Groundwater quality near an underground coal gasification experiment

Abstract Groundwater sampling and analysis have been carried out at the site of an underground coal gasification experiment conducted near Gillette, Wyoming. Water from more than 12 wells in the vicinity of the experiment has been sampled before, during, and up to 25 months following gasification. Water samples were analyzed for a variety of characteristics, including the presence of 70 inorganic species, phenolic materials and volatile and semivolatile organics. We find a greatly increased concentration of organic materials, particularly phenols, just outside the burn boundary and a variety of inorganic species issuing from within the residual ash bed. All detectable contaminants rapidly decreased in concentration with distance, although above-background levels of some materials were detected 30 m (100 ft.) from the burn zone within three days of the gasification. Several important contaminants showed a large decrease in concentration with time due, probably, to adsorption. Our results suggest a simple physical picture of the development of groundwater pollution near an underground coal gasifier.