Prospección de placeres aluviales en el río Upano ubicado en la parroquia Alshi 9 de octubre, cantón Morona, provincia de Morona Santiago.

Abstract

This study aims to identify placer mining areas on alluvial gold deposits by using panning and sediment analysis to mark out the area of possible potential of gold in the Upano river, in Alshi 9 de Octubre parish, Morona district, province of Morona Santiago; through geochemical sampling in relevant sites, depending on the conditions of alluvial deposits. Twenty sampling locations were determined in seven kilometers of distance. Field service was conducted by collecting the river sediments samples. Each sampling location was registered via data sheets. Samples were analyzed in the Chemistry Laboratory of Geological and Energetic Research Institute (IIGE), with physical and chemical process to determine the gold concentration, by fire assay (Reference Method: ASTM E1335) and spectrophotometry atomic absorption (Reference Method: SM 3111). According to the results of gold concentration samplings it was conducted a geostatistical analysis through statistics and estimation with the Kriging method. Two main areas of gold concentration have been identified with 27,35 and 26,9 mg/kg value (gold milligrams contained per kilogram sample). In the gold concentration analysis and in the gold potential demarcation area it was used the Modified Lepeltier method, which determined geochemical criteria with values of 3,878 Background; 11,998 Threshold; 20,118 sub anomaly and 28,238 anomaly. Two areas with the highest gold enrichment have been demarcated in 26,9 and 27,35 ppm (parts per million). It is recommended to prospect in the two main areas of the Upano river, to collect quantified information about the alluvial deposits and based on it, set positive scenarios with the purpose of designing a profitable small-scale mining project for artisanal miners.