Optimisation of cemented aggregate backfill at New Luika Gold Mine

Cemented aggregate fill (CAF) and cemented rockfill (CRF) have successfully been used as a low-cost, highstrength backfill material in underground mines. The placement of the material and flowability generally limits the technology to low throughput application and smaller stope sizes if tight filling is required. Optimisation of CAF/CRF flowability and strengths is most readily achieved by optimising the Fuller–Thompson gradation curve. CAF/CRF relies on the materials available on the mine site and the additional costs of borrow pits or additional crushing adds significant cost to a material that is usually chosen due to low cost. This paper presents a case study of an optimisation of a CAF material by the addition of tailings in order to increase the paste fraction of the material. The main aim was to decrease the angle of repose to improve filling ability in addition to decreasing the required binder content.