IMPORTANCE OF GEOCHEMISTRY - THE BLACK ANGEL LEAD-ZINC MINE, GREENLAND

The Black Angel lead-zinc mine operated from 1973 to 1990 using seawater in the froth flotation mill process and submarine tailings disposal to the Affarlikassa (''A'') fjord Within 1 year from startup, elevated lead and zinc levels were found in Qaumarujuk (''Q'') fjord outside the receiving ''A'' fjord. Elevations in cadmium also were found at a later date. Extended geochemical and oceanographic studies established that the ore and the tailings contained significant oxidized lead and zinc minerals soluble in the ambient pH seawater and confirmed that seasonal under-ice destratification of the water column allowed dispersal over the sill between the ''A'' and ''Q'' fiords. A shoreline waste rock dump also contributed to the contamination. Detailed mineralogic, leaching, and oceanographic studies, which are now conventional at proposed new mines, would have produced more detailed information on which to base the decision whether submarine tailings disposal (STD) was appropriate at this particular site.