Predictive waste classification using the geochemistry-mineralogy-texture-geometallurgy (GMTG) approach at a polymetallic mine

Abstract

Management of mine wastes, particularly waste rock, requires careful planning to reduce the likelihood of sulfide oxidation, and generation of ARD. Such a waste management strategy must be based on a thorough understanding of the environmental characteristics of the future waste rock materials. In this study, a waste management strategy for characterizing underground waste rock was developed at a polymetallic mine to determine which materials were appropriate for surficial placement. The criteria for surficial placement set by the regulator were that materials had to be non-acid forming and non-metalliferous. A range of cost-effective field based tools and state-of-the-art laboratory techniques were used on a suite of representative samples collected from the site to determine an appropriate waste management strategy. Ultimately, a modified geochemistrymineralogy- texture-geometallurgy (GMTG) approach was designed, whereby ARD focused logging and simple pre-screening tools such as paste pH and sulfur analyses were used at stage-one; routine acid base accounting and leachate tests at stage-two, and validation tools including X-ray diffractometry and laser ablation ICPMS at stage-three. Such an approach should be considered for other mine sites at all life-of-mine stages with similar deposit characteristics to ensure correct screening and placement of potentially hazardous waste materials.