Investigation of Mining Backfill Materials and Techniques at Fosterville Gold

This project investigates the current practices and technologies for mining backfill. The advantages and disadvantages of varied techniques were investigated in order to identify the optimum solution to ensure efficient mining of ore at Fosterville Gold Mine, near Bendigo.

The proposed solution for the dilution of gold bearing rock from old stope is cemented paste backfill. Various cementing materials were mixed with tailings from gold extraction process. Four mixes were tested, 5% Portland Cement, 1% Silica Fumes + 4% Portland Cement, 2% Fly Ash + 3% Portland Cement, 4% Furnace Slag + 1% Portland Cement, to measure their compressive and tensile strengths, estimate and contrast their shear strength parameters (cohesion and angle of internal resistance) and quantify their elastic properties. These parameters were then employed to analyse the stability of the backfill. Finally, the economic feasibility and practicality aspects were assessed to determine the viable solution.

It was found that an alternate binder such as industrial slag would be a viable structural and feasible long term solution for Fosterville Gold Mine. However, for only a 1.5 years mine life, the implementation of a paste plant is not an economically feasible solution.