The explosion in Geilo was thought exceedingly powerful possibly because no safety mats were placed over the explosives, claimed the Norwegian Public Roads Administration (NPRA) as they begin their investigation on site after the accident.
The cause of the explosion is not yet confirmed as investigators still cannot get close to the area until bomb experts fully secure it. Police chief Cecilie Espelien said to Aftenposten it is too early to say anything about the cause of the accident.
The large safety mats are supposed to keep debris, such as stones, from triggering other explosives when they scatter following an explosion.
The site manager was preparing dynamite for an explosion when the fatal blast went off. It is thought safety mats had not yet been placed over the explosives, reported Aftenposten.
Hans Jan Håkonsen of NPRA said: “They placed explosives in the holes which were drilled into the ground rock. I don't know if they finished the full operation when the explosion happened.”
Håkonsen said the explosives were to be ignited electronically, while the operator remained at a safe distance. He added: "It is obvious something extraordinary must have happened. We have to figure out what and why.”
The work on building a new railway underpass in Geilo was to allow taller vehicles through. The construction work was almost finished and there was little demolition work still left to finish.
The company performing the work is a well-known company with many years of experience.
Three persons died in the accident early on Wednesday afternoon. Two people were lightly injured, a 37-year-old and 38-year-old male.