Controls of high-grade mineralisation in atlantic 1 mining licence, offshore Namibia
No Thumbnail Available
Date
2018
Authors
Amutenya, Elina M
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The placer deposit of the west coast of southern Africa is the world’s largest secondary diamond deposit. Geophysical, sampling and mining production data collected and analysed within Atlantic 1 has revealed that mineralisation across Atlantic 1 is not homogeneously distributed and not all of the licence area is equally prospective. Therefore, for the purpose of economic sustainability of the mine, it is important that areas of high-grade diamond mineralisation are identified and the geological and structural controls on the diamond concentration and distribution are well understood. The geological and geophysical data were analysed through GIS (ArcMap) to visualise the sea floor, delineate and interpret the features, patterns and trends that are associated with high-grade mineralisation. The analysis of geographical and geophysical data of the Atlantic 1 marine deposits has revealed that there are specific localities where marine diamonds are best concentrated resulting in high-grade diamond mineralisation. Such localities are associated with the nature of the surface terrain and favourable depositional environments, which are of great significance to the prospecting for, and the mining of diamonds. High-grade diamond mineralisation is best concentrated in the depressions, gullies, gravel beach berms, potholes, scarp slopes and near the outcrops and platforms where turbulence is fixed and where gravel accumulations are stable enough to retain high-grade diamonds. The highest grades in the Atlantic 1 mining licence are located in Region V, within the Pre-proto gravel suites. The Pre-proto gravel suites forms part of a large platform feature that extends through Regions O and V, characterised by north-south striking paleo-placer lineaments. The Pre-proto gravel deposit in Regions O, V and inshore of W is characterised by an irregular surface terrain, and the highest grades are located in the depressions or against the platform within the Pre-proto gravel suites.
Description
A RESEARCH THESIS SUBMITTED TO THE FACULTY OF SCIENCE, UNIVERSITY OF THE WITWATERSRAND, IN FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTERS IN ECONOMIC GEOLOGY.
05 September 2018