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Abstract

A coal mine in Mozambique, southern Africa, produces both metallurgical and thermal coal. A relatively high volume of coal washery wastes are produced due to a low average yield. Currently, the tailings are deposited as a slurry in a surface tailings storage facility (TSF1), while the rejects are hauled for disposal in dumps within the mine overburden. Due to the low dry density achieved by the settled tailings and the lack of suitable sites for new TSFs, dry disposal needs serious consideration for future tailings handling. This paper outlines the current tailings disposal issues and the potential dry disposal solution based around results from a pilot dewatering plant that was established to trial the most effective way of dewatering the tailings. The pilot plant was designed to trial the dewatering effectiveness of a paste thickener, a belt press filter and a centrifuge. The results indicate that the tailings can be effectively dewatered, a dewatered solution would be cost effective, tailings can be transported without issue and mixed with the rejects for co-disposal. Dewatering would eliminate the need to construct any further TSFs, increase the water recovery and reduce tailings disposal costs over the life of the mine.