Mount Isa Copper Mine
Mount Isa Copper Mine, Queensland, Australia As well as the lead-zinc-silver facilities at Mount Isa, George Fisher and McArthur River (see separate profiles), the MIM operations acquired by Xstrata include wholly-owned copper mining, smelting and refining operations in Queensland (including the Ernest Henry mine profiled elsewhere), plus the 50%-owned Alumbrera mine in Argentina (see separate profile). Copper production at Mt Isa, Queensland, is derived from separate orebodies from those that form the basis for lead and zinc mining, with the copper operations being regarded as stand-alone operations. Since acquiring MIM, Xstrata Copper has undertaken several steps to improve performance, and is now expanding its smelter capacity at Mt Isa to 300,000t/y.
GEOLOGY AND RESERVES Brecciated siliceous and dolomitic rock masses within the Urquhart Shale (see Mount Isa lead mine profile) contain several orebodies that comprise complex veins and irregular segregations with chalcopyrite, pyrite and pyrrhotite, and grading 3% to 4% copper. Production currently comes from the 1,100 and adjacent 1,900 orebodies at the south end of the property and the deeper 3,000 and 3,500 orebodies below the lead mine in the north. As of mid-2005, Xstrata reported resource figures as:
X41 mine (1,100 and 1,900 orebodies): 35Mt proven ore grading 2.2% Cu with measured resources of 61Mt at 2.3% copper.
Enterprise mine (3,000 and 3,500 orebodies): 33Mt at 3.6% Cu proven, with measured resources of 57Mt grading 3.5% copper. The resource potentially available for open-pit mining contains 98Mt of indicated ore grading 1.4% copper.
MINING "Capacity has kept pace with the smelter at 260,000t/y, and was raised to 280,000t/y by mid-2006."Copper mining started at Mount Isa in 1953, in parallel with lead-zinc-silver production. Until the late 1980s, one mine was designed to work all the copper ores down to the base of the 1,100 orebody, with its main access through the 1,015m-deep X41 shaft. Some 2,000m further north, near the lead mine shaft, the 1,154m U62 shaft hoists ore from below the 21 Level (1,076m). Highly mechanised sub-level stoped ore is railed on 19 Level, dumping to the crushers below via ore passes.
To work some deeper 1,100 ore in the mid 1990s, another crusher was installed directly below the orebody on 23 Level and a decline conveyor connects this to the U62 skip loading station.
During the late 1980s, MIM started to develop the orebodies located between levels 21 and 36. A ramp was driven down from the U62 loading station and an ABB-Kiruna electric truck hoisting system fitted. Production started in 1993. In 1996, MIM launched the AU$370m Enterprise Mine project designed to raise deep copper output to 3.5Mt/y. The 713m-deep internal M62 shaft opened in 2000, with refrigeration and paste backfill plants completed in 2001. Meanwhile the 1100 operation became the X41 Mine. In June 2004, Xstrata approved development of the Northern 3,500 orebody to maintain rated capacity by supplying 5.3Mt ore grading 4.5% Cu over 11 years, starting in late 2006. This should enable the Enterprise mine to achieve its rated concentrator throughput of 3.5Mt/y.
ORE PROCESSING The copper concentrator was rebuilt in 1973, with rod and ball milling and three-stage flotation, to supply the roaster and conventional blister copper smelter on site. In 1981, Mount Isa commenced anode casting as well. In 1988–89, two 6.4MW AG/SAG grinding mills replaced the rod and ball mills at a cost of AU$35m. With the development of Ernest Henry, MIM modified the pre-flotation, column flotation and slag-cleaning circuits to increase the plant's throughput. The flotation capacity was increased again in FY2003 with the addition of the latest-design Jameson cells. Smelter investments have included the copper IsaSmelt plant in 1994 and an expansion in 1998–99. During 2004, Xstrata decided to add 40,000t/y of copper output by slag treatment and related developments, and also approved a 2,500t/y copper-leaching plant to treat smelter electrostatic-precipitator dust.
MIM established Copper Refineries Pty Ltd near Townsville in 1956 and started treating blister copper in 1959. Capacity has kept pace with the smelter at 260,000t/y, and was raised to 280,000t/y by mid-2006.
PRODUCTION
In 2005, Mount Isa increased the tonnage milled to 5.6Mt of ore, yielding 694,00t of concentrates containing 177,500t of copper. The smelter also took concentrate from Ernest Henry, recovering a record 220,000t of anode copper. The Townsville refinery produced 219,000t of cathode copper. The cash cost of North Queensland copper, after by-product credits, was US$0.714/lb.
Other Mining Machine Site:
Stone Crusher SBM Machine Hammer Crusher Vibrating Feeder Vibrating Screen Stone Crusher Jaw Crusher Impact Crusher Cone Crusher Grinding Mill Raymond Mill Belt Conveyor Ball Mill VSI Crusher Sand Washing Machine