|1923 mining review article|
The following article is from an issue of Chemical Engineering and Mining Review of 5 February 1923.
Coal Mining in New South Wales - XXI
The Western District
State Coal Mine, Lithgow
It is situated in Mort's Gully, about 11 miles north of the main western railway at Eskbank. Its area of holding is about 10,000 acres of crown lands most all of which has the main Lithgow coal seam of workable section. The site of the shafts having been decided on in 1916, a start was made to sink the upcast shaft through the alluvium covering the bed of Mort's Gully, boilers and sufficient machinery having been carried to the site by drays and motor transport. After a deal of difficult work had been done on the shaft, the New South Wales cabinet decided to suspend all operations, and this was done on July 10, 1917. In 1920 parliament passed a short act vesting the control and working of the mine in the chief commissioner of railways for the purpose of supplying coal for the use of the railways.
The work done while the control of the mine was in the hands of the mines department consisted chiefly of clearing the site, erection of sinking headgear, winches, etc., and the sinking of the up-cast shaft through the alluvial deposits and into solid strata, a depth of some 80 ft, the shaft sides being secured through the alluvium by sheet piling, the ordinary ring curbs and timber being used on the underlying strata. Operations were suspended in 1917, the reason given for so doing being that war conditions affecting the financial side of the matter made it inadvisable, to carry on at that stage. The place remained shut down till April 1921, when operations were resumed by the railway commissioners. After unwatering the shaft, the depth already sunk through was secured by bricking, when sinking recommenced, operations being concentrated on the getting down of one shaft first. Water gave considerable trouble in the initial stages of the sinking.
This, however, was largely minimised later by the putting in of a water ring and the driving of an "inset" into which the water was collected and pumped to the surface. The strata passed through consisted chiefly of drift sand and shingle, shales, and sandstone, the total depth to the floor of the seam being 263 ft. This shaft was bottomed in November, 1921, when headings north and south were turned away.
A commencement was then made with the sinking of No. 2 or downcast shaft. This shaft was carried down in much the same way as the previous one, when the permanent walling was put in for this depth, concrete 18 in. thick being used. This effectually sealed back the flow of water from the alluviums. Sinking then continued and operations were later expedited by rising for a short distance from a heading in the coal seam. In the sinkings, jackhammers (air driven) were used and gave very good results in the shale strata.
For keeping the shaft dry the ordinary duplex type of pump was used. This was seated on the sinking cradle and driven by compressed air. All sinking shots were electrically fired.
Owing to the restricted area available for mining in the vicinity of the shafts (the main area lying practically due north about 1 1/4 miles away), a large output was not looked for, at least for some considerable time ahead. To reach the main area two pairs of headings and a separate travelling way (five places) were set away, and these, with their necessary cut-throughs, together with a limited amount of the bord area south and west, have afforded an 'increasing output which at present is 750 tons per day of two shifts.
The probable output for 1922 is 65,000 to 70,000 tons and about 290 persons are employed - 130 underground, and 160 on the surface. The estimated output for 1923 is 140,000 tons. Both shafts are being equipped to permit of a large output being obtained when fully developed. Up to 2,500 tons per day can be dealt with.
Size, depth and fittings of shafts
Diameter of downcast 20 ft. in the clear, 265 ft. to floor of seam. Both shafts will be equipped to wind coal, air-locks being provided at the upcast for this purpose. Two being provided at the upcast for this purpose.
Two cages in each shaft, single decked, carrying two tubs, each having a carrying capacity of 30-35 cwt., will be fitted with wire rope guides. At present a temporary cage carrying one tub is in use. It is dealing with the output pending the putting-in of the permanent plant.
Thickness of Seam
Headgear, Boilers, Screens, Tipplers, etc
Height of downcast headgear 81 1/2 ft. to centre of pulleys; rolled steel joints 12 in. x 6 in. x 44 lb., will form the main legs, with 8 in x 6 in. x 35 lb. rolled steel horizontal bracings diagonally braced and stiffened with 6 in. x 3 in. x 1 in. T bars.
Net load to be lifted at each wind, 3 to 3 1/2 tons of coal. Diameter of pulleys 12 ft. 4 in. running on 6 in. diameter shafts.
Winding Engines, Fan, Pumps, Haulage and Electric Plant.
The manager of the mine is Mr. Frederick Hemmingway, and Mr. Wm. McGhee, late of Sydney Harbour Colliery (Balmain), is the engineer.