Assessing geo-environmental risk using intact materials for early life-of-mine planning - a review of established techniques and emerging tools

As the importance of geo-environmental characterisation is increasingly recognised by mine operators at various life-of-mine stages, evaluating the application of analytical techniques and how they can be integrated into deposit-scale mineralogical domaining is vital. To enable a large throughput, hyperspectral mineral analysers are an effi cient tool to determine the neutralising characteristics of a deposit. However, microscaled textural evaluations (<0.5 mm) are not possible and the spectral inactivity of sulfi de minerals (eg pyrite, chalcopyrite) in the short wave infrared (SWIR) and thermal infrared (TIR) regions creates limitations. Therefore, integration of micro X-ray fluorescence (XRF), laser induced breakdown spectroscopy or laser Raman analysers have potential to improve sulfide identification but require technological optimisation (eg laser power, repetition rate, sensor sizes and detection speeds) before being capable of rapid analysis of drill core materials for geo-environmental domaining applications. Advanced tools such as laser ablation inductively coupled plasma mass spectrometry (ICP-MS) provide lower detection limits, enabling metal leaching forecasts from future wastes, and currently are used to analyse well-prepared representative samples in laboratory environments. However, the authors’ ongoing research is examining how this technology can be modified to also analyse drill core materials. While the individual use of these technologies has been explored, integration of data sets using algorithms must be pursued to allow for user-friendly, integrated geo-environmental modelling. To support best practice waste characterisation well into the future, new analytical tools should be considered. For example, microcomputed tomography has the ability to improve kinetic testing through in situ temporal 3D characterisation, while prompt gamma neutron activation analysis could be used to screen waste materials during operations, enhancing the practice of waste control. Integrated use of all these tools will allow for early forecasting of the geo-environmental properties of future waste materials, creating the opportunity for transforming how waste materials are characterised and ultimately managed.