This work presents several mathematical models of underground coal gasification processes. Through these models, a much better theoretical understanding of underground coal gasification becomes possible. Specific phenomena studied were the effects of high amplitude pressure oscillation, reverse combustion, spontaneous ignition at high pressures, an analytical model of reverse combustion channeling, an exploratory study of electrolinking, cavity growth behavior, and a technical evaluation of the Forestburg underground coal gasification field test at Forestburg, Alberta. This test is especially interesting because the site was escavated after completion of the experiment.