Coal Geology of Okmulgee County and Eastern Okfuskee County, Oklahoma--A Preliminary Report

Leroy A. Hemish

This paper summarizes the location, quantity, chemical characteristics, and geologic character of the Desmoinesian and Missourian (Pennsylvanian) coal beds and associated strata of Okmulgee County and eastern Okfuskee County, Oklahoma. Four named coal beds are of minable thickness in the area. Listed in order of commercial importance, they are Croweburg, Mineral, Dawson, and Tulsa coal.

Remaining coal resources for the two-county area total 484,370,000 short tons, of which 15,707,000 tons are recoverable reserves. The Croweburg coal contains the most remaining resources (447,018,000 tons) and the most recoverable reserves (10,185,000 short tons).

Standard analyses indicate that the coals are mostly high-volatile A bituminous and high-volatile B bituminous in rank.

More than 100 analyses indicate that the Croweburg coal averages 8.8% ash and 2.6% sulfur on an as-received basis. On the moist, mineral-matter-free basis the Croweburg coal averages 13,753 Btu/lb. The other coals all have higher ash and sulfur content and lower heat values. Because of its superior qualities, greater bed thickness (52,737 ac are underlain by coal > 2.4 ft thick), and amenability to both surface and underground mining, the Croweburg coal has the greatest potential for use.

By state law, all coal-fired electric utility plants in Oklahoma are now required to burn a mixture of coal containing a minimum of 10% Oklahoma-mined coal calculated on a Btu basis. The recoverable reserves from Okfuskee and Okmulgee Counties could supply compliance coal to these Oklahoma plants for more than 10 years at 1 million tons/year.

AAPG Search and Discovery Article #91025©1989 AAPG Midcontinent, Sept. 24-26, 1989, Oklahoma City, Oklahoma.