Recently, a five-year field lysimeter study designed to evaluate the reclamation and leachate generation characteristics of eastern oil shale material was completed. Leachates from the lysimeters were subjected to detailed chemical analyses, and the elemental release patterns were examined as a function of time. The objectives of the present study are to provide a more detailed characterization of the chemistry of lysimeter leachates by subjecting the leachate concentration data to chemical equilibria model analysis.