• TECHNOLOGY
While pre-feasibility work includes desk studies and site walkovers , the feasibility stage could require a more comprehensive desk study , limited intrusive investigations such as test pitting and drilling . Design level investigations would typically need geophysics work , borehole drilling and laboratory testing , while the detailed design stage calls for additional in-situ testing and even large-scale trials ( if required ), in addition to further pitting , drilling and laboratory testing . Monitoring , testing and inspection of open excavations are among the tasks conducted during construction stage .
By utilising 3D geological ground modelling techniques , comprehensive and detailed representations of the subsurface can be created . This enables a more thorough understanding of the geological features , structural complexities and soil properties of a given site . Such precise characterisation is essential for assessing the stability and integrity of TSFs , thereby aiding in the identification and mitigation of potential risks .
Furthermore , 3D geological ground models offer enhanced visualisation capabilities , facilitating effective communication among stakeholders involved in TSF management and decisionmaking processes . By presenting geotechnical data and site conditions in a clear and intuitive manner , 3D models enable improved comprehension , collaboration and informed decisionmaking , ultimately contributing to enhanced safety and risk management in the design , operation and monitoring of TSFs .
Using the example of a recent TSF project on a South African platinum mine , Booyens highlighted the critical importance of as-built drawings and surveys in elements such as the foundation footprint preparation and the starter wall foundation excavations . Logging and inspections along open excavations was also critical , as a larger exposure of the underlying material provides invaluable additional insight into the site conditions .
“ I would recommend working on a 3D model prior to the construction of the TSF ,” he said . “ This helps design engineers to understand not only the underlying ground conditions , but also informs them on the larger scale geomorphological setting of the site .”
He said that working with the data in a 3D model has another valuable benefit . By allowing the engineering geologist to work effectively with all available data , they are better able to identify any gaps - these gaps then guide the planning of future investigations , which can focus on the identified areas of interest .
Booyens ’ presentation was titled ‘ 3D Geological ground modelling : Practical examples of tailings storage facility footprint investigations ’ and was delivered as part of SAIEG ’ s seminar series on Engineering Geology in Practice . •
3D models enable improved comprehension , collaboration and informed decision-making , ultimately contributing to enhanced safety .
20 • African Mining • October 2023 www . africanmining . co . za