The Soviet literature contains a number of empirical correlations which interrelate important variables in the underground coal gasification (UCG) process. These correlations are based on the results of a massive field testing program conducted over a period of more than 40 years. Can the Soviet experience be used as a qualitative guide to this country's field testing of UCG which is still in its infancy? A theoretical analysis of Soviet field test data with the aid of a mathematical model helps determine the chemical and physical phenomena governing the behavior observed, and similar conditions and behavior can be expected in field tests in the United States. The mathematical model predicts such effects quantitatively.