n
 Ekhurleni -26.18928 28.17985 ###### 10 10 1 100 Subsidence
 No safety
 measures. An
 open hole at
 Cedar Dump. A
 water ingress
 point. Opening
 very shallow
 1 5 6 Low
 96 ERPM27 ERPM Ekhurleni -26.19276 28.16437 ###### 20 10 3 200 Subsidence
 Subsidence
 backfilled.
 Small openings
 developing,
 however.
 Shallow
 undermined
 land
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 97 ERPM28 ERPM Ekhurleni -26.19348 28.16414 ###### 1 1 2 1 Subsidence
 It appears that
 opening was
 backfiiled and
 re-opened.
 3 5 8 Medium
 98 ERPM29 ERPM Ekhurleni -26.19345 28.16465 ###### 4.5 4.5 1.5 20.25 Subsidence
 Opening was
 backfilled.
 3 5 8 Medium
 99 ERPM3 Shaft ERPM Ekhurleni -26.21288 28.25465 ###### 2 2 5 4 Excavation
 Shafts
 backfilled by
 ERPM after
 discussions
 with CGS
 0 5 5 Low
 100 ERPM30 ERPM Ekhurleni -26.19346 28.16438 ###### 7 7 10 49 Subsidence
 It appears that
 opening was
 backfiiled and
 re-opened.
 3 5 8 Medium
 101 ERPM31 ERPM Ekhurleni -26.19347 28.16436 ###### 3 3 2.5 9 Subsidence
 Trenches
 backfilled
 3 5 8 Medium
 102 ERPM32
 Centurio
 n
 Ekhurleni -26.19434 28.1608 ###### 4.7 4.5 2.6 21.15 Subsidence
 Subsidence
 occurring on
 shallow
 undermined
 land
 0 5 5 Low
 103 ERPM32Y
 Centurio
 n
 Ekhurleni -26.19442 28.1609 ###### 3 2 0 6 Subsidence
 Subsidence
 occurring on
 shallow
 undermined
 land
 1 5 6 Low
 104 ERPM32Z
 Centurio
 n
 Ekhurleni -26.114036 28.93858 ###### 2 2 4 4 Subsidence
 Subsidence
 occurring on
 shallow
 undermined
 land
 3 5 8 Low
 105 ERPM33
 Centurio
 n
 Ekhurleni -26.19553 28.16078 ###### 4 1.3 1.5 5.2 Structure
 An old mine-
 related
 structure
 1 5 6 Low
 106 ERPM34
 Centurio
 n
 Ekhurleni -26.204166 28.13495 26/10/2004 22 12 7.5 264 Subsidence
 No safety
 measures.
 Water ingress
 point
 3 5 8 Low
 107 ERPM34X
 Centurio
 n
 Ekhurleni -26.20472 28.13529 26/10/2004 6 5 5.6 30 Subsidence
 No safety
 measures.
 Water ingress
 point
 3 5 8 Low
 108 ERPM35
 Centurio
 n
 Ekhurleni -26.20442 28.13533 26/10/2004 3.5 3 2.5 10.5 Subsidence
 No safety
 measures.
 Water ingress
 point
 1 5 6 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 109 ERPM36
 Centurio
 n
 Ekhurleni -26.20411 28.13527 17/12/2004 20 8 3 160 Shaft Incline
 No safety
 measures.
 Water ingress
 point
 1 5 6 Low
 110 ERPM36X
 Centurio
 n
 Ekhurleni -26.20465 28.13549 17/12/2004 3 2 2 6 Shaft
 No safety
 measures.
 Water ingress
 point
 3 5 8 Low
 111 ERPM36Y
 Centurio
 n
 Ekhurleni -26.2045 28.13551 17/12/2004 2.5 2 2 5 Structure
 No safety
 measures.
 Water ingress
 point
 1 5 6 Low
 112 ERPM37
 Centurio
 n
 Ekhurleni -26.20508 28.13527 26/10/2004 2 1.5 7 3 Shaft
 No safety
 measures.
 Water ingress
 point
 5 5 10 Low
 113 ERPM37X
 Centurio
 n
 Ekhurleni -26.20441 28.13495 26/10/2004 4.5 4 3 18 Subsidence
 No safety
 measures.
 Water ingress
 point
 3 5 8 Low
 114 ERPM37Y
 Centurio
 n
 Ekhurleni -26.20485 28.13539 26/10/2004 4.5 3.5 6 15.75 Subsidence
 No safety
 measures.
 Water ingress
 point
 5 5 10 Low
 115 ERPM37Z
 Centurio
 n
 Ekhurleni -26.20531 28.13447 26/10/2004 5 5 7 25 Subsidence
 No safety
 measures.
 Water ingress
 point
 3 5 8 Low
 116 ERPM38
 Centurio
 n
 Ekhurleni -26.204445 28.135555 17/12/2004 6 2 1 12 Structure
 No safety
 measures.
 Water ingress
 point
 1 5 6 Low
 117 ERPM38X
 Centurio
 n
 Ekhurleni -26.20528 28.13441 17/12/2004 1.5 1 1.9 1.5 Subsidence
 No safety
 measures.
 Water ingress
 point
 3 5 8 Low
 118 ERPM39
 Centurio
 n
 Ekhurleni -26.20482 28.13026 25/11/2005 2 1 10 2 Subsidence
 Opening
 backfilled.
 Exact closure
 method
 unknown.
 0 5 5 Low
 119 ERPM4
 No.1 South
 Shaft
 ERPM Ekhurleni -26.2131 28.2549 ###### 2 1.5 5 3 Excavation
 Shafts
 backfilled by
 ERPM after
 discussions
 with CGS
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 120 ERPM40
 Centurio
 n
 Ekhurleni -26.204166 28.133333 16/11/2004 5 1 10 5 Subsidence
 Opening
 backfilled.
 Exact closure
 method
 unknown.
 0 5 5 Low
 121 ERPM41 ERPM Ekhurleni -26.203888 28.133055 16/11/2004 2 2 5 4 Subsidence
 Opening
 backfilled.
 Exact closure
 method
 unknown.
 0 5 5 Low
 122 ERPM42 ERPM Ekhurleni -26.203888 28.134167 16/11/2004 2 2 5 4 Subsidence
 Opening
 backfilled.
 Exact closure
 method
 unknown.
 0 5 5 Low
 123 ERPM43 ERPM Ekhurleni -26.20206 28.2213 16/11/2004 12 10 3 120 Shaft
 Plugged and
 backfilled by
 Chestnut
 Projects.
 0 5 5 Low
 124 ERPM44 ERPM Ekhurleni -26.20117 28.22009 16/11/2004 5 5 5 25 Subsidence
 Suspected to
 have been
 closed by
 Chestnut
 Projects. Exact
 closure method
 unknown.
