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Gas Pains

Tom grew up in Milwaukee, bartended in Wauwatosa in the '70s and moved here in 1984.

Commentary, observations and musings about the outdoors, life in general and maybe Tosa politics and personalities will be the order of the day. He savors a lively debate as much as terrific cooking.

Tunneling Under Tosa

Technology, Impressive Construction Projects, Just For Fun

A week or so before deer camp I was driving down Bluemound Road on the way to the day job when I spied a curious piece of machinery. It was a gigantic tubular thing that had an equally giant (but festively-painted) cutting head. 

I’m thinking - It’s certainly not part of a rocket booster or a carnival ride. It’s probably a tunneling machine. 

Since then I have learned that this was the beast that is going to bore underground to connect the MMSD western flood basin with a diversion structure at Underwood Creek.

In case any of you have forgotten - the flood control project is not yet complete and the whole idea of the tunnel is to divert excess flood waters from Underwood Creek to the basins by means of an underground channel. That way the probability of Tosa Town flooding will be reduced and the flood water can be gradually released into the Menomonee River.

Map Courtesy of MMSD

The other day I had an opportunity to check out this project up close and personally.

Here is the machine I spotted.

It even has a name-

Luminita

I could not find a translation for it so it’s probably one of those manufactured names. It certainly is a pretty name – as far as tunneling machines go - much better than Tom or Jill.

And here is the 400 ton Manitowoc crane than hefted this lovely boring machine into position.

Luminita has a giant cutting head that has a mouthful of hardened (and replaceable) grinding teeth that can chew through all sorts of stuff. It can even digest boulders. All except for the black boulders that are as big as your washing machine. Those are indigestible. If Luminita chokes on one of those it has to back-up and a real miner has to split those with a drill so that Luminita can eat them.

As I was marveling how they keep the paint job looking so nice it occurred to me that I better move-on in case someone turned it on. 

Getting caught in there could wreck your day. (Actually - when this picture was snapped they were still positioning the thing so I was safe.  It wasn't plugged-in).

Attached to Luminita is an extensive train of machinery designed to facilitate the digging, removal of spoils, building of a prefabricated tunnel liner and sealing it. By the way – that is a 200 ton crane in the background that was used to position the trailing machinery and will assist with the lifting of debris to be hauled away.

And if you don’t get the whole thing pointed in the correct direction you’ll have nothing but trouble. 

For any of you narrow gauge rail aficionados – there are miniature locomotives – that will cart the stuff out of the tunnel. They’re just like what they use over at the Zoo.

What powers all of that stuff?

That is an easy question. And the answer is - Luminita is attached to a really humongous extension cord. I’m not making this up. You can see it there on the left.

That big black extension cord? Wow! How much juice goes through that sucker?

This much.

What I find fascinating is that Luminita is going to bore a hole 19 feet and 2 inches across, is going to lay behind it prefabricated tunnel segments with an outside diameter of 18 feet, 8 inches.

After the tunnel pieces are assembled they'll be cased with extruded grout (similar to lining a well casing only on a grander scale). Leaving a sealed tunnel with an inside diameter of 17 feet in its path. The project consultant described it quite aptly – As the machine advances it poops the tunnel out the back end.

17 feet! That’s a big tunnel for sure. You could probably drive a Jeep through it!

I suppose you could because this is exactly what is used to construct a third rail transit system tunnel. But after it is completed I suspect someone will put a sign at the entrance that says: Keep Out

So don’t get any ideas.

So you’re saying they’re going to drive this thing underground? How do they know where to come out on the other end? What if the machine veers off course and comes out in the wrong location? What then?

Good question.

I asked the same thing myself.

What I was told is that Luminita has a self-seeking laser guidance system that makes use of inclinometers with forward and back and side to side sensors. Bottom line – it’s a proprietary secret.

What I can tell you as that the first time Luminita tried this was in Washington State for King County’s Brightwater wastewater treatment project. The contraption bored a 2.6 mile tunnel, came out the other end and was off-course by only an inch.

 Photo Courtesy of King County

This is the second tunnel for Luminita. I’m guessing that at 2700 feet in length the second time should be a charm.

Stay tuned...

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