Nils Trauffer is the foreman for rock stabilization at Gasser Felstechnik AG. He and his team made sure it was safe to build the new mountain station for the 3S cableway and that it would be protected from rockfalls.
1. Mr Trauffer, you’re a rock stabilization foreman: how would you explain your job to the layman?
Whenever a construction site is being set up in a certain location or where natural hazards pose a risk to the infrastructure or building site, the rock stabilization department is called in. The rock stabilization foreman is involved in projects of this kind from the initial calculations through to implementation and final invoicing. Our work includes managing natural hazards, for example rock blasting to prevent rock slides, landslips or scree slides, and working on high alpine sites to fit protective netting to prevent rockfalls.
2. What level of knowledge is required?
As a rock stabilization foreman you obviously do need theoretical knowledge, like a qualification as a construction site foreman. But then there’s no training specifically to be a rock stabilization worker, so you learn a lot on the job and in-house training courses are very important. Our employees on the construction sites carry out a lot of tasks by hand, which they do by abseiling with the aid of climbing harnesses, so you have to be physically fit and have a particularly good head for heights. It’s a major advantage if you can enjoy the views even when you're high up!
3. Has your job changed at all as a result of global warming?
We have always had to deal with natural hazards in Switzerland, but we have seen an increase in the number of stabilization jobs resulting from thawing permafrost. Above 3'000 metres there’s a big chance of being in an area of permafrost – like on the Klein Matterhorn. In the summer the top two or three metres of the ground thaw out and freeze again at night. This freeze-thaw effect leads to pieces of the rock surface breaking loose. For this reason, we have fitted net covers and rockfall defences above the new mountain station and at the third tower, or pylon. That was the only way to make sure it was safe to build the station. At the same time, the mountain station and tower were anchored into the rock floor and fitted with measuring sensors so that we can respond immediately to any changes in the surrounding area caused by permafrost.
4. Have you carried out any other work?
Yes, after mounting the net covers and rockfall and snow defences we removed a total of 10'000 m3 of rock to create a plateau for the new mountain station. Then there were temporary anchors for the cable winching process, the materials cableway and the foundations for the crane, and permanent anchors for the mountain station and the third tower. At the second tower we also carried out exploratory drilling to ascertain where the rock is stable so we can make the best foundations for the tower.
5. Were there any special challenges involved during your work at almost 4000 metres above sea level?
The weather on the Klein Matterhorn makes working there very challenging per se. Daytime temperatures down to minus 30 degrees and winds of up to 240 km/h place special demands on men and machines. The equipment was adjusted in advance to the appropriate air pressure for these altitudes and all our employees were given expedition gear to wear. At the start of the building phase in particular a lot of jobs had to be carried out manually as the crane hadn’t yet been secured in place, and that was very demanding. Another example was getting the permanent anchors into position to secure the new mountain station. We repeatedly had to use water heated to 20 degrees to warm up the permanently frozen rock. This involved filling the drill holes with the water to get the rock up to a temperature of 4 degrees so the mortar could set. And then the anchors, which are up to 20 metres long, also had to be pre-heated before we could apply the mortar. Dealing with large quantities of hot water and pre-heated anchors in plastic sleeves at this altitude demanded a lot of our team.
6. What is your best memory of the time spent on the Klein Matterhorn?
One particularly satisfying moment was when we finished excavating the rock in August 2016. It was a long hard job but finally the plateau was ready for the new mountain station. But that was surpassed by the amazing teamwork from everyone involved. Everyone knew from the start that the only way to stay on schedule was by working shoulder to shoulder together, so I have to say thank you to all the highly motivated specialists in my team and those in the partner companies.