 0 5 5 Low
 125 ERPM45 ERPM Ekhurleni -26.200556 28.220278 16/11/2004 5 5 0 25 Shaft
 Suspected to
 have been
 closed by
 Chestnut
 Projects. Exact
 closure method
 unknown.
 0 5 5 Low
 126 ERPM46 ERPM Ekhurleni -26.200834 28.219999 16/11/2004 5 4 0 20 Shaft
 Suspected to
 have been
 closed by
 Chestnut
 Projects. Exact
 closure method
 unknown.
 0 5 5 Low
 127 ERPM47 ERPM Ekhurleni -26.20146 28.21478 16/11/2004 5 5 20 25 Shaft
 Suspected to
 have been
 closed by
 Chestnut
 Projects. Exact
 closure method
 unknown.
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 128 ERPM48 ERPM Ekhurleni -26.19988 28.21644 16/11/2004 5 5 20 25 Subsidence
 Suspected to
 have been
 closed by
 Chestnut
 Projects. Exact
 closure method
 unknown.
 0 5 5 Low
 129 ERPM49 ERPM Ekhurleni -26.201111 28.220556 16/11/2004 9 8 30 72 Subsidence
 Suspected to
 have been
 closed by
 Chestnut
 Projects. Exact
 closure method
 unknown.
 0 5 5 Low
 130 ERPM5
 No.1 Incline
 Shaft
 ERPM Ekhurleni -26.21265 28.25518 ###### 4 4 10 16 Shaft Incline
 Shafts
 backfilled by
 ERPM after
 discussions
 with CGS
 0 5 5 Low
 131 ERPM50 ERPM Ekhurleni -26.19952 28.21592 16/11/2004 13 9 30 117 Subsidence
 Suspected to
 have been
 closed by
 Chestnut
 Projects. Exact
 closure method
 unknown.
 0 5 5 Low
 132 ERPM51 ERPM Ekhurleni -26.19906 28.20664 14/1/2005 4.7 4.7 10 22.09 Shaft Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 133 ERPM52 ERPM Ekhurleni -26.19857 28.2065 14/1/2005 3 3 100 9 Shaft Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 134 ERPM53
 Ventilation
 Shaft
 ERPM Ekhurleni -26.22988 28.25993 1/3/2005 2 2 10 4 Shaft vertical
 Shaft enclosed
 in a fence.
 5 5 10 High
 135 ERPM54 ERPM Ekhurleni -26.232 28.26981 1/3/2005 8 8 0 64 Shaft Incline
 Shaft closed.
 Closure
 method
 unknown.
 1 5 6 Low
 136 ERPM55 ERPM Ekhurleni -26.20011 28.21025 1/3/2005 8 8 10 64 Shaft Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 137 ERPM56 ERPM Ekhurleni -26.20016 28.21006 1/3/2005 5 5 7 25 Subsidence
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 138 ERPM57 ERPM Ekhurleni -26.19625 28.15622 18/3/2005 0.5 0.5 50 0.25 Subsidence
 No safety
 measures.
 Opening on
 shallow
 undermined.
 Woman
 working for
 Rand Water
 fell into this
 opening. She
 survived
 5 5 10 Low
 139 ERPM6
 Blue Sky
 Main shaft
 ERPM Ekhurleni -26.21418 28.25783 ###### 3 3 35 9 Shaft
 Shaft lie open
 in a vacant
 land. Wire-
 mesh placed
 over shaft.
 5 5 10 High
 140 ERPM61
 Centurio
 n Gold
 Mines
 Ekhurleni -26.19725 28.15554 18/7/2007 1.5 2 15 Excavation vertical
 Opening
 closed. Closure
 method
 unknown
 5 0 5 Low
 141 ERPM7 Cason Shaft ERPM Ekhurleni -26.21009 28.24544 ###### 5 5 100 25 Shaft
 Fenced and
 walled.
 0 5 5 Low
 142 ERPM9 Shaft ERPM Ekhurleni -26.20969 28.24041 ###### 6 4 100 24 Shaft
 No safety
 measures
 5 5 10 High
 ERPM 64
 Centurio
 n
 Ekhurleni 16/11/2007 5 1.5 100 7.5 shaft Incline
 Community
 erected fence
 5 5 10 High
 143 F004 Shaft
 Rand
 Leases
 Ekhurleni -26.19145 27.89992 4 3 10 12 Shaft Incline
 Possibly
 entrance to
 shaft. Opening
 covered with
 landfill
 0 5 5 Low
 144 F008 Shaft
 Rand
 Leases
 Ekhurleni -26.18608 27.91704 28/9/2005 8 5 100 40 Shaft Incline
 Shaft closed by
 DRD.
 0 5 5 Low
 145
 Geldenhuis
 Shaft
 S&J Rudd
 Shaft
 Simmer
 & Jack
 Ekurhuleni -26.21432 28.15341 ###### 10 4 100 40 Shaft vertical
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 146
 Geldenhuis
 Shaft B
 Simmer
 & Jack
 Ekurhuleni -26.21418 28.15342 5/9/2006 4 3 30 12 Structure vertical
 Structure
 dangerous and
 open
 5 5 10 Low
 147
 Gosforth
 Hole
 Simmer
 and
 Jack
 Ekhurleni -26.22925 28.13783 14/1/2005 3 2 10 6 Shaft
 No safety
 measures.
 5 5 10 Low
 148
 Gosforth
 Incline
 Shaft
 Simmer
 and
 Jack
 Ekhurleni -26.22924 28.13782 14/1/2005 3 2 20 6 Shaft Incline
 Open shaft. No
 safety
 measures
 5 5 10 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 149
 Haggie
 Shaft
 Howard
 shaft
 Nourse
 Mines
 Ekhurleni -26.21985 28.12825 25/11/2004 8 3 30 24 Shaft
 Shaft sealed
 with concrete
 slab
 0 5 5 Low
 150
 Knights
 Shaft
 Rose Deep
 No.1 Shaft
 Primros
 e
 Ekhurleni -26.19659 28.17168 30/11/2004 8 4 100 32 Shaft
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 151
 Langlaagte
 Main 2
 Langlaa
 gte
 Johannesburg -26.2035 27.9687 5/9/2006 4 4 100 16 Subsidence
 No safety
 measures
 5 5 10 Low
 152
 Langlaagte
 Main 3
 Langlaa
 gte
 Johannesburg -26.20341 27.9683 5/9/2006 4 2 100 8 Subsidence
 No safety
 measures
 5 5 10 Low
 153
 Langlaagte
 Main 4
 Langlaa
 gte
 Johannesburg -26.20331 27.96818 5/9/2006 4 4 100 16 Subsidence
 No safety
 measures
 5 5 10 Low
 154
 Langlaagte
 Main 5
 Langlaa
 gte
 Johannesburg -26.20316 27.96779 5/9/2006 3 3 100 9 Subsidence
 No safety
 measures
 5 5 10 Low
 155
 Langlaagte
 Main 6
 Langlaa
 gte
 Johannesburg -26.20321 27.96767 5/9/2006 8 8 100 64 Subsidence
 No safety
 measures
 5 5 10 Low
 156
 Langlaagte
 Main 7
 Langlaa
 gte
 Johannesburg -26.20306 27.96737 5/9/2006 8 6 100 48 Shaft
 Wall
 surrounding
 shaft
 vandalised.
