Geophysical methods for BR tailings dam research and monitoring in the mineral complex of Tapira-Minas Gerais, Brazil

Abstract

The use of geophysical methods in the BR dam at Tapira mining complex in Minas Gerais state, Brazil, had as main objective to develop a research geophysical methodology complementary to the existing conventional monitoring system. Electrical resistivity and GPR (ground penetrating radar) methods were used. Ten geophysical sections were acquired parallel to the main axis of the BR dam. The water table level delineated by geophysics was later compared to five type-sections data, which comprised the readings of 9 water level indicators (INA’s). The electrical resistivity results delineated the level of the water table and showed the moisture areas in the BR dam. Low resistivity zones (LRZ) were correlated with regions saturated or with a high moisture content with resistivity responses below 250 ohm-m. The GPR responses, saturated zones presented strong attenuation in the reflectors, being this effect smaller with the decrease in the water content. In some sections it was possible to correlate, patterns of reflectors to different resistive zones. Geophysics results showed great efficiency in the BR dam investigation and monitoring, through the generation of continuous indirect indicator data. Which after processing resulted in a complete 2D and 3D view of the interior of the studied dam.