Seepage Slowing Tailrace Work; Price Rise Sought

Press, Volume CVI, Issue 31119, 23 July 1966, Page 1

Seepage Slowing Tailrace Work; Price Rise Sought

(New Zealand Press Association) INVERCARGILL, July 22. Utah-Williamson*Burnett, the consortium driving the tailrace tunnel from Deep Cove to Lake Manapouri’s West Arm, has asked for an increase in the £9,387,787 contract price for the job.

Mr N. S. Long, manager of the Bechtel Pacific Corporation, the Government’s consultant on the scheme, said this today.

“The contractors have filed a claim with the Bechtel Pacific Corporation for an increase in the contract price of the tailrace tunnel. “The contractors have said the conditions being met in the tunnel were not as anticipated, and have asked us to investigate. “We are making this investigation at the present time.” Mr Long said he believed the amount of water being encountered in the tunnel was the main reason for filing the claim. A number of other smaller matters were being investigated. Bechtel’s decision would be given to the contractors and the Government as soon as it was ready, he said. The tunnel has now been pushed 11,260 ft through the mountains from Deep Cove towards West Arm, and still has 20,720 ft to go. Between March and June last year tunnellers drove forward 2070 ft In the same

period this year progress dropped to 726 ft. Water has been the curse of the 150 driving men and their 15 supervisors in the tunnel. In an attempt to find some solution to the enormous problems it poses, both Utah-Wil-

liamson-Burnett and Bechtel have called in world experts to study the situation. The report of one of the experts, Mr J. C. King, had been in part acted on and had helped to some extent. That of the other man, Mr J. P. Elston, also an American, was under consideration, Mr Long said. As much as 6536 gallons of

water has had to be pumped from the tunnel a minute, more than nine million gallons a day—far more than many of the original estimates of the water flow. Coming from thousands of small water-bearing seams, the water has behind it pressures as high as 14001 b per square inch, and can be dangerous to workers.