 Shaft
 accessible
 5 5 10 Low
 157
 Langlaagte
 Main B
 Langlaa
 gte
 Johannesburg -26.20372 27.96878 21/8/2006 5 2 100 10 Subsidence
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 158
 Langlaagte
 Main Shaft
 Langlaagte
 Main Shaft
 Langlaa
 gte
 Johannesburg -26.20372 27.96878 4 4 100 16 Shaft Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 159
 Langlaagte
 West Deep
 Shaft
 LL West
 Deep
 Lanlaagt
 e
 Johannesburg -26.20678 27.96055 22/6/2002 4 3 100 12 Shaft
 Shaft closed.
 Closure
 method
 unknown
 0 5 5 Low
 160
 Macro
 Shaft
 Crown
 Gold
 Mines
 Johannesburg -26.21455 28.00197 ###### 4 3.5 15 14 Shaft
 Shaft closure
 in progress
 5 5 10 Low
 161 Memorial 1
 Langlaagte
 Outcrop
 (LLPI)
 Langlaa
 gte
 Ekhurleni -26.21075 27.98853 18/11/2004 2 2 100 4 Excavation
 No safety
 measures.
 Opening along
 the reef
 outcrop
 5 5 10 High
 162 Memorial 2
 Langlaa
 gte
 Ekhurleni -26.21051 27.98727 18/11/2004 3 2 5 6 Excavation
 No safety
 measures.
 Opening along
 the reef
 outcrop
 3 5 8 Medium
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 163 Memorial 3
 Langlaa
 gte
 Ekhurleni -26.21017 27.98876 18/11/2004 0 0 5 0 Excavation Incline
 No safety
 measures.
 Opening along
 the reef
 outcrop
 3 5 8 Medium
 164
 Old Wits
 Vertical
 shaft
 Wits
 Gold
 Mine
 Ekhurleni -26.19702 28.17823 24/8/2006 9 5 15 45 Shaft vertical
 Shaft within
 industrial area.
 No safety
 measures
 5 5 10 Low
 165
 Pencil Park
 Shaft
 Geldenhuis
 Shaft
 Centurio
 n Gold
 Mines
 Ekhurleni -26.20896 28.1325 25/11/2004 7 2.7 100 18.9 Shaft
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 166
 Private
 no.1 Shaft
 Langlaa
 gte
 Johannesburg -26.21489 27.97038 18/11/2004 2.5 2.5 6.25 Shaft Incline
 No safety
 measures.
 0 5 5 Low
 167
 Private
 no.2 Shaft
 East Deep
 Vertical
 Langlaa
 gte
 Johannesburg -26.20929 27.9687 18/11/2004 10 3 100 30 Shaft vertical
 No safety
 measures.
 0 5 5 Low
 168 R39
 Crown Mine
 No.17 shaft
 Rholes Johannesburg -26.22242 27.96353 ###### 4 3 5 12 Shaft
 Trenches to
 the south and
 east of the
 shaft.
 5 5 10 High
 169 R41
 Crown Mine
 No.15 shaft
 Crown
 Gold
 Mines
 Johannesburg -26.23458 27.99817 ###### 4.3 2 >100 8.6 Shaft vertical
 No safety
 measures.
 Shaft cache
 still in the shaft
 5 5 10 High
 170 R42 ERPM Johannesburg -26.20592 27.9306 ###### 1 1 10 1 Structure
 Hole is
 cemented on
 sides.
 5 2 7 Medium
 171 R43 ERPM Johannesburg -26.2057 27.93066 ###### 1 1 3 1 Structure
 Hole is well
 cemented
 inside.
 3 2 5 Medium
 172 R44 ERPM Johannesburg -26.20595 27.93069 ###### 1 1 6 1 Structure
 It looks like a
 shaft but is
 just a hole.
 5 2 7 Medium
 173 R45 ERPM Johannesburg -26.20265 27.93245 ###### 2 2 3 4 Subsidence
 There is a rock
 on the
 northern side
 of the hole
 3 2 5 Medium
 174 R49
 Cleaveland
 Shaft
 Centurio
 n Gold
 Mines
 Ekhurleni -26.20736 28.12326 ###### 2.9 2 >100 5.8 Shaft vertical
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 5 5 10 High
 175 R50
 Centurio
 n Gold
 Mines
 Ekhurleni -26.2058 28.12474 ###### 16 5 5 80 Subsidence Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 176 R51
 Centurio
 n Gold
 Mines
 Ekhurleni -26.20583 28.12461 ###### 3 3 >10 9 Subsidence Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 177 R52
 Centurio
 n Gold
 Mines
 Ekhurleni -26.20582 28.12447 ###### 2 1.5 1.2 3 Subsidence Incline
 No safety
 measures
 0 5 5 Low
 178 R53
 Centurio
 n Gold
 Mines
 Ekhurleni -26.20585 28.12433 ###### 4.7 3.9 >10 18.33 Shaft Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 179 R56
 KR No. 2
 Incline
 Rand
 Leases
 Ekhurleni -26.20021 27.89754 ###### 5 4 100 20 Shaft Incline
 No safety
 measures.
 Shaft close to
 thoroughfares
 in the area.
 5 5 10 High
 180 R58 CMR Johannesburg -26.20614 27.91239 ###### 5 3 30 15 Shaft Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 181 R58A CMR Johannesburg -26.2079 27.91678 28/5/2006 2 2.5 5 Subsidence
 opening closed
 by CGS
 5 0 5 Low
 182 R59
 KR No. 19
 Shaft
 CMR Johannesburg -26.20767 27.91621 ###### 6 6 35 36 Shaft Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 183 R59A CMR Johannesburg -26.20795 27.91745 30/8/2006 Shaft
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 184 R60
 Consolid
 ated
 Main
 Reef
 Johannesburg -26.20002 27.92502 ###### 4.5 4.5 100 20.25 Shaft Incline
 Shaft closed.
 Closure
 method
 unknown.
