Mt Carlton is a gold-silver-copper mine located 150km south of Townsville in Queensland, Australia. It is a high-sulphidation epithermal style deposit, discovered in 2006.
The mine is 100% owned by Evolution Mining, who has invested more than $200m for the exploration and development. Macquarie Bank provided $100m loan facility for the mine’s development.
The mine’s definitive feasibility study was completed in February 2010. The first concentrate was produced in March 2013 and the commercial production began in July 2013. The expected mine life is 12 years.
Geology and mineralisation of the Mt Carlton mine
The Mt Carlton deposit is located on the northern margin of the Permian Bowen Basin. Gold mineralisation is present as native gold within pyrite while silver and copper are present respectively as silver arsenic sulphides (tetrahedrite/polybasite) and copper arsenic sulphides (enargite).
The mining operation consists of two deposits namely V2 and A39, which are 200m apart. The V2 deposit is a flat lying deposit situated 20m to 180m below surface. It is pre-dominantly a gold deposit with a thickness of 70m and extends over an area of 500m x 500m. The A39 is a high grade silver deposit averaging at 552g/t.
Mt Carlton mine reserves and resources
The proven and probable gold reserves at Mt Carlton mine are estimated to be 9.13million tonne (Mt) graded at 2.8g/t, as of December 2012. The silver and copper reserves are estimated to be 10.4Mt each graded at 48g/t of silver and 0.26% copper respectively.
Mining and processing of ore at Mt Carlton mine
Conventional drill, blast, load and haul method of mining is applied at Mt Carlton mine. The mining equipment is hired on a dry-hire basis.
Mining at the V2 open pit deposit is done in three stages over nine years. The high-grade ore will be mined and processed at early stages, while the low-grade ore will be stockpiled and processed after the completion of open pit mining. The A39 deposit’s ore is mined as a single-stage open pit.
The processing plant is a conventional crushing plant and bulk sulphide flotation plant. It has a capacity of processing 800,000tpa for an initial period of 10 years.
Production and sale of concentrate from the Mt Carlton mine
Mt Carlton’s A39 deposit commenced production in March 2013, while production at the V2 deposit started in July 2013. The mine is expected to produce 65,000 to 75,000 gold equivalent ounces during 2013-14.
The produced concentrate is loaded in bulk bags and exported. An off-take agreement for purchasing the concentrate was made with Shandong Humon Smelting in July 2011. The first shipment was delivered in August 2013.
Mt Carlton mine construction and infrastructure facilities
Construction at the gold-silver-copper mine began in December 2011 and was completed in March 2013. The major activities included construction of a tailings storage facility, main water dam, site roads, high-voltage mains and processing plant.
The power supply for the mine is provided from the ERGON switchyard connected to the main substation via a 132kV connection. It also comprises of 18.5km of 22kV overhead supply.
A permanent accommodation camp was set up for accommodating the workers. The infrastructure facilities consist of an administration building and maintenance workshops.
Contractors involved with the development of Mt Carlton mine
Calder Projects Services was awarded the contract for providing detailed engineering and procurement services for the mine in February 2011.
The contract for the construction of non-plant buildings was awarded to North Queensland-based construction company TCS. The $7.5m contract included the construction of foundations, slabs and structure for the processing plant.
Project Engineering Services was awarded the QA/QC contract. The scope of work included installation of machine control GPS system, QA documentation, erosion and sediment control design, safety management systems auditing, and so on.
The contract for the construction of site accommodation, offices and camp kitchen facilities was awarded to Hutchinson Builders.
The contract for the construction of the processing plant and supply of materials was awarded to Spaceframe Buildings.
Larpro Projects was awarded the construction management contract. The contract for conducting site works for setting up the gold processing plant was awarded to Newlands Civil.
Pan Process was awarded a contract for the 132kV/22kV power line construction. The contractual scope included the installation of four transformers and cables, ADSS cabling, and fibre splicing.
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