The strategic and tactical value of a 3D geotechnical model for mining optimization, Anglo Platinum, Sandsloot open pit

Geology and the detailed understanding of its properties are fundamental to the optimal design and successful operation of any mine. To that end, extensive fieldwork was conducted at Sandsloot open pit (PPRust— Anglo Platinum) to collect geotechnical information both from exploration boreholes and in-pit mining faces. Over a fie-year period, geotechnical data were collected from 29, 213 m of exploration core and 6 873 m of exposed mining faces. Extensive field and laboratory testing was undertaken in order to define the complete set of geotechnical properties for each rock type in the Sandsloot mining area. The geotechnical information collected was stored in the Datamine mining software package. The architecture of the database was developed along the principles used for generating an ore reserve model. The geotechnical data, namely mining rock mass rating system (MRMR), uniaxial compressive strength (UCS), fracture frequency per metre (FF/m) and rock quality designation (RQD), was modelled using geostatistics to generate a 3D geotechnical model. Data was interpolated between exploration boreholes and exposed mining faces. The modelling was constrained, using wireframes, by rock type and major structural features. The result is a block model containing 15 m3 blocks of interpolated geotechnical information. The size of the model blocks are linked to the mining bench height of 15 m. By having detailed geotechnical information available in a 3D model, which can be readily accessed and interpreted, significant production optimizations, feasibility studies and planning initiatives can be implemented. From a slope design perspective, the model is used to target data deficient zones and highlight potentially weak rock mass areas. As this can be viewed in 3D, the open pit slopes can then be designed to The strategic and tactical value of a 3D geotechnical model for mining optimization, Anglo Platinum, Sandsloot open pit