The presence of coal in the Sydney area was confirmed in 1891 when Cremorne Bore No. I intersected cindered coal at 1 854 m. The decision to develop Sydney Harbour Colliery was based on the results of Cremorne Bore No. 2 (drilled in 1892) in which a 3.12 m. seam of unaltered coal was encountered at 889 m. Geologists from the New South Wales Department of Mineral Resources consider that this seam is probably equivalent to an upper split of the Bulli seam. Long Cove at Balmain was selected by Sydney Harbour Collieries Ltd._x000D_
as the site for mine development in 1896. This was due to opposition to the proposed establishment of a colliery on the north shore of Port Jackson near Cremorne. Construction of the main access and ventilation shafts (termed Birth- day and Jubilee), other mine infrastructure and the quay wall occurred between 1897 and 1902. A fatal accident in which five men were killed occurred during the construction of the Birthday Shaft in 1900. This acci- dent resulted in amendments to the Mining Act providing for guide rails in shafts.