304 COALFIELDS AND COLLIERIES OF AUSTRALIA. 



Operations are carried on under the ocean. A five chain\ 

 barrier pillar of coal is left between the ocean and land work- 

 ings, the former extending for 700 yards past the barrier. 

 There are 131ft. of solid rock overhead, though the depth of 

 cover required by law is only 120ft. The ocean workings 

 have bore holes put in advance, not less than 15ft. in length, 

 and at every 20 yards driven, bores 30ft. high are put in the 

 roof to test the rock overhead. 



The mine is dry and dusty, and is worked with picks only, 

 on the bord and pillar system. The picks weigh 2-| to 3|lbs. 



At 9 a.m. on 21st March, 1898, there was an explosion,, 

 causing the death of all in the mine at the time, viz., 15 men, 

 including the manager and two deputies. On account of the 

 fire that took place after the explosion, the mine was tempor- 

 arily sealed down from 24th March, to 17th June of that year. 

 The Court of Investigation found that the explosion was 

 caused by the ignition of firedamp at a naked light, and that 

 it was intensified by the agency of coal dust. Since then the 

 Cambrian safety lamp has been used, in which are burnt three- 

 parts of colsa and two parts of kerosene oil. 



Prior to the explosion they worked with 8-yard bords and 

 8-yard pillars, but now they work with 8-yard bords and 12- 

 yard pillars, as it will be cheaper to work the larger pillara 

 later on. Up to the present, no pillars have been worked. 

 Under the ocean they are compelled to have bords not wider 

 than 6 yards, and to have pillars at least 8 yards wide. 



Air is circulated by means of a 30ft. Waddle fan. A 

 white mark is painted conspicuously on the fan, so that the 

 manager can see from a distance whether it is revolving at the 

 proper rate. This is the more necessary since the upcast and 

 downcast shafts are situated further apart than is usually the 

 cose, and intervening trees somewhat obscure the view. The 

 fan is given 48 to 50 revolutions per minute, the pressure of 

 the air being one inch water gauge. The fan engine is duplicated 

 in case of accident. There is a lever by means of which the 

 valve can be pressed close against the valve seating of the 

 steam chest as they wear, thus preventing leakage of steam. 



The haulage below is all done by horses. These are 

 stabled at the surface, and sent below every day. Gates are 

 put on the end of the cages when raising or lowering horses,, 

 but there is no occasion to tie them up when once they be- 

 come accustomed to travelling in a cage. There is a well- 

 appointed saddler's room at the surface, in which a saddler 

 is employed mending and making harness. 



The well-known Humble 's safety detaching hook is used 

 in case of over-winding. 



The hoisting engine is duplex, worked on the first motion . 

 with slide valves, cylinders 26in. in diameter, and a 4ft. 6in_ 



