What should be done with the chimney tower at the old New Plymouth power station?
The New Plymouth Power Station chimney has been the outstanding feature of the city's landscape since it was built 40 years ago. It provides a reference point, along with the nearby Paritutu Rock, and although man-made, it is as defining to many of us as the beautiful natural features of our rugged coastline.
Port Taranaki bought the power station last year because it wanted the 12 hectares of flat land on which the station sits, but it decided that it could acquire enough land for its needs without demolishing the iconic chimney.
Port Taranaki chief executive Roy Weaver says the demolition planning was huge, "especially the health and safety organisation".
How times have changed. In the early seventies, when the chimney was constructed, health and safety was a matter for the bosses and the workers.
For most of them, it was just common sense - if you were careless or stupid, bad things would happen. On a project of this size nobody could afford to make a mistake. It took many hundreds of builders to construct the chimney, which at that time was the tallest man-made structure in New Zealand and stood 198 metres above ground level.
The main structure of the chimney is a 27.4m diameter, reinforced concrete windshield containing five 3.3m diameter brick flues. Those bricks were laid at the rate of 10,000 a day. It contained 16,400 tonnes of concrete, 1200 tonnes of reinforcing steel and almost one million bricks.
The concrete windshield was constructed using slip forming, a method in which the concrete is poured continuously. The workers whose job it was to place the steel reinforcing rods into the concrete to ensure a smooth pour stood on a platform that was raised by a hydraulic jack.
Much of this was new technology and attracted a lot of attention from the citizens and the newspapers, with stories and photographs following every stage of construction.
Originally, it was planned to burn coal at the power station - horror of horrors in this day and age - but in 1970, after the discovery of Maui gas, the boilers were redesigned to burn fuel oil and natural gas.
Fuel oil was used for the first two years of operation before switching to Kapuni gas in 1976 and Maui gas in 1979.
While the thinking on the provision of power has changed dramatically in the four decades since the power station was built, the fact remains that this was a building feat of some magnitude.
The chimney required innovative thinking to solve the engineering solutions and a huge number of men to carry out the work. No one company could provide all that manpower so the work was done on design-and-build contracts, with Fletchers holding the main contract and various other Taranaki firms supplying their own expertise.
It was a job well done and one in which those involved rightly took great pride. It continues to stand as a monument to the past and to the courage and skill of those who built it.
- © Fairfax NZ News
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