St George Mining Limited (ASX: SGQ) has received “excellent” results from a metallurgical programme for the Stricklands Deposit at its flagship high-grade Mt Alexander Project, located in the north-eastern Goldfields of Western Australia.
Executive Chairman, John Prineas, said the mineralisation at Mt Alexander has a unique combination of high-grade nickel, copper, cobalt and platinum group metals which the company believes has potential to produce concentrates of exceptional value.
“We are very pleased that the detailed metallurgical programme by XPS has confirmed that widely-used flotation techniques can produce separate clean concentrates for nickel and copper, with both concentrates also showing high payable credits for other metals including palladium, platinum, gold and cobalt,” he said.
“These results, supported by a flowsheet for potential commercial production, are an important milestone for the starter mine concept at Mt Alexander. Further optimisation work will be considered as we progress marketing studies with potential off-take customers.
“With the prices for all metals in our commodity suite at historical highs, we will also look to expand the area of known mineralisation to include additional high-grade massive sulphide lenses intersected in previously announced drilling as well as untested targets at shallow depth surrounding the Stricklands Deposit.
“We look forward to reporting on these development activities as they progress.”
Metallurgical Results
A detailed metallurgical programme has been completed by XPS Expert Process Solutions, a Glencore Company (XPS), based in Falconbridge, Canada.
XPS is internationally recognised as leaders in processing solutions for nickel-copper sulphide mineralisation. Testwork was undertaken on mixed massive and disseminated “life-of-mine” sulphide ore from the Stricklands Deposit at the Mt Alexander Project.
Commercial Grade Concentrates Produced: A sequential flotation flowsheet was employed consisting of a copper float followed by a nickel float. A rougher stage was followed by three cleaner stages and locked cycle testing.
Within locked cycle flotation testing the copper recovery was a combined 95.9% to the copper and nickel concentrates, of which 80.9% of the copper occurred in a 27.8% Cu concentrate. Nickel concentrate grade is 11.5% Ni with a nickel recovery of 68.7% to the nickel concentrate, equivalent to 95% of the nickel sulphide mineral content of the ore.
Precious metals recoveries to the combined concentrates were 74% for Au, 59% for Pd and 47% for Pt with both concentrates carrying the precious metal content.
No deleterious elements: The concentrates produced do not contain any deleterious elements that could adversely affect their saleability.
The MgO grade in the nickel concentrate was 6.8%, slightly higher than the target of 5%. It is expected that a conventional flotation circuit could be easily modified to achieve an MgO grade of around 5%.
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