The Energy and Environmental Research Corporation (EER), in cooperation with the University of Alabama (UA) and the Mining Division of Jim Walter Resources, Inc. (JWRI), was awarded a U.S. Department of Energy (DOE) contract to retrofit an existing fire-tube boiler to bum coal-water fuel (CWF). A fire-tube boiler on the UA campus was retrofitted, and the CWF was made from Blue Creek coal fines produced by JWRI, which is located 45 min from the UA campus. The boiler was successfully operated for 800 hours on CWF. Operating with CWF required a boiler derating of 20% and natural gas as a support fuel. This article reports on the mechanical details of the conversion of the fire-tube boiler from naturalgas to CWF. The rationale for conversion to CWF and the background on CWF atomization and combustion are given.