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Application for Technical Revision to MLRB Permit 80-<l7 Page 2 of 7 Approximately 16 miles north of Parachute, Colorado Approximate elevation: 7,000 - 8,000 feet Map showing the location of the proposed project is attached as Annex A. Land Ownership: Private General Project Description: ExxonMobil Upstream Research Company ("URC"), a subsidiary of Exxon Mobil Corporation, has an ongoing research program into oil shale conversion technology. This reseazch has led to URC filing for patents on its ElectrofracT"~ process. The envisioned process involves fracturing the oil shale rock using conventional oil well fracturing techniques, injecting a proppant that will conduct electricity within the fractures, and establishing an electrical current within the propped fracture which maybe used to resistively heat the rock. All research and development of this process thus far has been done in a laboratory. The Electrofrac concept, along with laboratory and modeling results, was presented in a paper given by W.A. Symington at the Colorado Energy Research Institute 26`h Oil Shale Symposium last yeaz. Experiment Description ExxonMobil now plans to begin field testing aspects of the ElectrofracT"' process at the Colony Shale Oil Project site. The objective of this testing is to develop reliable methods to construct an Electrofrac electrically conductive fracture. This involves drilling one or more horizontal boreholes within existing mine entries at the mine bench of the Colony Shale Oil Project. The boreholes will be two to four inches in diameter and approximately 100 to 200 feet in length. The oil shale surrounding these boreholes will then be fractured using conventional oil well fracturing techniques and an electrically conductive inert material, such as calcined coke, injected into the fractures. It is expected, based on the reseazch work done, that the fractures will extend approximately 30 to 50 feet in height (total vertical disturbance above and below the boreholes) but remain in the Mahogany Zone of the oil shale formation. A schematic diagram of how these fractures might be positioned and connected is shown in Annex B. The experiments are designed to evaluate how best to construct an electrically conductive fracture. It is not the intent of this experimental work to generate oil and gas from the oil shale. Temperatures will be monitored at numerous locations around the propped fracture. If temperature sensors detect a localized elevated temperature zone, then the electrical current will be shut off before temperatures in the rock approach a level at which oil and gas would be generated. Maximum temperatures in the experiment are not expected to exceed forty to eighty degrees Fahrenheit above subsurface ambient temperature.