242 COALFIELDS AND COLLIERIES OF AUSTRALIA. 



the Stockton colliery, both seams were in most cases taken 

 out ; stone drifts being driven to the top seam, and care be- 

 ing taken to leave the pillars of the lower seam directly below 

 those of the upper; but further west, the distance between 

 the seams being greater, each seam has to be worked sepa- 

 rately. About the Wallsend and Co-operative collieries, 

 there are 60 to 70ft. between the two seams. In some places 

 the Young Wallsend is too dirty to work. The Young Wall- 

 send colliery is the only place where it has been worked, and 

 here it is 47 to 60ft. above the Borehole seam. At Duckenfield, 

 the Young Wallsend seam was tapped on the boundary of the 

 Young Wallsend colliery, where it was found to be thin and 

 dirty. From there to West Wallsend, Seaharn, and Killing worth, 

 the lower seam improves ; the jerry of the other collieries en- 

 tirely disappears, and the coal rests on the Waratah sandstone, 

 the true floor of the Borehole seam, which is used as a building 

 stone in the Newcastle district. At Seaham, the two seams 

 are 20ft. apart; at Killingworth they are only divided by 

 3ft. ; the Young Wallsend seam being 10ft. 7in. thick, 

 and the Borehole seam 8ft. Sin. At the Northumberland 

 colliery, the two seams are 60ft. apart. At the Pacific, the 

 Young Wallsend seam is Oft. lOin., separated by 52ft. 2in. of 

 rock, from the Borehole, which is 4ft. 9in. thick. Proceed- 

 ing south from the Sea pit, towards Burwood and Lambton 

 B. collieries, the Borehole seam becomes thinner, 5ft. Sin. 

 to 5ft. 6in., and west of these collieries, at Teralba, there are 

 only 3ft. Gin. of workable coal. 



Backs and facings are very well defined in the Newcastle 

 coal, and influence the mining. Dykes do not occur so fre- 

 quently as they do in the Southern coalfield. The dyke-rock 

 has not yet been determined, as it is so altered ; but it is of a 

 basic nature, probably basalt. Crushes have occurred at the 

 Hetton, Stockton, A. A. Company, and Wickham and Bullock 

 Island collieries. In the case of the latter, an area of 70 

 acres was affected, but no water was admitted to the work- 

 ings. 



The Stockton, Hetton, New Winning or Sea Pit, of the 

 Australian Agricultural Company, the A and B pits of the 

 Newcastle Coal Mining Company, and also the Dudley Coal 

 Company, have all worked beyond high-water mark. The 

 Scottish Australian Mining Company also intend to work coal 

 under the ocean from their Burwood and Lambton B. pits. 



A. A. Atkinson,* the New South Wales Chief Inspector 

 of Coal Mines, says that due consideration should be given 



^Working Coal lender the River Hunter, the Pacific Ocean 

 and its Tidal Waters, near Newcastle, in the State of New 

 South Wales (T. I. M. E., 1902). 



