FAULT AT ARAPUNI.

New Zealand Herald, Volume LXVII, Issue 20602, 28 June 1930, Page 15

FAULT AT ARAPUNI.

POWER HOUSE TILTED.;

CHARACTER OF CRACKS. ' TEMPORARY BLOCK. IN TUNNECr The reference to " cracks in th« power-house" in the summary of the technical committee's report on Arapuni published yesterday, was explained in greater detail by the Minister of Public Works, the Hon. W. B. Taverner, in his introductory remarks. The Minister said that at the time of his visit on June 9 investigations indicated that some movement had taken place in connection with the power-house, the turbines being slightly out of true level. " It was also ascertained that the high-, level suspension bridge spanning tho gorge had sagged to some extent, presumably on account of movement of one of the supporting towers," the Minister continued. " Also, tho heavy traffic lowlevel bridge just below the power-house gave indications that movement had taken place there. All these displacements support tho theory that whatever movement took place was inward toward the old gorge." The Minister mentioned that overhanging material from the cliff face wall above the intake to the diversion tunnel slipped away at intervals during the night of June 13-14, and the gates of the diversion tunnel' were blocked on three occasions. The lake was finally drained on the morning of June 24. " On Friday, June 20, certain cracks one-fiftieth of an inch in width, were reported as having been discovered in the floor of the power-house round No. 2 unit," Mr. Taverner said. "On telegraphing for further particulars as to the positions and directions of these cracks,

the information was received next day that they had become' visible round all three machines and extended from the upper machine floor down approximately to the top of the turbine scroll cases. These cracks were believed by the staff to have developed in the last few days, as with a number of men constantly looking for signs of damage it seems inconceivable they could have been missed previously if there." Several sentences were omitted from the summary of the committee's report as telegraphed. One states that " the _ tilt of the power-house . . . attained about one minute of arc." Fol-

lowing the reference to the observation of tremors and vibrations

from the initial movement of the blocks the report says:—" These tremors, together with the tremors caused by tha progressive probably jerking return of tha block on removal of the water which gave rise to the hydrostatic head, caused vibrations and cracks to appear in the powerhouse."

The Minister described this part of hi* statement as " a summary of the findings " of the technical committee and remarked that the full geological report \ made by the experts would be issued later, j Referring to the question of power, supply, the Minister said:— " Realising that the demand for electricity grows continually, even faster than the population, immediately tha gravity of the position became manifest I cabled to the High Commissioner to make inquiries as to the possibility of . securing for prompt delivery a steam plant which could be installed in the Waikato district handy to the coalmines.Negotiations concerning this are still in progress, and I expect to be able to report before long "that, a conclusion baa been reached and definite arrangements made for the supply and installation of this plant." Every effort would be made to alleviate the position as soon as but under its agreement w:ith the boards the Government was relieved from liability as the result of such happenings.