Rather, mines need to plan their water management strategies thoroughly, taking account of the region's variable rainfall and long dry spells. "South Africa needs the electricity that can be generated by the Waterberg's coal, and mining will provide many much-needed jobs in the province," said Shepherd. "But we cannot afford more coal-related environmental problems like we've had in the Emalahleni (Witbank) coalfields - where we have pollution from the coalfields entering the river systems either directly (via discharge points) or indirectly (via seepage)."
He said the natural run-off in the region would not sustain the water needs of the many mines that are likely to be developed, so water will have to be piped in - either as treated sewage or from other river basins.
Apart from the challenges of constrained water supply, the environmental impact of spillage is also likely to be greater in the Waterberg because of the semi-arid environment - with less flowing water to dilute water-borne pollution. This could have devastating effects for tourism, agriculture and the communities close to mines.
"We've only got one shot at this," said Shepherd. "If we get it wrong in the Waterberg, the impact will be far worse than it has been around Emalahleni, where a lot of the pollution has actually been diluted by the permanently flowing rivers there."
He said that the mining industry has only in the last decade or so started treating water on-site as a matter of course, having accepted that this is a necessary part of conserving water and protecting the environment.
"The mining companies that set up in the Waterberg area will need to incorporate treatment works right from the start because - despite the drier climate - there is still going to be groundwater ingress into open pits, so water will need to be discharged from time to time," he said.
Variability in rainfall means that there is also likely to be excess water from run-off on mine properties. Recent rainwater levels at a mine in Limpopo reached 400mm in a single month, said Shepherd.
"It does not matter how good your facilities are - unusually high rainfall will result in excess water that the mine can't store and use," he said. "Some of it has to be discharged, so a treatment facility is vital to ensure that discharged water does not contaminate the surrounding areas."
Accordingly, treatment facilities need to be part of the initial design, and built into start-up costs. Shepherd said it could be disastrous if a new operation did not fully understand and incorporate water treatment costs in its financial model, only to discover too late that water has become an additional cost that the project cannot afford.
He estimated that mines need a minimum of about 250 litres per tonne of mined material. "You might get away with less, but generally you need these levels or the mine is simply not viable and cannot be built," he said.
Shepherd is convinced that co-operation between mines is the key to environmentally-friendly mining in the Waterberg. "The Limpopo River is particularly vulnerable to the impact of coal mining, and the only way to avoid it becoming polluted is for mines to work together," he said. "There is going to have to be some kind of corridor, away from the Limpopo River, that is protected by all mining players working in a concerted way. The mines may have to get together into some type of forum to protect the environment in this highly sensitive river basin."
The idea of a forum has often been employed in dealing with water supply issues, but he acknowledged that the liability attached to environmental damage does make the use of forums more complex.
"If there is a spill from a particular mine, then there is a chance that the forum might get blamed, making the non-offending members of the forum feel they are being held responsible for something they did not do," said Shepherd. "But these risks need to be worked through, and should not become an excuse to dismiss the need for collaboration."
The basin extends across South Africa's borders into Botswana and Zimbabwe, where mining also takes place; so the co-operation is also required at an international level, he argued. "The Limpopo River is a vital supply for a number of countries, and it will be impossible to protect this life-giving resource without collective effort," he said.
Technology is already playing its role in helping conserve water at mining operations, and needs to be further applied. Evaporation from waste water facilities, for instance, can be reduced by filtering slurry to extract as much water as possible for use elsewhere on site. Using a combination of gravity and mechanical pressure, filter systems are widely used in mining applications in dry climates - some even producing 'dry' tailings.
He said water was also lost through seepage, a problem that can be solved by lining tailings dams and maximising seepage collection facilities. Mines use liners beneath tailings dams, water reservoirs, waste rock dumps, or wherever required to limit the loss of water and potential contamination of groundwater resources.
He highlighted opportunities to treat water to a quality that can be used in the various operational elements within a mine; this cuts down the amount of potable water that has to be used in plant and mining processes, substituting it for water of a lower quality. Dust suppression, for instance, is important to control air quality, but can be wasteful of water if the appropriate quality is not used; in extreme cases, he said, the extra cost of coating or surfacing a road would have to be considered if water availability was critical.
"If a mine only treats water at a stage where the water cannot be used elsewhere in the circuit, then they can conserve water substantially and reduce costs," said Shepherd. "There are a number of technologies that can reuse dirty water more often than presently used in, say, the cooling facilities."
He said that SA has, on the whole, done quite well at addressing water shortages around the country. "But what we are not so good at is preventing pollution - which sterilises a lot of water, reducing what is available nationally, and forcing us to look elsewhere to meet our growing needs," he said.
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