John Erik Tveitdal, 22, said he had decided to use his machine to break open the safe as "a bit of fun" at the end of his shift.
"'Suppose there is a million in there,'" I joked to a colleague, but I never thought there would be any money in a safe someone had thrown away," he told Norway's VG newspaper.
"I put the safe on the ground and beat down on it with the arm of the excavator," he said.
Eventually he managed to rip off the front door of the safe, and immediately saw that it contained six bags of cash.
"I felt I was in heaven and I thought I must be dreaming," he told the paper. "I stood there with 117,000 kroner in my hand and thought that right there I had a holiday in the tropics and a hot tub for the wife and me, but instead I ran straight to the boss and gave him the money."
Unfortunately for Tveitdal, his company Norsk Gjenvinning Group, then tracked down the owner of the safe and passed them back the money.