OAKKY I 'A UK COLLTKUY 



125 



cost of making coke, the coal is cheaper to mine than on the 

 South Coast. The roof is good, whether it consists of top coal 

 or sandstone, and requires scarcely any timber, thus saving 

 the cost of timber and time in setting- up. The workable coal 

 is a suitable height to extract, and, as the mines are not gassy, 

 the men can work with naked lamps, which give a better light 

 than .safety lamps. The fine coal used for coking is hauled up 

 an incline in a skip, which has a sliding door at the lower end. 

 To this door is attached a pair of wheels which, when the 

 skip arrives near the end of its journey, runs on a short steepe' 

 incline outside the rails on which the skip proper runs (Fi; 1 . 



Fig. 66. Automatic Discharging Skip. 



66). This causes the door to slide up when over the Carr's 

 disintegrator. The disintegrator breaks up the coal to a suit- 

 able size for coking, and by doing so the beaters, which were 

 originally circular in cross-section, wear to a triangular shape. 

 The powdered coal falls into one of a pair of sluices ; one sluice 

 is cleaned up while the other is in use. The dirt collects in 

 the upper portion of the sluice, while the coarser coal, with 

 a small amount of dirt on the top, settles a little lower down r 

 and the finer washed coal occupies the lower section. The 

 sluice has an occasional riffle bar placed across it. A tram line 

 runs alongside the sluices, and the dirt is dug out or skimmed 

 off the top into skips, and run over the tip. The coal is sluiced 

 down into a washed-coal hopper to settle. There are four of 

 these hoppers, which have a capacity of about 27 tons each, 

 and each hopper has a separate branch from the sluice to itself. 

 These hoppers are Y-shaped, and the water drains off from the 

 coal while in them. When fairly dry the coal is drawn off 

 through slide-gates into canisters, which convey it to the top 

 of the ovens. By washing the coal they get rid of about 10 

 per cent, of dirt. There are 32 old style of beehive ovens, in 

 which the needles of coke spring from the floor. Black ends, 

 which consist of improperly coked coal, are mostly found at 

 the bottom. Very little ash from burnt coke is found on the 

 top of a charge. There are also 40 improved type of beehive 

 oven, of an estimated capacity of 10 tons each per week, built 

 so that the finished product can be pushed out by a ram. The 

 walls are built of good local machine-made common bricks, 

 and the roof of Lithgow Valley shaped fire bricks. The iron- 

 work for these were made by William Davies, of Wollorig'ong. 



