Cleaning of coarse and small coal

Methods for cleaning coal particles greater than 1.0 mm in size are discussed. Water-based technologies include jigs, dense (heavy) medium baths and cyclones, fluidised beds and Reflux Classifiers (RC). Dry-based methods include air jigs, air-fluidised beds and tables and optical/X-ray sorting. Likely future trends in plant design are discussed. Continued improvement in dry-based methods may see them being used more often as a preliminary de-stoning step for coarse particles. Improved water-based technologies will enable an increase in the upper size of the fine coal circuit, from 1 mm up to say 4 mm, which should significantly increase plant capacity.