Abstract: An insulated bulkhead seals an access drift adjacent a hot portion of a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort. The bulkhead includes a steel plate for closing the cross-sectional area of the drift. The periphery of the bulkhead is anchored in concrete in a slot cut into the walls, roof and floor of the drift. A first layer of heat insulating material is applied to a face of the bulkhead plate adjacent the hot portion of the fragmented mass for reducing heat transfer to the bulkhead from the fragmented mass. A second layer of heat insulating material covers the walls, roof and floor of the drift adjacent the insulated face of the bulkhead plate to minimize thermal degradation of formation surrounding the periphery of the bulkhead.

Abstract: Impurities are removed from impure water by introducing the impure water into a fragmented permeable mass of particles containing raw oil shale. The water introduced can be water containing hydrocarbons such as water obtained from retorting oil shale or water containing suspended solids such as blowdown from a steam generator. After introducing impure water into the fragmented permeable mass, the mass of particles can be retorted. This is particularly advantageous when the introduced water contains hydrocarbons because at least part of the hydrocarbons removed from impure water can be recovered by retorting.