754' REPOET — 1891. 



the other crank ; both cylinders are fitted with Cornish valves, and on the high- 

 pressure cylinder there is fitted automatic variable expansion, worked by a governor, 

 and the initial pressure of steam will be 150 lbs. per square inch. This engine will 

 be fitted with a plain cylindrical drum, 18 feet in diameter, and a balance rope will 

 be attached to the underside of the carriages, so that everything will be in perfect 

 balance. 



Between the high- and low-pressure cylinders is a receiver on which is fixed a 

 valve arrangement, by which the steam can be expanded out of the receiver, or 

 live steam can be admitted into it. This arrangement greatly facilitates the ease 

 of starting the engines. 



As it is intended to raise the load from the bottom to the top of the shaft in 

 forty seconds, and as, during part of each lift, the speed will probably get up to 

 3,500 feet per minute, the engines at that time will probably indicate 1,500 

 horse-power. 



Mechanical ventilation, by exhausting the air, has almost entirely superseded 

 the furnace ventilation in general use many j'ears ago, and which created a current 

 by heat. There are many types of fans ; the best known are the ' Schiele,' 

 ' Guibal,' and ' Waddell.' Some very large fans are now in use, and at the present 

 time the large quantity of 500,000 cubic feet of air per miuute is capable of being 

 passed through one of the mines in this district by a ' Schiele ' fan, with a water- 

 gauge of 4 inches. A very exhaustive series of trials is being made by a committee 

 appointed by the North of England Institute of Engineers, which I have no doubt 

 will bring to light many interesting features in the various types of fans in general 

 use, and indicate accurately the relative economic values of each. 



Some of our coal mines are very heavily watered, and this involves large and 

 costly pumping machinery, which takes various forms, the most generally used of 

 which is perhaps the old-fashioned but economical Cornish vertical condensing 

 steam engine, which, with its heavy rods and pumps, occupies a considerable 

 portion of the room in the shaft. In recent years, however, there has been a ten- 

 dency to apply the direct-acting forcing engine, fixed at the bottom of the shaft, of 

 which there are various forms ; and still more recently, pumps, worked by electrical 

 power, are being brought into use, and in underground workings far away from the 

 shafts this power seems eminently suitable, as the work in pumping required can be 

 so regulated as to be constant, thereby reducing the risk of danger from sparking. 



Many excellent forms of direct-acting pumping engines have been designed, the 

 most economical being the compound condensing direct-acting ram-pump, which 

 takes up little space. Perhaps the worst feature in adopting direct-acting pumps 

 is the fact that steam must be conveyed down the shaft, which means a certain 

 loss by condensation ; a loss which can, however, be very materially reduced by 

 having the steam pipes properly protected from exposure by suitable coverings. 

 The steam and water pipes for this type of pump take up much less pit room than 

 those of the Cornish pump, and this is of very great moment where the area of the 

 shafts is limited. 



A type of pump which has been adopted in some of our northern mines, and 

 which I should like to notice, is the hydraulic pump patented by Mr. Joseph 

 Moore, C.E., of Glasgow. 



The object of this invention is attained by means of hydraulic pressure, and one 

 of the prominent advantages gained, is that it enables the steam engine, which 

 generates the power, to be placed on the surface, and near to the boilers, thus ob- 

 viating the loss due to the condensation of steam when conveyed great distances. 

 To the steam engine on the surface is attached a double-acting power ram, of the 

 ordinary type, and there are also similar power rams attached to the pump under- 

 ground ; these rams are connected to each other by small pipes, filled with water, 

 which, when under pressure, convey the reciprocating motion of the engine on 

 the surface to the pump underground. 



Anotlier type of pumping engine now largely used in mining is that manu- 

 factured by Messrs. Hathorn, Davey, & Co., of Leeds ; a notable instance of this 

 type of engine is at Bradley, in Statfordshire, where one engine raises 4,000,000 

 gallons a day, a height of 490 feet. The chief improvements introduced in these 



