Chemical and mineralogical changes of waste and tailings from the Murgul Cu deposit (Artvin, NE Turkey): implications for occurrence of acid mine drainage.

摘要: Being one of the largest copper-producing resources in Turkey, Murgul deposit has been a source environmental pollution for very long time. Operated through four open pits with an annual production about 3 million tons ore at average grade 0.5% Cu, to date produced enormous pile waste (exceeding 100 tons) tailings composed 36 % SiO2, 39% Fe2O3 and 32% S, mainly form pyrite quartz. Waters vicinity vary from high acid-acid (2.71-3.85) high-extremely metal rich (34.48-348.12 mg/l total) near neutral (6.51-7.83) low (14.39-973.52 μg/l downstream environments. Despite contents pH levels latter, their suspended particle loads are extremely quartz clay minerals highly elevated Fe (3.5 24.5% Fe2O3; 11% on average) S (0.5 20.6% S; 7% average), showing that is lesser hematite. They also contain concentrations As, Au, Ba, Pb, Zn. collected along course polluted drainages supersaturated respect phases such as goethite, hematite, maghemite, magnetite, schwertmannite ferrihydrite. Secondary Fe-sulphates only found pits, but not streams due conditions, where pebbles covered cemented by Fe-oxides hydroxides indicating oxidation taken place especially times water load. It follows, then, pyrite-rich sediment load fed currently big threat aquatic life environment will continue be so even after closure deposit. In fact, enhanced acidity increased natural which necessitates strong remedial actions taken.