Stress redistribution in stope-and-fill mining operations with respect to cemented paste backfill material

Over the past decade, the mining industry has seen an increase in the application of the stope-and-fill mining method as conventional underground deposits have been depleted and operations have been forced to produce at deeper depths and in more challenging ground conditions. Through the utilization of cemented paste backfill (CPB) material for localized ground support, modern stope-and-fill mining operations have been able to increase productivity, effectively manage mine waste costs, as well as provide a safer mining environment. While the application of CPB has allowed for an increase in ore recovery, it is important that engineering and operations personnel have a clear understanding of the fill material as well as the limitations of the fill design to provide the most efficient, cost-effective, and safe extraction of underground reserves. Despite extensive use of CPB in mines around the world, many fundamental factors affecting the design of safe and economical fill structures are still not well understood. A critical issue in the design of backfilled stopes is the determination of the stress state within the fill material and surrounding rock mass. Recently work has been conducted further investigating stress distributions within engineered fill material as well as the stress interactions between the fill and the rock mass. While these works, as well as past research, have provided a wealth of knowledge on stress developments within the fill material itself, there is much room for further development of a more accurate understanding of the ability and mechanism of which the material is able to redistribute the stress around the excavation and through the fill material. This paper provides and overview of current research with respect to stress distributions for stope-and-fill mining operations and suggests areas in which further research is needed to fully comprehend the effectiveness of this newly developing ground support material.