This is one of three reports evaluating hypothetical industry-scale projects for mining and processing of oil shale and/or associated sodium minerals in Colorado. Option I is concerned only with material from a white nahcolite bed in the Piceance Creek basin, Colorado, containing a high concentration of sodium bicarbonate at a nominal depth of 1900 feet. A nahcolite mine and processing plant is designed to mine 8000 tons of nahcolite ore per calendar day yielding 4071 tons per calendar day of soda ash product. The soda ash will yield an annual income of $52,749,400. Annual operating expenses including labor, materials, maintenance, taxes, insurance, payroll overhead, and depreciation will be $18,821,900 in 1971 dollars. The discounted cash flow rate of return is equal to 30.74 percent based on a weighted average depreciation life of 12.88 years.