Artemis Resources has produced exception recoveries of gold, copper and cobalt from the preliminary metallurgical test work program on two high grade, bulk ore composites from its flagship Carlow Castle project, located near Karratha in WA.
The company was able to recover up to 48% of the gold content via gravity separation techniques.
The gold not recovered by gravity or into flotation concentrates, was easily won by cyanide leaching, leading to the excellent overall recovery of between 98% and 99% of the contained precious metal.
The test work processing also recovered an average of 96% of the total silver content.
In addition, between 77% and 85% of the total contained copper content was recovered, producing a premium grade copper concentrate of about 30% from conventional metallurgical flotation processes.
Artemis also attained superb total cobalt recoveries ranging from 73% to 79% with flotation producing concentrates of the valuable metal between 2.3% and 5.3% cobalt, which are typical smelter feed grades, with grades exceeding 5% cobalt considered high grade.
The laboratory scale test work was designed to determine the metallurgical recovery characteristics of fresh ore composites from Carlow Castle and their amenability to conventional gravity, leach and flotation processing.
The results effectively confirm that the deposit’s ores can be separated producing high recoveries of the in-situ metallic content and providing support for further optimisation of an ore processing flowsheet from additional, ongoing geometallurgical test work studies.
Artemis Chief Executive Officer Wayne Bramwell said: “Artemis is encouraged by the amenability of the deposit to conventional processing options and the excellent recoveries of the three key minerals.”
“Gold and high-grade copper concentrates will be the primary value drivers at Carlow Castle with cobalt representing a third and valuable product stream that should appeal to many potential off-take partners.”
The results of the metallurgical test work and upcoming mineral resource update for Carlow Castle will underpin the project’s development activities, which include estimation of the in-situ resource and subsequent open pit optimisation studies to maximise revenue from the combined ore stream.
The results of the test work will form the basis of discussions with smelters and potential off-take partners and enable the commencement of an informed scoping study during the first half of 2019.
The current indicated and inferred mineral resource for Carlow Castle is 2.3 million grading 1.3g/t gold, 0.5% copper, 0.11% cobalt and 1.6g/t silver, within a larger global resource of 4.5 million tonnes @ 0.9g/t gold, 0.4% copper, 0.07% cobalt and 1.3g/t silver, dating from January 2018.
The company has more than tripled the amount of drilling it had completed at the emerging project only a year ago and commodity prices for the three major ore products – gold, copper and cobalt – have held up well in that 12-month period.
The initial metallurgical test work results for Carlow Castle appear to be very encouraging and the prize will be optimising the processes to obtain the highest metal recoveries possible from the multi-commodity ore deposit.
By Matt Birney
