In the study the research potential offered by the Scanning Electron Microscope to investigate into the surface of hard coal for mineral substances, especially of chlorine, was utilized. The identification of such substances basing upon the resulting X-ray spectra and photographs - allowed one to corroborate the usefulness of further investigation step - viz. leaching. Variable parameters in those investigations were: grain size, leaching temperature, time and leaching cycles. Of great importance for the efficiency of the leaching process is granulation. The smaller the grain of coal, the more chlorine was removed because the opening of pores closed in the process of fragmentation increases the carbon surface available for water molecules. (C) 2011 Elsevier B.V. All rights reserved.