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Characteristics and Utilization of Kanawha Formation Splint Coals in Central and Southern West Virginia

William C. Grady, Cortland F. Eble, Kenneth C. Ashton

The Winifrede, Coalburg, and Stockton-Lewiston coalbeds of the upper Kanawha Formation in West Virginia are known as "splint coals" because of their characteristic very hard, dull-luster, grayish-black splint layers. Splint coals have long been known to be poor coking coals and, recently, they have also been shown to perform poorly in modern combustion equipment. In this study, nine full-channel samples and five 0.5-ft increment columns of the Coalburg coal and two full channels and four 0.5-ft increment columns of the Stockton-Lewiston coalbed were studied. By use of petrographic analysis, the splint layers were identified as having very high inertinite contents (40-60% mmf [mineral mater-free] vol. %), low vitrinite contents (< 40% mmf), low ash yield (< 10%), low sulfur (< 1%), and a kaolinite dominant mineralogy. Palynologic analyses of these layers showed high percentages of marattiaceous tree fern spores (Laevigatosporites globosus, Punctatosporites minutus and Punctatisporites minutus.). The petrographic results suggest that splint layers represent peat that accumulated on raised, well-drained portions of tropical equatorial swamps, similar to the modern swamps of coastal Sumatra, Indonesia. The very high rainfall necessary to maintain raised swamps is inferred to have caused oxidation of the peat and the formation of abundant inertinite macerals, which contributes to the poor coking and combustion characteristics of splint coals. Rainwater leaching of inorganics from the peat is also implied to have contributed to the low mineral matter c ntent and pyrite abundances observed in splint coals, and to their resultant low ash and sulfur contents and high ash fusion temperatures.

AAPG Search and Discovery Article #91031©1988 AAPG Eastern Section, Charleston, West Virginia, 13-16 September 1988.