COLERIDGE POWER

Evening Post, Volume CXXV, Issue 150, 28 June 1938, Page 12

COLERIDGE POWER

LEAK IN TUNNEL

EFFECTING REPAIRS

(By Telegraph—Press Association.)

CHRISTCHUBCH, June 27.

Commenting further on the development of a leak in the adit tunnel leading off the main tunnel between Lake Coleridge and the surge chamber at the power-house, a situation which threatens the power supply of Christchurch, the Minister of Public Works (the Hon. R. Semple) said that the only safe course to take now was to line the main tunnel with ferroconcrete. While the present situation was allowed to remain the station would always be in jeopardy.

"The present construction might last six months and it might last five years, but its security is decidedly indefinite,' he said. "The grouting of the tunnel provided no real remedy to the trouble. We will have to tackle the job of making repairs that will be lasting and permanent. This will cost a great deal of money, but it is better to spend money on this work than to run the risk of losing the station." The Minister added that he hoped the plant would be able to remain in operation until two additional generating units could be obtained for the Waitaki station. With the output from Waitaki augmented in this fashion, the work of making repairs at Lake Coleridge could proceed without difficulty. Immediately on his return to Wellington he would make all arrangements possible to expedite the delivery of the new units to the Waitaki station. These were not expected for two years, but it was possible that their construction and delivery could be speeded up. Mr. Semple said he estimated that it would take six months to place a ferro-concrete lining inside the existing tunnel at Lake Coleridge. It was imperative that the work should be put in hand j»s early as possible and it had to be done for the protection of the interests of the people. Reports from engineers indicated that nothing really serious was to be feared as yet, but should there be any sign of the trouble growing worse it was possible that the station would have to be closed down and the job of tackling repairs commenced at once. While the cracks remained there was a constant menace that the water would break through. In shingle country of the type at Lake Coleridge a breakaway by water could cause havoc. A serious blunder had been made in the original construction and the weakness in the tunnel could only be repaired by building a new lining that would be capable of resisting the tremendous pressure exerted in the heavy country around the lake.

Christchurch has no standby station such as Evans Bay, since a Dieseldriven plant was transferred to the West Coast, apart from the Tramway Board's standby to the tramway system. The Coleridge system does not, however, 'stand alone, any more than do the three main North Island stations (Arapuni, Waikaremoana, and Mangahao) operate separately: Coleridge and Waitaki operate together.

Inquiries made today were answered by statements that there is no need for any alarm over the position at Coleridge, but nothing can be left to look after itself-in a major engineering work. The situation has been under close observation from the time that the first trickle was observed.