The minimum wage that can be paid for a tunnel hand in San Francisco is around $34/hr plus overtime and benefits. See http://www.dir.ca.gov/oprl/pwd/Determinations/Northern/NC-02...

You have to remember that tunnel jobs are almost always run by a municipality which means that they're almost always union. I would imagine it is similar in Switzerland.

Tunneling is a niche industry and commands a high price.