Into the pit: Take a look inside Concrete Materials’ quarry

It started with a historical exhibit on the quarry that has been mined in northwest Sioux Falls since the 1940s.

“And we said, ‘How about seeing a real quarry?’ And it worked out, and we’ve had a great partnership,” said Clark Meyer, president of Concrete Materials, which operates the quarry and nearby plant at Madison Street east of Interstate 29.

You’ll need to move fast to get into one of those tours, by the way.

“They fill up crazy fast,” said Adam Nelson, marketing coordinator of Siouxland Heritage Museums.

“I think it is the fact that everyone drives by that hole and no one really knows what goes on at the bottom of it.”

This year, Concrete Materials, which has been owned by Knife River Corp. since 2018, decided to offer more tours, beginning this week. The dates in May and June are filled up already, but there might be more added this summer.

“Part of it is the backlog of ones that got canceled last year,” Nelson said.

“And it’s kind of this unknown thing that’s right there. Some people have always wanted to go down, and you can’t just drive down yourself.”

But, thanks to a seat on a recent bus tour, we did. So here’s the next best thing to touring it yourself.

Down 240 feet below the interstate, we started at the North Hole – “we’re genius-naming people,” Meyer joked – which is the oldest section, started in the 1940s.

In 1980, mining began in the South Hole.

They’re mining quartzite – 1 million tons a year – and most of it stays within 60 miles of Sioux Falls.

“We drive on it, we walk on it, our homes are built on it,” Meyer said. “It’s around us every day. And it’s just nice to know where it’s coming from. We’re fortunate to have a local source right here in Sioux Falls.”

Because it’s mined in Sioux Falls, it doesn’t have to go far to be made into asphalt or ready-mix concrete. That means fewer trains and trucks going through town.

And speaking of controlling traffic, this is definitely one of the most memorable parts of the tour: a tunnel, built in the early 1990s to keep rock trucks from continually crossing Madison Street.

“This eliminates the traffic on the road,” Meyer said.

There’s water down here, too, including little waterfalls and a reservoir holding pond that has 1 million gallons a day pumped into it.

Trucks haul 50 tons of rock at a time.

It’s a busy place, especially this time of year catching up from winter’s shutdown. The quarry is active 20 hours a day, with a four-hour maintenance shift every 10 hours.

“If you’ve ever gone by at night or on a plane and seen the lights, that’s the night shift,” Meyer said.

The tour continues to the processing plant, where the rock is turned into material for customers.

“Everyone loves it. They’re amazed,” Meyer said. “They’re amazed by the size of the equipment. They’re amazed by the size of the hole. And they love seeing where it all comes from.”

To keep watching for the next available tours, click here.