Investigation of the Effect of Using Sungun Copper Mine Tailings Instead of Fine-Grained Materials in Concrete Construction on Mechanical Properties and Heavy Metal Leakage

Mining is an upstream industry in the supply of industrial raw materials. The large volume of mine tailings as well as the considerable concentration of toxic pollutants, resulted from mining activities, cause irreparable damage to the surrounding environment. The leakage of toxic elements from the mine tailings to the environment is considered as a crucial issue. Therefore, the management of mine tailings is an important approach to reduce environmental damage. The reuse of mine tailings in concrete industry is considered as one of the main management techniques to reduce their probable adverse effects. In this study, the tailings of Sungun copper mine were collected to investigate their applicability in concrete construction instead of fine-grained materials. The results revealed that the concentrations of copper, arsenic, lead, chromium, cobalt, and nickel in copper mine tailings were higher than the environmental criteria but less than the amounts required for economic recovery. Thus, tailings with a grain size of less than 297 μm were used in the construction of two series of concrete samples to replace 50 and 100% of the fine-grained part of the concrete. Moreover, some experiments including concrete slip, compressive strength, resistance to chlorine penetration, and TCLP were performed to ensure the applicability of copper mine tailings in concrete construction. In samples where copper tailings replaced 50 and 100% of fine-grained materials, the 28-day compressive strength was 32 and 41 MPa, respectively. The compressive strength increased with increasing replacement rate. According to the results, the highest leachate rates of copper, chromium, lead, zinc, cobalt, cadmium, and arsenic were 21, 2.8, 3.9, 106, 75, 0.39, and 0.82 mg/L, respectively. Thus, it could be concluded that if copper tailings are used in concrete, the amount of heavy metals leachate will be reduced to values below the environmental criteria level.