A method for collecting gas from subterranean formations having a plurality of spaced-apart coal seams containing methane gas includes the steps of drilling a shaft from the earth's surface to a depth sufficient to intersect a plurality of seams containing gas and thereunder to create a sump. A plurality...http://www.google.es/patents/US4600061?utm_source=gb-gplus-sharePatente US4600061 - In-shaft drilling method for recovery of gas from subterranean formations
In-shaft drilling method for recovery of gas from subterranean formations
