OCR

for boiler burning tests. Present reserve estimates for the Navajo Mine are in excess of 1/2 billion tons of strippable coal, the coal lying in several seams having thicknesses varying from two to 20 feet. The main seam, which contains the bulk of the coal reserves, is about 13 feet thick and averages 9,500 BUT/pound. The beds dip at about 1-1/2 degrees toward the east or southeast. Minor faulting and rolls occur within the lease area, but no serious geological disturbances have been noted which would affect mining operations. Proceeding from north to south along the lease, the coal seams become more numerous and generally thicker. As a consequence, approximately one-half of the coal reserves are concentrated in the southern one-third of Utah's lease. Potential Markets Utah conducted many studies to define the potential markets for its coal. Considering transportation problems , competition from other fuels , lack of strength in the coal-chemical market, and other relevant matters, it became apparent that the most feasible immediate use of the coal would be as a fuel for thermo-electric generation. After discussing the feasibility of a power plant located in the Four Corners area with several utility companies that provide service in the Southwest, Utah signed a fuel agreement in August 1960 calling for the delivery to Arizona Public Service Co. of energy equivalent to 1,500,000 tons of coal annually for 35 years, with an option to extend the term for an additional 15 years, and to provide additional fuel as the generating capacity is increased. The attraction of high electric consuming industries to the area has been and will continue to be an objective of Utah. Arizona Public Service Co. APS Co. , serving an area covering 40, 000 square miles including 215 communities in 10 of Arizona's 14 counties, broke ground in March 1961 for a steam generating plant consisting of two 175,000-kw turbine generators. It placed the facility in commercial operation in May, 1963. Ebasco Services, Inc. , was the prime contractor for the plant. At the initial rating of 350,000 kw, the plant and the 292-mile trans- mission line to Phoenix, Ariz. represents an investment of $95 million. APS Co. already has commenced construction of a third unit rated at 225, 000 kw at a cost of $25 million to expand the generating capability to 575, 000 kw by the summer of 1964, and a fourth unit presently is being contemplated. The Four Corners Plant layout and the related cooling and storage reservoir are designed to permit ultimately the operation of six unite totaling 1,250, 000 kw to 1, 500,000 kw. Artificial Lake To supply cooling water to condense steam at the plant, a 1,200 acre artificial lake was formed with water pumped from the San Juan River some three miles north of the plant. Utah took steps to acquire the right to use this water in 1955., The 100-foot deep lake, named Lake Morgan