Application of Quebec recycling guidelines to assess the use feasibility of waste rocks as construction aggregates

Abstract

The mining industry generates large volumes of solid wastes, which are potentially suitable for recycling in the construction sector. Serious issues are mostly connected to the sustainable management of these wastes from a technical, environmental and policy levels. In the present study, the recycling potential of gold mining waste rocks as construction materials has been investigated according to Quebec (Canada) recycling guidelines of non-hazardous inorganic wastes based on a scientific point of view. Waste rocks were collected from a gold mining site (Quebec, Canada) and prepared using crushing and sieving methods. Acid generation potential, chemical analysis, mineralogy and pollution potential of waste rocks were assessed. Concrete mixtures were then prepared using crushed waste rocks and their mechanical performances and environmental properties were evaluated. The results showed that waste rocks sample contains 46% of coarse material similar to the normalized concrete aggregates. The toxicity characteristic leaching procedure (TCLP) highlighted the nonhazardous character of the studied gold waste rocks. The concentrations of leached pollutants were significantly lower than the limits fixed by the environmental protection agency (US-EPA). The same sample is classified as non-acid generating material. Considering the measured technological and environmental properties, concretes with good mechanical performances could be manufactured using gold mining waste rocks.