 0 5 5 Low
 185 R61
 CMR No.5
 vertical
 Consolid
 ated
 Main
 Reef
 Johannesburg -26.19961 27.92281 ###### 4 4 100 16 Shaft vertical
 No safety
 measures.
 400m from
 school
 5 5 10 High
 186 R62
 Randleases
 4 or A Shaft
 Rand
 Leases
 Johannesburg -26.19592 27.91327 ###### 6 2 35 12 Shaft Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 187 R62 East
 Rand
 Leases
 Johannesburg -26.1965 27.91604 21/8/2006 5 4 100 20 Shaft Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 188 R62 West
 Rand
 Leases
 Johannesburg -26.19561 27.91259 21/8/2006 4 4 20 16 Subsidence vertical
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 189 R63
 CMR No.3
 Verical
 Consolid
 ated
 Main
 Reef
 Johannesburg -26.20786 27.94545 ###### 7 5 150 35 Shaft Incline
 Razor-wire
 erected around
 shaft,
 otherwise no
 stringent
 safety
 measures.
 5 5 10 High
 190 R64 Shaft
 Rand
 Leases
 Johannesburg -26.20202 27.90082 ###### 10 8 60 80 Shaft Incline
 No safety
 measures.
 Shaft close to
 thoroughfares
 in the area.
 5 5 10 High
 191 R65
 KR No. 2
 Ventilation
 shaft
 Rand
 Leases
 Johannesburg -26.20046 27.89709 ###### 3.7 3 100 11.1 Shaft Ventilation
 No safety
 measures.
 Shaft close to
 thoroughfares
 in the area.
 5 5 10 High
 192 R68 CMR Johannesburg -26.19025 27.92696 27/6/2007 6 5 100 30 Shaft vertical
 shaft enclosed
 in a wall. The
 wall is falling
 apart
 5 5 10 High
 193 R69 CMR Johannesburg -26.19131 27.93114 27/6/2007 2.5 2 100 5 Shaft vertical
 shaft enclosed
 in a wall.
 5 5 10 High
 194
 Rand
 Leases Adit
 Rand
 Leases
 Johannesburg -26.20113 27.89825 20/6/2006 8 8 100 64 Shaft
 No safety
 measures
 5 5 10 High
 195
 Rand
 Leases
 no.1 Shaft
 Randleases
 11 Vertical
 Rand
 Leases
 Johannesburg -26.19026 27.89768 ###### 4 7 100 28 Shaft
 No safety
 measures
 5 5 10 High
 196
 Rand
 Leases
 no.4
 Incline
 Shaft
 Rand Leases
 No.7 Shaft
 Rand
 Leases
 Johannesburg -26.18127 27.89526 5/9/2005 6 3 100 18 Shaft Incline
 Shaft sealed
 with a concrete
 slab
 0 5 5 Low
 197 RD01E RD01E
 Village
 Main
 Johannesburg -26.21924 28.05225 22/6/2006 6 2.5 100 15 Shaft vertical
 Shaft enclosed
 in a wall. Wall
 no longer
 intact
 0 5 5 Low
 198 RD02E RD 02E
 Village
 Main
 Johannesburg -26.21911 28.04677 22/6/2006 8 3 100 24 Shaft vertical
 Shaft enclosed
 in a wall. Steel
 grate on top of
 the wall
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 199
 Roodepoort
 5A
 Roodep
 oort
 Johannesburg -26.16714 27.87061 6/3/2007 12 7 100 84 Subsidence
 Opening to be
 closed by
 Chestnut
 during II Phase
 0 5 5 Low
 200
 Roodepoort
 5B
 Roodep
 oort
 Johannesburg -26.16705 27.87053 6/4/2007 4 3 100 12 Shaft Incline
 Opening to be
 closed by
 Chestnut
 during II Phase
 0 5 5 Low
 201
 Roodepoort
 5C
 Roodep
 oort
 Johannesburg -26.16714 27.87044 6/5/2007 10 6 100 60 Subsidence
 Opening to be
 closed by
 Chestnut
 during II Phase
 0 5 5 Low
 202
 Roodepoort
 5D
 Roodep
 oort
 Johannesburg -26.16769 27.8709 6/6/2007 15 6 100 90 Shaft Incline
 Opening to be
 closed by
 Chestnut
 during II Phase
 0 5 5 Low
 203
 Roodepoort
 7
 Roodep
 oort
 Johannesburg 0 Shaft vertical 5 5 10 High
 204
 Roodepoort
 no.1
 Roode01 DRD Johannesburg -26.16512 27.86381 ###### 4 2 100 8 Shaft vertical
 Shaft enclosed
 in a wall. Shaft
 accessible
 5 0 5 Low
 205
 Roodepoort
 no.2
 Roode02 DRD Johannesburg -26.16492 27.86652 ###### 6.5 6.5 100 42.25 Shaft vertical
 Shaft enclosed
 in a wall
 5 0 5 Low
 206
 Roodepoort
 no.3
 Roode03 DRD Johannesburg -26.16653 27.86835 ###### 12.2 12.2 100 148.84 Shaft vertical
 Shaft enclosed
 in a wall. Shaft
 accessible
 5 0 5 Low
 207
 Roodepoort
 no.4
 Roode04 DRD Johannesburg -26.16849 27.87084 ###### 12 12 100 144 Shaft vertical
 Shaft enclosed
 in a wall. Shaft
 accessible
 5 0 5 Low
 208
 Roodepoort
 No.4
 Original
 Shaft
 No. 4
 Roodepoort
 DRD Johannesburg -26.16834 27.83362 7 5 100 35 Shaft vertical
 Shaft closed.
 Closure
 method
 unknown
 0 5 5 Low
 209
 Roodepoort
 no.6
 Wilford No.
 7 incline
 shaft
 DRD Johannesburg -26.16715 27.83845 29/05/2006 13 12 100 156 Shaft Incline
 No safety
 measures
 5 0 5 Low
 210
 Rose Deep
 no.2
 Simmer
 & Jack
 Ekhurleni -26.19726 28.16702 28/9/2005 6 3 100 18 Shaft vertical
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 0 0 Low
 211
 S & J
 Rhodes
 Shaft
 S&J Rhodes
 shaft
 Simmer
 & Jack
 Ekurhuleni -26.21543 28.14012 14/6/2006 6 5 100 30 Shaft vertical
 Shaft closed.
