750 REPORT — 1891. 



adtnittino' high-pressure steam to either end of low-pressure cylinder when 

 required." The working pressure of steam is 90 lbs. per square incli. This engine 

 has proved so satisfactory that the management of the mine have been induced to 

 erect a new horizontal condensing compound air-compressing engine in place of 

 their existing plant. This engine will have high- and low-pressure cylinders of 

 1.5J and 27 inches diameter respectively, by 48-inch stroke, and the air cylinder is 

 22 inches in diameter, with an equal stroke, and is fitted with Trestrail's patent inlet 

 and outlet valves, and is arranged for a working pressure of 100 lbs. per square inch. 



At the Greenside Lead Mines, near UUswater, a waterfall of upwards of 

 100 horse-power is now being utilised by means of a turbine to drive dynamos, 

 the eneroy from which is transmitted for the purposes of winding, pumping, and 

 lighting ; and, again, at the Morgan Gold Mmes, near Dolgelly, there is a modern 

 example of the successful utilisation of water-power for compressed air, and for 

 drivint^ forty head of stamps. The water-power for driving the mill is obtained 

 from the river Mawddach, and is brought on to a 22-inch turbine, ^^•ith a 68-feet 

 head ; this fall, with 650 cubic feet of water, easily drives the mill, stone breakers, 

 &c. and with 800 cubic feet of water applied, if required, the water-power can be 

 raised to 100 horse-power. 



And, as an example of the very large amount of mechanical power applied in 

 exceptional circumstances to metalliferous mining operations, the Whicham 

 Hfematite Iron ilines, in South Cumberland, may be named, where the quantity of 

 water raised frooi a depth of 552 feet occasionally exceeds 4,800 gallons per minute, 

 the machinery employed consisting of — 



Firstly, a Cornish beam-condensing pumping engine, having a 90-inch diameter 

 cylinder by 11-feet stroke, with a 10-feet stroke in the pumps. The beam weighs 

 50 tons. There are attached to this engine three pump-rams, each 28 inches in dia- 

 meter, fixed at certain points in the shaft, the bottom ram being fixed 552 feet 

 below the surface, from which level the whole of the water is pumped. The quan- 

 tity of water delivered per minute is 2,210 gallons. There is also another Cornish 

 beam-condensing pumping engine, with a cylinder of 110 inches in diameter by 

 11-feet .stroke, with a 9-feet stroke in the pumps. This beam weighs 55i tons. 

 Attached to this engine are three 30-inch diameter pump-rams forcing from the 

 same level as that before mentioned a quantity of 2,295 gallons of water per 

 minute. In November and December during heavy floods as much as 4,680 gallons 

 have been pumped from this mine per minute by these two engines. 



The average consumption of coal by these engines is equal to about 4 lbs. per 

 indicated horse-power. 



There is another engine erected at this mine which is kept in reserve in the 

 event of anything happening to either of the two other engines which I have 

 described, viz., a tandem horizontal compound condensing pumping engine, having 

 a 40-inch high pressure, and a 70-inch low pressure cylinder by 9-feet stroke. This 

 eno-ine is fitted with Davey's difierential valve gearing. There is attached to this 

 enoine two 24-inch diameter pump-rams fixed at a point 372 feet below the surface. 

 Tliese pumps are capable of dealing with 280 gallons of water with each stroke of 

 the engine, and the maximum .speed is seven strokes per minute, which represents, 

 therefore, 1 960 oallons of water per minute. Provision is made with this engine 

 to extend the pumps to a lower level when necessary. 



The weight of the pumps and pipes connected with these engines is about 

 250 tons. 



In the raising of coal from our mines and placing it on board ship in our 

 docks, there is a vast amount of machinery employed, much of which is now of an 

 obsolete type. Where, however, new winnings have been made, or where in old 

 mines it has been found necessary to replace the old machinery by new, the ques- 

 tion of efficiency and, at the same time, economy in machinery has of late years 

 received serious attention. 



The consideration of the question of economy in the employment of steam in 

 coal-mining operations has resulted in boilers of the most modern construction 

 being erected, working to pressures varying from 80 to 150 lbs. per square inch, as 

 compared with pressures varying from 40 to 50 lbs. per square inch in the old 



