LOKOMO – 100 vuotta konepaja- ja terästeollisuutta: Poimintoja yhtiön historiasta

Searching for wastewater solutions in Finnish mining industry. Lessons learned by Outokumpu Co.This article surveys experimental studies and practical trials on how Outokumpu Company tried to solve pollution problems in Outokumpu and other Finnish mines. Early on, Outokumpu copper mine had severe environmental impact. In Outokumpu municipality, Outolampi Lake below the Outokumpu mine was becoming a dirty tailings pond in the 1910s. Pollution of the ground water became a problem for local inhabitants in the 1940s. The issue was raised to the public eye in the 1950s. The most common and persistent environmental risk in the tailings disposal areas of sulphite mines was and is the acidification of waters. This is mainly due to the oxidation of iron sulphides. Tailings are pumped to the disposal areas with water. Acid water dissolves heavy metals and, when entering surface and ground waters in the surroundings polluted large areas below the Outokumpu mine. Where the tailings were in dry land, there was dusting. Hammaslahti mining area was as a laboratory in nature. Outokumpu Co. developed environmental technology and it was an important partner linking new technology to improved environmental standards. Environmental hazards caused by oxidation can be kept under control if groundwater and surface and rain waters can be prevented from entering the tailings. The tailings must be isolated from oxygen and ground water