gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1998.62A.1.142 High Pressure Adsorption of Natural Gas on Coal as a Possible Fractionation Mechanism Caja M. Ungerer P. Thermodynamics and Transport Department, Institut Français du Pétrole, 92852 Rueil Malmaison Cedex, France Prinzhofer A. Geochemistry Department, Institut Français du Pétrole, 92852 Rueil Malmaison Cedex, France 1998 62A 1 269 270 Copyright © 1998, The Mineralogical Society 1998