Print this pageDeep Coal Resources of the Black Warrior Basin in Alabama: A Look Toward the 21st Century
PASHIN, JACK C., and RICHARD E. CARROLL
Coal mined from depths between 500 and 2,200 feet now accounts for more than 60 percent of the 25 million short tons of coal mined annually from the Black Warrior basin of Alabama; this percentage is increasing each year. More than 80 percent of the underground production is from eight mines producing metallurgical and steam coal ranging in rank from high-volatile A bituminous to low-volatile bituminous. Reserves are being depleted, and operators are actively seeking new sources of high-quality subsurface coal.
Coalbed methane drilling in the eastern part of the Black Warrior basin, where nearly all prospective coal resources are located, provides a database of more than 4,000 high-resolution density logs that can be used to estimate coal thickness to within 0.3 foot. Proximate and ultimate analyses of coal from exploratory core holes provide supporting data on coal quality, although coverage is incomplete. To facilitate coal exploration and expansion of the demonstrated reserve base, the Geological Survey of Alabama is actively compiling data from coalbed methane wells and exploratory core holes.
Preliminary examination of deep subsurface data has identified significant resources shallower than 2,000 feet that may be mined with existing technology. Prospective coal beds are locally thicker than 7 feet, and sulfur content generally ranges from 0.6 to 2.4 percent. Rank in undeveloped areas reaches a maximum of high-volatile A bituminous and is thus lower than that of metallurgical coal now being mined. Even so, deep coal beds in the Black Warrior basin have the potential to provide a stable source of coal for power generation well into the 21st century.