Technological assessment of tailings from quartzite mining sites in Alpinópolis (Minas Gerais–Brazil) as aggregates in concrete block paving (CBP)

Abstract

The quartzite minings of Alpinópolis—Minas Gerais—Brazil represent an important share of the regional economy; however, the difficulties of the miners in meeting the environmental requirements have led to the closing of the activities in many places, which reflects both a social problem, increasing unemployment, and an environmental problem due to the large environmental liabilities caused by the piles of tailings resulting from the activity. This article discusses the search for alternatives for this problem and trusts in the reuse of these tailings as aggregates for the civil construction as a way to promoting socio-environmental sustainability in the region. The objective of the research was to evaluate the feasibility of using the tailings thrown in the mining tailing piles as fine and coarse aggregate for the production of concrete block paving as an alternative to the use of conventional aggregates. The steps of the research were: choosing and preparing the study materials; technological characterization of aggregates; aggregate dosing study; producing and testing of concrete parts; and economic feasibility study. Parts made with different fine and coarse aggregate dosages of quartzite tailing presented satisfactory results for different applications; however, the parts which were replaced only with the coarse aggregate were those that achieved the best resistance values. In the economic feasibility study, it was estimated that a cost reduction of around 23% would result from the implementation of paving when only the conventional coarse aggregate is replaced by the tailing quartzite and a 37% reduction when both the coarse and the fine aggregate were replaced.