Assessing Mineral Potential in Bolivia; Phase I

Abstract

Bolivia, located in the west-central part of South America, has extracted only a small amount of its total economic mineral potential, making it an ideal place for economic opportunity. The Bolivian Tin Belt, for example, contains some of the world’s largest Sn/Ag porphyry granite systems in the world. Sinchi Wayra, S. A., Emicruz LTD, Comsur, Zonge, Engineering and Sander Geophysics LTD provided LandsatTM, geochemical and geophysical data in hopes of determining phase I locations for potential economic mineral extraction. This work is the initial stage of more desktop studies and field work. Unreliability in ratioing of the LandsatTM images reduced the number of indices that could be created. Layer stacking of LandsatTM images from the Potosi region (in the red, green and blue of clay, ferrous minerals and iron oxides respectively) revealed a few areas of high iron content (moderate adjacent clay minerals) that deserved further attention. Only a few ratio images coincided with areas of sufficient rock chip sampling. However, in all cases, the ratio images matched the described alteration (from rock chip sampling). Geochemical data revealed two locations of economic mineralization and fourteen other locations with enough potential for further study. Most of the areas of mineral potential are located within or adjacent to the Bolivian Tin Belt, in the central and southern portions of the Eastern Cordillera, and show anomalous values of As, Bi, Sb, Ag, Sn, Pb, Zn, W, Cu and/or Au. The majority of these mineral occurrences are epithermal polymetallic vein deposits related to felsic or intermediate porphyrytic/equigranular intrusions. Radiometric data revealed at least one major site of interest with elevated U and Th values near the Boliva-Brazil border. Several other anomalies (based on airborne magnetics) revealed strong dipoles in eastern Potosi and in southeastern Bolivia.