"TRW has been tasked by Applied Management Services (AMS) to provide the Department of Energy with an assessment of potential ground water contamination due to underground coal gasification experiments at the Hoe Creek Site south of Gillette, Wyoming. This report will provide a brief synopsis of the problem including a hydrogeologic description of the area, highlights of the baseline data collection program, and description of some significant process characteristics which may have affected the distribution of contaminants. The present interest in contaminated ground water or the Hoe Creek site came as a result of reports by Lawrence -Livermore Laboratory, the conductor of UCG experiments at this site, that higher than background levels of dissolved phenol were present very near the Hoe Creek site's eastern boundary. The observation well from which this sample was taken, WS-14, was a monitor well installed for the Hoe Creek II experiment, (October 28, to December 25, 1977) . Because this site was the focus of attention, and because of the limited time available, this report will focus mainly on the contamination problems associated with Hoe Creek II. A similar methodology could be applied to the study of the effects of Hoe Creek III. TRW began its effort at sorting out the effects of the UCG experiments at the Hoe Creek site by obtaining available data on the water quality sampling and water level measurements from the Laramie Energy Technology Center (LETC). This data was supplemented by LLL reports and other analyses of the area from published sources and government publications, which are listed in the bibliography at the end of this report."