Use of vertical boreholes for assisting ventilation of longwall gob areas

Author:	Elder, C. H.
Year:	1969
Document Type:	TPRM
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines ;
SUDOC:	I 28.26/6:13
Series:	Technical progress report ;
Report Number:	13
Subjects:	Mine ventilation
	Methane
Link:	https://hdl.handle.net/2027/mdp.39015077584095