332 



MINING FOR COAL 



1515 



hibited in one of these compartments, it will be proper to describe the mode of taking 



the coal from one of them, before describing the wholeextent of the workings of a mine: 



Let Jig. 1515 represent a side of work: A, the ribs or walls of coal left standing, 



round, constituting the side of work; a, the pillars, 8 yards square; c, the stalls, 11 



yards wide ; d, the cross openings, or through 

 puts, also 11 yards wide ; e, the bolt-hole, cut 

 through the rib from the main road, by which bolt- 

 hole the side of work is opened up, and all the 

 coals removed. Two, three, or even four bolt- 

 holes open into a side of work, according to its 

 extent; they are about 8 feet wide and 9 feet 

 high. The working is in a great measure regu- 

 lated by the natural fissures and joints of the 

 coal-seam ; and though it is 30 feet thick, the 

 lower band, of 2 feet 3 inches, is worked first ; the 

 miners choosing to confine themselves within this 

 narrow opening, in order to gain the greater ad- 

 vantage afterwards, in working the superjacent 

 coal. Whenever the bolt-hole is cut through, the 



_ work is opened up by driving a gallery forward, 



1 1 4 feet wide, as shown by the dotted lines. At the 



sides of this gallery next the bolt-hole, each miner 



breaks off in succession a breast of coal, two yards broad, as at//, by means of which 

 the sides of the rib-walls A, are formed, and the area of the pillars. In this way each 

 collier follows another, as in one of the systems of the Shropshire plan. When the 

 side of work is laid open along the rib-walls, and the faces and sides of the pillars 

 have been formed, the upper coals are then begun to be worked, next the rib-wall. 

 This is done by shearing up to a bed next the bolt-hole, and on each side, whereby the 

 head coals are brought regularly down in large cubical masses, of such thickness as suits 

 with the free partings or subordinate divisions of the coals and bands. Props of wood, 

 or even stone pillars, are placed at convenient distances for the security of the miners. 

 In working the ten-yard coal, a very large proportion of it is left underground, not 

 merely in pillars and rib-walls, but in the state of small coal produced in breaking out 

 the coal. Hence from four-tenths to a half of the total amount is lost for ever. 



The thick or ten-yard coal has, however, been worked on the long-wall method by 

 Mr. Gibbons, near Dudley, with great advantage in the yield. He works 12 to 14 

 feet of the upper part of the seam first ; and after allowing the strata to become 

 somewhat consolidated, the lower part is worked, leaving 2 to 3 feet of coal for a 

 roof, some portion of which is picked out of the gobb. About 12 per cent, of the coal 

 is left by this method. 



Edge coals, which are nearly perpendicular, are worked in a peculiar manner ; for, 

 the collier stands upon the coal, having the roof on the one hand, and the floor on the 

 other, like two vertical walls. The engine-pit is sunk in the most powerful stratum. 

 In some instances the same stratum is so vertical as to be sunk through for the whole 

 depth of the shaft. 



Whenever the shaft has descended to the required depth, galleries are driven across 

 the strata from its bottom, till the coals are intersected, as is shown in fig. 1516, where 

 we see the edge coals at a, a ; A, the engine-pit ; b, b, the trans- 

 verse galleries from the bottom of the shaft ; and c, c, upper 

 transverse galleries, for the greater conveniency of working the 

 coal. The principal edge-coal works in Great Britain lie in the 

 neighbourhood of Edinburgh. 



The modes of carrying coals from the point where they are 

 excavated to the pit-bottom, are nearly as diversified as the 

 systems of working. 



One method employs hutches, or baskets, having slips or cradle feet shod with iron, 

 containing from 2 to 3 hundred weight of coals. These baskets are dragged along 

 the floor by ropes or leather harness attached to the shoulders of the workmen, who are 

 either the colliers or persons hired on purpose. This method is used in several small 

 collieries ; but it is extremely injudicious, exercising the muscular action of a man in 

 the most unprofitable manner. Instead of men, horses are sometimes yoked to these 

 basket-hurdles, which are then made to contain from 4 to 6 hundred weight of coals ; 

 but from the magnitude of the friction this plan cannot be commended. This method 

 is now almost entirely extinct. 



An improvement on this system, where men draw the coals, is to place the basket or 

 corve on a small four-wheeled carriage, called a tram, or to attach wheels to the corvo 

 itself. Thus much more work is performed, provided the floor bo hard ; but not on a 

 soft pavement, unless some kind of wooden railway bo laid. 



1516 



