General Minerals hunts for silver in western Bolivia

General Minerals (GNM-T) is returning to Bolivia, this time in search of silver.

The Denver-based junior, known chiefly for its copper porphyry targets in Chile, has acquired 70.5 sq. km in the central part of the country, around the historic Atocha mine.

Previously, in 1995, the company explored the Brazilian copper property known as Azuritas, which it subsequently dropped. Then, earlier this year, it acquired the 19.5-sq.-km Atocha mine property and proceeded to pick up an additional 51 sq. km which surround it. The property occupies a mineralizing system which General Minerals believes may contain disseminated silver mineralization over a strike length of more than 22 km.

However, much of the earlier work at Atocha, which dates back to the Spanish colonial period, concentrated on high-grade vein material, particularly from the Condor and Carmen zones. The company is looking for disseminated mineralization, which was largely ignored by previous efforts.

To date, General Minerals has extracted 41 channel samples from the Condor underground workings. The samples indicate that mineralization in an area measuring 800 by 200 metres is more extensive than the workings indicate.

Both Condor and Carmen occur in an intensely silificified zone measuring 2 by 300 metres, with associated argillization and hydrothermal brecciation. At Condor, disseminated mineralization occurs in a high-angle, left-lateral fault system that cuts sandstone units, whereas mineralization at Carmen is more structurally controlled.

Highlights from the sampling include a 1.8-metre channel sample grading 812 grams silver per tonne, and a 2.1-metre channel sample grading 590 grams silver. A grab sample from Carmen assayed 329 grams silver. Other base metal values, such as lead and zinc, were largely absent.

The company plans to tunnel beneath existing workings to test the downdip extensions, as well as carry out geophysics to assess the potential along strike.

Farther south, at the Escalones copper project in central Chile, roads are being cleared of snow in preparation for a November drill program, while at the Productura copper project, also in central Chile, field mapping and 90 line km of ground magnetics have been completed.

In northern Chile, General Minerals is fine-tuning the initial feasibility study at the Vizcachitas porphyry, looking for possible reductions in operating costs and capital costs. The company has been entertaining joint-venture proposals since July, when Boliden (BOL-T) walked away from the project.