Name: Kanmantoo mine.

Location: The Kanmantoo mine is located in the Adelaide Hills region of South Australia.

Controlling Company: Hillgrove Resources.

Brief History: Copper was discovered at Kanmantoo in the 1840s, with intermittent mining occurring until the 1930s. In the 1960s, there was renewed interest in the area and extensive drilling revealed a major orebody. In 1970, the newly formed Kanmantoo Mines, a consortium of North Broken Hill, South Broken Hill and EZ Industries, developed a 900 000 t/y operation, which produced a total of 4.1-million tonnes at 0.9% copper until it closed in 1976. Hillgrove began its involvement in the region in April 2003. Following completion of definitive feasibility studies undertaken during 2007, Hillgrove Resources announced the redevelopment of the Kanmantoo copper mine. Construction of the mine was completed in 2011.

Brief Description: The Kanmantoo mine has a throughput of 2.8-million tonnes a year, producing an estimated 80 000 dry metric tonnes a year of concentrate, with exploration potential for further copper/gold mineralisation. The area in which the mine is located remains one of the most underexplored and prospective base metal provinces in Australia, showing outstanding potential for copper/gold and silver/lead/zinc mineralisation.

Mining Method: Opencut mining.

Products: Copper, gold and silver.

Major Infrastructure and Equipment: The proposed treatment route is a conventional copper and gold flotation plant, comprising single-stage crushing, closed-circuit grinding in a semiautogenous milling circuit, rougher flotation and regrind before cleaning, as well as concentrate dewatering and filtration.

The major process water source for the mine is treated with wastewater from the Mount Barker District Council’s Laratinga water treatment plant.

Concentrates are transported 80 km by trucks on the Princes highway, East Terrace at Callington and then the South Eastern freeway to the Port of Adelaide. A private road provides access to the Princes, which bypasses the township of Kanmantoo.

Geology/Mineralisation: The Kanmantoo copper deposit is located in the Cambrian Kanmantoo trough, which is part of the Adelaide geosyncline. Mineralisation in the vicinity of the deposit occurs as discordant copper/gold stockworks within a host rock, consisting of quartz/biotite and alusite/garnet/chlorite schist. The deposits commonly exhibit pipelike dimensions, with podiform lenses and veinlets of chalcopyrite, pyrrhotite, pyrite, magnetite, chalcocite and covellite.

Mineralisation is grossly discordant to bedding and lodes occur parallel to the local and regional axial plane schistosity (S2), with local thicken- ing owing to folding. There are also some discordant 020 to 045 degree-striking mineralised shears/faults, with shearing and remobil-isation of mineralisation. Structural studies conducted by Hillgrove indicate that the main controls on mineralisation are the north- to south-striking shear zones (parallel to S2) and the north-north- east to north-east-striking cross shears, and it appears that the intersection of these shear zones define the steep north-east plunge of ore shoots. Shallow oxide mineralisation in the upper part of the deposits moves into a chalcopyrite-dominant assemblage in the primary zone. Gold is coincident with the copper and also occurs as gold-only zones.

Reserves: Total proven and probable reserves, as at April 2010, were 14.8-million tons, with a grade of 0.85% copper, 0.17 g/t gold and 3.1 g/t silver.

Resources: Total mineral resources, as at March 2012, were 32.8-million tons, with a grade of 0.8% copper, 0.15 g/t of gold and 2.2 g/t silver.

Prospects: The installation and commissioning of the new primary crusher circuit for the mine has enabled throughput to increase from 2.4-million tons a year to more than 2.8-million tons a year.

With the mine achieving increased yearly production levels, the new life-of-mine plan announced in February 2013, together with the improving copper feed grade to the mill, will consolidate and increase Kanmantoo’s positive cash generation in the extended ten-year period of operation.

Contact Person: MD Greg Hall.

Contact Details:
Hillgrove Resources, tel +61 2 8247 9300,
fax +61 2 8247 9399, and website http://www.hillgroveresources.com.au.