Catalyst Metals Limited (ASX: CYL) and JV partner Gold Exploration Victoria Pty Ltd announced that preliminary metallurgical test work carried out on samples of primary material from Boyd’s Dam prospect within the Four Eagles Gold Project Joint Venture in Victoria’s Whitelaw gold corridor has reported excellent results.
The JV partners announced that the test work results indicated that the material is non-refractory; 97% gold recovery was achieved by gravity concentration and direct cyanidation; 99% gold recovery was obtained in a combined gravity and flotation concentrate; and results enable processing alternatives to be evaluated for Boyd’s Dam.
Initial metallurgical test work at Boyd’s Dam
CYL and JV partner had recently completed initial metallurgical test work on primary material from Boyd’s Dam prospect to assess gravity, flotation, and cyanide dissolution performance.
The company said that the initial metallurgical test work was done to determine the merit of producing gravity and flotation concentrates from the Boyd’s Dam Prospect and thereby demonstrating combined concentrates could be transported to other facilities in Victoria or elsewhere for gold dore production; and to determine if gold recoveries achieved by cyanidation ensure treatment would be viable should an alternative treatment route be available through an existing process plant in Victoria.
Excellent metallurgical results
The company said that excellent metallurgical results were achieved from the preliminary metallurgical test work.
Gravity and flotation concentrate test work
CYL said that a 202-kilogram composite sample derived from a strongly mineralised zone within reverse circulation drill hole FERC284 with an estimated grade of ~50 g/t Au was sent to Australian Minmet Metallurgical Laboratories (AMML) mineral processing and metallurgical laboratory for metallurgical analyses.
The company reported that using a Knelson concentrator, at a P80 75 μm grind size, a 94% gold recovery was achieved, into a concentrate that was less than 3 % of the original composite sample weight.
The -850 μm material was milled to P80 75 μm and put through a Knelson gravity concentrator, resulting in a gravity concentrate with a grade of 709 g/t Au into a 0.55 wt% mass yield, recovering 76% of the gold. The tail from the above gravity test, grading 1.24 g/t Au and representing 99.5% of the -850 μm mass, underwent flotation test work resulting in a 25 g/t Au concentrate grade, with mass yield of 4.5 wt% and float tail grade of 0.035 g/t Au.
The company said that the positive metallurgical results mean that a high-grade gravity and flotation concentrate could be processed at any facility with cyanide capability, including the circuit at the Henty Gold Mine in Tasmania.
Cyanide dissolution test work
Following gravity testing of the -850 μm milled to P80 75 μm sample, another sample of the tail from the gravity test work underwent cyanide leaching test work.
The company said that the strong correlation between Bulk Leach Extractable Gold (BLEG) and fire assay data determined during exploration analyses suggested the mineralisation was non refractory.
The company said that this test work confirmed the non-refractory nature of Boyd’s Dam primary mineralisation with a combined gravity and cyanidation gold recovery of 97%. CYL said that the optimisation and variability test work is yet to be undertaken.
“Catalyst…is very pleased with the initial metallurgical test work phase undertaken on primary mineralisation from Boyd’s Dam Prospect”
Bruce Robertson, Catalyst’s Chief Executive Officer said: “Catalyst, on behalf of the Four Eagles Joint Venture, is very pleased with the initial metallurgical test work phase undertaken on primary mineralisation from Boyd’s Dam Prospect.
It demonstrates that subject to defining an economic outcome, a treatment route for processing concentrate may already be available to the joint venture. The test work removes the reliance on the approval for a cyanide licence as a requirement for the Victorian projects to be given the go ahead, and potentially reduces the capital intensity of any potential development at Boyd’s Dam.”
Image Source: Catalyst Metals Limited