PILOT SCALE DEVELOPMENT OF INTEGRATED PASSIVE WATER TREATMENT SYSTEMS FOR MINE EFFLUENT STREAMS
The South African mining industry is facing major problems with regard to the management and treatment of contaminated mine water. These problems exist with regard to operational mines and, importantly, they also exist for mines which have ceased operations and which have long term water quality problems.
Currently available effluent treatment technology for dealing with water quality problems is primarily of a chemical or physical nature. Although this technology is generally effective, it typically has very high capital and operating costs and intensive, ongoing, long-term maintenance requirements. This is a particular problem for those mines that have ceased operations and where it is not practical or cost-effective to construct an active treatment plant that requires constant supervision and maintenance.
An urgent need was, therefore, identified to develop low cost, self-sustaining, low maintenance passive treatment systems to address the problems of acidification and salinisation (in terms of sulphate) at operating, defunct and closed mines in South Africa. A research project was, therefore, commissioned by the WRC to address the following objectives:
Objective 1: The development of preliminary management guidelines which can be used by the gold and coal mining industries to select, design, operate and maintain the most appropriate integrated passive treatment systems, for various effluent streams, during the operational and closure phases of mining projects.
Objective 2: The identification, through pilot studies, of appropriate sulphate and acidity removal passive treatment systems and designs, either singly or in combination. which should be evaluated at field scale on actual mine effluents.
Objective 3: Evaluate the structure and function (in terms of sulphate and carbon cycles) of constructed pilot scale passive systems.
Objective 4: Investigate, evaluate, quantify, and where possible, model the physical, chemical, geochemical and biological mechanisms which operate within the selected passive systems.
Objective 5: Investigate and develop management strategies whereby the development of passive treatment systems can be integrated into the ongoing environmental management programme of the mine, such that mine closure can be granted at the end of the mine's productive life.