 Headgear
 remains visible
 on rock dump
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 212 S & J11
 Simmer
 & Jack
 Ekhurleni -26.20302 28.14115 25/11/2004 4 3.5 14 Shaft Incline
 Barbed fencing
 and conctrete
 slab
 5 5 10 Low
 213 S & J12
 S&J Incline
 Shaft
 Simmer
 & Jack
 Ekhurleni -26.20053 28.1482 25/11/2004 3.2 2.8 8.96 Shaft Incline
 Shaft sealed
 with a concrete
 slab. Slab
 vandalised
 5 5 10 Low
 214 S & J15
 Primrose
 No.4 Shaft
 Simmer
 & Jack
 Ekhurleni -26.20325 28.15537 24/11/2004 3 3 12 9 Shaft Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 215 S & J16
 Simmer
 & Jack
 Ekhurleni -26.20269 28.15509 24/11/2004 25 25 20 625 Shaft Incline
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 216 S & J16A
 Simmer
 & Jack
 Ekhurleni Shaft
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 217 S & J17
 Simmer
 & Jack
 Ekhurleni -26.20297 28.13514 24/11/2004 12 7 15 84 Shaft Incline
 Shaft closed.
 Closure
 method
 unknown
 0 5 5 Low
 218 S & J18
 Hammoned
 Shaft
 Simmer
 & Jack
 Ekhurleni -26.20692 28.16501 25/11/2004 8.7 2.6 100 22.62 Shaft vertical
 Shaft closed by
 CGS. Shaft
 plugged and
 backfilled
 0 5 5 Low
 219 S & J20 S&JKIMI
 Simmer
 & Jack
 Ekhurleni -26.22768 28.14109 24/11/2004 4 3 100 12 Shaft Incline
 Razor-wire
 erected around
 shaft,
 otherwise no
 stringent
 safety
 measures.
 5 5 10 High
 220 S & J21
 South Deep
 Shaft
 Simmer
 & Jack
 Ekhurleni -26.22869 28.14085 24/11/2004 8 4 100 32 Shaft vertical
 Shaft sealed
 with a concrete
 slab
 0 5 5 Low
 221 S & J23
 Simmer
 & Jack
 Ekhurleni -26.20172 28.15936 27/9/2005 0.5 0.5 100 0.25 Shaft
 Shack built on
 old mine
 structures
 3 2 5 Low
 222 S & J24
 Stanhope
 N0.5 Shaft
 Simmer
 & Jack
 Ekhurleni -26.20533 28.12828 27/9/2006 6 5 100 30 Shaft Incline
 Shaft probably
 still active
 0 5 5 Low
 223 S & J25
 Incline East
 Shaft
 Simmer
 & Jack
 Ekhurleni -26.19395 28.15108 6 5 100 30 Shaft Incline
 Shaft enclosed
 in a wall.
 Security
 personnel on
 site
 0 5 5 Low
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 224 S & J8
 North
 Vertical
 Shaft
 Simmer
 & Jack
 Ekhurleni -26.20651 28.14174 24/11/2004 3 2 6 Shaft vertical
 Shaft enclosed
 in a fence.
 5 0 5 Low
 225 S & J9 No.1 Shaft
 Simmer
 & Jack
 Ekhurleni -26.20651 28.14174 24/11/2004 5 2 10 Shaft vertical
 Shaft closed.
 Closure
 method
 unknown
 0 5 5 Low
 226 S&J15B
 Simmer
 & Jack
 Ekurhuleni -26.20238 28.15443 29/6/2006 6 4 100 24 Shaft vertical
 Shaft enclosed
 in a wall
 5 0 5 Low
 227
 Sharland
 Shaft
 Milner Shaft Johannesburg -26.21445 28.14779 ###### 10 3 100 30 Shaft vertical
 Shaft sealed
 with a concrete
 slab
 0 5 5 Low
 228
 South
 Deep Shaft
 Simmer
 & Jack
 Johannesburg -26.22651 28.14052 24/11/2004 4 4 20 16 Shaft vertical
 No safety
 measures.
 0 5 5 Low
 229
 Start of
 Kimberley
 Reef Shaft
 S&J No.1
 Incline
 Simmer
 & Jack
 Ekhurleni -26.2266 28.13986 24/11/2004 3 1.5 3 4.5 Shaft Incline
 Razor-wire
 erected around
 shaft,
 otherwise no
 stringent
 safety
 measures.
 5 5 10 High
 230 TD21
 Hercules
 South
 ERPM Ekhurleni -26.23904 28.23528 7/1/2005 11.3 11.3 100 127.69 Shaft vertical
 No safety
 measures
 5 5 10 High
 231 TD22
 South East
 Shaft
 ERPM Ekhurleni -26.24428 28.24360 6/1/2005 6 5 100 30 Shaft vertical
 Shaft still
 active
 0 5 5 Low
 232 TD25
 Cinderella
 North East
 Shaft
 ERPM Ekhurleni -26.14364 28.16092 6/1/2005 14 2.3 100 32.2 Shaft vertical
 Shaft still
 active
 5 5 10 High
 233 TD26
 Hercules
 Shaft
 ERPM Ekhurleni -26.22011 28.23326 6/1/2005 6 5 100 30 Shaft vertical
 Shaft still
 active
 0 5 5 Low
 234 TD28 ERPM Ekhurleni -26.13472 28.15388 6/1/2005 4.5 2.8 100 12.6 Subsidence 2 5 7 Medium
 235 TD31
 Central
 Vertical
 ERPM Ekhurleni -26.22774 28.21965 6/1/2005 5 4 100 20 Shaft vertical
 Shaft still
 active
 0 5 5 Low
 236 TD35
 Far East
 Vertical
 ERPM Ekhurleni -26.25745 28.26141 6/1/2005 6 5 100 30 Shaft vertical
 Shaft still
 active
 0 5 5 Low
 237 TD40
 South West
 Ventilation
 ERPM Ekhurleni -26.21663 28.18363 6/1/2005 5 5 100 25 Shaft vertical
 Shaft still
 active
 0 5 5 Low
 238 TD41 ERPM Ekhurleni 26.13199 28.16557 7/1/2005 2.8 2.2 100 6.16 Shaft vertical
 Shaft sealed
 with a concrete
 slab
 0 5 5 Low
 239 TD45
 Cinderella
 East Shaft
 ERPM Ekhurleni -26.13415 28.15559 7/1/2005 4.3 4.3 100 18.49 Shaft vertical
 Opening
 closed. Closure
 method
 2 5 7 Medium
No.of
 holes
 CGS Hole
 Name
 Original
 Shaft
 Name
 Area Municipality Latitude Longitude
 Date
 logged
 Length
 (m)
 Width
 (m)
 Depth
 (m)
 Area
 (m?)
