Common methods of controlling gob gas in U.S. mines are by means of ventilation of gob areas and gas drainage through surface boreholes. Costs of drilling surface gob holes increase as deeper coalbeds are mined. Where gob holes cannot be drilled because of topography, ventilation is the only means of control. Even then, sufficient air may not be available to dilute methane in the bleeder entries to acceptable levels. Thus, new methods of gob gas control need to be developed that are independent of surface topography, and of the mine ventilation system, less costly than present systems. Except for slight variations in procedures and equipment, Great Britain, the Federal Republic of Germany, France, Belgium, Poland, and czechoslovakia use a common methane control method that is different from the systems generally used in the United States. This Bureau of Mines paper reviews European mining methods, mining conditions, and methane control technology and discusses their applicability to U.S. mines.
Chap. 9 in "Longwall-shortwall Mining, State of the Art", 1981, PP. 75-80