Zinc, copper, silver, indium, sulphuric acid
The Kidd Creek copper/zinc mine is located near Timmins, Ontario, Canada. Along with copper and zinc it produces indium, silver-bearing slimes, nickel-copper carbonate, liquid SO2 and sulphuric acid. Kidd Creek is 100% owned and operated by Xstrata plc, which acquired the complex through its take-over of the former owner, Falconbridge Ltd, in 2006. The operations incorporate two business units: Kidd Mining Division and Kidd Metallurgical Division.
GEOLOGY AND RESERVES
Kidd Creek is based on a rich, steeply dipping volcanogenic sulphide deposit located in the Archaean Abitibi greenstone belt. There are two major orebodies, with associated smaller lenses. The ore is hosted in felsic rocks of the Kidd Volcanic Complex and is cut by mafic sills and dykes. Structural deformation resulting from several phases of folding and faulting affects the distribution of sulphide lenses.
Three ore types predominate: massive, banded and bedded (MBB) ores (pyrite, sphalerite, chalcopyrite, galena and pyrrhotite); breccia ores containing fragments of the MBB ores; and stringer ores consisting of irregular chalcopyrite stringers cutting a siliceous volcaniclastic host.
At the end of 2005, Kidd Creek’s proven and probable reserves were stated as being 19Mt grading 1.8% copper, 5.5% zinc, 0.18% lead and 53g/t silver. Measured and indicated resources totalled 2.6Mt at 2.2% copper, 6.3% zinc, 0.2% lead and 48 g/t silver, with a further 11.9Mt in inferred resources at 2.7% copper, 4.8% zinc, 0.3% lead and 81g/t silver.
The mine started production in 1966 from an open pit. The orebody is now mined at depth through three shafts as the No.1, No.2 and No.3 Mines. Phase 2 of No.3 Mine is currently being developed. Mine D will extend Kidd Creek below No 3, from a depth of 2,100m to 3,100m.
Blasthole stoping with cemented backfill is used to extract the ore underground, Kidd Creek being the world’s second-largest user of cemented backfill (after Mt Isa in Australia). Blastholes are drilled using Ingersoll Rand, Mission and Cubex drills and broken ore is hauled underground by Tamrock load-haul-dump units. The hoisting shafts are equipped with an ABB Hoist Automation System, which has significantly increased the efficiency of raising ore from depth.
The run-of mine ore is shipped to the Metallurgical Division, 27km southeast of the mine. This division consists of a concentrator, copper smelter and refinery, zinc refinery, cadmium plant, indium plant and two sulphuric acid plants.
The Kidd concentrator crushes and grinds the ore before flotation. Zinc concentrates are roasted, and the sulphur oxides and trioxides are passed to the sulphuric acid plant. The zinc calcine is leached, the zinc-rich solution then being processed in a purification stage where cadmium is extracted. The purified zinc-rich solution is sent to the electrolysis plant where zinc is plated onto aluminium cathodes. Indium, zinc and copper are recovered from smelter dusts processed in the indium plant.
The smelter has a capacity of 150,000t/y of blister copper, which is then refined at the company’s 147,000t/y-capacity refinery. Silver-bearing slimes are also produced and shipped to other facilities for processing.
The zinc plant has a capacity to produce 147,000t/y of zinc metal, with the Kidd Mining Division supplying 61% of the feed and the rest coming from outside sources. In 2004, the Kidd smelter produced 121,557t of zinc and 115,578t of copper.
Kidd Metallurgical Division’s Custom Feed Business processes concentrates from outside Kidd Mining in order to ensure that the smelters and refineries run at full capacity. Outside imports include concentrates from Sudbury, Collahuasi, Minera Escondida Ltda and others, while zinc comes from Billiton Metals Canada and other sources.
PRODUCTION AND COSTS
Kidd Creek processed 2.3Mt of ore in 2005, at head grades of 2.0% copper and 6.2% zinc, from which it produced 42,738t of copper, 119,960t of zinc and 3.7Moz of silver. Smelter and refinery production totalled 118,973t of smelted copper, 111,231t of refined copper and 113,711t of refined zinc.
By the end of 2005, Kidd Creek had spent C$518m on the development of its Mine D area, below the existing mines. Commissioning began in 2004, with Mine D scheduled to increase the operation’s capacity to 2.4Mt/yr of ore. Transition to the new mine area was 90% complete by the end of 2005, with a total project budget of C$68m.
Kidd Creek is also processing ore from from the company’s Montcalm nickel-copper mine, which began production in 2004.
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