Induced Polarisation Effect Associated With Acidic Groundwater In Witwatersrand Gold Mining Areas

Acidic mine water is generated in situ in the hanging and foot-walls of mines. In the gold mines of the Witwatersrand the oxidation of pyrite generates acid. This acid infiltrates groundwater and is and will continue to be a major environmental hazard specifically in and around the mines. Non-invasive geophysical techniques make it possible to map the extent and the flow pattern of acidic water. Induced polarisation (IP) in conjunction with direct current resistivity will be used to map the extent of acidic mine water at a bioremediation program near the Vaal River in the Northwest Province. Data will be collected where the survey can be repeated in order to monitor the time dependence of the phenomenon. Ways of separating the environmentally-associated IP signal from electromagnetic coupling and cultural noise will also be investigated.