THE REHABILITATION OF ACID MINE EFFLUENTS AND TOXIC HEAVY METAL POLLUTION, EMANATING FROM GOLD MINES IN SOUTH AFRICA

摘要

Pollution emanating via water sources from gold mines, within a very short period, becameuncontrollable. At the end of their period of ore production, South African gold mines have to getfinal permission for closure, which has been previously granted virtually automatically. The resultis that pollution, including uranium pollution at unacceptable levels, is rife in the streams and damsthat have an origin in the areas where the gold reefs were mined. The treatment of the residualchemicals in the acid mine effluent (AME), released into nature to become potentially hazardouspollutants of all water supplies that are in contact with them, is discussed in this paper.The method of pollution control proposed here is not only a corrective measure, but also one aimedat producing recoverable concentrations of potentially valuable heavy metals, based on the principlesthat the main source of pollution is the slimes dams of the gold mines and that spillage and rain waterrun-off therefore becomes the first priority; that the metals in solution must be removed from theAME in a controlled manner; that the pollutants must be entrapped and taken out of the transportcycle and must eventually be recoverable in a manner that will be economically beneficial; that asimple and cheap corrective system can be developed, using minerals that are presently availablewithin economically transportable distances from the mines; and that the metals so extracted maypay for the clean-up of the system.It is proposed that, using the principle of adsorbing toxic minerals onto clay, a new method isfound for the concentration of the remnant uranium, and possibly other potentially valuable metals,including gold, that are present in the slimes. Thus the rehabilitation of all AME and toxic heavymetal pollution is possible and it can effectively be done using only two mineral substances, ie lime(CaO) and bentonite clay.