 Hole
 Type
 Incline
 Safety
 Report
 Hazard Proximity
 Priority
 Rating
 Risk
 unknown
 240
 West Gate
 Shaft
 Worcester
 No.2 Shaft
 Johanne
 sburg
 Johannesburg -26.20934 28.03341 ###### 4 3 100 12 Shaft vertical
 Shaft enlosed
 in a wall
 5 5 10 High
 241 West Shaft ERPM Ekhurleni -26.20021 28.20979 16/11/2004 15 15 17 225 Shaft
 No safety
 measures
 0 5 5 Low
 242
 West Shaft
 Incline
 Shaft
 ERPM Ekhurleni -26.20023 28.20982 16/11/2004 5 5 17 25 Shaft Incline
 No safety
 measures
 0 5 5 Low
 243
 Wilford
 Incline
 Shaft
 Wilford
 Incline
 DRD Johannesburg -26.16496 27.84966 7/7/2006 5 4 100 20 Shaft Incline Shaft closed 0 5 5 Low
 244
 Wilford
 Shaft
 DRD Johannesburg -26.09832 27.51522 3/3/2006 5 5 100 25 Shaft shaft closed 0 5 5 Low
APPENDIX G:
 PHOTOGRAPHIC RECORD OF MINE
 OPENINGS
17. 18.Clem 19. 20
 9.Balmoral 10
 12.
 16.
 11.Benr
 - ?
 21.CMR 22.CMR 23.CMR 24.C 25.CM
 31.Crown
 27.CMR Old
 32.Crown Mine
 28.CMR Old 29
 35. Crown Mine
 12 Incline
 33.Crown Mine
40.Crown Mine39.Crown Mine
 42.Crown Mine 17 Vertical 43.Crowr Mine 2 shaft
 shaft a
 45.Crown44.Crown
 5 58.DRD 1
 64.DR
 38.Crown Mine
 49.Crown
 54.D
 59.DRD 2
 61.drd 4 62.DRD 4 incline shaft a
 66.drd 8 67.DRD 9 vertical shaft 68.DRD 70.East
 63.DRD 4
 FT-7' 1
 4
7 772.
 94.92
 1
 F t I 4
 V i
 c '
 - - -
 ' ' - '? 7 0: .:7
 111
 102.E
 74 75.E
 80.
 81 8
 77.
 88
 93. 99
 996. 9 1
 103. 104.
112.
 1 1 2
 137
144.
 167. Private
195. Rand leases
 196. Rand
 208.
 Roodepoor
 194 Rand
 187
 201
 202.20
 209.Roode207. 211. S&J210. Rose
 1
2
 2 2
 2 2
 2
 227.
 22
 2 240. West
 22
 2
APPENDIX H:
 HISTORICAL METHODS USED TO SEAL MINE
 OPENINGS
Closure Methods of 'Previously Closed' Mine Openings
 Central Basin
 No.of
 holes
 CGS Hole Name
 Original
 Shaft Name
 Closure
 Method
 1 A006 Backfill
 2 A002
 No original
 opening name
 Backfill
 3 A004
 No original
 opening name
 Backfill
 4
 Angelo Deep
 Shaft
 Angelo Deep
 Shaft Backfill
 5
 Angelo Ventilation
 Shaft
 Angelo
 Ventilation
 shaft Backfill
 6 Benrose Shaft Worhuter Shaft Wall
 7 Chris Shaft Chris Shaft Backfill
 8
 City Deep no.1
 Shaft
 City Deep No.3
 Vertical
 9
 City Deep no.2
 Shaft
 City Deep No.4
 Shaft
 Wall
 10
 City Deep no.4
 Shaft
 City Deep No.5
 Shaft
 Wall
 11
 City Deep no.5
 Shaft
 Worcester
 N0.1 Shaft
 slab
 12 Clement Shaft Clement Shaft Backfill
 13 CMR - R 67B
 14 CMR Central Shaft
 CMR Central
 shaft
 15 CMR no.10 Shaft
 CMR No.10
 shaft
 Backfill
 16 CMR no.2 Shaft
 CMR No. 2
 shaft
 slab
 17 CMR no.4 Shaft
 No.4
 Compound
 Shaft
 Backfill
 18 CMR no.8 Shaft
 CMR No. 8
 shaft
 Backfill
 19
 Crown Mine 12
 Ventilation
 Crown Mine 12
 Ventilation
 Wall
 20
 Crown Mine no.10
 Shaft
 Crown Mine
 No. 18 West
 shaft
 slab
 21
 Crown Mine no.11
 Shaft
 Crown Mine
 No.16
 Ventilation
 shaft
 Wall
 22 Crown Mine no.12
 23
 Crown Mine no.12
 Incline Shaft
 Crown Mine 12
 Incline
 Backfill
 24
 Crown Mine no.14
 Shaft
 Crown Mine
 No. 10 Incline
 Backfill
Closure Methods of 'Previously Closed' Mine Openings
 Central Basin
 No.of
 holes
 CGS Hole Name
 Original
 Shaft Name
 Closure
 Method
 shaft
 25
 Crown Mine no.15
 Shaft
 Crown Mine
 no.7 shaft
 Plug
 26
 Crown Mine no.16
 Shaft
 slab
 27
 Crown Mine no.17
 Shaft
 Crown Mine
 no. 14 shaft
 Plug
 28
 Crown Mine no.17
 Ventilation Shaft
 Crown Mine
 17Ventilation
 slab
 29
 Crown Mine no.17
 Vertical Shaft
 Crown Mine
 17Vertical
 slab
 30
 Crown Mine no.2
 Shaft
 Crown Mine
 No. 18
 Ventilation
 shaft
 Wall
 31
 Crown Mine no.3
 Shaft
 Backfill
 32 Crown Mine no.4 Backfill
 33
 Crown Mine no.5
 Shaft
 Crown Mine
 No. 1 shaft
 slab
 34
 Crown Mine no.6
 Shaft
 Crown Mine
 No. 5 shaft
 slab
 35
 Crown Mine no.7
 Shaft
 Crown Mine
 No.3 shaft
 36
 Crown Mine no.8
 Shaft
 Crown Mine
 No. 16 Vertical
 shaft
 slab
 37 DRD 3 Vertical
 DRD No.3
 Vertical shaft
 38
 DRD Bitcom
 Incline Shaft
 DRD Bitcom
 Incline shaft Plug
