374 



M I K E. 



Minos of 

 Coal. 



Working 

 under dip- 

 coals. 



PLATK 

 cccxciv. 

 Fig, 3. 



Fig. 4, 



Having stated, in the preceding part of this trea- 

 tise, the manner of working coals to the rise of the 

 engine-pit shaft, we have now to state the plans 

 which have been adopted for working coals a dip- 

 ping of, and deeper than the engine-pit bottom. This 

 has become an important point in colliery operations, 

 and has been greatly improved within these last twen- 

 ty years. 



In the early periods of coal-mining, and when the 

 running of day levels and sinking of pits were attend- 

 ed with great loss of time, and uncommon expence, the 

 working of coals under dip of the day-level and engine 

 pit bottom was a common operation. The first plan 

 resorted to, was running a downset mine in the coal, 

 and carrying the water either out in pails by men, or 

 by placing dams across the mine of about a foot or fif- 

 teen inches deep at regular distances, so that the wa- 

 ter was laved with scoops from the dip-head, and from 

 dam to dam, until it reached the pit bottom, or day- 

 level. 



The next improvement was to raise the water by 

 means of sloping hand-pumps from one dam to another, 

 which slope-pumps had long wind-bores corresponding 

 to the dip of the coal and range of the atmospheric pres- 

 sure, with several valves to retain the water in the wind- 

 bores in case of leakage when the pumps were not go- 

 ing, or pumps were placed in small pits, and the water 

 carried in spouts from the top of one pump to the bot- 

 tom of the next, until it reached the engine-pit, or clay- 

 level. This last plan was improved, by laying a work- 

 ing barrel with a long wind-bore at the bottom of the 

 downset mine, having a smooth rod working through a 

 collar, at the top of the working barrel. At one side 

 of which, near the top, a kneed pipe is attached, and 

 from it pipes are carried to the point of delivery, ei- 

 ther at the engine-pit bottom, or day-level, as repre- 

 sented in Plate CCCXCIV. Fig. 3. The spears are 

 wrought sometimes by rods connected with the ma- 

 chinery at the surface, in which case, if the spears 

 are of great length, they are either suspended from 

 swing or pendulum rods, or move on friction rollers. 

 But as the action of the spears, running with great ve- 

 locity the full length of the engine stroke, very soon 

 tore every thing to pieces, the motion of the spears be- 

 low ground is reduced from 6 or 8 feet, the stroke of 

 the engine to about 15 inches : and the speed in the 

 pump is produced by the centering of a beam, and 

 the attachment of the spears to it, as represented in 

 Plate CCCXCIV. Fig. 4, where a is the working bar- 

 rel, b the beam centered at c, having an arc head and 

 martingale sinking-chain. The spears d are attached 

 by a strong bolt, which passes through the beam; and 

 there are several holes, by means of which the stroke 

 in the pumps can be made longer or shorter as necessi- 

 ty may require. A strong iron quadrant, or wheel, at 

 the pit-bottom, regulates the movement of the spears. 

 In level free coals, these pumps can be wrought by a 

 water wheel placed near the bottom of the pit ; which 

 wheel is moved by water descending the shaft, and is 

 discharged by the day-level. We have also seen a wa- 

 ter-wheel used in the same manner, where the engine 

 had great command of the water ; and the wheel was 

 moved either by water descending from the sides of the 

 pit, or by water first pumped up by the engine, and al- 

 lowed to discharge from the side of the pumps upon 

 the wheel. The coals were brought up also by the 

 same means. When water is very inconsiderable in 

 these under- dip works, it is raised sometimes by a com- 



Mines of 

 Coal. 



mon forcing engine, such as is used for extinguishing 

 fires, but of a small size ; or by forcing pumps, wrought 

 by one or two men with a fly wheel and pinion, the 

 shaft having two cranks whicli work two small reci- 

 procating iron beams connected with two pump barrels, coals. 

 These machines have a spherical air vessel attached, in 

 order to keep the water in constant flow, which is a 

 great relief to the workmen, as they have not the * 

 inertia: to overcome every stroke or revolution of the 

 fly-wheel. 



But the greatest improvement for working under-dip Improved 

 coal, has been brought forward by the Newcastle en- P lan - 

 gineers. Their plan is to run a mine a dipping of the 

 engine-pit in such direction of the dip as may be most 

 suitable ; and both water and coals are brought up the 

 rise of the coal by means of high pressure engines, 

 which work with a power of from 30 to 50 pounds 

 upon the square inch. These machines are quite under 

 command, and as much power is produced in little 

 space, they are the most applicable for under -ground 

 work. An excavation is made for them in the strata 

 above the coal, and the air used for the furnace under the 

 boiler, is the returned air after ventilating the mines, 

 the smoke is conducted in a room or board to the rise, 

 until it is discharged into the upcast shaft, where it 

 quickly rises to the pit top. In the dip mine a double 

 tram road is laid, so that while a number of loaded 

 corves are ascending, an equal number of empty ones 

 are descending; and although this improvement has 

 only been brought forward within these few years, un- 

 der-dip workings have been already executed very near- 

 ly an English mile under-dip of the engine-pit bottom, 

 by means of three of these high pressure engines placed 

 at equal distances in the under-dip mine. Hence we 

 conclude, that there is no limitation to this mode of 

 working ; and in place of contemplating the sinking of 

 pits of excessive depth upon the dip of the coal, at 

 an almost overwhelming expence, we are of opinion 

 that much of the under-dip coal will now be wrought 

 by means of the present engine pits. These great im- 

 provements in coal-mining are to be seen in full action 

 in the Newcastle district, where coals are not only 

 wrought under dip, and under the river Tyne, but 

 where in an engine-pit of 115 fathoms in depth coals 

 are now working under dip of the engine pit bottom 

 above 1600 yards, and fully 80 fathoms of perpendicu- 

 lar depth more than the bottom of the pit. There are 

 instances, where coals may be thus wrought from the 

 dead crop and a dipping, by means of machinery pla- 

 ced at the crop, without cross cutting the strata by a 

 pit, which in many situations would be a great saving, 

 where the water and sand beds render it very difficult 

 to pass through, and where the expence is great, 

 amounting to above ,100 per fathom. We see no physi- 

 cal objection to the carrying on of this system of un- 

 der-dip working almost to any extent, provided the 

 air can be circulated in abundance ; and we think this 

 can be accomplished equally well in this system as by 

 the other. 



Besides these plans of working under-dip coals, there 

 are several others in common practice. 



If an engine pit is sunk to a particular coal, found 

 at any given depth, all the other coals of the coal-field 

 both above and below the coal sunk to, can be drained 

 and wrought to the same depth, by driving a level 

 cross-cut mine, both to the dip and rise, until all the 

 coals are intersected, as represented in Plate CCCXCIV. PLAT* 

 Fig. 5, where A is the engine-pit bottom reaching the E," cx f* v ' 



