Análise do uso de rejeito de mineração para aplicação em camada de sublastro ferroviário

Abstract

Mining activities generate a significant amount of waste and tailings, byproducts of the mining and beneficiation process, which have mineralogical, geotechnical and physical-chemical characteristics that vary depending on the type of ore and the beneficiation process itself. This situation has been a concern for mining companies due to environmental, technical and economic issues. Therefore, the use of alternative techniques and materials has become viable, given the lack of financial resources for application in the most diverse sectors of the economy and the need for environmental protection. The addition of polymers to granular materials, such as mining tailings, is a soil improvement technique that provides increased mechanical resistance to the composite, reducing impacts on the environment. The sandy tailings studied were collected in the municipalities of Congonhas and São Gonçalo do Rio Abaixo in the state of Minas Gerais. The main objective of this research was to evaluate the possibility of reusing iron ore tailings in the construction of a structural layer for railway paving. The experimental research carried out physical characterization studies with granulometric analysis tests, Atterberg limits and true density. For the mineralogical characterization, X-ray diffraction tests were performed, and for the mechanical characterization of the tailings, compaction, expansion and California Bearing Index (CBR) tests were performed. Based on the results obtained with the aforementioned tests, it was possible to conclude that the use of sandy tailings for a sample in a railway subballast layer is not viable, since the tailings do not present mechanical properties of interest to paving, with low support capacity. However, for the sample with chemical stabilization with the addition of 2% of the SOILTECH polymer, the results were satisfactory. There was an increase in optimum moisture, specific mass, CBR, and reduction in expansion