 39 DRD Bitcom Shaft
 DRD Bitcom
 Shaft Backfill
 40
 DRD Bitcom
 Ventilation Shaft
 DRD Bitcom
 Ventilation
 shaft Backfill
 41 DRD Hole
 42 DRD Hope Shaft
 DRD Hope
 shaft
 Backfill
 43
 DRD Monaliza
 Shaft
 DRD Monaliza
 shaft
 Backfill
 44 DRD no.1 Shaft
 DRD
 Greatbrittan
 incline shaft
 Backfill
 45
 DRD no.1 Vertical
 Shaft
 DRD No. 1
 Vertical shaft
 Backfill
 46
 DRD no.2 Vertical
 Shaft
 DRD No. 2
 Vertical shaft Backfill
Closure Methods of 'Previously Closed' Mine Openings
 Central Basin
 No.of
 holes
 CGS Hole Name
 Original
 Shaft Name
 Closure
 Method
 47 DRD no.3 Shaft
 DRD No. 07
 Shaft
 Wall
 48 DRD no.5 Shaft
 DRD N0.5
 shaft Backfill
 49 DRD no.7
 DRD No. 6
 shaft
 slab
 50 DRD no.8
 DRD No. 9
 shaft
 Backfill
 51 DRD Tinkla Shaft
 DRD Tinkla
 shaft Backfill
 52
 East Memorials
 Shaft
 LL Proprietry
 Incline shaft
 53 ERPM 58 fence
 54 ERPM 59 Plug
 55 ERPM 60 fence
 56 ERPM 63 fence
 57 ERPM1 Shaft Backfill
 58 ERPM2 Shaft Backfill
 59 ERPM22 Backfill
 60 ERPM23 Backfill
 61 ERPM26 Backfill
 62 ERPM27 Backfill
 63 ERPM29
 64 ERPM3 Shaft Backfill
 65 ERPM30
 66 ERPM31
 67 ERPM33 Backfill
 68 ERPM39 Backfill
 69 ERPM4
 No.1 South
 Shaft
 Backfill
 70 ERPM40 Backfill
 71 ERPM41 Backfill
 72 ERPM42 Backfill
 73 ERPM43 Plug
 74 ERPM44 Plug
 75 ERPM45 Plug
 76 ERPM46 Plug
 77 ERPM47 Plug
 78 ERPM48 Plug
 79 ERPM49 Plug
 80 ERPM5
 No.1 Incline
 Shaft
 Backfill
 81 ERPM50 Plug
 82 ERPM54 Backfill
 83 ERPM61 Plug
 84 ERPM7 Cason Shaft Fence
 85 F004 Shaft Backfill
 86 F008 Shaft Backfill
 87 Haggie Shaft Howard shaft slab
Closure Methods of 'Previously Closed' Mine Openings
 Central Basin
 No.of
 holes
 CGS Hole Name
 Original
 Shaft Name
 Closure
 Method
 88
 Langlaagte West
 Deep Shaft
 LL West Deep
 Backfill
 89 Macro Shaft Plug
 90 Private no.1 Shaft slab
 91 R53 Plug
 92 R60 Backfill
 93
 Rand Leases no.4
 Incline Shaft
 Rand Leases
 No.7 Shaft
 slab
APPENDIX I:
 SRK CONCRETE PLUG DESIGN
 (COUNCIL FOR GEOSCIENCE, 2007)


APPENDIX J:
 MATERIAL QUANTITIES
 FOR INSTALLING CONCRETE PLUGS IN
 CENTRAL BASIN MINE OPENINGS
 COUNCIL FOR GEOSCIENCE (2007)
No. Contract Ref. No.
 Start
 Date Finish Date Method Used
 Lined
 Shaft
 Unlined
 Shaft Conc. Qty m3 H1(m) L2(m) L1(m) D1(m) W1(m) H2(m) D2(m) W2(m) H1+D1 h2+d2
 1 BAL1 6/20/2006 7/27/2006 Vertical Plug X 54 5 3 4 4.5 9.5 0
 2 BALVert 6/20/2006 7/15/2006 Vertical Plug X 30 5 3 3 3.5 8.5 0
 3 Cons Mod 31/7/2007 16/9/2007 Vertical Plug X 159 3 5.5 3.5 7 10 0
 4 DRD BC (Bit Com ) 12/3/2007 3/4/2007 Inclined Unlined X 28 2.5 3 3.1 3 0 6.1
 5 ERMP-21 5/15/2006 5/19/2006 Incline Plug X 18 3 3 2 2 0 5
 6 ERPM 57 (Cent. 1) 14/7/2007 22/7/2007 Inclined Lined X 38 1.8 3.75 2.75 3 0 6.5
 7 ERPM 59 (Cent. 2) 14/7/2007 22/7/2007 Inclined Lined X 37 1.9 3.3 3.7 3.3 0 7
 8 ERPM16 5/24/2006 6/6/2006 Incline Plug X 24 6 3 2 2 0 5
 9 ERPM-17 4/6/2006 9/19/2006 See Note 1 0 0
 10 ERPM-18 4/6/2006 6/24/2006 Incline Plug X 108 8 31 2 6.75 0 33
 11 ERPM-18 A 4/6/2006 6/24/2006 Incline Plug X 72 6 3 2 6 0 5
 12 ERPM-20 5/15/2006 5/19/2006 Incline Plug X 32 5.3 3 2 3 0 5
 13 ERPM32 5/25/2006 5/6/2006 Incline Plug X 24 6 2 2 2 0 4
 14 ERPM32A 5/25/2006 5/6/2006 Incline Plug X 29 7 2 2.1 2 0 4.1
 15 ERPM32B 5/25/2006 5/6/2006 Incline Plug X 32 5.3 2 3 3 0 5
 16 ERPM-51 4/6/2006 4/21/2006 Incline Plug X 24 4 3 2 3 0 5
 17 ERPM-52 4/6/2006 4/21/2006 Incline Plug X 26 4.3 3 2 3 0 5
 18 ERPM-55 4/6/2006 5/4/2006 Conc.Slab 102 0 17 0.5 12 0 0.5
 19 ERPM-56 4/6/2006 4/21/2006 Incline Plug X 43 4 3 3 3.5 0 6
 20 Geld 2 2/7/2007 19/7/2007 Vertical Plug X 90 2.5 2.4 10 2.4 4.9 0
 21 Geld A 10/4/2007 17/6/2007 Vertical Plug X 55 2 2.8 4.8 3 5 0
 22 Geld B 10/4/2007 17/6/2007 Inclined Unlined X 100 2 5.3 6.3 3 0 11.6
 23 Geld C 10/4/2007 17/6/2007 Inclined Unlined X 145 2 5.3 5.5 5 0 10.8
 24 Geld D 10/4/2007 17/6/2007 Inclined Unlined X 9 2 2 2.4 2 0 4.4
