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Berenguela, Peru
Location and History
Berenguela is located five kilometers (three miles) northeast of Santa Lucia on the altiplano of southern Peru. Access is good with a major paved highway adjacent to the property. A main-line railway passes within five kilometers of the property.
A British firm mined the deposit for 60 years starting from 1905. Production totaled 500,000 tonnes averaging 750 grams of silver per tonne (21.9 ounces of silver per ton) for a total production of 12 million ounces of silver. Exploration in the 1960's comprised channel sampling of 17,700 meters of underground workings, bulk sampling and diamond drilling of 6,628 meters in 108 holes. In the 1990's, Kappes, Cassiday & Associates developed processes to optimize metal recovery.
Geology and Metallurgy
The deposit is composed of flat-lying beds in a folded dolomitic limestone. It was formed as a replacement of limestone where hydrothermal solutions deposited hydrated iron and manganese oxides with silver, copper and minor zinc. The deposit is located at surface and forms a body 500 meters wide, at least 1500 meters long and averages 60 meters thick. Bulk sampling by Asarco Incorporated in the 1960's averaged 27% manganese dioxide, 201 grams of silver per tonne and 1.61% copper.
Kappes, Cassiday & Associates has developed a process of conventional crushing followed by leaching with sulfuric acid and sulfur dioxide. Manganese, copper and silver are then recovered in separate procedures. Testwork on a bulk sample of ore recovered greater than 90% of all three components.
Project Scope and Plans
Current studies suggest that with a milling rate of 700,000 tonnes per year, an operation with a 10-year mine life could produce 3.9 million ounces of silver per year.
Our plans are to undertake a scoping study to optimize development of the project.
For details on the reserves and resources of the Berenguela Project,view the current Resource Summary (312 kb pdf).