[Updated May 26, 2011] A new, cleaner, longer version of the video has surfaced on YouTube recently. You can see it embedded below. It includes some footage of attempts to "water bomb" the rock loose as well. [/Updated]
Dave’s Landslide Blog was where I found this amazing video from Norway showing a 1.8 tonne (4,000 lb) "sledgehammer" suspended beneath a helicopter being used to scale loose rocks off of a huge cliff above the approach to a tunnel. Don’t miss this one! I don’t know anything else about the video since my Norwegian is a little rusty. Anyone?