THE SYDNEY HARBOUR COLLIERY. 133 



There are two shafts placed 168ft. apart from centre to 

 centre, their mouths being 80ft. above low water mark. The 

 ground round about has been levelled off and supported by 

 strong rubble retaining walls. The Birthday shaft, 2935|ft. 

 deep, was the first to be sunk, this being let on contract to Mr. 

 T. Cater. It is the main winding and downcast shaft. The 

 Jubilee shaft, 2950Jft. deep, is the upcast, but will also be 

 used for winding, if necessary. 



Considerable disappointment was felt when coal was 

 struck in the Birthday shaft, for the seam at this point was 

 found to be split up. The upper searn, which was met with at 

 2880ft. from the surface, consisted of : 



2ft. 4in. bituminous and splint coal. 



3ft. to 3ft. 2in. very dark, jointy, carbonaceous coal. 



2in. inferior splint coal. 



Gin. to Sin. bituminous and splint coal. 

 This dipped 1 in 40, bearing N. 75deg. E. 



The middle seam came in 29ft. llin. lower, and consisted 

 of 1ft. 8in. bituminous coal, dipping 1 in 17, and bearing N. 

 47deg. E. The lower seam was met with at a further depth 

 of 15ft. lOin., or 2933ft. Tin. from the surface. This comprised : 



3in. black shale. 



3in. cannel coal. 



Sin. carbonaceous cloy shale, and thin layers of biti\- 

 minous coal. 



The dip was 1 in 11, and the bearing N. 13deg. E. A borehole 

 sunk from the bottom of the shaft passed through a 9in. thick 

 band of splint coal at a depth of 2990ft. 3 Jin., and a bed of 

 bituminous coal about a foot thick, at a depth of 3007ft. 



The sinking was started with two steam cranes, one of 5 

 tons, the other of T tons capacity. The jibs acted as headgear 

 over the shafts, and enabled the material obtained from the 

 sinking to be easily spread around the shaft, thereby assisting 

 in levelling the ground and saving time in waiting till the 

 hoisting machinery could be erected. These cranes gave satis- 

 faction, though the speed of winding was rather slow, but the 

 depth for which they could be employed was limited by the 

 length of rope that could be coiled on the barrel in a single lap. 

 In the Jubilee shaft a depth of 125ft., that is from 29ft. below 

 the surface to 154ft., was sunk through hard sandstone by this 

 means during four weeks. At a depth of 71ft. in the Birthday 

 shaft a tunnel has been turned off towards the quay wall, the 

 idea being that all heavy stores, such as pit timber and rails, 

 could be run in from the quay direct. This tunnel is 14ft. by 

 12ft. in the clear at the shaft, and is then reduced to 8ft. by 

 10ft., but has not been completed. Both shafts are 18ft. in 

 diameter, and there is a pillar of solid ground left round them, 

 having a radius of 375 yards. 



