Tipos de ruptura geológico e geotécnica, tipos de ruptura e estabilidade de taludes na mina de ferro do bonito em Jucurutu - RN

Abstract

Located near the city of Jucurutu in the state of Rio Grande do Norte, the iron mine of Bonito is inserted into the tectonic framework of the Province Borborema. More specifically, in Domain Rio Piranhas-Seridó, neoproterozoic.The iron ores of the Bonito mine are sedimentary and hydrothermal origin, and were metamorphosed and deformed along with quartzites, schists and marbles of Jucurutu and Serra dos Quintos formation. These rocks compose together, a kilometric sinformal structure with axial plane oriented N-S and axis dipping southward. The tectono-metamorphic, hydrothermal and supergene processes that occurred during the evolution history of the deposit, generated ductile and brittle structures, causing changes in the physical and geomechanical properties of the ore and host rocks This set of geologic features influences the shear strength and slope stability during mining operations. The geological and geotechnical investigations of the characteristics and features of the rock make it possible to identify conditions that may influence the stability of rock slopes of Bonito mine. The geotechnical behavior is indicated by the conformation of the types of discontinuities and disruptions generatedThe main tectono-metamorphic foliation (Sn), commonly parallel and concordant to the sedimentary layering (SO), has preferred orientation ranging between E-W and NE-SW, dipping SSE. This framework can serve as sliding plane and produce planar disruptions to consider preferential advancement of mining in north predominant direction. Sets of fractures with NS, NNW-SSE and NNE-SSW direction acting on the lateral detachment of rock blocks along with the main foliation. Also, penetrative discontinuities ofhigh angle dipping into the slope faces plunging SSE direction to cause tipping blocks. The study also showed that the presence of discontinuities added to existing typological variation in itabirites mine leads to different geomechanical behavior of the rock linked to the degree of fracturing, coherence, alteration and the resistance of the rock mass. It was also found that an integrated analysis of the largest possible number of factors is necessary for the geotechnical approach the reality observed in the field. Through this it is clear the importance of geological knowledge in advance of mining activity.