Abstract
Quantitative mineralogy-based techniques allow us to quantify mineral compositions, associations, and textures with increasing resolution and throughput. Even though applications have been more extensive in mineral exploration and processing, quantitative mineralogy has emerged as a tool for studying the reactivity of mine wastes. Particularly, analysis of the degree of liberation of acid-generating versus neutralizing minerals enables higher certainty in effluent quality predictions. Yet, integrating the microscale mineral and textural features of mine waste materials with the long-term evolution of wastewater quality dynamics at industrial scales remains a challenge. To mechanistically integrate the parameters that govern the mineralogical and geochemical dynamics of mine wastes, we must strategically incorporate variables that capture the heterogeneity of solid-liquid interfaces within waste materials.
In this study, we investigated the evolution of the effluent water quality and mineral dynamics of waste rock materials derived from accelerated weathering experiments in leaching columns. A reconciliation based on multivariate statistics between the variations in the chemistry of the leachate data and the mineral features of the waste rocks using Mineral Liberation Analysis (MLA) allowed us to demonstrate that key drainage features can be quantitatively linked not only to carbonate-sulfide interactions but also to the particle size and associations with silicates and oxides. By comparing microscale parameters with bulk geochemistry (XRF) and mineralogy (XRD), we further determined the representativeness of MLA-derived textural parameters in effluent quality predictions. The results from this study provide a road map towards better integration of mineral dynamics in mine wastes with contrasting lithologies.