Upscaling our effort to minimise nitrate contamination

Water is undeniably one of our most valuable resources on earth. Remediating water contaminated with nitrates at our Letšeng mine is, therefore, a top priority and forms part of our water management strategy.

Bioremediation uses naturally occurring organisms to break down pollutants such as nitrates into less toxic substances. It thus creates less waste than more expensive methods such as reverse osmosis, and has also proven to be less labour intensive and more cost effective.

Our bioremediation pilot project, initiated in 2015, has proven to be effectual in the treatment of nitrates. Large-scale application of the project is currently being explored to ascertain its viability in treating all contaminated water leaving the mine site. We expect the study to be finalised in the first quarter of 2019, and next steps will be determined based on these findings.

As part of our nitrate management strategy, we continued to conduct leach tests during 2018. These tests involve collecting bulk rock samples at intervals across the blasting process. These are then analysed to get a better understanding of the leaching characteristics of the nitrates contained in the samples. We have found the tests invaluable in generating models that inform our interventions to reduce nitrate pollution from blasting.

Interior of the bioremediation plant at Letšeng.