ARAPUNI DAM.

Hawera Star, Volume XLVI, 29 January 1927, Page 7

ARAPUNI DAM.

FINAL PHASE BEGUN.

SLUICE GATES THAT WEIGH 27 TONS. Tlio colosusl construction work at Arapuni has now entered its final ph? B ® The engineers attached to the staff of the contractors (Sir W. G. Armstrong, Whitworth and Company) are no longer fighting the river god at the dam site. The victory has been theirs, and in the peace that lias followed all brains and hands are turned to the constructive tasks of building. 'Before the concrete can be poured in for the construction of the huge dam the bed of the river has to be deepened 30 feet to curry tlie foundations'. This work has been partlv completed and the first few yards oi concrete mixture are being permitted to set but a good deal of rock has still to be ’excavated before the concreting can start in earnest (reports the Taranaki Herald’s Auckland correspondent). At present the Waikato plunges through the diversion tunnel with no obstacle to its progress, but before long it will be possible to shut or open the huge underground passage at will. Control, will be effected by two gigantic sluice valves, completely closing the tunnel when necessary, turning the river back into its old channel and heaping up waters behind the dam. The sluice valve 3 are situated about 100 feet LE side the tunnel from the intake and will be operated from the surface through a shaft which has already been sunk and lined with concrete. It is a rectangular hole 38ft Gin by Bft. AVoikmen are now engaged in converting it into two by the insertion of a concrete dividing wall down the middle. in each of the shafts so formed hydraulic lifts will be installed, working in evlinders, for the purpose of lifting and lowering the gates into the diversion tunnel. The gates, of which there are two. each weigh 27 tons. They are of steel. 2ft thick, and measure 21ft 6in by lift Pin. These weighty objects have already been lowered in parts into the shaft and assembled, and they now' rest on steel girders 35 feet above the water which is plunging through the tunnel. When the lifting gear is installed it will be possible to take the weight off the girders and remove them, permitting the gates to be lowered at will into the tunnel, closing it completely or partially according to the depth to which they are allowed to descend. Then the river waters will pile behind the dam and submit it to the test which will pronounce judgment on the work oi years.