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Funny looking boat


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Looks like the tunnel boring machine thats just poked a new wastewater discharge pipe from the Army Bay Wastewater Treatment Plant into Tiri Channel.

This would have popped out on the channel side. Looks like they've floated it around to Gulf Harbour to grab back. MacDow's are the head contractor, not allowed to leave stuff like that in the marine environment any more.

 

Not sure of the name of this TBM (its customary to name TBM's with ladies names, kind of like ships used to). One recently was called Alice, as in Alice in Wodnerland, going down the rabit hole... Might have been the Waterview tunnel, I think the wonderland reference was to do with all the political BS surrounding that job, and the constantly moving opening date...

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Given the price of that machine you wouldn’t want to leave It behind!


 


This machine is called Blanche, Waterview was indeed Alice.


The one still under Mairangi Bay was Amelia Rose, and the Hobson Bay machine was Lily.


 


This one was specifically designed for retrieval off the seabed, much the same as the ones we did in Christchurch and Dunedin.


Mairangi Bay however was a different story. Much bigger diameter, and also 30m below the seabed.


Trying to put in an offshore shaft to recover it would have been prohibitive, both from a cost and ecological point of view.


Instead we removed everything from inside the machine and just left a steel shell, which was then encased in concrete.

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Given the price of that machine you wouldn’t want to leave It behind!

 

This machine is called Blanche, Waterview was indeed Alice.

The one still under Mairangi Bay was Amelia Rose, and the Hobson Bay machine was Lily.

 

This one was specifically designed for retrieval off the seabed, much the same as the ones we did in Christchurch and Dunedin.

Mairangi Bay however was a different story. Much bigger diameter, and also 30m below the seabed.

Trying to put in an offshore shaft to recover it would have been prohibitive, both from a cost and ecological point of view.

Instead we removed everything from inside the machine and just left a steel shell, which was then encased in concrete.

 

Sounds like you weren't at Gulf Harbour by chance today... ;-)

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That's the one.

 

A shaft had already been drilled from the seabed down, had a GRP liner installed with a flange on the bottom and a steel end plate, which had all been fully grouted in.

We drove the TBM underneath it, I think we had 50-75mm clearance. The machine was stripped out, leaving just the steel shell. We then cut a hole in the top of the shell to find the bottom of the GRP riser. I say hole, out TBM was about 3.3m diameter, and the flange was about 2m, so it turned into a pretty big hole, a few rock bolts and some  shotcrete was involved.

 

We then bolted a transition bellmouth onto the end of the GRP shaft, then used a machined polystyrene form in the tunnel to pour concrete against to make a nice smooth curved path from the horizontal tunnel up to the riser. Needed to be a nice curve as there is up to 6000l/s going though there at full flow if memory serves.

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The sewage tunnel was the biggest and most expensive engineering project ever completed by the North Shore City Council in 2010. 

The tunnel takes the wastewater sewage from the Shore and also west Auckland (former Waitakere).

The treated water is pumped out 2km from land into the channel.  Previously it was only 600m out from Castor Bay, and the locals didn't like the water or smell.

 

The funny thing is all the North Shore ratepayers paid for this - good for the next 100 years.

Then the Supercity gave it all to Watercare, and they tripled our water rates.   :roll:

Now the North Shore ratepayers have to help pay the rest of Auckland to upgrade their sewage systems!   :wtf:

 

More details here:

http://www.stuff.co.nz/auckland/local-news/north-shore-times/4018300/Tunnels-vision-is-finally-a-reality

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And the Townies call dairying dirty, we would be fined for that sort of behaviour.

It’s like their rubbish collection, once you put it out on the curb or flush it you think it’s towed outside the environment

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To be fair watercare are pushing forward with the central interceptor sewer. Which will unlock a lot of capacity to split the current system where large rain events cause untreated sewage to go into the stormwater system

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