Geologic factors causing roof instability and methane emission problems: the lower kittanning coalbed, Cambria County, Pa. [17 refs]

Technical Report · Mon Jan 01 04:00:00 EST 1973

OSTI ID:7158427

McCulloch, C M; Deul, M

A geologic study of Mines 32 and 33 in Cambria County, Pa., was conducted as part of a methane control research program. Areas of high methane emission and roof instability are encountered which are related to the structural and stratigraphic features that characterize the geologic setting of these mines. Locally the folds trend N 20/sup 0/ E +- 2/sup 0/, the direction of the butt cleat in the Lower Kittanning coal. The face cleat strikes at N 69/sup 0/ W +- 2/sup 0/ and the systematic rock joint in the surface bedrock strikes N 67/sup 0/ W +- 2/sup 0/. This suggests that a directional stress oriented N 70/sup 0/ W produced the folds and influenced the directions of coal cleat and systematic joint sets. Analysis of SLAR indicates three directions of prominent regional lineation: N 39/sup 0/ E, N 31/sup 0/ W, and N 70/sup 0/ W. Little gas was encountered during development mining; large volumes of gas are encountered when roof falls. Most of the gas comes from strata above the mined coal; therefore, to control methane, roof instability must be controlled. Roof falls and high rates of methane emission are most likely where less than 30 feet of many thin layers of limestone, shale, and sandstone occur between the Lower Kittanning coal and the next coal and in zones along the margins of a sandstone channel.

• Research Organization: Bureau of Mines, Pittsburgh, Pa. (USA). Pittsburgh Mining and Safety Research Center
• OSTI ID: 7158427
• Report Number(s): BM-RI-7769
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
012000* -- Coal
Lignite
& Peat-- Mining
016000 -- Coal
Lignite
& Peat-- Health & Safety
ALKANES
CARBONATE ROCKS
CENTRAL REGION
COAL MINES
CONTROL
CRYOGENIC FLUIDS
FLUIDS
GEOLOGY
HYDROCARBONS
LAYERS
LIMESTONE
METAMORPHIC ROCKS
METHANE
MINES
MINING
NORTH AMERICA
ORGANIC COMPOUNDS
PENNSYLVANIA
RESEARCH PROGRAMS
RESERVOIR ROCK
ROCKS
ROOFS
SANDSTONES
SEDIMENTARY ROCKS
SHALES
STABILITY
UNDERGROUND MINING
USA