Preliminary tests on samples from legacy stockpiles at the historic Cangai copper mine owned by Castillo Copper (ASX: CCZ) have produced high recoveries and grades of up to 22%, demonstrating the ore can be beneficiated materially.
Metallurgical tests along the line of lode at the McDonoughs stockpiles, within the Jackaderry project tenure near Grafton in northeast New South Wales, have so far confirmed solid copper concentrate recoveries of more than 80% and grades of up to 22% copper and 300 parts per million cobalt.
McDonoughs is one of five high-grade legacy stockpiles along the line of lode at Cangai which Castillo is keen to bulk sample and monetise.
It was the last ore lens found during A-level adit development at the western end of the mine and was in production until the mine’s closure in 1917.
The legacy stockpiles have been earmarked as potential early cashflow generators provided Castillo is successful in its efforts to fast-track the recommencement of mining operations.
The company said the preliminary sample results provide a key insight to copper recoveries and grades for the remaining historic stockpiles at Cangai and is confident of continued improvements as further testwork is carried out.
Cangai production history
With a JORC inferred resource of 3.2 million tonnes at 3.35% copper, the Cangai mine remains one of Australia’s highest grade copper resources.
The mine was discovered in 1901 and was in production for 13 years from 1904, but only ore greater than 13% copper was extracted during that time using manual techniques.
A copper smelter was also built onsite, allowing the mine to produce 5080 tonnes of copper, 1035 kilograms of silver and 53kg of gold during its life.
Over the last century, two groups have conducted geological work at Cangai but their work was deemed unsuccessful.
Castillo acquired the mine in 2017 as part of the Jackaderry project and is reviewing re- opening the mine given encouraging results to date.
At midday, Castillo Copper shares were trading 10.34% higher at $0.032.