Control of Methane in Gob and Bleeders by the Cross-measure Borehole Technique.
Proc 14th Ann Inst on Coal Min H S & Res, Blacksburg, Virginia, 1983 Aug; :139-148
In Europe and the United Kingdom, small-diameter drainage holes (cross-measure boreholes) are drilled into strata overlying a longwall to control methane in the gob and to prevent it from mixing with the ventilation air. These drainage holes are connected to an underground pipeline that is maintained under a partial vacuum by surface vacuum pumps. Bureau of Mines tests in the Upper Kittanning coalbed utilizing the cross-measure borehole system demonstrated the capture of 50 pct of the total methane generated by the mining operation. The angle of the hole above horizontal, depth of penetration of the hole into the gob, and location of the pipeline and collar of the hole are important parameters affecting the performance of the cross-measure borehole technique.
Proc. 14th Ann. Inst. on Coal Min. H. S. & Res., Blacksburg, Virginia, Aug. 23-25, 1983, PP. 139-148