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,, ~ , E. ~J -3- 16,250 yd3 per month. This rate will remain relatively con- stant depending on the number of working areas available underground and the amount of equipment breakdowns that are encountered. This mining facility is expected to remain a research and development activity for the foreseeable future. Revegetation of the raw shale will begin within one year of any area becom- ing inactive, such as benches not being used as part of the on- going operations. The slopes of the dumps and other affected areas will be prepared for revegetation activities upon abandon- ment which is anticipated to be in the year 2040. The life of the mine is expected to be 63 years. Geology - Nature, depth and thickness of the ore body: The geology of the Callahan Trust/D.A. Shale property has been investigated from the viewpoint of using that property as the in-situ test site for the Occidental Oil Shale process. The Callahan Trust/D.A. Shale area is located in Garfield County, Colorado, between DeBeque and Grand Valley in the southern part of the Piceance Basin. The oil shale described in the follow- ing section on stratigraphy outcrops along the Roan Cliffs on the north side of the Colorado River. Mt. Callahan is in the eastern part of the area with an elevation of 6606 feet and is almost 3600 feet above the river. Riley Gulch and Logan Wash, the two major drainages of the area, range in depth below the ridges from several hundred feet to almost 3000 feet. However the ridge tops are as much as a quarter mile wide, and travel by four-wheel drive vehicle across the area is not difficult once the top of the ridges has been reached. Stratigraphic units outcropping in the Logan Wash area include the Wasatch formation of Eocene age, the Green River formation, also of Eocene age, and basalt of late Tertiary age. The Wasatch formation does not outcrop on the property. How- ever, it must be crossed by every access road reaching the area from any direction except north. The Wasatch formation is of continental origin and comprises siltstones with a high per- centage of clay and sandstones. It underlies the oil shale formation throughout the basin. The main oil shale section is contained in the Green River formation which is comprised of three units, the Douglas Creek member, the Garden Gulch member, and the Parachute Creek member containing the oil shale, and overlain by the sands of the Unita formation. The Douglas Creek member is formed of cross-bedded ripple-marked sandstone with some limestone and shale. It forms a prominent outcrop in Logan Wash. The Garden Gulch member overlies the Douglas Creek member and underlies the Parachute Creek member. The predominant rock type r'