Mount Isa Mines Limited (Xstrata Plc) operates two separate mining and processing streams, copper and zinc-lead-silver, at Mount Isa. Together the company's 4 underground mines form one of the largest underground mining operations in the world.
Xstrata's Mount Isa copper operations consist of 2 underground mines, X41 and Enterprise and a concentrator producing 600,000 t/y copper concentrate and smelter producing 240,000 t/y copper anode. The zinc-lead-silver operations consist of the George Fisher (formerly Hilton North) and Hilton underground mines and the newly developed Black Star open pit mine. Together these mines produce 192,000 t/y zinc concentrate and 140,000 t/y lead and 11 Moz/y silver in lead/silver bullion.
Discovered in 1923 with one of the world's largest underground mining complexes, production commencing in 1931, Mount Isa is Australia's and one of the world's largest underground mining complexes. Even though the existence of copper ore in quantity was confirmed in the 1930's, it was not mined until a wartime scarcity of copper brought a request from the Australian Government. In 1943, the mine ceased silver-lead-zinc production and switched to copper to help the war effort. In 1946, copper mining stopped, and the mine reverted to silver-lead-zinc. Parallel production of silver-lead-zinc and copper ores commenced in 1953 and continues to this day.
With the recent development of the Black Star open cut, Mount Isa has reserves to support a mine life of approximately 11 years. The George Fisher/Hilton mine has reserves to support a mine life of approximately 15 years.
Xstrata employs about 3400 staff and contractors at Mount Isa.