 25 Geld E 10/4/2007 17/6/2007 Inclined Unlined X 287 2 9.9 5.8 5 0 15.7
 26 Geld F 10/4/2007 17/6/2007 Inclined Unlined X 34 2 3.8 3 3 0 6.8
 27 Geld G 10/4/2007 17/6/2007 Inclined Unlined X 51 2 4.5 3.8 3 0 8.3
 28 Geld H 10/4/2007 17/6/2007 Inclined Unlined X 110 1.8 5.5 4.8 4.1 0 10.3
 29 Geld I 10/4/2007 17/6/2007 Inclined Unlined X 4 1 1.5 1.5 1.5 0 3
 30 Geldenhuys 6/26/2006 23-Jul-06 Vertical Plug X 56 5.1 8.75 2 3.2 7.1 0
 31 Gos Inc. 16/4/2007 25/6/2007 Inclined Lined X 27 2.5 3 3 3 0 6
 32 Gos Inc. 1 16/4/2007 25/6/2007 Inclined Lined X 27 2.4 2.5 2.5 4.3 0 5
 33 Knights 5/18/2006 5/23/2006 Vertical Plug X 36 4 4.4 1.8 4.5 5.8 0
 34 Langlaagte Main 8/15/2006 9/2/2006 Incline Plug X 18 3 3 3 2 0 6
 35 Langlaagte Main 1 8/21/2006 9/2/2006 Incline Plug X 18 3 3 3 2 0 6
 36 LL 4 20/3/207 3/4/2007 Inclined Unlined X 31 3 3.4 3 3 6 0
 37 LL2 20/3/207 3/4/2007 Inclined Unlined X 23 2 3.2 2.4 3 5 0
 38 LL2A 20/3/207 3/4/2007 Inclined Unlined X 28 1.9 2.9 2.9 3.3 5.2 0
 39 LL3 20/3/207 3/4/2007 Inclined Unlined X 8 2 2 2 2 4 0
 40 LL3 B 20/3/207 3/4/2007 Inclined Unlined X 14 3.7 1.8 2.1 3 6.7 0
 41 LL3A 20/3/207 3/4/2007 Inclined Unlined X 32 2 2.5 5 2.6 4.6 0
 42 LL5 20/3/207 3/4/2007 Inclined Unlined X 17 2 4 1.8 2.4 4.4 0
 43 LL6 20/3/207 3/4/2007 Inclined Unlined X 44 3 4 3.7 3 6 0
 44 LL7 20/3/207 3/4/2007 Inclined Unlined X 44 3 4.2 3.5 3 6 0
 45 OWS 27/7/2007 28/8/2007 Vertical Plug X 144 4 9 4 4 8 0
 46 Pencil Park 7/15/2006 9/5/2006 Vertical Plug X 42 5.8 7 2 3 7.8 0
No. Contract Ref. No.
 Start
 Date Finish Date Method Used
 Lined
 Shaft
 Unlined
 Shaft Conc. Qty m3 H1(m) L2(m) L1(m) D1(m) W1(m) H2(m) D2(m) W2(m) H1+D1 h2+d2
 47 Private 2 7/17/2006 9/5/2006 Vertical Plug X 65 6 8.1 2 4 8 0
 48 Pvt 2 A 20/3/207 3/4/2007 Inclined Unlined X 11 2 3 1.9 2 4 0
 49 R50 5/24/2006 6/7/2006 Incline Plug X 18 4.1 2 2.4 1.8 0 2.4
 50 R51 5/24/2006 6/7/2006 Incline Plug X 18 4.1 2 2.4 1.8 0 2.4
 51 R55 / R55A 5/24/2006 6/7/2006 Incline Plug X 18 4.1 2 2.4 1.8 0 2.4
 52 R58 6/7/2006 5/25/2006 Incline Plug X 24 4 2 3 2 0 5
 53 R58 A 5/28/2006 6/28/2006 Incline Plug X 24 4 2 3 2 0 5
 54 R59 6/7/2006 7/10/2006 Incline Plug X 24 4 2 3 2 0 5
 55 R59A 7/17/2006 7/20/2006 Incline Plug X 18 4.5 2 2 2 0 4
 56 R62 7/3/2006 7/25/2006 Incline Plug X 42 3.5 3 3 4 0 6
 57 R62E 7/3/2006 7/26/2006 Incline Plug X 24 4 3 3 2 0 6
 58 R62W 7/3/2006 7/26/2006 Incline Plug X 24 4 3 3 2 0 6
 59 RO 1 19/2/2007 9/3/2007 Vertical Plug X 30 2 3.6 1.6 5.2 7.2 0
 60 RO 2 19/2/2007 9/3/2007 Vertical Plug X 16 1.8 1.8 2.8 3.2 5 0
 61 RO 3 19/2/2007 9/3/2007 Vertical Plug X 78 2 8 3 3.1 5.1 0
 62 RO 4 19/2/2007 9/3/2007 Vertical Plug X 24 2 2 5 2.4 4.4 0
 63 RO 5 19/2/2007 9/3/2007 Inclined Unlined X 63 2.6 8 3.1 66.1 0
 64 RO 5 A 19/2/2007 9/3/2007 Inclined Unlined X 12 2 2.5 2 4.8 6.8 0
 65 RO 5 B 19/2/2007 9/3/2007 Inclined Unlined X 19 2 3.3 2.4 2.4 4.4 0
 66 RO 5 C 19/2/2007 9/3/2007 Inclined Unlined X 36 2 3 4 3 5 0
 67 RO 5 D 19/2/2007 9/3/2007 Inclined Unlined X 169 3 6 9.4 3 6 0
 68 RO 5 E 19/2/2007 9/3/2007 Inclined Unlined X 86 3 5.4 4 4 7 0
 69 Roode 6 12/3/2007 3/4/2007 Inclined Unlined X 58.5 2.7 5 3.9 3 0 8.9
 70 Roode 6 A 23/7/2007 21/8/2007 Unlined Incline X 46 1.6 3.4 3.5 4 0 6.9
 71 Rose Deep 2 5/29/2006 6/10/2006 Vertical Plug X 30 4 4.4 1.8 3.8 5.8 0
 72 SJ 11 10/4/2007 17/5/2007 Inclined Lined X 20 1.8 5 2 2 0 7
 73 SJ 15 B 25/6/2007 25/7/2007 Vertical Plug X 9 1.5 3 1.4 2.1 3.6 0
 74 SJ 8 10/4/2007 17/5/2007 Vertical Plug X 20 2 4.9 2 2 4 0
 75 SJ-15 5/4/2006 6/24/2006 Incline Plug X 108 2 10.2 32 3.5 3 2 35.5
 76 SJ-15A 4/6/2006 4/16/2006 Incline Plug X 36 2 33 4 4 0 37
 77 SJ-16 5/4/2006 6/24/2006 Incline Plug X 42 0 0
 78 SJ-18 7/12/2006 8/23/2006 Vertical Plug X 68 3.5 9.7 3.5 2 7 0
 79 WEST 4/6/2006 5/4/2006 Vert .Plug X 51 5.5 6 1.8 4.7 7.3 0
 80 WEST INCL 4/6/2006 5/4/2006 Incline Plug X 53 6.4 5.5 2 4.1 0 7.5
 0 0
 0 0
 0 0