| dc.description.abstract | The mining sector has a fundamental financial and economical role in the country where it practices these activities. In addition to employment creation and social-cultural development, the mining sector brings economic growth to the country. However, the sector is facing challenges due to COVID-19, incidents involving tailings dam facilities, rising energy costs, low grade ore deposits, restrictions in mining regulations and access to the available resources. In this context, the main objective of the study was to identify gold ores below cut-off grade from the underground mine at Córrego do Sitio Mineração, located at Santa Barbara, Minas Gerais. The methodology used in this work included the identification of ores below cut-off grade; operation of the ore sorting plant; chemical analysis of the ore sorting plant concentrated and bench tests, finally, the technical and economic feasibility analysis was carried out to ensure the benefit of the total operation. In order to carry out the technical analysis, the parameters currently used in the mining were considered. For processing plant, the results of granulometry and metallurgical recovery were evaluated for the main chemical elements: gold (Au); sulfur (S); carbon (C); antimony (Sb); iron (Fe) and arsenic (As). The financial analysis included the costs currently practiced in the mining operation, in the ore sorting plant, in the processing plant and the metallurgical recoveries obtained during the all stages. Three different scenarios were carried out, considering gold price at: 1,400 US$/oz, 1,500 US$/oz and 1,600 US$/oz. The potential of underground refractory gold ore viability using ore sorting technology has been proven technically feasible for a very specific stope application at Córrego do Sitio Mineração. The overall recovery (including fines) in ore sorting was 92% for 65% of the mass and based on metallurgical test work, the predicted processing plant recovery was 89.9%. From an economic perspective, based on the cost benefit analysis, for 1,400 US$/oz, 1,500 US$/oz and 1,600 US$/oz, the stope starts to be profitable after 1.07 g/t, 1.02 g/t, 0.94 g/t of gold, respectively. | |
