Mistakes On Matahina

Press, Volume CIV, Issue 30779, 17 June 1965, Page 3

Mistakes On Matahina

(N.Z. Press Association) WELLINGTON. June 16. The estimated civil engineering costs of the Matahina hydroelectric project were now £13,940.000, the Minister of Works (Mr Allen) said today. This was £2,200,000 more than last year’s estimate.

“Rising costs over the year accounted for some £700.000 of this higher figure.” said Mr Allen. “It has been an unusually steep rise, mainly because of (he general wage order of 6 ner cent which has been reflected in the price of material and in plant rates, as well as in labour costs.

“Still more unpleasant discoveries about the nature of the site, made as work progressed. accounted for another £500.000 ” Additional excavation, additional filling and a more extensive grout curtain than was earlier envisaged were found to be necessary. He said design changes of this kind, like the major changes announced last year were hazards which had to be faced when hydro-electric projects had to start before detailed designs and firm estimates could be prepared “At Matahina the difference i between what was anticipated as a result of considerable investigation, and what was disclosed by the work itself proved to be far greater than anything experienced before.” Mr Allen said. ' “In this case, the nature of the underground problems j was such that discovery by drilling was virtually impossible.”

He said it had to be ac-i cepted there was an elemen - ' of risk in estimating in all j major works. “Sometimes it works to our advantage. At Benmore, for example, the further explorations and studies as the work went ahead showed the way to substantial savings. Some of the increased cost of Matahina. however, the Ministry of Works has frankly admitted, was due to error. One such error was the

wrong application of a credit of £500,000 for recoveries likely to be made on completion of the job, when certain remaining assets could be sold or transferred to other work. “There were other errors of judgment in estimating that accounted for £500,000. The Ministry of Works finds itself increasingly forced to place very great responsibility on young and relatively inexperienced engineers." Mr Allen said.

“Unless the department can retain reasonable numbers of experienced men to check and re-check estimates, it remains vulnerable to errors. “Where a choice must be made between employment of experienced people on design or on estimating, then design must come first, because safety is involved.”

Mr Allen said the most extensive and costly investigations might still leave undisclosed difficulties, but the departments concerned would, in future, do their utmost to ensure that at the stage at which schemes were recommended for approval to the Government, they were more firmly based on site explorations than had generally been the case in the past. The departments also would do their utmost to ensure that design proposals and estimates were prepared in much greater detail. It had to be noted that if the upward trend in costs continued. as seemed likely, another £260,000 would probably be required before the Matahina proiect was completed in April, 1967.