MANKATO — Bank vaults are built to not be broken into.
Trying to tear one down isn't so easy either.
"It was protected pretty good," said Stewart Carleton, whose company is demolishing the former U.S. Bank building in downtown Mankato to make way for a civic center expansion.
His crews spent this week using a wrecking ball and giant jackhammer mounted on a piece of heavy equipment to slowly break up the vault, which from the outside looked like a simple small concrete building.
But inside the nearly 2-foot concrete walls was plenty of reinforcement with up to 2-inch steel rebar, spaced every 2-3 inches. "There were four layers of re-rod, horizontal and vertical," said Carleton of Blue Earth Environmental Co. in Mankato.
He also found an added layer of security in the vault walls. "They laced electrical wiring through it, so even if you had the equipment to get through the wall, it would (set off an alarm)."
As crews swung the giant wrecking ball at the vault, it would respond with a dull thud but little apparent damage to the walls. Carleton said the wrecking ball loosens the structure up enough to make the jackhammering go easier. "Every time you hit it, the vibration loosens the rods up in the wall. Most concrete, one hit and it's done. But not this."
Carleton, who's been in the business 43 years, has taken down his share of reinforced structures in the Midwest. "I've taken down a couple of prisons, several jails and a number of banks."
U.S. Bank President Todd Loosbrock, who's been watching the demolition of the 1972 building from the new bank building across the street, said new bank vaults are now made from steel panels welded together.
"But even our new vault here, there is an amazing amount of rebar in the floor."
Loosbrock said that moving the contents of the vault, including all of the safety deposit boxes, from the old bank to the new one was a big affair. A covered walkway was built across the street from one building to the other during the move.
"It was a major production. There were a lot of people with guns," Loosbrock said.
The safety deposit boxes, he said, were removed in larger sections that contained several boxes. "It's a huge deal when you start dealing with safety deposit boxes. You have to make sure you don't violate anyone's security. They move them in sections so individual boxes weren't opened or exposed."
Carleton's crew will recycle or reuse 95 percent of the old bank building. There are a couple of items Carleton pulled from the bank that still need a home. The two vault doors and their frames are in storage. "Each door and frame weighs 6,000 pounds," he said.
Carleton tried to talk Loosbrock into taking one. "He wants me to put it in my basement," Loosbrock said. "I do want the hardware from one of the doors and then make a replica door for my basement. But not the whole door. Can you imagine if kids got their finger in that when it closed?"
Carleton admits it takes a certain personality to want a bank vault door. He once sold a vault door in another state to a guy who owned a successful bowling alley.
"The guy built a vault under his garage and to his house and put two bowling lanes in it. He'd go down spiral stairs from his garage with the groceries, through the (vault) door and into his house. It takes an eccentric type who wants vault doors."