Poland is the second biggest European producer of hard coal. This raw product is cleaned in 49 preparation plants. Production capacities of the preparation plants depend on the demand for coal. The clean-coal production mostly depends on the quality demands of customers. Polish hard-coal is of good quality. It is enough to remove grains of clean stone to get saleable products of ash content between 8 and 12%. Rarely the ash content is up to 15%. The coal can be cleaned to 4-6% ash content, but there is a very small demand for this type of coal. Gravity separation (via heavy liquids, jigs, cyclones) removes the grains of pure stone. Currently, no preparation of the coal after grinding is conducted. (C) 2003 Elsevier Science Ltd. All rights reserved.