geopiet Jul 18, 2013:

Reservoir simulation-based modeling for characterizing longwall methane emissions and gob gas venthole production - http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.124...

geopiet Jul 18, 2013:

known as “gob” In addition, substantial reductions in total methane release can be achieved by pre-draining the methane from the coal seam, known as degasification, prior to the coal being mined and also draining methane from post-mining operations, known as “gob”. This reduces the amount of methane that will be released into the mine that would need to be vented through a VAM process, and produces a very high quality gas that can be sold. - http://www.catf.us/resources/whitepapers/files/201209-Barrie... - page 4

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geopiet Jul 18, 2013:

There are two general methods for extraction of methane.
1. Pre-mining drainage methods
2. Post-mining drainage methods

http://www.rpsea.org/attachments/contentmanagers/3480/07122-... - page 1

geopiet Jul 18, 2013:

degasification / drainage Degasification system: A system that facilitates the removal of methane gas from a mine by ventilation and/or by drainage. However, the term is most commonly used to refer to removal of methane by drainage technology.

Drainage system: A system that drains methane from coal seams and/or surrounding rock strata. These systems include vertical and directionally drilled pre-mine wells, gob wells, and in-mine boreholes.

http://www.epa.gov/cmop/docs/cmm_primer.pdf - page 7