--> ABSTRACT: Petrographic Investigation of River Gem Coal, Whitley County, Eastern Kentucky Coal Field, by James D. Pollock and James C. Hower; #91041 (2010)

Datapages, Inc.Print this page

Petrographic Investigation of River Gem Coal, Whitley County, Eastern Kentucky Coal Field

James D. Pollock, James C. Hower

The River Gem coal of the Breathitt Formation (Middle Pennsylvanian) was studied at three sites in a surface mine in the Holly Hill quadrangle, Whitley County, Kentucky. The River Gem coal is correlative with the Lily and Manchester coals in neighboring Knox, Laurel, and Clay Counties, Kentucky, and the Clintwood coal in Pike County, Kentucky.

At the northern site, a 14-cm rider is separated from the 92.5-cm seam by 22 cm of shale. At the two southern sites, the rider is missing. At the latter sites, the 10 cm thick top bench of the seam is separated from the lower 63 cm of the seam by a 14-cm bony lithotype not found at the northern site. The lower 63 cm of the seam in the south and the main seam in the north are characterized by moderate ash and sulfur percentages (4.4-6.8% ash, 1.4-2.3% total sulfur, 0.6-1.1% pyritic sulfur, 74-81% vitrinite, 23-32% Fe2O3, and 2.3-4.5% CaO). In contrast, the upper bench in the south and the rider have 18.7-27.0% ash, 8.8-11.4% total sulfur, 5.1-6.4% pyritic sulfur, 92.3-93.6% vitrinite, 45.7-57.8% Fe2O3 and 0.13-0.20% CaO. The bone has over 26% ash, 5.5% total sulfur, 3.2% pyritic sulfur, and 93.1% vitrinite. The overall similarity of the seam and rider characteristics between the north and south suggests that the southern bone is the lateral equivalent of the northern shale.

The sulfide in the upper bench or rider and in the bone consists of fine (generally less than 10 µm), euhedral and framboidal pyrite with common massive pyrite. Massive pyrite appears as an overgrowth of fine pyrite in some places. Massive forms of marcasite, less abundant than pyrite, exhibit some evidence of developing later than the massive pyrite. A variety of < 2-µm pyrite occurs as abundant, but isolated, unidimensional to tabular grains within corpocollinite, some of which is transitional to resinite.

AAPG Search and Discovery Article #91041©1987 AAPG Eastern Section Meeting, Columbus, Ohio, October 7-10, 1987.