Bema boosts reserves potential at project in Chile

Recent drilling by Bema Gold (TSE) has expanded the reserve potential of the Verde deposit, one of three known mineralized bodies on the company’s 50% owned Refugio gold property in northern Chile. But it will take several more months before the company is able to release a minable reserve estimate for the Verde deposit where some 180,000 ft. of drilling in two phases has been completed to date.

By early January of next year, the company expects to release the results of its preliminary feasibility study which is being supervised by Mineral Resources Development Inc. (MRDI). Scheduled to be completed in December, the study will determine the minable portion of current geological reserves (and strip ratios) at Verde, optimization of recovery methods and production rates, and site-plant design criteria. By the time the study is released, Bema expects it will have spent US$8 million on the Refugio project.

The Verde deposit is now estimated to contain preliminary reserves in all categories of 218 million tons grading 0.026 oz. gold at a cutoff grade of 0.015 oz. per ton. Reserves were calculated using kriging within grades zones, and the calculations were supervised by MRDI.

If only oxides and mixed reserves are taken into account at a marginally higher cutoff grade (0.016 oz.), preliminary reserves decrease to 79 million tons grading 0.028 oz. The bulk of this reserve is in the proven and probable categories (73 million tons), with 70% classed as oxides and 30% as mixed.

President Clive Johnson said recent drilling has shown some loss in anticipated oxide reserves in the western portion of the Verde deposit, although this was partially offset by an increase in oxide reserves in the eastern portion.

Based on tests to date, the company expects an ultimate recovery of about 75% for oxide mineralization types with low reagent consumption. Further tests will be carried out to confirm early indications that the sulphides may be amenable to cyanide heap leach extraction methods (the gold is not encapsulated in the sulphides).

Johnson said the prefeasibility study will evaluate as many as five different scenarios for production development of oxide and sulphide reserves at Verde, including the economics of both heap leaching and milling, or a staged combination of both.

“The next several months will be a major number crunching stage,” Johnson said. “This will be a thorough prefeasibility because we intend to go out and use it as a basis for lining up project financing.”

In the meantime, more drilling is planned for the Verde deposit, and a US$500,000 initial drill program is planned for the nearby Pancho copper-gold zone which is not considered to be heap leachable. Johnson said the results from the Pancho drill program will be used to help determine which of several processing options would be best suited to the longer-term potential of the Refugio property.

“We believe the Pancho zone has potential for a higher-grade situation than we are seeing at Verde,” he said.

Bema is also continuing work at two gold projects in Idaho which it plans to develop into modest-sized heap leach operations next summer. The company already operates the Champagne heap leach gold mine in Idaho where it has a 85% interest.