The Powder River basin of northeastern Wyoming may be the richest coal basin in North America. Coal beds are present in the upper part of the Tertiary Fort Union Formation (Tongue River Member), and in the lower part of the overlying Wasatch Formation. These

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coal beds crop out along the eastern flank of the basin.

In the central part of the basin, the coal beds are at depths of 1,000-2,200 ft. Many holes drilled for oil have penetrated the coal-bearing interval. Although determinations from mechanical well logs are questionable, it is believed possible to identify these coal seams and to measure their thickness. Individual coal beds average about 50 ft thick, but locally may increase in thickness to 100-150 ft. The depth interval contains gross coal thicknesses of 200 to 400 ft: The total coal-bearing section is made up of as much as 30% coal.

The site of Project Thunderbird is underlain by coal beds which contain a reserve of more than 20,000-million tons of coal. On an energy basis, this coal has a greater Btu content than twice the proven oil reserves of the United States today (31-billion bbl).

Because the country's energy demands are soaring, techniques for extracting the coal energy from the reserve at Project Thunderbird should be developed. Several coal-energy extraction proposals are offered, including the use of a nuclear device to allow gasification of coal underground.

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