Big Earth Fall In Tokaanu Tunnel

Press, Volume CIX, Issue 31976, 1 May 1969, Page 26

Big Earth Fall In Tokaanu Tunnel

iNew Zealand Press Association)

ROTORUA, April 30.

A big fall occurred in the tunnel between Lake Rotoaira and Tokaanu on the Tongariro power development scheme this morning.

About 1000 cu. yd of earth fell but no-one was injured and no equipment was buried. Tunnellers on the job had warning of the impending cave-in. A flow of water started from the tunnel roof near the face, 3750 ft in from the Tokaanu end of the 4Jmiie tunnel. About 2.30 a.m. the flow increased until the fall occurred at 6 a.m.

Water is now flowing at the face at the rate of 1000 gallons an hour. It is the first cave-in on the Rotoaira-Tokaanu tunnel, although there have been three in the tunnels between the Whakapapa and Wanganui rivers. The last was at the Tawhiti-

kuri upstream face in March when 300 cu. yd of material came down. The others were in June and July last year, when 8100,000 worth of tunnelling equipment was buried. News of today’s fall was not released until about 1.15 p.m. by the Ministry of Works.

The tunnel portal is about 400 ft above Tokaanu. The tunnel will cany water from the storage lake of Lake Rotoaira to the power-house. The contractors on the Rotoaira-Tokaanu tunnel are Downer and Associates. The Italian combine, CodelfaCogefar, is making the Wanganui-Whakapapa tunnels.