Unsaturated water movement through paraho retorted oil shale at Anvil Points, Colorado

Abstract

Surface retorting of oil shale on a commercial scale will require disposal of large quantities of spent shale, representing a potential environmental problem. Concern is with release and migration of pollutants from spent shale, controlled by water movement in proposed disposal piles. The hydrology of spent-shale disposal was investigated by using a one-dimensional, unsaturated flow model. A disposal pile in final constructed form, a disposal pile constructed over time, and a disposal pile with a revegetated surface were considered. Results of simulation indicate that at water contents proposed by the oil-shale industry, water movement through the disposal piles is a long-term process. Simulation of plants demonstrates that revegetation significantly reduces water storage in the profile. A first-order sensitivity analysis demonstrates that the model is sensitive to parameters controlling supply of water in the profile and less sensitive to parameters controlling movement of water. Recommendations are made for future research in both modeling and field measurements.