The field trail used a mixture of steam and air with various levels of oxygen en-richment. Steady conditions were achieved in the field trail which produced high qualityhydrogen-enriched syngas. To understand and optimize the UCG process, a simplifiedheat and mass transfer model was presented, providing a predictive tool for temperatureand the major constituents of the syngas production. The model is compared with the fieldtrail measurements for air and two levels of oxygen enrichment, showing reasonableagreement for the channel temperature and product syngas concentration profile.