b'FeatureMore than oreFigure 3.Example of application of geophysical analysis to water stewardship and mine-planning decisions (N. Tabain, personal communication). are particles that come from supernovae. They strike the EarthSimilarly, water stewardship is critical to what we do, we cannot as cosmic rays that are uniform in space and time. Their lifetimeoperate without water but water can itself be a scarce resource. is several microseconds, which is exceedingly long for anWe have a responsibility to effectively manage the ways in unstable particle. They lose energy by ionising the medium theywhich we interact with water resources to avoid and minimise are travelling through at a rate proportional to its density. Thepotentially adverse impacts.sensors need to be placed below the zone of interest to capture them. As muons irradiate the earth from all angles, they can beThe analysis shown in Figure 3 was undertaken as part of inverted to give a 3D representation of a volume of earth above.a study to better understand the connectivity between a By placing sensors in tunnels below our zone of interest at Cliffssensitive environmental ecosystem in a large gorge which is mine in Nickel West, we were able to highlight known areas ofreliant upon the regional groundwater system with proximal massive sulphides and further highlight a previously unknowncurrent and potential future mining dewatering activities. anomaly strongly indicative of massive sulphide. Its safe to sayThis work informs relative detrital cover thickness and the idea of characterising our deposits using cosmic rays alwaysunderlying alternating shale and Banded Iron Formation creates some excitement! rich stratigraphic units, both of which are crucial to informing the hydrogeological conceptual model. Resistive blocks 67 ms/m are set to transparent. The detrital are Ensuring a positive legacy characterised by the thin surface conductor underneath which lies the major shale-rick stratigraphic units that show Safety of people operating in our mines and the safety andup well on this electromagnetic survey. The map of indicative integrity of our legacy assets, the environment and hostcover thickness generated from the model shows three communities are of utmost importance to ensuring that welarge hot spots where the shales intersect the gorge and leave a positive legacy. there is a high likelihood that erosion has occurred. Utilising Rock mass characterisation for structure, mechanical andgeophysics in this way allows for low heritage, environmental hydrogeological properties are critical to ensuring safeand safety impacts by minimising drilling, whilst rapidly geotechnical design. My first visit to a mine underground withdelivering valuable information to be incorporated into our geotechnical experts was a transformative experiencefuture mine planning recommendations.for me. As we stood in the mine, my colleague pointed out toFinally, in our legacy assets, waste and tailings have a me some of the sounds of rock settling, saying, did you hearperpetual life. Leveraging geophysics effectively allows us to that? Thats your micro-seismic. Despite having spent morecharacterise the host rocks and local hydrogeology to ensure than two decades immersed in seismic research I had neverthat we site these deposits to avoid future issues. Existing thought of it in such immediate terms. It was then that I gotdeposits often have partially unknown composition and hence a profound sense of how the work that we do can directlypoor understanding of the potential for acid mine drainage impact the decisions we make that protect people in our(AMD), which has implication for closure design. Front end mines. It was both a humbling and motivating experience.loading geophysics gives us the opportunity to build the Front loading our geoscience knowledge as early as possibleknowledge we need, ultimately with the intent of building informs the mine design decisions that ultimately keep usa true digital twin to predict and monitor the stability and safe. This same knowledge has implications beyond safety.drainage from these man-made sedimentary deposits. At Our understanding of the structure and stability of our pitBHP we have a number of research collaborations underway walls informs the trade-off on pit wall angle between safety,incorporating geophysical analysis to remotely characterise the footprint of the mine and recoverable tonnes. One or twoour legacy landforms to provide data for closure planning. In degrees of pit wall angle in super-deep open pits translatesthe example shown in Figure 4, in Australia we are partnering to enormous quantities of additional waste being removedwith the University of Queensland, Gap Geophysics, the for the same recovery. If we can improve our knowledge andUniversity of Waterloo, the French National Centre for Scientific safely adjust those walls, we can avoid creating waste in theResearch and the Australian Research Council to investigate first place. We can design to avoid rather than just mitigatethe use of a range of geophysical techniques, including some of the impacts of our mining activities. Electrical Resistivity Tomography (ERT), Spectral Induced 57 PREVIEW APRIL 2023'