Ore mining fundamentally depends on the definition of its tenor and volume, something extremely complex in disseminated mineralization, as in the case of certain types of deposits of gold and sulfites. This article proposes the use of electrical tomography for definition of a geophysical signature in terms of electrical resistivity and chargeability, in an outcrop of mineralized quartz lode at the end of an inactive gold mine. One of the targets was to analyze the continuity of the mineralized body, the occurrence of new outcrops and the applicability of the method as an auxiliary tool in mineral extraction. Three parallel lines of electrical tomography in a dipole-dipole arrangement, being orthogonal to the orientation of the gold lode, were installed in an area outside the mine. The results allowed the geophysical characterization of the mineralized zone by high resistivity (above 1000Ω.m) and high chargeability (above 30mV/V). The results of the 2D inversion models were interpolated in 3D visualization models, which allowed definition of the contour surfaces for the physical parameters measured, and the morphological pattern modeling of the mineralization. The data reveal the existence of a new lode in subsurface, localized 30m to the south of the lode outcrop. The versatility of the acquisition and data processing indicate the application potential of electrical tomography as a criterion for sampling and tenor definition in ore extraction activities, since it is objective and low cost.

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Landfills are the main destination of solid waste generated in Brazil. Based on technical criteria, the construction of a landfill aims to minimize environmental impacts since it can present problems of high complexity. This paper discusses the use of electric resistivity tomography applied in a waste cell of a landfill, and its objective is to evaluate the effectiveness of such tool in the detection of possible leachate's leakage points in the landfill's geomembrane. The leachate is a liquid effluent characterized by a high content of dissolved salts produced by the decomposition of organic matter. Therefore, a signature of low electrical resistivity defines the presence of this compound in soil and groundwater. The analysis of 12 sections of electrical resistivity tomography in Schlumberger arrangement allowed the estimation of 47 Ω m as the minimum resistivity value for the natural conditions, in addition to the possibility to provide the identification of the area under the waste cell with lower resistivity values. The integration of a software that compiles 2D data into 3D viewing models enabled isosurface adjustments of 7 and 14 Ω m in resistivity maps to − 4 and − 10 m depth levels at the base of the landfill and the aquifer, respectively. These areas define points of infiltration in soil, by leakage at geomembrane in the bottom of the landfill. The results show the applicability of the method in the diagnosis of leachate contamination in a high-complexity environment. In addition, it is possible to establish an effective system for the remediation in a place where the installation of monitoring wells can increase the environmental impact.

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The discovery of new mineral resources involves various research techniques through direct and indirect studies. The geophysical methods are important tools in the detection of deep deposits because they use the contrast between the physical properties of the hosting rocks and the mineralized zone. In this sense, electrical geophysical methods are widely used in the prospecting of sulfide deposits. This work presents and discusses the results of the application of the Induced Polarization geophysical method in the investigation of a tin mineral occurrence associated with greisen, located on the western border of São Sepé Granite. The study area is located in the central portion of the Rio Grande do Sul State, in the municipality of São Sepé (RS), housed in the metavolcano-sedimentary rocks of the Vacacaí Metamorphic Complex. Six lines of electrical tomography were parallel arranged in the N30W direction. The 2D inversion models allowed to identify areas of high chargeability (above 5.0 mV/V), possibly attributed to areas with sulfide accumulation. The areas with low values (below 1.9 mV/V) area associated with soil and rocks absent of mineralization. Through the 3D visualization models, it was possible to identify that the mineralized zone apparently has continuity for more than 36 m. These models also allowed identifying the morphology and the lateral continuity of the sulfide zone. Thus, the results of this work demonstrate the possibility of using Induced Polarization in the research of cassiterite deposits with associated sulfides due to the contrast of physical properties obtained from the high polarizability of the sulfides.