Valorization of Gold Mining Tailings Sludge from Vetas, Colombia as Partial Cement Replacement in Concrete Mixes

The accumulation and improper management of mining tailings represent significant environmental and public health challenges globally, due to their potential for water contamination and the presence of heavy metals. In recent years, various studies have explored the feasibility of using mining wastes, such as tailings sludge, as partial replacements for cement in concrete mixes. The literature highlights the pozzolanic properties of mining tailings attributable to their silica and alumina content, which contribute to the improved structural characteristics, chemical resistance, and enhanced durability of concrete. This research evaluates the specific potential of gold mining tailings sludge (REMI) from the municipality of Vetas, Santander, Colombia, as a sustainable substitute in cementitious materials. Characterization methodologies including X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM) confirmed the pozzolanic behavior of REMI due to its high content of silica- and alumina-rich amorphous phases and verified negligible contamination levels (Hg and cyanide below detectable limits). Concrete mixes with varying cement substitution levels (0% to 50%) were formulated and systematically evaluated to determine optimal substitution ranges based on criteria such as density, workability, setting time, and compressive strength. Consistent with previous studies, the results revealed an optimal replacement rate between 10% and 20%, with a particular emphasis on the 20% substitution achieving mechanical strengths comparable to traditional concrete. These findings underscore the technical viability and environmental benefits of using mining tailings sludge, contributing both to sustainable waste management and the advancement of eco-efficient concrete technologies.