at better prices when the market becomes stronger and demand increases at a rate that will press the industry's ability to supply. The fourth parent company operation is a steam coal mine in the Four Corners area of New Mexico which is supplying coal to five utility-owned mine-mouth generating units with a combined capacity of 2,085,000 KW. The coal requirements of these generating plants is being provided under two long-term contracts with escalation clauses running for 35 years with options on the part of the customer to extend for another 15 years. From a production of 963, 000 tons in 1963 our deliveries of steam coal increased to 5-1/2 million tons in 1970 and are expected to approximate 8 million tons annually under the existing contracts now that all the generating units are on stream. Our Navajo mine is the largest coal mine in the United States, sells its coal at the lowest price in the United States, and still produces a profit that compares favorably with our competitors in this area. The existing long term contracts only commit approximately 40% of the available reserves and we will continue to seek new customers to utilize the remainder of this valuable reserve of low-cost energy. Let us turn now to Utah Development Company, whose prospects are among the more exciting that our company has to offer. Once a wholly-owned subsidiary concerned with Utah's coking coal operations in Australia, we decided last year to convert it into our operating vehicle in Australia and to sell an interest in it to the Australian public. For obvious and understandable reasons the Australians are eager to participate in the exciting mining developments taking place in that country. To accommodate them we made 6.