‘Twas hard slog on Deep Cove tunnel’
A concreter/builder on the Manapouri Power Station remembers building the structure deep underground
Foxton man Bruce McCormack still recalls the hard slog involved that led to the Manapouri Power Station on the west coast of the South Island. McCormack, an Invercargill builder by trade working for Richardson’s, managed to get a job doing what he did best: concreting.
“I worked on the construction of the tail race tunnel of the Manapouri Power Station. This started in 1964 and the tunnel breakthrough happened October 1968.”
“I applied for the job when it was advertised by the Utah Construction and Mining Company, and got accepted. They were one of two companies contracted for the project, the other being Bechtel Pacific Corporation,” McCormack said.
“You caught the bus from Invercargill to Pearl Harbour Manapouri, and then were ferried by boat 35kms up near the west arm end of the lake. The only other way in there was by flying boat.
“There was a battery logi rail system built for the removal of the granite rock which was excavated, then taken out of the tunnel, crushed and mixed with cement which was quick dry for the concreting.
“And this was then taken back in for the arch of the ceiling and later for the floor, and there were three mixes every half hour. About 1.4 million tonnes of granite were excavated for the entire tunnel project,” McCormack said.
“We worked a 12-hour alternating shifts and got every second weekend off. There were only three women on site, the doctor’s wife and two nurses.”
The company provided entertainment for the workers in the form of the Howard Morrison Quartet and Eddie Low among others, then there was the Miss New Zealand Show, provided by Joe Brown from Dunedin. All this was paid for by the company for the workers, Bruce said.
Construction of the Manapouri Hydro station was a big engineering achievement.
This project took 1800 workers, 8 million man hours and almost seven
You caught the bus from Invercargill to Pearl Harbour Manapouri, and then were ferried by boat 35kms Bruce McCormack
years to complete, starting in 1964 and finishing in late 1971. Sixteen workers lost their lives during that time. The cost for the project was $135.5 million.
This was achieved in very harsh and trying conditions, McCormack remembers.
The power station is housed in a cavern 111m long, 18m wide and 39m high.
It was excavated out of solid granite rock which is set deep at 200 metres below Lake Manapouri.
The dimensions for the tail race tunnel were 9.817km long with a diameter of 9.2 metres. The station was purpose-built to supply power for the Tiwai Point Aluminium smelter near Bluff.
The workers travelled by bus, a half trip over Wilmot pass road from
Deep Cove to the project and many workers were housed on a ship, the Wanganella.
This floating hostel was living quarters for the men who worked on the building of the Deep Cove tail race tunnel, which was built so the water could pass through to the power station 10km further down.
Being housed on the Wanganella, which was moored at Deep Cove in Doubtful Sound in Southland, was a luxurious experience, McCormack remembers.