Abstract

Puracé is the only active volcano in the Pliocene volcanoes of the Cauca-Patía batholith in the Central Cordillera of Colombia. Eruptions are explosive, and the ejected rocks are andesite-augite. The upper cone of the volcano is built by andesitic lavas, bombs, lapillis, and ashes, and the lower one by andesite and dacite tuffs.

The surveys and drilling revealed important data on sulfur deposits and the mineralized zone’s strength and magnitude. In addition, they proved that sulfur mineralization occurs in the porous rocks of andesite and dacite tuffs in the form of impregnation and fracture filling (cold sulfur).

Twelve holes were drilled at the surface, revealing four mineralized layers, and increasing the proven reserve to over four-million-ton s. The probable reserve is estimated at approximately two-million-ton s.

The ore treatment still requires many trials, but we are convinced that the flotation plant combined with the Japanese autoclave could give satisfactory results.

The valuation figures and calculations for the life of the mine are used to make new investments.

The geological exploration was carried out successfully; therefore, Industrias Puracé, S.A. can make new capital investments to improve the sulfur ore treatment process.

We believe that the company can supply the country's needs for fifty years without new surface drilling.