Waste water in metal mining industries.

The different types of mineral industries wastes are characterized. Total tonnage in the world of finely ground wastes from i.a. flotation and leaching operations amounts to around 1 500 million tons per annum. The major environmental problems arise from slowly settling fine particles, dissolved metal ions and chemicals retained in the effluent. The paper discusses the toxic effects of dissolved metal ions in waste water as well as the effect of pH and sediments on water fauna. The comminution in mineral processing operations yields the surface of the waste mineral products a high reactivity. Therefore mineral wastes have a high adsorptive power for dissolved contaminations, i.a. metal ions and organic substances. This has a very positive effect on the water environment. The layout and operation of settling ponds as well as the use of flocculation agents are discussed. Legal and environmental aspects of metal mining wastes are considered.