The spalling-enhanced-drying model which has been recently advanced to predict water influx is modified by incorporating a more realistic cavity-growth model. Cavity-geometry predictions from this improved model are compared with coring data from the Hanna 2 field-test site. The predicted maximum cavity height of Hanna 2, Phase 2 is shown to be within the error of the coring measurements. The predicted cavity geometry for this field test shows good agreement with the coring studies. A control strategy is described which keeps the ratio of water influx to coal consumed constant during a test similar to Hanna 2, Phase 2. This strategy would help to keep the product-gas heating value constant.