Preliminary metallurgical test work on samples from the Big One deposit in North-West Queensland have delivered encouraging initial results, according to project owner Castillo Copper.

The beneficiation potentially transformed several ore samples into a copper concentrate with confirmed upgrades ranging from 5x to 10x for copper metal.

The company has further test-work is underway to optimise the outcome – a move it says is critical to boost the prospect of securing a processing agreement with a blue-chip partner in the Mount Isa copper-belt.

“The board is delighted with the preliminary metallurgical test-work results, especially with the beneficiation potentially transforming the ore from the Big One deposit into a viable copper concentrate,” Castillo Copper managing director Dennis Jensen said.

“Moreover, receiving these initial results now is timely as the board is now ramping up efforts to secure a processing agreement and clear path to market.”

The company contracted ALS Metallurgy, Perth, Western Australia, to undertake test-work on a circa 33kg composite.

The best result saw a sample with 0.72 per cent head-grade taken to 7.2 per cent post-test-work.

The Big One deposit is part of Castillo’s Mount Oxide project, located 150km north of Mount Isa near the old Mount Oxide copper mine.

It has a global inferred mineral resource estimate of 21,886t contained copper metal (2.1Mt at 1.1 per cent copper).

Related: Maiden copper resource out for Big One

The Castillo board has been revising plans for the Big One deposit and plans to do the following:

– Conduct a third drilling campaign to extend known mineralisation through focusing on the sizeable known bedrock conductor that is north of the line of lode; and
– Undertake additional geophysical surveys to identify new targets for test-drilling.