Stope productivity improvement through application of cut-and-fill mining method variant at Bogala graphite mines, Sri Lanka

Abstract

Vein graphite mining is more often carried out by underground mining in Sri Lanka due to its mode of occurrence. Bogala underground mine is one of the major graphite mines in the country, where overhand cut-and-fill mining method is used for the extraction of graphite since the ore bodies are steeply dipping, with considerable vertical extent and clear and stable ore boundaries. According to the standard practices at the mine, ectraction is carried out at the stope by blasting of both rock and graphite vein in the exposed face, followed by hand sorting to collect graphite. Blasting the host rock and veins are carried out separately. Waste rock generated is used to fill the lower bench. Simultaneously, stope support is carried out and the working platform prepared. In this practice one cycle extends for four shifts and the research was launched with the objective of improving stope productivity by reducing the cycle time. In the proposed methodology, blasting of the face (graphite vein and rock) was carried out simultaneously resulting in the reduction of cycle time to two shifts. Therefore, in the research carried out, with the proposed alternative stope technique followed by froth flotation relevant performance indicators or parameters of productivity, cost and safety were analysed.