AERIAL ROPEWAY FROM MINE

Press, Volume LXXXVI, Issue 26031, 7 February 1950, Page 4

AERIAL ROPEWAY FROM MINE

CONVEYANCE OF COAL TO BINS WORK COMMENCED ON £550,000 STRUCTURE 'From Our Own Reporter WESTPORT, February 6. Work has been going on for some time on the construction of towers and other structures for an aerial ropeway, estimated to cost £550,000, to be used for conveying coal from the underground and open-cast works at the Stockton State coalmine to the bins at Ngakawau. Details of the ropeway, which is being built by the Public Works Department, given by Mr R. R. Dawber, district engineer for the department at Westport, show that the total weight of steel ropes, fittings, and other gear will be approximately 1830 tons, and that half of this will be used in the towers and main structures. Altogether, 110 steel towers, varying from 16 to 100 feet in height, will be needed to carry the ropeway. The foundations have been completed for 45 towers, and four have been raised. Five and a quarter miles of cable will be required for the ropeway. The longest span will bfe of 1700 feet, over the Goal Creek gully. The main carrying rope will have a six-inch circumference, with a breaking strain of 80 to 90 tons to the square inch. The return rope will have a circumference of three and a quarter inches and almost the same breaking strain. For the largest span the rope will have a breaking strain of from 115 to 125 tons, and its circumference will be six and a quarter inches. Seven divide and tension stations built of concrete blocks will be used. Coal will be carried at the rate of 250 tons an hour in 30cwt buckets. The ropeway will carry 187 fully laden buckets and the same number of empties at the same time. The three loading or connecting points for the aerial will be at the existing 1000-ton bin at No. 3 loop, at the 500-ton bin at “D” Hill or Webb mine, and at the 1000-ton bin near the open-cast field. Power to drive the cable will be supplied by five 86 h.p, motors spaced at intervals along the route and equipped with two-speed gears. All will be controlled from one main station, most likely at Ngakawau. Saving in Cost The aerial ropeway will mean a considerable saving in the cost of carrying coal from the mines to the railhead, Mr Dawber said. The present cost from No. 3 loop to Ngakawau was about 5s a ton. Allowing for interest and depreciation on the ropeway, the price would not be more than Is a ton. The output of coal would also be greatly accelerated, as the ropeway could deliver 2000 tons in an eighthour day to the bins, whereas the maximum capacity of the existing tram line was 1400 tons for perhaps a slightly longer day, he said. To JJLr T. McGhie (Superintendent of State Mines in the Buller district) must be given the credit for conceiving the idea, Mr Dawber said. Mr McGhie had submitted the plan for the ropeway to the Stockton Coal Company, as its manager, before the State took over the colliery and had arranged for a survey to be made, so that the Mines Department was well acquainted with the scheme before it assumed control at Stockton.

The ropeway was designed, fabricated. and is being built by the British Ropeway Engineering Company. An engineer from that firm is to arrive at Westport this week to supervise its erection.