Collection and Processing of Geotechnical Data as Part of a Stoping Panel Span Optimization Study at an Eastern Bushveld Complex Platinum Mine

A study for the optimization of mining layouts required the collection of a large volume of geotechnical data, from a wide area, for parts of the analysis. Geotechnical data was collected to verify the rock mass conditions and provide input parameters for the probabilistic numerical modelling analysis. This paper details the methodology used for underground mapping, data collation, verification, categorization, and analysis. The process produced a number of learning points and several shortcomings were identified. Scanline mapping was performed at 29 sites across two shafts. The strategy was to collect mapping data from as many areas and depth ranges as possible. This would allow for comparison across all areas, to establish whether the geotechnical environment was similar, or if different domains existed. This mapping process produced a large data-set, the management and interpretation of which created some unique challenges. The data generated from the mapping exercise was processed and analysed using an iterative approach, eventually producing valuable information detailing the joint set orientations and characteristics, as well as the likely key block shapes and sizes for the mine. The information allowed the project team to better define the geotechnical environment using improved data and facts, validating the current knowledge base. Joint set orientations were better defined and comparisons could be made across the shafts, providing a clearer understanding not only for the study but for future mining, support methodologies and rock mass behaviours.