Abstract
The Molongo River was polluted by gold, lead, zinc and copper mines between 1938 and 1962. Acid mine water and finely divided tailings included high concentrations of base metals. Stabilization and rehabilitation of mine workings and waste deposits was initiated in 1974. River water quality was unsuitable for rainbow trout survival both before and after closure of the mine. Present concentrations of zinc and copper in water downstream from mine site are 50-60 times higher than found in water upstream from the mine. Caged trout can survive upstream of the mine but not downstream. The extensive rehabilitation of the abandoned mine workings has been ineffective. (McFarlane-PTT)