330 



MINING FOE COAL 



When the operation is commenced by -working on the long-wall plan, the dip-head 

 levels are driven in the usual manner, and very large bottom-pillars are formed, as 



represented iu fig. 1511. Along the rise-side of the 

 dip-head level, chains of -wall, or long pillars, arc 

 also made, from 8 to 10 yards and upwards in 

 breadth, and only mined through occasionally, for 

 the sake of ventilation, or of forming new roads. In 

 other cases no pillars are left upon the rise-side of 

 the level ; but, instead of them, buildings of stone 

 are reared, 4 feet broad at the base, and 9 or 10 

 feet from the deep side of the level. Though the 

 roads are made 9 feet wide at first, they are reduced 

 to half that width after the full pressure of the 

 strata is upon them. Whenever these points are 

 secured, the operation of cutting away the -whole 

 body of the coal begins. The place where the coal 

 is removed, is named the gobb or waste ; and 

 gobbin, or gobb-stuff, is stones or rubbish taken away from the coal, pavement, 

 or roof, to fill up that excavation as much as possible, in order to prevent the crush 

 of superincumbent strata from causing heavy falls, or following the workmen too fast 

 in their descent. Coals mined in this manner work most easily according to the -way 

 in -which the widest backs and cutters are ; and therefore, in the Shropshire mode, 

 the walls stand sometimes in one direction, and sometimes in another; the mine 

 always turning out the best coals when the open backs and cutters face the -workmen. 

 As roads must be maintained through the gobb or goaf to the working face, pillars 

 of stone, called packs, are formed along each side of the road of several feet in.width ; 

 and the rock over head along this road is blasted down of sufficient height, so that 

 when the superincumbent strata have sunk, there may be ample height to convey the 

 coals with ponies. In many cases these roads are 6 to 7 feet high, and seldom less 

 than 4 feet. In some coal-fields stone cannot be got in the mine to build the road 

 pillars or packs ; but a substitute is found in cord -wood, -which is formed into a pillar 

 on each side of the road by building it up, and making it as solid as possible with 

 small coal and other small refuse. The pressure of the strata soon makes this a very 

 compact pillar. This method is common in the Leicestershire coal-field. 



There are two principal modifications of the long-wall plan. The first, or the 

 original system, was to open out the wall round the pit-bottom ; and, as the wall face 

 extended, to set off main roads and branches, very like the branches of a tree. These 

 roads were so distributed, that between the ends of any two branches there should be 

 a distance of 30 or 40 yards, as might be most convenient (see fig. 1511). Each space 

 of coal betwixt the roads is called a wall ; and one half of the coals produced from 

 each wall is carried to the one road, and the other half to the other road. This is a 

 great convenience when the roof is bad ; and hence a distance of only 20 yards be- 

 twixt the roads is in many instances preferred. In fig. 1511, A. represents the shaft; 

 B B, the wall-face ; a, the dip-head level ; b, the roads, from 20 to 40 yards asunder ; 

 c, the gobb or waste, with buildings along the sides of the roads ; and d, the pillars. 



The other plan is represented in fig. 1512, where A shows the pit, with the bottom 

 pillars ; b, the dip-head levels ; c, the off-break from the level, where no pillars are 



left ; d, the off-break, where pillars remain to se- 

 cure the level. All roads are protected in the 

 sides by stone buildings, if they can be had, laid 

 off 9 feet wide. After the crush settles, the roads 

 generally remain permanently good, and can, in 

 many cases, be travelled through as easily 50 

 years after they have been made as at the first. 

 Should stones not be forthcoming, coals must be 

 substituted, which are built about 20 inches in the 

 base. In this method, the roads are likewise from 20 to 40 yards apart ; but instead 

 of ramifying, they are arranged parallel to each other. The miners secure the waste 

 by gobbing ; and three rows of props arc carried forwards next the wall faces a, with 

 pillars of stone or of coal reared betwixt them. This mode has a more regular appearance 

 than the other ; though it is not BO generally practised in Shropshire as in Derbyshire. 

 In the post-and-stall system, each man has his own room, and performs all the 

 labour of it ; but in that of Shropshire, there is a division of labour among the work- 

 men, who are generally divided into three companies. The first set curves, holes, or 

 pools the coal along the whole line of walls, laying in or pooling at least 3 feet, and 

 frequently 45 inches, or 5 quarters, as it is called. These men are named holers. As 

 the crush is constantly following them, and impending over their heads, causing fre- 



fre- 



