EFFECT OF COMBINED MODIFIED IN SITU/ABOVE GROUND PROCESSING OF OIL SHALE.

Advantages to combining surface retorting of mined shale and modified in-situ retorting are illustrated. A brief discussion of the importance of the oil shale reserves and the development stage of the two technology types is provided. With the combined process, resource recovery would be increased by a factor of 3 to 4. 14 over surface processing, and about 1. 25 over modified in-situ. It was assumed that the recoveries shown in the laboratory, computer predictions, and in the smaller scale in-situ tests, are achievable on the larger scale retorts. In trying to determine the economics of the combined process, it was concluded that engineering feasibility studies are needed. The author feels that a development/demonstration program for combined process should be undertaken.