"On Sept. 28, 1977, a meeting was held at the Department of Energy's, Vernal, Utah tar sands site to review the progress of the in-situ burn which is currently taking place. It was pointed out at that meeting that the reverse burn was not moving in the proper direction to encompass the entire target zone as required for maximum resource recovery. As a result of that meeting, Science Applications, Inc. was requested to analyze the current data and to make recommendations as to the best methods to move the reverse burn flame front in the desired direction and to spread it out over the southern and eastern sections of the formation. These recommendations were to be made in conjunction with D.O.E. personnel and coordinated through them. Numerous phone conversations between SAl and D.O.E. people resulted in a preliminary set of recommendations which were transmitted to L. Marchant by memo from J. Winter dated Oct. 21, 1977. This then is a more complete analysis and set of recommendations offered by SAl to apply to future experiments as well as to the current burn. the data which was analyzed included initial tracer tests, daily temperature and pressure profiles, daily product gas G.C. analysis, and day to day changes in the operation of the site. The following methods were used to evaluate the accrued data: 1. The CO2 - CO ratio was plotted vs. time and compared to the equilibrium constants vs. temperature. This information reveals the approximate temperature through which the product gas has passed. 2. Temperature profiles of the observation wells were plotted. 3. Equations were developed and computer contour plots created from the observation well temperatures. 4. Results of tracer tests were compared with temperature profiles to determine directions of the reverse burn."