Equinox advances J&L project to feasibility

Equinox and partner Pan American Minerals (VSE) are aiming to prove up and develop a polymetallic mining operation, with the main challenge being the complex metallurgy of the gold, silver, lead and zinc deposit found on the property.

Since taking on the project last fall to earn a 70% interest, Equinox completed a 32-hole underground drill program in addition to extensive flotation, sink/float, and pressure leaching tests on drill core.

Ross Beaty, president, said the average grade of mineralization intersected in all 32 holes was 0.32 oz gold, 2.4 oz silver, 3.3% lead and 6.0% zinc over an average true width of 6.4 ft.

Updated reserves for the Main zone on the J&L property are now reported as 721,000 tonnes proven and probable grading 6.8 g (0.199 oz) gold and 69.0 g (2.0 oz) silver per tonne, 2.6% lead and 5.4% zinc, using an 0.2 oz gold equivalent cut- off grade and assuming a 5.2 ft mining width. Proven, probable and possible reserves in the zone are reported as 7,950,000 tonnes.

The Main zone was developed by Equinox and previous operators by 116 drill holes, 3,320 ft of drifts and 328 ft of raising. The zone has been traced on surface over a strike length of 10,958 ft.

With potential reserves of 5,160,000 tonnes in the North zone, the J&L project has total reserves in all categories of 13,110,000 tonnes. Although insufficient data exists to provide an over-all grade estimate, the J&L deposit on average contains 5% arsenic.

Based on results from metallurgical test work done by Lakefield Research, the company is planning to upgrade ore material by a sink/ float plant so that a 250-tonne-per- day mill could be used with a 500-tonne-per-day mining rate.

John Wright, manager of operations, said the plant will lower capital and operating costs for the milling of the massive sulphides which are found in lenses separated by sheets of phylittes and quartzites.

“By taking advantage of the substantial differences in specific gravity of the heavier massive sulphides and the lighter quartzites and phyllites we can use the sink/ float plant to reject waste material with a lighter specific gravity than three,” he said.

The company said flotation tests “indicate that saleable lead and zinc concentrates could be produced,” and bench scale pressure leaching tests “confirm the economic extractability” of gold from arsenopyrite using an autoclave with a 100- tonne-per-day capacity.

The process leaves the insoluble compound ferric arsenate as a tailings product which Wright said was generally acceptable to environmental agencies.

In early May Lakefield Research will operate a pilot plant for four weeks on a previously mined 300 tonne bulk sample to confirm the viability of the metallurgical process and refine capital and operating costs. More underground work is planned for May.

“We think we have about a four year mine life in proven and probable reserves now,” said Wright. “But our objective is to bring this up to a minimum 7-year mine life.”

Equinox also holds a 24% interest in the producing Buckhorn gold- silver mine in Nevada, is developing the 100%-owned Zenda gold mine in California for production, and recently took over as operator at a small, recently-acquired gold mining operation in Costa Rica.

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