TWO BLIZZARDS HAVE STRUCK AT TUNNELLERS ON TONGARIRO POWER DEVELOPMENT SCHEME NEAR WAIOURU

Taupo Times, Volume XIV, Issue 38, 18 May 1965, Page 4

TWO BLIZZARDS HAVE STRUCK AT TUNNELLERS ON TONGARIRO POWER DEVELOPMENT SCHEME NEAR WAIOURU

Although winter has even nellers on the upper Moawhango dam, part of the Tongariro power miles frorn Waiouru, have alreadg cut teeth on two blizzards.

Snow driven by howling gales has swept the dizzy cat-walks for up to four hours, making work impossible. Geologically the Moawhango sites are 'out of the box" in that the rock structure of the gorges looks ideal for dam construction. Rainfall is relatively low, but for ruggedness and for cold, the Moawhango probably takes some beating. Both sites are deep in a sheer-walled gorge, shady most of the day, accessible only by ingeniously rigged catwalks, swing-bridges and goat tracks. Both are more than 2000 feet above sea level, close to the rugged Kaimanawa Ranges.

Tunnel entrances are ! perched high on perpendicular cliffs, with the river foaming through a narrow defile up to 150ft. below. Gales frequently sweep through the gorges, freezing everything in their path. Frosts never thaw in the depth of winter. On the lofty catwalks a slip in the wrong place can mean almost certain death. Death can also come from above in the Moawhango. High above the catwalks the gorge walls are extnemely weathered and hung with loose stone and boulders, some of them tons in wright. Tunnellers have been keeping a wary eye on some of the loose ones, _ particularly after blasting or frosts.

The work on the Moa- j whango is under the direct supervision of Harry Gowans, Scotsborn engineer who joined the Ministry of Works in 1958 to work on the Ohakuri dam. Harry gained some underground experience with the National Coal Board in the United Kingdom, and is fairly well equipped to head a team of professional MoW tunnellers. His last big job was on the Atene tunnel on the Wanganui River. Twelve tunnellers are working on the Moawhango putting in test drives to obtain additional information about the nature of the rock in which the dams are to be built.

The information obtained will be avaiiable to the contractors tendering for the various projects when tenders are called later in the year. On the Upper Moawhango site, seven tunnellers under Supervisor Cec Woodney are putting in four 6ft. by 4ft. experimental drives. Aided by riggers and carpenters they have had to install 1200ft. of staging and a 150 foot long swingbridge to reach the tunnel sites. The swing-bridge, 50ft. above the water, was built after a flash flood roared downstream, smashed a low-level bridge and flung about 100 yards of staging up the bank. On the Lower Moawhango, senior overseer,

Allan Fairbanks, a tormer tunneller from New Zealand's famous Homer Tunnel, heads a team of flve tunnellers and two riggers. They are putting in four 50ft. long test tunnels, two on either side of the gorge at approximately the centre line of the future 190ft. dam. The two lower tunnels are 50ft. above the foaming stream, which cascades at that point through a gorge 12ft. wide at its narrowest. Two higher tunnels are to be gouged in the sheer cliff face 150ft. above the river. At present only a fly could reach the higher sites, and engineers are

still not sure how the job will be done. Most likely approach will be the rigging of a staging down from the top of the gorge, about 300ft. above the water. The future Lower Moawhango lake will cover a big area of tussock country, forming an attractive new recreational water not far from the Desert Road. Water from the lower dam will be pumped into the Upper Moawhango dam, and piped through a 94mile tunnel under the Kaimanawas to the Tongariro. The tunnel has fairly early priority on the Tongariro hydro scheme. Contracts for the tunnel are expected to be awarded about next October.