Methane drainage with cross-measure boreholes on a retreat longwall face

Journal Article · Sun Dec 01 04:00:00 EST 1985 · Min. Eng. (Littleton, Colo.); (United States)

OSTI ID:5972784

Thakur, P C; Cervick, J; Lauer, S D

Methane drainage by cross-measure boreholes on retreat longwall faces can be a viable alternative to the vertical gob degassing boreholes under favorable circumstances. The research was done in a mine working the Pittsburgh coal seam in northern West Virginia under USBM Cooperative Agreement No. 14-09-0050-3252. The study was the first application of this technique to a Pittsburgh coal seam. A total of 14 small diameter, inclined boreholes were drilled over a retreat longwall panel from gate roads, to intersect the overlying coal seams. All boreholes were manifolded to a pipeline and the gob gas was extracted by a surface exhaust fan. The methane capture ratio was poor at 7% to 18% at various stages of the longwall panel. A vertical gob degas borehole captured an additional 20% gas. Poor results were due to premature failures of the cross-measure boreholes leading to air leakage. For better performance, the boreholes should be drilled from a point 30 to 45 m (98 to 148 ft) from longwall pillar over the largest chain pillar. The standpipe should be grouted for at least 6 m (20 ft), and the entry containing boreholes and the pipeline must be supported to ensure access for maintenance and optimization of methane capture. Coursing the ventilation air around longwall such that it forces methane migration toward cross-measure boreholes can further improve methane capture. The optimum vertical inclination is 45/sup 0/ + or - 10/sup 0/.

• Research Organization: Conoco Inc., Morgantown, WV.
• OSTI ID: 5972784
• Journal Information: Min. Eng. (Littleton, Colo.); (United States), Journal Name: Min. Eng. (Littleton, Colo.); (United States) Vol. 37:12; ISSN MIENA
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
012000* -- Coal
Lignite
& Peat-- Mining
ALKANES
BOREHOLES
CAVITIES
CHEMICAL COMPOSITION
COAL DEPOSITS
COAL MINES
COAL SEAMS
DEGASSING
GEOLOGIC DEPOSITS
HYDROCARBONS
LEAKS
LONGWALL MINING
METHANE
MINERAL RESOURCES
MINES
MINING
ORGANIC COMPOUNDS
RECOVERY
RESOURCES
RETREAT MINING
SEALS
STRATA CONTROL
UNDERGROUND FACILITIES
UNDERGROUND MINING