COAL MINING. 305 
and removing the vast subterraneous lakes of water, while forests of prop- 
wood had to be planted underground to insure safety to the hauling 
roads and working places of the mines. 
Fire-damp, that dreaded and fatal enemy of the English miner, 
was given off in increasing and alarming volumes. The rude systems 
in use before the application of steam to mining were totally un- 
fitted for the deeper and extensive mines, which followed the appli- 
cation of Newcomen’s engine for lifting water. The increasing weight 
of the superincumbent strata produced crushes by which the pillars of 
the mine were ground to pieces, or creeps which overran the workings, 
the pillars sinking into the floor, and destroying the economy of the 
whole underground arrangements. New systems had to be devised, 
adapted to all the varying conditions and circumstances. 
A number of eminent mining engineers, notably Robert Bald and 
John Buddle, devised new and improved methods of laying out the 
underground workings of mines, and in British practice there are four 
general systems now in use, a brief description of which may not be out 
of place in this paper. 
DIFFERENT Systems OF British MINING. 
There are four general systems in British mining practice, as 
follows: | 
1. Working with pillars and rooms, and leaving pillars of no 
greater strength for the support of the superincumbent strata than is 
actually necessary as the workings progress. 
2. Working with pillars and rooms of extra size and strength, 
with the object of attacking the pillars in the interior of the mine, and 
removing them after all the rooms have been finished up, partially or 
bodily, according to circumstances. 
3. Dividing the workings up into pannels or squares, and drawing 
the pillars of the pannel after its rooms have been finished during the 
forward progress of the work. 
4, Laying out the workings on the long-wall system, and mining 
out all the coal, leaving no pillars whatever, as the excavations advance 
progressively forward. ! 
There are many modified plans of the above systems in use, as, for 
example, in working by long-wall, the main galleries of the mine are 
20 G. 
