Tests were conducted in a salt media for the purpose of simulating single- and multi-cavity sweep in underground coal gasification (UCG). Two-dimension tests were run with 1 foot well spacings. Single-column, two-column cavity progression from one set of wells to another set of wells in downstream progression, etc., and three-column tests were like-wise conducted. Nearly complete resource recovery was achieved wherein supported columns were left for subsidence (support) considerations. 4 refs.