METALLOGENY APPLIED TO GOLD RECOVERY AT SOUTHERN BOLÍVAR GOLD DISTRICT - COLOMBIA AND ITS ENVIRONMENTAL IMPLICATIONS

Gold mining in Colombia has been the main livelihood of some ancestral populations, which have had developed artisanal mining methods, such is the case of the mining district of southern Bolívar where some records describe work of barequeo since the 18th century. The current situation shows the execution of mining with little technology in areas with evident environmental problems. As a result, considerable losses occur in the recovery values, due to few detailed studies in the area. The extraction is done only by the expertise of the miner.

Petrographic, metallographic, electron microprobe and x-ray diffraction analysis, were performed to characterize properly the mineralization present in the sectors of Culoalzao and San Pedro Frío, obtaining a detailed panorama of the deposit from the compositional and textural outlook. The deposit consist mainly of sulfides (pyrite, pyrite+As, chalcopyrite, sphalerite, galena, arsenopyrite), tellurides (hessite, petzite) and oxides in a sectorized way. In addition, the presence of important gold content was reported, both native and electrum. It was also possible to observe the occurrence of compositional, textural and abundance variations in the two sectors studied.

The understanding of the mineralogy present in the deposit allowed to make a better approximation to adequate recovery techniques to extract the largest amount of gold given its distribution and the technological availability of the artisanal miners. Moreover, this results will lead to an improvement in the environmental issues related to the mining processes.