352 



MINE. 



Working 

 of coal. 



Mines of very loud, but hollow and obtuse ; this last kind of 

 sound the workmen very emphatically term thud- 

 ding. 



It is the opinion of the most eminent of the New- 

 castle engineers, who have had the greatest experience, 

 that when goaves are wrought under very deep cover, 

 the rupture of the strata does not in general con- 

 tinue up to the surface, but that the upper part only 

 bends down a little. As the pillars of the pannels are 

 taken away, the pannel-walls are also wrought pro- 

 gressively backward to the pit-bottom, so that by this 

 operation, only a very small proportion of the coal is 

 lost. This is, as far as can be judged, the very best 

 method of working such coals as those at Newcastle, 

 taking into consideration their great depth from the 

 surface, their comparative softness, and the great abun- 

 dance of inflammable air. It is evident, that the larger 

 the pillars and pannel walls are in the fir.-t working, 

 the greater will be the security of the workmen, and 

 the certainty of taking out in the second working 

 the greatest proportion of coal. This system is appli- 

 cable in many instances through the collieries in 

 Great Britain ; by it the saving of coal is uncommonly 

 great, compared with any of the post and stall plans. 

 Though we may view this wonderful operation as one 

 which shews in a strong light the bold and determined 

 spirit of man, even in the mechanical part of the ope- 

 ration, where the massive rocks are reft and torn to 

 pieces over the head of the miner, a more difficult and 

 delicate operation has to be attended to during the 

 process, that is, in conducting atmospheric air to the 

 workmen to counteract and carry off the excessive 

 flow of hydrogen gas, which issues from every quarter 

 ready to destroy them, as will be noticed when treat- 

 ing of ventilation ; so that man may be considered in 

 tins case as contending with the elements of nature, 

 which are every moment ready to overwhelm him. 

 The consideration of these circumstances shews the 

 importance and nature of that charge, which devolves 

 upon a mining engineer in these deep and very dan- 

 gerous collieries. 



Shropshire Under the fourth system of coal-mining, is that 

 system. named the Shropshire method, long way, or long wall. 

 This system was first pursued in Shropshire, but 

 the name of the person who had the merit of inventing 

 it is not known ; the plan must r.t first have been un- 

 commonly hazardous, though now it is reckoned as 

 safe, if not safer for the workmen, than the other sys- 

 tem with rooms and pillars. 



The object of the Shropshire system is to begin next 

 the pit-bottom pillars, and at once to cut out every inch 

 of coal progressively forward, and allow the whole su- 

 perincumbent strata to crush behind and over the 

 heads of the workmen. This system is confined chiefly 

 to coals which are thin, and very seldom practised 

 when the coals are seven feet thick ; from four to five 

 feet is reckoned the most favourable thickness for go- 

 ing on comfortably, when attended with ordinary cir- 

 cumstances, as to the kind of roof, pavement, &c. 



When a pit is sunk to a coal where this method is to 

 be adopted, the first consideration is, the situation of 

 the coals which lie above the lowest one sunk to; if 

 they are near to one another, it will be most expedient 

 to work the upper coal first, and the others in succes- 

 sion downwards ; but if they are about eight fathoms 

 or more apart, with strata of strong composition be- 

 twixt them, the working of the lower coals first will do 

 no injury to the upper coals, excepting the breaking of 



Mines of 

 Coal. 



them a little more than usual. In many instances, 

 upper coals are rendered by this operation in a lower 

 coal much easier wrought. When the operation is be- 

 gun by working in the Shropshire plan, the clip-head 

 levels are driven in the usual manner MS bt f ure de- 

 scribed, and very large pit-bottom pillars formed as 

 represented Fig. 2. Plate CCCXC II. Along the rise PLATE 

 side of the dip-head level, chains of wall or lung cccxcii. 

 pillars are also formed, from eight to ten yards in *'-^' 

 breadth, and only mined through occasionally for the 

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

 other instances no pillars are left upou the rUe-.-uie of 

 the level; but in place of these, buildings of stone are 

 formed four feet broad in the base, and nine or ten 

 feet from the dip-side of the level ; and although the 

 roads are formed nine feet wide at first, tlu>y are re- 

 duced to half that width after the full pressure of the 

 strata is upon them. When these points are secured, 

 the operation of cutting away the whole of the coal 

 commences. The place where the coal is taken away 

 is named the gob, or waste ; and gobbin, or gob stuff, 

 is stones and rubbish taken from the coal, pavement, 

 or roof, to fill up the excavation as much as possible, 

 so as to prevent the crush of the superincumbent strata 

 from making heavy falls, or following too hard upon 

 the workmen. Coals which are wrought in this manner 

 work easiest, according to the way in which the wid- 

 est backs and cutters are, as explained in the post and 

 stall system ; and, therefore, in the Shropshire method, 

 the walls are sometimes in one direction and some- 

 times in another, the mine always turning out the best 

 coals when the open backs or cutters face the work- 

 men. In many cases, when an immediate and great 

 output of coals are wanted, the walls are carried for- 

 ward to the rise and also level course on each side of 

 the pit. As roads must be kept through the crushed 

 strata, the miners in the first place cut away about 15 

 feet of coal around the pit-bottom pillars, and along 

 the upper sides of the dip-head chain- walls; and at 

 the distance of nine or ten feet carry regular build- 

 ings of stone three feet broad, with props set flush 

 with the face of these, if necessary. As the workmen 

 proceed forward, they set small pillars of roof or pave- 

 ment-stone in regular lines with the wall face, and 

 sometimes with props intermediate. In other in- 

 stances, two, and sometimes three rows of props are 

 carried regularly parallel with the wall-face, the front 

 row being at the distance of four feet from it ; as the 

 workmen proceed forward, all the back row of props 

 are drawn, the space adjoining them having been pre- 

 viously filled up with gobbing. These props are 

 placed again next the wall face, so that the process of 

 drawing and setting the props goes alternately forward 

 every day. When the roof is strong, fewer props and 

 stone pillars are placed ; but when it is bad they are 

 set very thick. The intention of the props is for the 

 security of the workmen to keep up the roofstone; 

 they have no effect in resisting the crush of the super- 

 incumbent strata. When the gobbing is scarce, and 

 the roof strong, it has been found a good plan to form 

 the gobbing into wastes, which is, that in place of 

 leaving the gobbing at a distance from the roof, to 

 form it into long heaps at right angles to the wall-faces, 

 as represented Fig. 5. where a is the roof, b the pave- Fig. 5, 

 ment, c the gobbing, and d the wastes. As the pressure 

 comes on, the gobbing spreads out, and the wastes 

 are made narrower; yet they frequently remain so 

 open, as not only to form air courses in case of neces- 



