406 



of the mine required double ones ; for when the latter are 

 used and kept well in advance of the benks, they will nearly 

 drain that coal of its gas before the hewers in the benks come 

 behind. For the " slines" of the coal (lines of cleavage 

 running in the direction of the end" or nearly north and 

 south), and which always contain, especially in this seam, 

 large quantities of gas, are thus previously intersected and 

 relieved before the following up benks arrive, so that there 

 is less gas comes out of the face of the coal, and less to 

 escape into the goafs. But if single board-gates are used at 

 40 or 50 yards apart, they cannot be kept much in advance 

 of the working of the benks, (simply because their intercom- 

 munication is by means of the benks,) and, therefore, the 

 slines cannot be cut across much in advance of the main 

 workings, and where there is much gas the accumulations 

 in the goafs thus become very dangerous. See Plate II. 



There is no person who understands better the ventilation 

 of the Barnsley or Thick Coal than Mr. Sutcliffe, the in- 

 telligent manager of the Gawber Hall Colliery ; and he has 

 both the single and double board-gates used, according as 

 certain localities of the mine are more or less affected with 

 gas. He has also a most excellent mode of ventilating his 

 goafs, and which is directly opposed to that now so prevalent 

 of keeping the air " dead" in them; and it is to leave all the 

 " slits" open into the goafs on the windward side, and all 

 walled up on the leeward side, excepting the one in use and 

 the one next to it, which last is kept partially open. Thus 

 the upper end of every goaf and next the workmen is always 

 free comparatively of fire damp, according as the general 

 circulation of the mine will permit. As a proof of the 

 excellency of Mr. Sutcliffe's plan, and the general care 

 which he has exercised over the colliery, he has, at all times, 

 this pleasing and very solacing reflection, that in a period of 

 twenty-four years, in a most extensively worked colliery, he 



