"In 1969, the U. S. Department of the Interior resulted in Gulf Oil Corporation and Standard Oil Company (Indiana) acquiring an oil shale lease for Tract C-a in the Piceance Creek basin of northwest Colorado. Gulf and Standard submitted the high bonus bid for Tract C-a ($210,305,600) at a lease sale in Denver on January 8, 1974. Rio Blanco Oil Shale Project (RBOSP) an organization directed an staffed by representatives of Gulf and Standard, was formed later that year for the purpose of developing Tract C-a. In the past two years, RBOSP has conducted extensive geotechnical and environmental data collection programs designed to establish baseline conditions on and around Tract C-a and to provide input to engineering studies leading to the selection of mining and processing plans for Tract C-a development. This 4-vo1ume detailed development plan (DDP) describes the baseline conditions and RBOSP's proposed construction and operation of a commercial-scale oil shale complex and support facilities on and around Tract C-a. Three major requirements must be met before development operations on tract C-a can begin : • The Area Oil Shale Supervisor, U.S. Geological Survey, must approve the development plan. • Key Federal and State actions must be fulfilled and permits issued. -The proposed development described in this plan must be commercially feasible at the time investments are committed."