MINING FOE COAL 333 



Tho transport of coals from the wall-face to the bottom of tho shaft was greatly 

 facilitated by the introduction of cast-iron railways, in place of wooden roads, first 

 brought into practice by Mr. John Carr of Sheffield. The rails are called tram-rails, 

 or plate-rails, consisting of a plate from 3 to 4 inches broad, with an edge at right 

 angles to it about two inches and a half high. Each rail is from 3 to 4 feet long, and 

 is fixed either to cross-bearers of iron, called sleepers, or more usually to wooden 

 bearers. In some collieries, the miners, after working out the coals, drag them along 

 these railways to the pit-bottom ; but in others, two persons called trammers are em- 

 ployed to transport the coals ; the one of whom, ia front of the corve, draws with 

 harness ; and the other, called the putter, pushes behind. The instant each corve 

 arrives from the wall-face, at a central spot ip the system of the railways, it is lifted 

 from the tram by a crane placed there, and placed on a carriage called a rolley, which 

 generally holds two corves. Whenever three or four rolleys are loaded, they are 

 hooked together, and the rolley driver, with his horse, takes them to the bottom of the 

 engine- shaft. The rolley horses have a peculiar kind of shafts, commonly made of 

 iron, named libers, the purpose of which is to prevent the carriage from overrunning 

 them. One of these shafts is represented in fig. 1517. The hole 

 shown at a, passes over an iron peg or stud in front of the rolley, so 

 that the horse may be quickly attached or disengaged. By these 

 arrangements the work is carried on with surprising regularity and 

 despatch. Where the roads are well constructed, a horse will con- 

 vey a load of 7 to 8 tons on the level. 



We shall now describe briefly the modes of working coal dip of or on tho deep 

 of the engine-pit bottom. Headings are driven either on the full dip of the mine, 

 or any convenient angle to it, the requisite distance. The water is pumped up 

 these dip headings by the pumping-engine on the surface. A pump-rod or spear 

 passes down the side of the shaft, and is attached to a quadrant at the bottom of 

 the shaft, which quadrant transfers the perpendicular motion of the spears in the shaft 

 to the spears or pump-rods in the dip headings. The quadrant is constructed so that 

 the stroke of the pump in the dip headings can be lengthened or shortened as required. 



In level free coals, these pumps may be worked by a water-wheel stationed near the 

 bottom of the pit, impelled by water falling down the shaft, to be discharged by the 

 level to the day (day level). 



When the above arrangements are applied for pumping, the coals are drawn from 

 the deep either by horses or an engine placed on the surface. 



Where operations are very extensive, some mining engineers place the engine under- 

 ground for working the dip coal ; and it both pumps the water and draws the coal to 

 the bottom of the shaft. 



High-pressure engines are employed for this purpose, working at a pressure of 

 from 30 to 50 Ibs. per square inch. These machines are quite under command, and, 

 producing much power in little space, they are the most applicable for underground 

 work. An excavation is made for them in the strata and isolated from the coal, and 

 the air used for the furnace xinder the boiler is the returned air of the mine ventila- 

 tion if the mine is free from explosive gas. If the mine yields explosive gas, the boiler 

 furnace is supplied with fresh air. In the dip road a double tram-road is laid ; so that 

 while a number of loaded corves are ascending, an equal number of empty ones are 

 going down. Although this improved method has been introduced only a few years 

 back, dip workings have been already executed more than an English mile to the dip 

 of the engine-pit bottom in the Newcastle coal-fields. It may hence be inferred, that 

 this mode of working is susceptible of most extensive application ; and in place of 

 sinking pits of excessive depth upon tho dip of the coal, at an almost ruinous expense, 

 much of the dip coal will in future be worked by means of the pits sunk on the rise. 

 In the Newcastle district, coals are now working in an engine-pit 115 fathoms deep, 

 and dip of the engine-pit bottom, above 1,600 yards, and fully 80 fathoms of perpen- 

 dicular depth more than the bottom of the pit. 



The deep pit in Dukinfield is 2,004 feet below the surface to the point where it 

 intersects the Black Mine coal-seam, which is 4 feet 6 inches thick, and of the best 

 quality for domestic and manufacturing purposes and a further depth of 500 feet 

 has been attained by means of an engine-plane in the bed of coal, which dips at an 

 angle of 27, so that a great portion of the coal is now worked there at the depth of 

 2,n04 feet below the surface. 



The shafts at Pendleton are 1,635 feet deep, and in like manner a further depth has 

 been reached of about 500 feet, amounting in the aggregate to 2,135 feet, at which 

 point a large quantity of coal is daily worked. 



The Rose Bridge Pits near Wigan intersect the cannel at 1,773 feet below the sur- 

 face which varies in thickness from 2 feet 8 inches to 3 feet, and is of excellent quality. 



At the most extensive collieries in the north of England, engine-power is not only 



