January 3, 1888.] 



♦ KNO^ATLEDGE ♦ 



By W 



COAL. 



Mattieu Williams. 



THE PKAIX.iGE AND PUMPISG OF COAL-MIXES. 



HE vexed question of the duration of our 

 coal-fields woxild have been quite settled ere 

 this, had our means of removing the water 

 from coal-mines remained as they were pre- 

 vious to the inventions of James Watt. 

 As I long ago explained, the end of our 

 coal -digging will occur long l)efore our 

 coal-se-ams are exhausted, long before the physical po.ssi- 

 biUties of working the coal are exhausted. It will be deter- 

 mined commercially when the cost of obtaining coal at 

 home exceeds that of importing it from abroad, or of the 

 growing of wood. With the tread-wheels, hoi-se-gins, water- 

 wheels, and other pumping-machines that were in use at 

 the begmning of the last century applied to our present 

 workings, coal would now cost far more than firewood, and, 

 even with the steam-engines that preceded tliose of Watt, it 

 would cost nearly as much. As it is, in spite of all our 

 improvements, there are great well-known coal-seams re- 

 maining unworked, and pi-actically unwoikable, for the 

 simple reason that the cost of removing the water added 

 to the ordinary cost of coal-getting would exceed the market 

 value of the product. All this coal is, in colliers' expressive 

 language, " drowned out." 



If coal-seams occurred in non-porous rocks, such as granite 

 and compact hmestone, like the marble of Carrara (where I 

 have walked a couple of miles underground without seeing 

 water), no drainage nor pumping would be required, but this 

 is far from being the case ; the chai-acteristic rocks of the 

 coal measures are porous sandstone and shale. Here and 

 there are alternating strata of what the sinkera call " metal," 

 or hard compact rock practically impenetrable to water, but 

 for the most part the rock above the coal permits the in61- 

 tration of much of the rain water that falls on the surface. 

 That which oozes or pours through the sides of the shaft 

 may be resti-ained by " tubliing," as already described, but 

 the water that comes through the roof and sides of the 

 roads and workings must be first collected by drainage and 

 finally removed by pumping or hauling to the surface. 

 There are some few dry coal-mines, of which I shall speak 

 hereafter. 



The drainage is eftected by the simple device to which I 

 have already alluded, that of beginning to work on the 

 deep, i.e. at that part of the estate where the coal is deepest, 

 and then proceeding upwards along the natural slope of the 

 seam. The water may thus run down the roads or by 

 special drains or " water gates," until it reaches the shaft, 

 which is sunk to a considerable depth beyond the lowest 

 opening of the roads in order to form a sumph or receptacle 

 for the water, from which sumph it is drawn by winding 

 buckets or pumps. 



Some primitive coal-mines were drained without any 

 winding or pumping. This is possible wherever the seam 

 occurs in hilly districts and Kes at a higher level than the 

 bottom of the valley. In such cases, an adit-level, i.e. a narrow 

 tunnel, may be cut from the lowest part of the intended 

 working, through the side of the slope, into the open valley. 

 The water, of course, flows down this into the river, or in 

 some cases directly into the sea. This is still used wherever 

 the configuration of the counti-y renders it possible, but 

 unfortunately for the present generation, our forefathers 

 have nearly, if not entirely, exhausted such deposits of coal. 

 It is in lead and copper mines that adit drainage is now more 

 available. 



I need not describe the mechanism of pit-pumps — pumps 

 ai'e pumps everywhere, and are properly described in 

 treatises on such machines. The special feature of coal-pit 

 pumps is their great size in some instances, and the depths 

 from which they raise the water. In old times, when only 

 the seams of coal near to the surface were worked, the 

 simple so-called "suction pump" was used, acting, as in 

 these post-Torricellian days we all know, by the pressure of 

 the atmosphere. But this pressure could only sustain a 

 little more than a 30-feet column of water, and therefore at 

 greater depths, pumping by successive stages, or the use of 

 lift -pumps or force-pumps wiis adopted, or more commonly 

 in tlie early days the water in the deeper pits was raised by 

 winding, by using large buckets that dipped into the 

 " sumph" in the manner I described when on the subject of 

 pit-sinking. 



Costly as may be the raising of water from coal and other 

 mines, its costliness has made mankind the richer. This 

 cost was the chief stimulant to invention in the birth and 

 growth of the steam-engine. The primitive machines of 

 Papin, Savery, Xewcomen. Leupold, Beighton, and Smeatcm 

 were constructed for pumping water from mines, and the 

 first eflbrts of Watt with his separate condenser were de- 

 voted to the same object. There was a double advantage 

 in this. Not only was the engine especially suitable for 

 such work, but such work reacted with special benefit on 

 the engine which had to overcome a gi-eater deadweight 

 than that of water down in the darkness of a pit sumph. 

 The deadweight of prejudice had also to be b'fted out of the 

 still lower and darker depths of human stupidity, and the 

 inventions brought to the light in spite of the resistance of 

 vested interests. The damaging power of these detestable 

 agents was proved by the fact that they crushed Dud 

 Dudley's great invention of the manufacture of ii'on by pit 

 coal and ruined the inventor, thereby causing a halt of 

 about a century in the progress of this important branch 

 of industry. 



The impossibility of crushing the steam-engine and its 

 in\entors arose from the fact that its work in pumping 

 water from mines was so easily and obviously measui-able. 

 The quantity of water raised from a given depth by the 

 expenditui-e of a given amount of fuel admitted of such 

 definite statement that misrepresentation was drowned 

 by it. 



A few figures indicating the progress we have made in 

 this direction will be interesting. When Smeaton com- 

 menced his improvements, the average </?«?// — i.e. the 

 number of pounds of water raised one foot per bushel of 

 coal consumed was 5,590,000. In 1772 he erected an 

 engine at Wheal Busy which attained a duty of 9,450,000. 

 But presently — i.i;. between 1776 and 1779 — he was 

 beaten by Watt, and admitted that Watt's engines per- 

 formed double the duty of his own. Some were te-sted, 

 and proved to reach 19 millions, and the average of Watt's 

 engines in Cornwall amounted to 1 7 millions. Finally, his 

 engine at Herland attained 20 millions, and Watt was 

 satisfied, pronounced his work perfect, and expected no 

 further improvement. But in 1823 the proved duty had 

 reached 28 millions, in 1843 it had grown to 60 millions, 

 and now we even exceed 100 millions; the record of an 

 engine erected at Fowey Consols Mine having, while worked 

 under strict supervision during twenty-four hours, attained 

 a duty of 125 millions. Such maximum duty is attained in 

 Cornwall, where coal is dear, and the men in charge of the 

 engine are (or were) rewarded according to the duty they 

 obtained. Not so in the Black Country, where coal is so 

 ruinously cheap, and no record of engine duty is kept. 



When a seam is worked out and left, the old workings 

 usually become filled with water, and such occupation of the 



