The products included a copper sulphide grading 42% copper that can be blended with copper flotation concentrate to improve overall recovery and concentrate grade.
A high-quality, chemical grade cobalt sulphate at 29% cobalt and more than 99% cobalt sulphate was produced, with Great Boulder declaring the product “suitable for high-value use in the battery market”.
A high-quality nickel sulphide grading 42% nickel was produced, with test work to produce nickel sulphate to start soon.
Great Boulder managing director Stefan Murphy said the copper, nickel and cobalt results were “highly significant” as they showed high-quality products could be generated by applying both conventional and newly-developed processing techniques to Mt Venn ore.
Murphy reported: “These results provide more evidence of the strong development potential at Mt Venn.
“When they are combined with the extensive mineralised systems we have outlined at Mt Venn and the adjacent Eastern Mafic complex, the outlook for this project is very bright.”
READ: Great Boulder Resources makes steady progress across copper, nickel, cobalt exploration portfolio
To produce more definitive product specifications and recoveries, the company plans to:
separate test work on higher grade feed more representative of Mt Venn, and higher nickel tenor feed from the Eastern Mafic and Winchester deposits;
recycle leach solution to improve pregnant leach solution (PLS) grade;
optimise impurity removal, reagent dosage and pH profile to improve selectivity during each stage of metal precipitation/crystallisation; and
investigate which suite of products provides the best recoveries and payabilities to generate the highest revenue for the project.
Besides leach circuit activities, test work will be undertaken on the copper flotation circuit from samples more representative of the Mt Venn and the Eastern mafic deposits.
These samples will include “the more chalcopyrite (copper) dominant domains from Mt Venn and higher nickel tenor mineralisation from the Eastern Mafic”.