"This report describes a laboratory investigation to evaluate the behavior of nahcolite bearing oil shale mechanically loaded during leaching to determine if an open structure can be formed and preserved for subsequent in situ hot gas retorting. Experimental procedures and techniques were established to determine if the dissolution of watersoluble minerals from the leached strata would provide a useful porous media to circulate process fluids for the production and recovery of oil. The results of the experiments show that the nahcolite in nahcolite bearing oil shale may be dissolved by H20 under conditions of high CO2 partial pressure or external compressive load without disaggregation of the shale structure. The resulting connecting porosity provides an air path with permeability which will be required for in situ retorting."