The Application of Post Consumer Glass as a Cementing Agent in Mine Backfill

Abstract

This research evaluated the application of post consumer glass as a cementing agent in underground mine backfills. The underlying theory indicates that glass is pozzolanic and, when used in finely divided form, reacts as an activator to generate binding products, thus contributing to the development of backfill strength. The objective of the research was to evaluate the strength performance of backfills when Normal Portland Cement (NPC) is replaced with various percentages of post consumer glass.

The research evaluated the performance of backfills prepared using tailings from three candidate mines, namely Stobie, David Bell and Kidd Creek. Each backfill was prepared using unique recipes, and the strength and other properties were evaluated at cure times of 7, 14, 28, 56, 112 and 224 days. Laboratory work involved visual, physical and chemical material characterization followed by strength evaluations.

Results of strength assessment reveal that glass, when incorporated as part of the binder in backfill development is reactive, and can contribute to the strength of backfill. Further analysis of the results also indicated that the reactivity of glass may be affected by the incorporation of slag within the recipe, the availability of lime and the level of hydration of the binders.

The research concluded that, at 15 % glass replacement of NPC, backfill prepared with David Bell tailings, NPC and glass can achieve improved or equivalent strength performance compared to backfill prepared with David Bell tailings and NPC. NPC and slag outperformed backfills prepared with NPC, slag and glass at all replacement levels, using tailings from Kidd Creek and Inco-Stobie. However, future work should be designed to maximize the effect of specific pozzolan (for example glass) and material properties (aggregates) on backfill strength performance.