Use of ground waste glass and Normal Portland cement mixtures for improving slurry and paste backfill support performance

Research has demonstrated that finely ground industrial and municipal container waste glass can be utilized as an effective partial pozzolanic replacement for Normal Portland cement (NPC) in various types of mine backfill at significant potential cost savings. Information is presented that summarizes comparative strength behaviour of a variety of mine backfill products, from different mine sites, when manufactured in the forms of hydraulic slurry and paste backfill media. Strength comparison has been conducted for a range of NPC and ground waste glass-consolidated slurry and paste backfill products, with intercomparison also being made versus 100% NPC-consolidated products as control standard materials. For slurry and paste backfill mixtures, up to 35% of the Portland cement binder was replaced by ground waste glass material with excellent strength characteristics being developed. Ground waste glass has been shown to be capable of providing equivalent or better backfill strength characteristics with respect to Normal Portland cement in the long term, over cure intervals up to 224 days, and at potential cost savings of up to 50% being projected. The results of parametric studies to explore the sensitivity of ground waste glass pozzolans to variations in mixture moisture content, tailings mineralogy, pozzolan size distribution, cure temperature and glass type are also presented. Consideration of the competitiveness of ground waste glass as a partial replacement for NPC and other commonly-utilized mine pozzolan materials is based upon assessment of material grindability and other economic factors.