Stabilization of Hazardous Tin Mine Tailings for Extreme Climate Applications: Geotechnical and Environmental Perspectives

Abstract

This paper presents an experimental study of the stabilization and solidification of heavy metal–contaminated tin mine tailings (TMTs) using portland cement (PC). The objective was to explore its potential reuse as a geomaterial in cement-treated bases in pavements exposed to harsh climates. The research examined the mix design through the effects of varying cement content, durability test conditions, compaction density, and curing time on unconfined compressive strength (qu), accumulated loss of mass (ALM), and leached heavy metal concentration [using the toxicity characteristic leaching procedure (TCLP) method]. Results of the stabilization and solidification process indicate that the inclusion of a PC content of 10% by weight meets the regulatory requirements for reuse in stabilized structural pavement layers, improving mechanical strength, volumetric variation, and durability, and successfully immobilizes hazardous heavy metals such as As, Pb, Cr, Cd, Zn, and Cu. A strong correlation was found between the response variables and the adjusted porosity/volumetric cement content index (η/Civ index), which is used as a rational dosing methodology for artificially cemented TMT mixtures. The proposed dosage equations (ALM-η/Civ curves) reveal that, on average, the ALM under freeze–thaw conditions (ALMF-T) was 32.3% higher than under wet–dry conditions (ALMW-D).