334 COALFIELDS A^D COLLIERIES OF AUSTRALIA. 



centre of gravity, and the back wheels have a larger tread than 

 the front wheels. By having the rails horizontal at the sur- 

 face, and extra outer rails continued on. the incline, the for- 

 ward wheels keep to the inner rails, while the back wheels run 

 .on the outer rails, thus raising the bottom of the tank and 

 emptying its contents. When men are raised or lowered in this 

 tank, a chain is made to connect the bail with the lower side 

 of the alligator, so that there shall be no fear of it shifting 

 and precipitating the men. The alligators for jig sinking are 

 .smaller than those for tunnel sinking, while those for sinking 

 small airways are smaller still, and do not run on rails, but 

 have runners attached like a sledge, and slide on the coal. 



Ventilation is carried out by two 9ft. diameter Waddle 

 fans, and a three-quarter horse-power booster fan underground, 

 which is driven by electricity, to help the air current along. 

 The entrance to each bord is provided with a door to regiilate 

 the air, and the cut-throughs are stopped up as fresh ones are 

 made. The end of the bords past the last cut-through divide 

 the intake from the return by brattice cloth, as usual. The 

 levels not being wide enough for the use of brattices, a large 

 galvanised iron pipe is suspended from the roof, leading from 

 near the fan up to the first cut-through, for a distance not ex- 

 ceeding 50 yards. 



A fire occurred in one pannel of this colliery. It was, 

 however, not due to spontaneous combustion of coal in the 

 lower seam, which is the one being worked, but was due to a 

 crush taking place and admitting air through the roof to the 

 top seam, where spontaneous combustion started. 



Brick syphons are built in the lower stoppings of old 

 workings, so as to let out the accumulating water. Carbon 

 dioxide is found to emerge from the old bricked-in workings. 



This company owns the railway line from West Maitland 

 to Stanford Merthyr, the A. A. Co. owns the branch from Aber- 

 dare Junction to Cessnock, but the traffic is attended to by the 

 East Greta company. The workshops at the colliery are used 

 mostly in connection with railway work. 



A briquetting plant, belonging to a separate company, is 

 located near the East Greta colliery, but did not prove a com- 

 mercial success. 



Hedclon Greta Colliery. 



This colliery belongs to the Hecldon Greta Coal Mining 

 'Company Limited, and is under the management of Mr. James 

 Barnes. 



The mine is worked from tunnels, or rather slopes, at an 

 angle of 33 to 38 degrees, some 1600ft. long. The head gear 



