In this week’s water sourcing article Dave Walker discusses how it is getting more difficult to get permits for water sourcing in some geographical areas and the increasing importance of alternative supply options.
With successive generations, the body of knowledge on water and environmental issues improves and with it the difficulty or rigour in obtaining water related permits increases commensurately. With the increasing inevitability of serious climate change impacts coming in our lifetime and the lifespan of our children and grandchildren, the stakes are high and becoming higher all the time. In some geographies, the stakes are higher than others and the difficulty in obtaining permits is higher than others. In some jurisdictions, the permit conditions remain unchanged, but industry self-regulation or CSR is or should be a driver in improving water use and re-use.
Arid environments are the obvious example of strict water use policies dues to scarcity of supply; this covers mining operations in Saharan North Africa, Middle East, South American Andes and broad swathes of Asia. A number of mining operations in the interior of Australia face challenges of water supply too. Water scarcity can be overcome to a degree by piping water in great distances, making reliance on groundwater sources, desalination of some combination of the above.
However, the less obvious examples where alternative supply sources and water management and reuses is becoming increasingly important. These include river flows reliant on distal snowmelt and vegetation cover to sustain seasonal base-flows. A good example is the combined effects of climate change and deforestation around Mount Kilimanjaro changing upper catchment characteristics affecting river baseflow. Similar effects on a grander scale are being felt along the Yellow River in China, potentially affecting millions in decades to come. In eastern Australia, competing interests of mining, vineyards and horse stud farming, which include access to water and/or impacts on water resources, make for a particularly tough climate of permitting. Prolonged drought in the western USA combined with overexploitation of groundwater resources results in the risk of aquifer collapse and the injection of poor quality water back into the groundwater system to maintain aquifer integrity. Legacy mining impacts of abandoned or defunct mines in the eastern Highveld coalfields of South Africa or the Central Wits goldfields near Johannesburg has resulted in some extensive and damaging water quality impacts and rather expensive clean-up and treatment costs for government and industry alike. It does not take much to envisage the difficulty and high cost of new or amended water permits in these environments.
SLR recently assisted a mining company in Mexico in developing concepts for a water exchange program under which local ranchers, located close to the coast, would receive sea water treated with reverse osmosis, in exchange for the mine increasing groundwater withdrawals in the mountain surrounding the groundwater basin within which the farmers are located.
The team is also currently working on over a dozen abandoned mine sites in the Yukon and Northwest Territories in Canada and in California. Senior SLR staff members are involved in the closure planning and design for these mines where a major thrust is to restore the ground and surface water quality of future beneficial uses. Some of the conventional and innovative approaches being applied and consider include in-situ treatment of waters in underground and open pit mines, ex-situ treatment and discharge of pit lake waters, reverse osmosis treatment of leachate form mine waste management units, and the collection and storage of mine waste leachate with discharge controlled to occur during high flood flows when there is minimal impact on the receiving surface water.