Abandoned mineshafts have caused the repeated sinkholes along I-80 in Wharton. In Ogdensburg, visitors can see what it once looked like underground for themselves.

The Sterling Hill Mining Museum is living history of New Jersey’s mining past. There are more than 400 abandoned mines across New Jersey. At one point, they were essential to the state economy.

“Mining has to proceed, and we have to do it in an environmentally responsible way,” said Bill Kroth, the president of the Sterling Hill Mining Museum. “That always wasn't the case, but we learn from our mistakes.”

Visitors can walk through the carefully preserved first level of a 25-level zinc mine and see the payoff for themselves. The precious minerals, like zinc, glow under ultraviolet light.

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“We are the fluorescing mineral capital of the world,” Kroth said. “They had 500 men working around the clock. During World War II, this was actually protected by the U.S. Army in order to make shell casings.”

In Wharton, the miners were going after iron. But how the mines are preserved makes a critical safety difference.

Because the Sterling Hill mine has become a popular museum, it’s supported by high-strength rock and fills voids with concrete. Mines planned for temporary use years ago, like those in Wharton, were likely supported by nothing but timber, which eventually rots and collapses.

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“You can't blame those people,” Kroth said. “It was just their degree of knowledge, and they cannot predict the future. Of all places for it to happen, it's probably the worst.”

Suggestions from local leaders include a crossover lane or even a longer-term overpass.

“You have to prove that the new bypass is on sound ground also,” Kroth said. “In my opinion, it's turned into a disaster. And I'm sure federal aid will kick in.”

U.S. Transportation Secretary Sean Duffy will be visiting the site Saturday.