At the Wolverine massive sulphide deposit in the Yukon, parters
Expatriate holds a 60% interest in the project; Atna, the remainder.
The metallurgical studies are budgeted at $200,000 and expected to last six to nine months, to be followed by a prefeasibility study.
The grade of mineralization at Wolverine is high, with an average gross metal value of about $370 per tonne in contained zinc, copper, lead, silver and gold. These calculations are based on per-pound prices of US45 cents for zinc, US80 cents for copper and US25 cents for lead, plus US$5.50 per oz. silver and US$300 per oz. gold.
The resource is estimated at 6.2 million tonnes grading 12.66% zinc, 1.33% copper and 1.55% lead, plus 370.9 grams silver and 1.76 grams gold per tonne. This translates into 1.7 billion lbs. zinc and 72 million oz. silver (zinc and silver make up about 80% of the gross metal value).
Preliminary tests in 1997 identified an anomalously high amount of selenium in sulphide minerals. Selenium creates problems during smelting and refining, as it is not easily separated from the metal or sulphur products.
Studies suggest that the abnormally high levels of selenium at Wolverine would make it difficult to sell the concentrates. Initial copper and zinc concentrates were found to contain an average of 0.43% and 0.15% selenium, respectively, which is several times higher than normal. Lead sulphide and sulphosalt minerals account for half the selenium in the copper and zinc concentrates.
A team led by geoscientist Brad Marchant has been hired to investigate options for processing of Wolverine ores. They will be assisted by David Dreisinger, who holds the industrial research chair in hydrometallurgy at the University of British Columbia.
The team will focus on ways to capture half of the gross metal value that is commonly lost when concentrates are produced. These losses are attributed to metallurgical problems, smelting and refining charges, metal deductions, penalties and transportation costs.
One such process involves leaching, and although this method would result in higher and capital and operating costs, these costs would perhaps be offset by gains in metal recoveries.
In related news, Atna, Expatriate and
“Early on, Cominco and Atna both recognized that the shipping of concentrates would be a problem,” says Atna President Peter Delancey. “When we found that we both had metallurgical problems related to selenium, we began to consider consolidating because of the economies of scale in the area.”
Carol Ellis, investor relations officer for Expatriate Resources, agrees; “Consolidation of the camp is something that would move the projects forward.”
Discussions aimed at doing so are said to be at the preliminary stage.
Kudz Ze Kayah contains an indicated resource of 11.3 million tonnes averaging 5.9% zinc, 1.5% lead and 0.9% copper, plus 1.3 grams gold and 133 grams silver. All environmental permits are in hand; however, Cominco has placed the project on hold as a result of weak metals prices.
In 1998, another small deposit was discovered near the main ABM deposit at Kudz Ze Kayah. Inferred resources for this smaller deposit are pegged at 1.5 million tonnes averaging 6.4% zinc, 3.1% lead, 0.1% copper, 2 grams gold and 90 grams silver.
Wolverine and Kudz Ze Kayah are in the Finlayson Lake district of the southeastern Yukon.
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