Progress made on developing a predictive capability for in situ oil shale processing is described. Post-shot mapping on the single borehole crater shots conducted the previous quarter was completed. The mapping will permit an estimate of the void distribution in the rubble once the crater is excavated. The total increase in volume in the SB-1 test area was measured to be 29.7 m/sup 3/; the expansion in SB-2 was 25.4 m/sup 3/. The high speed photometric coverage taken during the blast has been reduced giving near surface rock velocities as a function of distance from the borehole. Measured velocities (after 30 ms) range from approximately 15 m/s near the borehole to less than 2 m/s three meters from the borehole. New simulations have been made using the code BLOCK to investigate the effects of jointing on rock motion. An initial series of laboratory tests that examine the effects of permeability contrasts on local yield have been completed. These runs demonstrated that yield losses can be introduced solely by permeability contrasts.