 In 2000 it was estimated that 3,500 tailings impoundments existed, and that every year, 2 to 5 major failures and 35 minor failures occurred; for example, in the Marcopper mining disaster at least 2 million tons of tailings were released into a local river.In 2015, Barrick Gold spilled over 1 million liters of cyanide into a total of five rivers in Argentina near their Veladero mine.In central Finland, Talvivaara Terrafame polymetal mine waste effluent since 2008 and numerous leaks of saline mine water has resulted in ecological collapse of nearby lake.