Geomaque eyes Marathon deposit in Ontario

Geomaque Explorations (GEO-T), best known for its open-pit gold mines in Latin America, is trying its hand at a polymetallic surface deposit in northern Ontario.

Polymet Mining (POM-V), which remains focused on its Northmet polymetallic deposit in Minnesota, has dealt Geomaque an option to acquire a 60% interest in the Marathon project in exchange for $2.7 million in expenditures over four years and a cash payment of $1 million.

Named after the nearby town, Marathon sits on the eastern edge of the Port Coldwell alkalic igneous complex. The deposit itself strikes for 2 km, as delineated by 208 holes drilled on 60-metre centres. Most of the holes were drilled by Anaconda American Brass, with a few collared by Fleck Resources, since renamed Polymet.

In 1989, BHP Engineering completed a prefeasibility study that pegged resources at 37 million tonnes averaging 0.38% copper and 0.032% nickel, plus 1.85 grams silver, 0.21 gram gold, 1.1 grams palladium and 0.27 gram platinum per tonne (minor credits of rhodium and cobalt were also detected). The deposit was considered amenable to open-pit mining and conventional milling.

Based on an annual production rate of 2 million tonnes, operating costs were projected at $11 per tonne; smelter revenue, at $18 per tonne. Both estimates were based on metal prices at the time.

Geomaque is re-evaluating the existing geological and metallurgical data in preparation for a bankable feasibility study. An independent review of the project’s economics, based on current metal prices, is also being sought.

Meanwhile, the company has suspended mining at its San Francisco operation, in Mexico, but expects to fire up the Vueltas del Rio project in Honduras shortly. Another 20,000-odd ounces are expected from residual leaching at the former, whereas about 60,000 oz. are expected from Vueltas del Rio in each of the next five years.

Vueltas del Rio hosts a reserve of 5.1 million tonnes grading 2.51 grams gold per tonne in an overall resource of 29.7 million tonnes averaging 0.75 gram. Mineralization remains open along strike and at depth.

Cash costs are expected to average US$169 per oz. over the life of the mine.

Meanwhile, Polymet has begun a 3,000-metre drill campaign at Northmet (also called Dunka Road). The drilling is concentrated in an largely untested area outside of the known resource.

Resources at Northmet are pegged at 808 million tonnes averaging 0.43% copper, 0.11% nickel, 1.5 grams silver, 0.06 gram gold, 0.44 gram palladium and 0.12 gram platinum. The deposit was discovered 40 years ago, but it only as a result of recent advances in the metallurgical process known as pressure-oxidation that is being reconsidered as a potential producer (T.N.M., Oct. 9/00).

A prefeasibility study is scheduled for completion early in the new year.