Abstract: The Luikonlahti Copper mine is located near the town of Kaavi in eastern Finland, approximately 30 km northwest of Outokumpu. The copper sulphide ore deposit formed the northern most part of the Outokumpu assemblage. During 15 years of operation, between 1968 and 1983, a total of 33 km of underground tunnels and 5.5 km of underground shafts were excavated in the mining of 6.85 million metric tons of ore. The underground working are now flooded with 2 million m(3) of contaminated water and three open pits contain over 1 million m(3) of contaminated water. Five separate waste rock piles exist and are actively forming acid mine drainage (AMD).