CCC/185 ISBN 978-92-9029-505-1

August 2011

copyright © IEA Clean Coal Centre

Abstract

Coal is prepared to meet end-user requirements such as limits on the proportion of fine coal and ash

forming minerals in the product. Preparation methods leave residues of fine material which can have a

wide range of compositions from a good coal product to very high ash, surface moisture and sulphur

contents. Regardless of composition, at the time of generation of these residues no market for them

existed and so large amounts (estimated as about 58 Gt) have been deposited around the world in

heaps or in slurry impoundments. Changes to the value of coal and developments in coal preparation

and utilisation technologies have enabled increasing amounts of these materials to be recovered and

used. The report provides an overview of the resource and opportunities for utilisation.