COAL MINING. 313 
economy of the field. Indeed, the crush or creep often overran the 
whole of the pillars, and was resisted only by the entire body of coal at 
the wall faces, so that the ventilation was entirely destroyed, the roads 
leading from the wall faces to the pit bottom shut up, and rendered 
useless, and the recovery of the colliery by means of new air-courses, 
new roads, and by opening up the wall faces or rooms, was attended by 
prodigious labor and expense. Even when the pillars stood well, the 
old method was attended with other very great inconveniences. If 
water broke out in any particular spot of the colliery, it was quite im- 
possible to arrest its progress to the engine pit, and if the ventilation 
was thereby obstructed, no idea could be formed where the cause might 
be found, there being instances of no less than thirty miles of air-courses 
in one colliery. And if, from obstructed ventilation, an explosion of 
fire-damp occurred while many workmen were occupied along the ex- 
tended wall faces, it was not possible to determine where the disaster 
had taken place, nor could the viewers and managers RON where to 
bring relief to the mutilated and forlorn sufferers. 
In Mr. Buddle’s system, all these evils are guarded noatnats as far 
as human science and foresight can go. He makes the pillars very 
large, and the rooms or boards very narrow, the pillars being in general 
cases, twelve yards broad and twenty-four yards long, the boards four 
yards wide, and the walls or thirlings cut through the pillars from one 
board to another, only five feet wide, for the purpose of ventilation. 
When the pillars of a panel are to be worked, one range of the pillars 
is first attacked, and as the workmen cut away the furthest pillars, 
columns of prop-work are erected betwixt the pavement und the roof, 
within a few feet of each other, till an area of about one hundred square 
yards is clear and without pillars, presenting a body of strata perhaps 
one hundred and thirty fathoms thick, suspended clear and without 
support, except at the line of the surrounding pillars. This operation is 
-termed “ working the goaf.” The only use of the prop-work is to pre- 
vent the seam, which forms the ceiling over the workmen’s heads, from 
falling down and killing them by its splintering fragments. Experience 
has proved, that before proceeding to take away another set of pillars, 
it is necessary to allow the last made goaf to fall. The workmen then 
begin to drive out the prods, which is the most hazardous employment. 
They begin at the more remote props, and knock them down one after 
another, retreating quickly under the protection of the remaining props. 
