Research done in South Africa shows that change in the global climate is affecting the way local mines need to plan and build their infrastructure, particularly when it comes to water management.
Studies by Lumsden and Schulze show climate change is going to make the eastern parts of SA significantly wetter, and western regions drier. In the eastern areas of the country, this means mines will experience a disproportionate increase in the amount of water that spills into the environment, while mines in the western parts will need to manage their water resources with greater care.
Managing the on-mine water balance in drier areas is going to call for better re-use strategies, including continued improvement in the design and implementation of ways to keep water within the mine boundary, and to limit the amount of clean water that mines procure from municipal or other sources. Rustenburg Platinum Mines have already taken steps to reduce the amount of water abstracted from the potable water system. Initially, their allocation of water was greater than 50Ml/d but, after implementing water saving strategies, the actual potable water abstraction was reduced by 30%. Additional water saving strategies will reduce the potable water use by a further 20%. Not only is this reuse of water allowing the mine to expand operations, it is also allowing additional growth in the Rustenburg area.
In areas where more rain is predicted, mines face the prospect of breaking the law if their infrastructure cannot limit mine spillage into the environment. Facilities in these areas must be designed or modified to comply with the new parameters that climate change brings. The Amandelbult Mine has implemented stormwater controls to minimise the mixing of clean and dirty water so that even under significantly higher flows, the risk of flooding will be minimised. With flood hydraulics, doubling of the flow does not double the size of the canal; the addition can easily be managed with a bund about 500mm as the Amandelbult area has proved, i.e. it is not necessary to double channel size; new flood flow can often be met with nominal increase in height of containment wall.
Using the Lumsden and Schulze research, SRK scientists Phillip Hull and Hediya Ghassai predicted that a 40% increase in rainfall could more than double the amount of contaminated water a mine spills into the environment. As an example of this, a return water dam in the Eastern Limb area of South Africa must be built 30% larger than needed under present climatic conditions. Mines are starting to include climate change in their design but need always to keep in mind the implications of climate change for their site infrastructure.
