ELECTRIC HAULAGE.

Star (Christchurch), Issue 17347, 30 September 1924, Page 7

ELECTRIC HAULAGE.

CABLE TRAMWAYS AT LAKE COLERIDGE. LABOUR SAVING METHODS. Good use is being made of the electric power available at Lake Coleridge in connection with the work of pushing forward the duplication scheme. Without the. aid of electric power the obtaining of sand and shingle for concreting the new tunnel and other works would be a tedious and costly job. At the power station end of the tunnel a tramway nearly a mile in length has been constructed from the Rakaia river bed to a point on the side of the hill above the outlet of the new tunnel. Sand and shingle are obtained from the river-bed and hauled by horses to the site of the end of the power house. A wire cable is affixed to each truck and it is* hauled rapidly up the side of the steep hill, the power being supplied by* a 50 h.p. electric motor. After each truck is emptied it is let down the hill at a speed in the vicinity of twenty miles an hour. For the purpose of controlling the tramway a temporary signal station has been built on top of one of the anchor blocks of the existing pipe line, from which the signalman has a clear view of the whole of the tramway line. Each truck holds two cubic yards of material and it can be filled in the riverbed, hauled to the top of the hill, emptied and let down again in a quarter of an hour. * The sand and shingle are\ obtained from the river-bed by a contractor, who is paid at the rate of 7s 6d a cubic yard, Mr J. Behan’s tunnelling party is also charged 2s 6d a yard for haulage. Material has also been deposited on the hillside, on the site of each of the huge anchor blocks for the new pipe lines. Tho tramway is one of the sights at Lake Coleridge, particularly when an empty truck is travelling down the hill at a rapid rate. No accidents have yet occurred, but on account of tho speed at which it travels no one is allowed to go up or clown the hill in the truck. A labour-saving cable tramway has also been constructed at the intake end of the tunnel, shingle boing hauled up the side of the hill from the beach of the lake. This tramway is of only a short length, but if electric power were not available considerable work would be entailed in getting shingle for concreting. Ibe spoil from the tunnel and from the gate shaft and surge chamber is taken along tramways and tipped down the bill. Tlie trucks in the tunnel at the outlet end are liorse-drawn. An up-to-date concrete mixing plant, worked by electricity, has been installed by the tunnel contractors at the outlet end. Sand and shingle are tipped into separate bins and the water is regulated automatically. The cement is shovelled into the mixer by hand. At the intake end the concrete mixing is being done by band on the usual concrete mixing-board, but probably when the work is further advanced quicker methods will be used. A 150 h.p. motor lias been installed at the intake for driving the huge air-

compressor plant which works the drills used in tunnelling through the solid

A good deal of electric lighting is also provided on the job, on account of the work being carried on for twenty-four hours each day.