The Asia Miner

APR-JUN 2019

The ASIA Miner - Reporting Important Issues to Mining Companies in the Asia Pacific Region

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the asia miner • volume 16 • issue 2 5 LEADING DEVELOPMENTS Closing the loop on tailings we also invesঞgate innovaঞve new methods for tailings handling, reuse and disposal." BACKFILL The first of these alternaঞve uses is the exisঞng, yet sঞll under-uঞlised pracঞce of using tailings for backfill. While both cemented paste backfills (CPB) and hydraulic fills are the two most established forms of backfill, paste backfill offers the most advantage. With substanঞal reducঞons in both the volume of tailings le[ to store and rehabilitaঞon costs, an esঞmated 60 to 80 per cent of the tailings' processed water can be recovered prior to backfilling, while the structural stability once filled offers a safer workspace for employees to conঞnue. In this way, uঞlising the mine's own tailings for backfill is not only a resource to the mine but it also reduces the need to store it in a storage facility. TAILINGS AS A RESOURCE Another producঞve means of uঞlising tailings is to create more sustainable by-products. This includes everything from commercial shotcrete and concrete products for self- sustaining uses such as mine roads, brick and ঞle manufacture, insulaঞon, or even foamed products. Tailings as a resource has further posiঞve implicaঞons for the environment – by recycling exisঞng 'waste' to manufacture products, less tailings requires storage, and, as in the case of backfill, less water is trapped within the tailings. "While de-watered tailings don't necessarily decrease the industry's footprint, they do produce a more stable product with less water uঞlisaঞon, which in arid areas is environmentally-sound pracঞce. It also means that you have more water to put back into your process," Mr Steward explains. "At Weir Minerals, the future of our work is to be able to thicken tailings sufficiently so that we can dispose of it as landforms. You can imagine the difference conঞnuous, rapid landforms will have on rehabilitaঞon – turning waste into a usable space." RE-MINING TAILINGS Finally, there is the opঞon to remine legacy tailings. This is possible through using new techniques to recover more valuable minerals, as is currently being achieved in Australia's Northern Territory gold mines. Meanwhile, remining old tailings for metals that were previously ignored or discarded, like lithium – a 21 st century golden-child in the renewable energy boom – to fund our technologically-driven world, turns 'waste' into a new treasure trove. As Job Kruyswijk explains, "if you start to look at tailings as having value, all of a sudden you are no longer a waste management facility but managing something of value and for the first ঞme, old tailings suddenly become a resource". By uঞlising tailings as a material with value, as opposed to waste, customers are able to extract 'treasure from trash', reducing the need for a whole new mine site to mine those minerals. In the face of new challenges and a changing mining landscape, the collapse of tailings dams demonstrates that safety cannot be compromised and new technology must be considered. As with any operaঞonal decisions, it is important to understand the advantages and disadvantages of the various opঞons available to determine what soluঞon works best for your unique business. Thankfully, the authoriঞes on the topic of tailings do the research for you. "With the conঞnual research and development we do in this field, a priority for us is working towards an innovaঞve way to help the industry through a safer disposal of tailings, while also reducing the impact on the environment," states Mr Abbo. 1. Assuming 18kt, 10g, with 1g/tonne gold. 2. Natural Resources Canada Green Mining Iniঞaঞve program descriptor as found at www.nrcan.gc.ca

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