Cradle to grave

Anglo American Coal ’ s Mafube Colliery in Mpumalanga has been selected as the first trial site to determine the long-term sustainability of using mine-impacted water in agriculture .

While irrigation with perceived poor-quality water is mainstream in arid countries like Israel , the South African mindset , understandably , has been one of caution . More than 30 years of research has shown , however , that mine water could well be safe for agricultural use .

The project — initiated by the Department of Water and Sanitation ( DWS ) and the Water Research Commission — has been spurred on by devastating drought conditions currently gripping several parts of the country . It also forms part of government ’ s national long-term approach to acid mine drainage . “ In a water-scarce country like ours , optimal use should be made of all available resources — mine water included ,” says Anglo American Coal South Africa water manager Ritva Muhlbauer .

The research project involves Mafube ’ s establishment of two 30-hectare trial sites — one on virgin land and the other on ground rehabilitated post-mining . Salinetolerant crops like wheat , maize , soya , and ryegrass are to be planted on a rotational basis .

The first crop — maize on virgin land — was irrigated with water from the Mafube pit and has since been harvested . The area yielded 14.5 tonnes per hectare , compared with eight tonnes per hectare from dryland crops .

If proven sustainable over the longer term , the concept could have major benefits , both for both the mining and agricultural sectors .

“ Mining activities in the Mpumalanga coalfields result in the production of large volumes of water that need to be carefully managed , both during a mine ’ s operational life and post-closure .

“ If we prove that irrigation with mine water is indeed sustainable , it would be considered a national asset rather than a liability , while increasing the profitability of farmland ,” says Muhlbauer .

Farmers would be able to plant crops year-round and not just during the rainy season . They would also be able to irrigate without abstracting water from already pressurised catchments .

Agriculture accounts for a respective 80 % and 70 % of the country ’ s total land and water use and plays a major role in job creation , particularly in rural areas .

All permissions from the Department of Mineral Resources and the DWS are in place in a unique project that sees government , the industry , and academia working together . The DWS is fully involved at both operational and governance levels to advise the team on any regulatory issues that may emerge , both within the context of the project and later with its potential nationwide roll-out . Coal miner South 32 and Anglo have covered the cost of two irrigation pivots , while Anglo American ’ s Mafube Colliery has dedicated employee resources towards the establishment of infrastructure , including the drilling of monitoring holes .

The practice is totally unique in that it would open up opportunities for rehabilitated mine land , thereby averting food shortages , particularly in times of drought , and the creation of post-mining opportunities by enabling small and large-scale commercial farming .

[ 34 ] MINING MIRROR OCTOBER 2018