NOTES ON THE CREMORNE BORE. 465 
feet, as has so often been experienced in other countries under 
somewhat similar conditions. 
VI. Possibility of Working the Seam,—With the efficient ven- 
tilation which can be secured by means of the most modern 
ventilating fans, there does not appear to be any reason to doubt 
that the temperature of the mine workings under the harbour at 
Sydney, can be reduced to 80° or even less. At the Metropolitan 
Colliery, Helensburgh, with a Schiele fan twenty feet in diameter 
working at the top of the upcast shaft, a ventilation of about 
350,000 cubic feet per minute is said to be obtained, and the con- 
dition of the air in the mine is very satisfactory. The depth of 
the coal below high watermark at Cremorne—about 2,774 feet is 
undoubtedly great, but it is not by any means the greatest depth 
at which coal has been worked. Thus in England at the Ashton 
Moss pit, at Dukinfield, the workings were carried to a depth of 
2,850 feet, while in Belgium at a Colliery near Charleroi a depth 
of 3,411 feet was attained.* 
It may therefore be reasonably expected that the difficulties of 
working the coal under Sydney harbour can all be overcome with 
the aid of the most improved appliances for ventilating and hoist- 
ing. ‘The only other question to be considered, viz., whether the 
trade that may be looked for in the near future will be sufficient 
to pay interest on the capital required to develop the mine, is a 
commercial rather than a scientific one, and is therefore outside 
the limits of this paper. 
* Vide Prestwich’s Geology, 1888, Vol. 11., p. 100. 
D p—Dee. 6, 1893.] 
