S5G 



MINE. 



Jlmes 



\Vorkin 

 coal. 



of ner, about half the thickness of the coal, or rather more, 



^ is brought down in tabular masses of various thick- 



of ness, having the men of war pillars left for the last of 



the work, which is taking down the coals next the 



roof; these are brought down in immense falls, of 



from 100 to 200 tons at a time, and in some instances 



even 300 tons. When the various sides of work in a 



pit- workings are in a prepared state, that is, prepared 



for taking down the upper coals, sometimes there are 



6000 tons in this way ready to fall. 



In the course of working and breaking out the coals 

 for going up the pit, all the culm-coal, and a great 

 proportion of excellent small coals, are left in the 

 waste, upon which the colliers stand when working 

 the upper coals, and when the height becomes great, 

 ladders and various kinds of scaffolding are used. The 

 last of the upper coals, in place of being wrought from 

 the bolt rib wall forward, are wrought from the oppo- 

 site rib wall towards the bolt rib for the safety of the 

 workmen. This operation is attended with great dan- 

 ger to the workmen, and therefore they are required 

 to be very expert miners from practice in that kind of 

 work, with much boldness and resolute determination. 

 The first operation is to shear along the face of the 

 back rib wall, and along the side ribs, leaving spurs at 

 regular distances ; the scaffolds are then withdrawn, 

 the men of war cut away as the miners retreat; and 

 the last operation is cutting away the spurs. As the 

 danger is very great working under so large a mass of 

 coal, no miner can approach to cut these away with 

 a common pick ; they are therefore provided with an 

 instrument or tool named a pike, very like a boarding 

 pike, 1 8 feet long, the shaft of wood, having a steeled 

 iron sharp pike, with a hook at the one side, similar 

 to a boot-hook. With this, the miners standing with 

 their backs to the bolt rib wall, cut away with the 

 point of the pike in the advance stroke, and with the 

 hook in the back stroke, the side spurs ni-xt the back 

 rib wall. In this manner the spurs are cut away in 

 succession, the miners retreating towards the safe 

 part of the mine, until all of them are cut. Some- 

 times the coal falls before all the spurs are cut, and 

 before the last of the men of war are cut down ; in 

 many instances the upper coals do not only fall the 

 height of the shearing, but up to the roof, by which 

 masses of coal, from 10 to 14 feet thick, fall at once, 

 and not only so, but immense pieces of the strong roof 

 stone fall at the same time, ot such a thickness, that 

 before the coal can be broken out, the miners have 

 to blast it with gun- powder, and remove many tons of 

 it. From this description of working the ten-yard 

 coal of Staffordshire, the very dangerous nature of such 

 work may be conceived ; but no correct idea can be 

 formed of the operations, or of the immense excava- 

 tions and caverns formed by the working of the coal, 

 and particularly by the fallen roof. The accidents 

 which take place in this coal are consequently very 

 many ; severe contusions and broken limbs are of fre- 

 quent occurrence, and not a few workmen are snatch- 

 ed from life to death in an instant by the coals and 

 roof falling when they least expect them ; but besides 

 the danger arising from these falls, they have also in- 

 flammable air to contend with, by which also many 

 have been killed. 



Various modifications of the mode of working a side 

 of work in this coal are practised, as best suits the na- 

 ture of the coal, the superincumbent strata, the various 

 local circumstances, and views of the malinger of the 

 colliery. 



When the crop of this singular coal was first wrought, Mines of 

 the miners only extended tneir operations to 20 yards Coal, 

 distance all around the pit bottom, and then begun a ^~^<~*' 

 new pit ; but as the pits became deeper and more ex- orkln ' 

 pensive, the distance of the workings was extended, 

 and the method of mining improved. The extent of 

 a pit's workings is now in general 100 yards on all 

 sides, that is, the area wrought is 200 yards upon the 

 side, and in a number of cases 300 yjrds, or 150 yards 

 of extent on each quarter of the pit. The greatest 

 distance ever attempted wns 450 yards from the pit 

 bottom, but this distance does not appear to be suit- 

 able. A number of the sides of work, as of the side 

 of work represented in the figure, constitute the work- 

 ings of a pit. The roads leading from the pit bottom 

 are from 3 to 4 yards wide, and the rib walls are of 

 various thickness; the main ribs being 12 y.^rdi, the 

 others about 5 yards in thickness. 



This coal, in the course of working, is, like many, 

 liable to take fire by spontaneous igni'ion. which is not 

 only exceedingly dangerous and troublesome, but re- 

 quires the greatest attention to prevent its formation. 

 It is here termed the breeding-fire, and will be treated 

 of when stating the accidents to which coal-mines are 

 liable. It is this which requires the workings to be laid 

 off in sides of work, as represented in the figure, with 

 one opening or bolt-hole, which is securely built up and 

 made air-tight as soon as the side of work is wrought 

 out. When a pit is wrought to its full extent, then, if 

 circumstances admit of it, it is wrought in the pillars 

 and ribs, beginning at the most distant corners, and as 

 much of the pillars and ribs are brought away as can 

 be done, consistent with the safety of the workmen. If 

 there are openings through the ribs to any other pit 

 workings, they are carefully built up with double wallsof 

 stone, a few feet asunder, and the space is filled up with 

 mine dust, (the refuse of calcined ironstone;) which 

 mine dust is found the most effectual remedy for keep- 

 ing the passage air-tight, in the event of a crush rend- 

 ing the walls, as the mine dust yields to the pressure 

 without admitting the air to pass. 



From this description of working the ten-yard coal, 

 it is evident that a very great proportion of the coal is 

 left underground, not only in pillars and rib walls, but 

 there is an uncommon quantity of small coal produced 

 in the operation of bringing down, and breaking out 

 the coal, so that in general from four-tenths to a half of 

 the whole is for ever lost; and it is also evident, that 

 from the long habit of the workmen, it would be almost 

 impossible to introduce any new method, though, to all 

 appearance, it would be decidedly preferable to the pre- 

 sent system. One plan has been suggested, which was 

 to work the upper part of the coal first, leaving a few 

 feet of coal for a roof, and then work all the lower coals 

 in benches, as described in the working of coals '20 feet 

 in thickness, the roof to be supported with props. It 

 is however questionable, how far this would be found 

 in the end better, or whether less small coal would be 

 produced. 



The next method of working coals of uncommon Johnstone 

 thickness is by stages or scaffoldings of coal, as practis- tliick coal. 

 ed in that coal of astonishing thickness found at John- 

 stone, near Paisley in Scotland, and represented in the 

 sections in the first part of this treatise, being from 50 

 to 60 feet thick in one quarter of the field, and in one 

 part no less than 9.) feet thick. There are. no doubt, 

 several thin bands of stone in it, but there are only two 

 of 27 inches thick each. The roof of this coal is so bad, 

 and the height so great, that it was found quite imprac- 



