August 25 – Les Jeurs, Le Chable (0 km, 0 miles)

Florence had to work again today, but she made plans to give Jenny and I a tour of the tunnel project that the company she works for is building. So in mid-morning Jenny and I hiked down from Les Jeurs to the valley bottom and met Florence at the company cafeteria for lunch. I say cafeteria, but it was really more of a restaurant. They had nice dishes on the tables with wine glasses, and there was a worker that came to the table to take our orders. Nice setup.

After lunch, Florence got Jenny and I equipped with hard hats, orange vests, and emergency respirators and locator devices for a tour of the tunnel. It’s an addition to an existing hydroelectric project, and they’re digging a new tunnel and turbine gallery to add more megawatt capacity to what they now generate. They started digging the new tunnel in late December of 2009 and they’ve now dug 1.6 kilometers of a total of about 6 kilometers. Then they have to blast out the turbine gallery inside the mountain and install the turbines. It’s a pretty amazing project, but like I said in a previous post, the Swiss can build anything, anywhere.

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Here's the entrance to the tunnel that's being constructed in order to increase the megawatt capacity of an existing hydroelectic project. As of today, the tunnel is 1.6 kilometers long and it has a 12% uphill slope, which you can see by the line of reflectors inside. The tube hanging from the ceiling provides a supply of cold, fresh air to the tunnel boring machine. The blue framework on the right supports the conveyor belt that transports the broken rock out of the tunnel. ^

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This is a view of the tunnel boring machine (TBM), as seen from the back end of it, looking forward. The stairs on the left lead to the upper levels of the TBM. The entire machine rides on rails that are anchored to the lower portion of the tunnel walls, which you can see in this photo. ^

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This is on the upper level of the TBM, only a few meters behind the front, rotating cutting face. As the machine makes forward progress through the rock, other sections of the TBM behind the cutting face install rock bolts and wire mesh on the tunnel walls. Other parts of the machine farther back spray a concrete lining over the mesh to stabilize the tunnel. ^

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This is underneath the TBM directly behind the forward digging face. The entire rotating face can be hydraulically steered left and right, and up and down, in order to make the tunnel curved or ascend or descend. The broken rock is funneled through the central longitudinal axis and is transported out of the tunnel by a conveyor belt. ^

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The entire 9.4 meter diameter by 140 meter long TBM is controlled from a central control room housed in a relatively sound and vibration proofed metal box. Here are just a few of the video monitors and controls. ^

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I took this photo at the digging face of the tunnel boring machine while it was operating, which explains the shaky, out-of-focus image. With the low light level in the tunnel and the extreme shaking of the entire 140 meter long TBM, it was impossible to get a sharp photo, even though my camera had an internal image stabilizer. It was an awesome, overwhelming experience to be on the TMB while it was busy digging into the mountain. It's an opportunity not many people get. ^

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After getting outfitted we took a walk into the tunnel. It’s 9.4 meters (31 feet) in diameter and slopes upward at a 12% angle. Like most modern tunnel projects, this one is not blasted out with explosives, but rather is dug with a huge tunnel boring machine. The one on this project is 9.4 meters in diameter and 140 meters (459 feet) long! The thing is huge. The business end is a huge rotating disk with 30 or so large tungsten wheels that press on and roll against the rock face with such force that the rock is fractured into small hand-size bits (we went into the control room and saw that one of the digital displays showed the rotating disk was pressing on the rock face with 750 kilonewtons (168,000 pounds) of force). The broken rock is then funneled through the center rotating axis of the machine to a conveyor belt that transports it out of the tunnel. Other parts of the boring machine install a steel mesh reinforcement and a concrete shell on the walls of the tunnel. We were lucky enough to be able to actually get on the machine and go right up to the digging face of it while it was operating. What an experience that was! The sound and vibration was intense. It was impossible to talk to someone standing just inches away, even if you were yelling. The whole machine was shaking and making so much noise that it was just an overwhelming experience. At one point they had to stop the rotating digging face for some reason, so we walked down some stairs and got underneath the machine. Just amazing. I’d read about such tunnel boring machines in magazines and always thought it would be cool to see one. I never imagined I’d get the chance to stand on one at the digging face while it was actually digging. Just incredible – I’m lucky to have had the opportunity.

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Florence still had to work a few more hours after the tunnel tour, so she loaned Jenny and I her car to drive up to the Emosson Dam and reservoir. The lake is one of two that supply the water for the existing hydro project and for the new addition. It’s located very near the Swiss/French border and the road up to it provides great views of Mont Blanc, the highest mountain in Europe. It was a cloudless day so we got several nice views of it.

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On the drive up to Emosson Dam, we got a nice view of Les Jeurs and the road up to it. The village is in the open pasture on the mountainside on the right-hand side of the photo. The switchbacking road is seen in the center of the photo. ^

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View of Mont Blanc from the road up to Emosson Dam. At 4,810 meters high (15,782 feet) it is the highest mountain in the Alps, and in western Europe. ^

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Another view of Mont Blanc. ^

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And here's a panorama of the Mont Blanc massif as seen from Emosson Dam. Mont Blanc is the glacier-covered mountain in the distance on the right-hand side of the photo. Click to to open a larger version.

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Florence made plans to take tomorrow off from work, so the plan is to go up to a mountain hut tonight and go on a hike tomorrow. So Jenny and I met Florence when she got off work and we all piled in her car for the drive to Le Chable where her parents live. Her older brother Bertrand drove us up to a point at about 7,000 feet and then Jenny, Florence, and I hiked the rest of the way up to the hut, situated in a saddle on a ridge at about 8,100 feet in elevation. In Switzerland the term “mountain hut” is a bit of an understatement. Their huts are more like rustic hotels, with cooks, hot meals, wine, beer, bunks with pillows and blankets, and so on. All you need is a small day pack – no need to carry everything you need as we’re accustomed to in the U.S. For dinner we had some nice wine and cheese fondue. Very tasty, and it was a great way to top off a great day. We’ll stay here tonight and then tomorrow we’ll take a hike up a 10,000 foot mountain.

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Our evening hike up to the mountain hut took us past this herd of cows high up in the mountains. All the cows had bells around their necks, and it was really neat to hear the sounds of the bells echoing across the peaks. It was classic Switzerland! ^

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Our evening destination was this hut, Cabane du Col de Mille, at an elevation of about 2,470 meters (8,100 feet). That's the Mont Blanc massif in the background. ^

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