M I N E. 



339 



Mines of are lifting the sand, in order to prevent the sand 



C'- flowing in from the back of the tubs; and it is ne- 



~"~~ """ * cessary to keep about a foot of water upon the top of 



* the sand, and to hang the pumps in such a manner as 



only to lie a few inches into it When these tubs are 



completely secured and wedged light at their junction 



with the rock head, and where they join each other, 



the whole internal face of the cribs is covered over 



with close jointed deals, an inch und quarter thick, 



which gives the pit an appearance of a smooth wooden 



cylinder. 



Can-iron The most effectual method for passing through beds 

 tubbing. of quicksand is by means of iron cylinders, termed 

 cast-iron tubbing. If the pit is of small diameter, 

 these are made about four feet in length, with strong 

 flanges, and bolt-holes inside of the cylinder, with a 

 counterfort ring at the neck of the fl.inge, with brack- 

 ets; the end of the lowett cylinder has no flange, but 

 is rounded to render its sinking through the sand 

 more easy. If the pit is of a large diameter, then the 

 cylinders are cast in segments of two, three, or more 

 pieces, joined together with in-ii!>- (lunges, having a 

 jointing of white lead and oakum. If the sand-bed is 

 thick, suppose eighty feet for example, the practice 

 now is, to divide that space into three sets of cylin- 

 ders, thirty feet each in length, and so constructed as 

 to pa*s through each other like the tubes of a tele- 

 scope. These cylinders are joined togct her piece after 

 piece, and pressed down by great weights, using the 

 same precautions in keeping tlie lower part always 

 farther down than the top of the sand where the men 

 are at work, and where the bottom of the pun 

 for drawing the water. When the first thirty feet 

 of cylinder* is put down, the lower part of the 

 next set of cylinders is passed through the first set, 

 and the finking carried on until ihe add-lional thirty 

 feet of cylinders are sunk, after which the third set 

 cylinders is passed down through the two former 

 sets, until the lower part readies the rock-head or im- 

 pervious stratum ; the joinings of the three ;cts of 

 cylinders are made tight by wedging with wood, h 

 is proper to remark here, that this mode of dividing 

 the deep sand to be passed through into spaces, is an 

 improvement but lately adopted at Newcastle. Be- 

 fore this improvement, almost every attempt to pas* 

 through very thick beds of quicksand was rendered 

 abortive. 



The engine-pit being thus secured by one of the 

 several ways before-mentioned, the process of sinking 

 through the rock is now ready to be begun; but, before 

 commencing, the divisions of the pit formed of carpen- 

 try-, named brattices, are made ; this is done in seve- 

 ral ways. 



In common practice, and where great tightness of 

 jointing is not required for ventilation, on account of 

 inflammable air, bars of wood, named bunions, of 

 about six inches thick and nine inches in depth, are 

 fixed in a horizontal position across the pit ; they 

 are placed at different distances according to circum- 

 stances, sometimes at th length of a pump from each 

 other, snd at other times there are two or three in ih.ii 

 space. These bunions are all placed in the same per- 

 pendicular line, and upon these, deals of an inch and 

 half thick are nailed, having their joints close; and 

 each length of these deals takes in the half of the up- 

 per and under bunion lo which il is nailed. In 



when the ventilation is to be carried on by the 

 brattice, the >-idc of the bunions next the pumps is co. 

 vered with deals in the same way, the joints nude u 



10, 



tight as possib c, and next the pit the irregular join- Mines of 

 ing is caulked with oakum, and fillets of wood fixed all Coal, 

 the way down on each side of the brattice ; this forms i^T"^ 



a double pit. TV*!f * 



... ,. ... _ . . . coal-field. 



lien a pit is divided, so as to form three pits, it is 



a more difficult process to form the bratlice, as none of 

 ihe bunions stretch across the pit, the three which 

 form the divisions meet, forming angles with each 

 other near the centre of the pit ; and in order to give 

 them stability and strength in their position, they do 

 not lie across in a horizontal line, but have a rise from 

 the sides to the centre of about nine inches where 

 they meet, and a three-tongued iron slrnp binds ihem 

 together by means of a bolt at each tongue. Fillets of 

 wood are carried down the whole depth, not only at 

 ihe joinings of the brattice with the sides of the'pit, 

 but also at the meetings of the brattice at the centre of 

 the pit ; and, for farther security, a prop of wood 

 reaches from the centre of one set of bunions lo th 

 centre of tho&e immediately above ; by this means a 

 rerjr strong piece of carpentry is formed, having its 

 strength depending upon the principles of the couple of 

 roof. These bunions are clad on all sides with deals 

 from top to bottom ; and the ends of all the deals 

 meet each other in the middle of a bunion. 



In fj-i.i.'.r.tnt pits the buntom cross each other in the 

 centre of the pit at right angles, and are generally only let 

 in about an inch into each other, in place of being half 

 checked. Plate CCCXC. Fig. J). is a double pit, A P" 

 the engine pit, R pit for drawing coals; Fig. 10. it cic. 

 a triple pit, A the engine pit, H and C pits for drawing * '!* s - 

 coals; rig. 11. is a quadrant pit, A the engine pit, B 

 pit for the ventilating furnace, C and L) pits for draw- 

 ing coals. 



Theae methods now described, being snch a.s are 

 wed in the practice of mining when sinking tlr. 

 the cover, securing the- ,! dividing 



the pit* by brattices, it must be remarked, that 

 ral of theae processes are attended with xuch im- 

 menae expence, that it is only in districts where great 

 ri-turns of profit are made, that they can be attempt- 

 ed. It is at Newcastle and Whilehaven where by 

 far the greatest capitals are employed, nnd where the 

 very expensive methods of sinkmg through quick- 

 and are adopted and prosecuted -our and 



ucceai. As engine-pits are now sunk in winnings of 

 collieries made from the depth of 20 to 1 50 fathcnns, 

 -, with pits having one set of pumps, to those 

 having five seta, the operation, though in nio.-t of the 

 circumstances the same, is very different as to labour, 

 difficulties, expences, and skill required. In winnings 

 of a moderate depth, if the water found in the cover 

 is kept from descending the pit, the feeders found in 

 the rock are allowed to flow down. In deep winnings, 

 the most minute attention is paid to prevent any waler 

 from descending, by methods to be descrilx-d r.f icrwards. 

 As 15 fathoms is reckoned rather :ver- 



ge depth of winnings or of engine-pits in Great Hri- 

 tain, and as in practice it embraces three sets of 

 pumps, by describing this operation, we describe also 

 the more simple winnings of one and two sets. 



A soon as the pit is sunk to such a depth that the Sinking 

 engine must be applied to pump the water, the first with 

 set of pumps is let down the pit ; these are termed pomps. 

 the sinking set, they arc jointed with strong (I. 

 and bolts having a jointing of lead of about half an 

 inch thick, covered with tarred flannel. There are se- 

 veral methods for suspending them during the process 

 of linking, as they must rest on the bottom of the pit. 



