106 COALFIELDS AND COLLIERIES OF AUSTRALIA. 



foot. The screens are placed at an angle of 25deg., and are 

 stationary. The bars, which are lin. wide on top, half-an- 

 inch wide at bottom, and 2in. deep, are arranged lin. apart 011 

 the top, and as the space widens below, there* is no fear of 

 the coal clogging the bars. Also, the; top, of the bars, which 

 are most subject to wear, is the strongest. As large lumps of 

 coal might slide down quickly and carry slack with them be- 

 fore it has time to be screened, there are two! or three) rows 

 of three knives, each weighted in such a manner at the end 

 of a lever as to retard the rush of coal, though they eventually 

 give way to the pressure, and as soon as the pressure is re- 

 lieved, the weight on the lever brings the knives back into 

 place again. When not required, these knives can be held 

 back. The screens are 4ft. wide by about 15ft. long. A 

 sheet iron brake is hung down to prevent the coal from over- 

 shooting when filling into D trucks. When slack is not being 

 filled direct into trucks, a sheet of iron is rigged up to guide 

 it into the- boot of an elevator, similar 1 to that used at the 

 Lithgow Valley Colliery (Fig. 4*2). The slack elevator is 

 worked from the endless rope, but as the latter only passes a 

 quarter of the way round the pulley, in wet weather it used to 

 slip, so filling pieces were bolted on to the pulley to give it a 

 better grip. The elevator pulley is arranged above the driving 

 pulley, and is put into gear by a common clutch. 



Great Cobar Limited Colliery. 



This is a small colliery worked by the Great Cobar Com- 

 pany in order to obtain coal for their own use. The whole 

 10ft. of the seam is extracted; any bands that can be picked 

 out are placed 011 one side. Horses draw the skip to the flat, 

 and as the road is high, big horses can be employed. An 

 engine plane is used to haul the skip up the incline to the 

 surface, and as the engine is located on one side of the in- 

 cline, the rope has to pass round a diverting sheave to direct 

 it down the roadway. The ventilation is carried out with the 

 help of a 'furnace. The motive power for the pump is com- 

 pressed air, used at 301bs. per sq. in. The air compressor is 

 one made by Horwood, of Bendigo. It has a single steam 

 and a single air cylinder, and is provided with spring valves. 



W. and J. Hoskin's Colliery. 



This is another small colliery, which only works coal for 

 use at the owner's local iron works. Being located between 

 those collieries that can reach their seam by tunnels on the 

 one hand, and those that have to sink shafts on the other, this 

 colliery has a slope, which is worked as an engine plane, and 

 is about a mile long from the suface. Six skips are brought 

 in a set from the far end of the workings to the flat, and from 



