Evaluating the application of the Optima® classifier as a secondary beneficiation stage at the Phola Coal Processing Plant

¹ Phola Coal Processing Plant, R555 Road Ogies, South Africa
² Gravitas Minerals, Unit 9 Liverpool Business Park, 3 Liverpool Rd, South Africa
³ Thungela Resources, 25 Bath Avenue, Rosebank, South Africa

Abstract

South Africa's coal mining operations frequently produce fine coal which is usually discarded due to the high costs of handling. Studies have shown that these fines possess acceptable market calorific values and low ash content. Processes have been widely developed to convert these fines into a marketable product to blend with coarse washed coal to improve overall yields. Phola Coal Processing Plant makes use of triple start spirals to produce three streams of coal from the feed namely: product, middlings and discard. The spiral product is added primarily to the main DMS secondary product and opportunistically to the primary product depending on the quality, while the spiral discard and middlings are rejected. The spiral product contributes 5.2 % of the overall secondary product yield as a percentage of the head feed. Currently, the spiral material does not satisfy the primary product specification, and the goal of this test work was to ascertain whether the spiral product can be upgraded using the Optima® Classifier 500 pilot unit (OPC) in a second stage beneficiation to meet the primary product specification. The test work was based on upgrading the spiral feed and a combination of spiral product & middlings to primary product. The results showed that when desliming the -0.15 mm material in the final product, the OPC was able to achieve the necessary upgrade to meet the export product specification at an overall yield of 2.8 %.