Browsing by Author "Marais, Timothy"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Accurate hyperspectral imaging of mineralised outcrops: An example from lithium-bearing pegmatites at Uis, Namibia
    (Elsevier Inc, 2021) Booysen, René; Nex, Paul A.M.; Lorenz, Sandra; Thiele, Samuel T.; Fuchsloch, Warrick C.; Marais, Timothy; Gloaguen, Richard
    Efficient, socially acceptable and rapid methods of exploration are required to discover new deposits and enable the green energy transition. Sustainable exploration requires a combination of innovative thinking and new technologies. Hyperspectral imaging (HSI) is a rapidly developing technology and allows for fast and systematic mineral mapping, facilitating exploration of the Earth’s surface at various scales on a variety of platforms. Newly available sensors allow data capture over a wide spectral range, and provide information about the abundance and spatial location of ore and pathfinder minerals in drill-core, hand samples and outcrops with mm to cm precision. Conversely, the complex geometries of the imaged surfaces affect the spectral quality and signal-to-noise ratio (SnR) of HSI data at these very narrow spatial samplings. Additionally, the complex mineral assemblages found in hydrothermally altered ore deposits can make interpretation of spectral results a challenge. In this contribution, we propose an innovative approach that integrates multiple sensors and scales of data acquisition to help disentangle complex mineralogy associated with lithium and tin mineralisation in the Uis pegmatite complex, Namibia. We train this method using hand samples and finally produce a three-dimensional (3D) point cloud for mapping lithium mineralisation in the open pit. We were able to identify and map lithium-bearing cookeite and montebrasite at outcrop scale. The accuracy of the approach was validated by drill-core data, XRD analysis and LIBS measurements. This approach facilitates efficient mapping of complex terrains, as well as important monitoring and optimisation of ore extraction. Our method can easily be adapted to other minerals relevant to the mining industry.
  • No Thumbnail Available
    Item
    The Uis pegmatites: morphology, mineralisation and distribution, with an emphasis on the V1 and V2 intrusions
    (2019-02) Marais, Timothy
    The Damara Orogen represents a typical Wilson Cycle initiating with extension through and culmination in a collisional environment. The geological units comprise a significant Pan‐African age succession of metasedimentary and metavolcanic lithologies with various associated granitic and granodioritic magmatic bodies. The pegmatites of the Damara belt, the trending branch of the Damara Orogen, represent the final phase of orogeny and magmatism, with mineralised pegmatites (Sn, Ta, Nb, Li, Be and W) exclusively forming in a post‐tectonic environment. The Cape Cross‐Uis pegmatite belt lies within the Northern Zone of the Damara Belt and runs northeast form Cape Cross to Uis. This belt is known to contain granitic pegmatites commonly enriched in Sn, Ta, Nb, Li and Be and contains 3 distinct pegmatite swarms, the Strathmore, Karlowa and Uis swarm. Each of the pegmatite swarms predominantly contain a pegmatite type with the Uis swarm primarily comprising Sn‐Ta‐Nb type pegmatites. The Uis swarm covers and area of approximately 650km2, AfriTin Mining owns a Mining License within this area which includes the historic Uis Tin Mine. An excess of 180 pegmatites were delineated proximal to the historic Uis mine, of these proximal pegmatites nine have been documented in detail. Additionally, ten of the existing excavations within the mine area have been mapped and described in detail.