- Water is a crucial resource for miners – it is required from dampening dust, cooling machinery, crushing ore, and tailings
- Associate Professor Claire Côte, director of the Centre for Water in the Minerals Industry at the University of Queensland discusses the impact of drough on mining operations
What is the importance of water in the mining industry?I think there is a level of misunderstanding in the general public about the context of water in mining. It’s not an industry that is only concerned with turning on a tap to obtain water, it has to manage a range of water-related risks, from ensuring supply to managing its environmental obligations. Some demands rely on the import of high quality water (similar to tap water), others on poor quality water collected when it rains. Water management is about meeting demands, and quite often this includes using water that is poorer quality than tap water. Water management is much more complex in this sector and because of that, it uses different measurement, analysis and tools. You also have to realise there are differences between geographies and commodities. Looking at the copper industry in Chile, they have tried really hard to reduce the water content of their wet tailings but have now reached a plateau where incremental improvements are becoming more and more difficult to achieve, mainly because of local geological constraints. As such, this is an industry that still relies on large volumes of water supplied by external sources, generally of very high quality. By comparison, the coal industry in Australia does not rely much on the import of high quality water: only longwall underground mines still need it and even then, the volumes are quite low.
So what is the situation like in Australia?In Australia, we have extensive water planning processes that establish how much water is available in all parts of the catchment. When a mine requires high quality water, it seeks a contract for a yearly allocation in accordance with the local water resource plan. The exact process varies depending on the state, but how much they have access to will be dictated by the government’s resource planning process. Mining, typically, is a drop in the ocean compared to agriculture, which gets about 90% of available water. The water that the mines do have access to, however, is often from high security allocations, and these are usually the last to be impacted in cases of drought. The Australian system works well provided there’s no political interference – but that’s a big ‘if’. When we see the politicians getting involved – like we have in the Murray-Darling Basin – putting pressure on scientists to modify components of a water resource plan for the benefits of agriculture, at the expense of environmental needs, then this leads to a disaster. It is paramount that the scientific method be respected. Most mines have developed a detailed water balance model. If a mine is at risk of drought, it would be captured by the water balance assessment and the mine would have put in place mitigation strategies. If mines have done their forecasting correctly, they should not be impacted. One issue that tends to happen with mining is that there is still a culture of not allocating resources to manage long term risks. It is a very short-term focused industry. The response to water scarcity is less about new technology being identified and deployed, and more about planning properly.
Would you be surprised to see operations closing due to water scarcity?Yes. But if they close, there could be several reasons: the historical climate data that was used in water balance assessment was not adequate, the forecasting and planning exercise was not done at all or, and in my view this is the most likely explanation, all the technical work was done adequately but they haven’t been able to secure the resources to implement a mitigation plan. With water (and environment in general), you must make the decision for the long term based on years of data. You can’t decide today you need to do something about water scarcity and have it come into effect in a month, it doesn’t work that way. For example, it takes a minimum of 18 months to install a desalination plant on a mine site. You would need to make the decision two to three years before the problem arises. The issue with the industry is they struggle with decisions for the long term. It’s driven by the market, it’s driven by commodity prices, and they fail to apply long term thinking.
Are things already changing in terms of planning and structure due to climate change?CC: It needs to ramp up. They are aware of it, they talk about it, but it’s about securing funds to actually do the work and there is still a struggle at this level. There’s a lot of discussion on closure planning as well, so when they think climate change they also tend to think post-closure. What does the mine look like after closure in the context of climate change? What do i have to do to adapt to what is predicted?
How do you think people should be responding to the issue of water scarcity?Three things: respect the water resource planning process, change the way you do business case analysis to include long term data sets and the potential cost of shut down, and thirdly; review tailings management in detail as this is where most of the water ends up. The more you dewater tailings, the less water you will require. The important thing for me is to maintain the integrity of the water resource planning processes, and to make sure these processes are not subjected to political interference. What we’ve seen in the Murray Darling Basin, I never want to see it anywhere else. Water resource planning is critical to mining, to everybody. Let the technical people do their work and accept their conclusions. If we want to make a difference to water use in mining, we need to focus on tailings. We wouldn’t have had tailings dam failures with dry tailings. Disposing of wet tailings is cheaper, until we have a dam failure. A large scale move to drier tailings would make a big difference.
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