Cawse Ni Mine, Ora Banda Goldfield, Kalgoorlie-Boulder Shire, Western Australia, Australiai

Regional Level Types
Cawse Ni Mine	Mine
Ora Banda Goldfield	Ore Field
Kalgoorlie-Boulder Shire	Shire
Western Australia	State
Australia	Country

The Cawse nickel mine is 9 kilometres east of Ora Banda, and 1 kilometres north of the Ora Banda-Broad Arrow Road. The site contains a High Pressure Acid Leach processing plant, several shallow to 60 metre deep pits on a north-south trend, a small pit one kilometre further north called Cawse North.

The location is on the western limb of the Googarrie-Mt Pleasant Anticline in the Ora Banda Domain. Oxide ores are found in limonite, talc, and siliceous cobalt, and smectite-saprolite ore (nontronite).

Liminotic clay contains variable proportions of vuggy goethitic silica containing 0.4% to 1.5% Ni. The higher the silica content the lower the Ni grades. Cobalt is 0.01% to 0.3%, at which point manganese stains the silica.

Siliceous cobalt mineralisation is 5% of the measured resource, occurring in a 1 to 6 metre thick horizontal layers in the upper weathered zone, characterised by dark blue to black siliceous rock with abundant manganese oxides such as todorokite, chalcophanite and cryptomelane. The cobalt grade is 0.3 to 0.7%, and Ni 0.5% to 5 %.

Talc mineralisation is found throughout the weathered profile proximal to the talc chlorite shear structures. Ni is 1 to 2%, with high Mg level at 8 to 15%.

Veteran prospector Robert Gardner purchased the mine through his Wingstar Investments in 2014. Gardner came to fame as one of the discoverers of the Evening Star gold nugget at 520 ounces in the early 1990's. He went on to invest in several gold mining companies, and is chairman of Nickelore which holds tenements bordering the Cawse mine.

The mine was developed by Centaur Mining and Exploration Limited. Much has been written about the initial failure of the processing of laterite nickel in Western Australia, particularly at Murrin Murrin and Bulong. The process involves subjecting the ore to high temperature and pressure sulphuric acid. The dry nontronite clays have a habit of clogging the system, precipitating gypsum requiring the plant to be closed to clean clogged pipes of calcium, and the acid corrodes parts of the plants. Cawse did better than the other two locations, but Centaur still sank under a sea of debt.

The OM Group purchased the mine. Cawse became part of Russian based Norilsk Nickel in March 2007, as part of its acquisition of the OM Group. Nickel concentrates were being shipped to its Harjavalta refinery in Finland. 1400 tonnes of nickel concentrate was produced in 2008, but operations have since been suspended due to low nickel prices.

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