Delaware City Council: Quarry officials describe blasting operations

Paul Comstock
ThisWeek
This aerial photo shows the National Lime & Stone Co. quarry at 2406 S. Section Line Road. U.S. Route 36 runs from left to right at the top of the photo. Section Line Road runs down the photo at the right.

The National Lime & Stone Co. quarry at 2406 S. Section Line Road has operated since the late 1800s and might continue operations for another 100 years, company representatives told Delaware City Council on April 12.

The quarry is just outside the city limits, but the company representatives gave details of the quarry's operations in a presentation made at the city's request.

Council member Chris Jones said residents of the city's far west side frequently feel or hear explosions used in the quarry's open mining process.

"Over the summer, I started getting some phone calls and emails about people asking more and more about the blasting (at) the quarry,” Jones said. “I was thinking about it today, I think, maybe because we were all home over the summer, that maybe more people recognized the blasting. But there's concerns just about making sure what does National do per safety standards and monitoring this and that?

"I asked the city manager (Tom Homan) to reach out to National ... just to give an update, and they would come in (and) do a presentation. They're excellent, excellent neighbors,” Jones said. “And they said that they'd love to just come in and (tell) the community their practices at what's going on at their company (and) just maybe ease some of the concerns the citizens might have."

Speaking to council were Dan Mapes, National’s director of administrative services, and Chad Doll, vice president of corporate relations and development.

They presented a multipage slide and video presentation during council's meeting, which was livestreamed on the city government's Facebook page.

The presentation showed National's operations must meet regulatory requirements of more than seven federal and state agencies, including the Ohio and U.S. Environmental Protection Agencies and the Ohio Department of Natural Resources.

Mapes said the explosions at the quarry are noticeable in part because humans can detect vibrations and sounds from blasts that are far below the power needed to cause damage to nearby buildings.

The blasts are infrequent, he said, averaging about 40 a year.

For decades, Mapes said, National has used a blend of fuel oil and ammonium nitrate to blast loose the limestone the quarry produces.

The mixture is easier to control than traditional dynamite, he said, and a series of explosions in rapid succession constitute a single blast, which he characterized as an efficient way to loosen any given amount of limestone.

Mapes said an independent vendor has seismographs at four nearby locations – one off Pittsburgh Drive, two along U.S. Route 36 and one west of Hull Drive in the city. 

The presentation showed the power of the explosions – measured in the wavelength of the blasts in inches per second – is well below the power needed to damage concrete, masonry, drywall or plaster, as demonstrated by the seismograph results. Monitoring also shows the decibel level of the explosions far below that needed to damage any material, including glass, he said.

The quarry produced about 3.7 million tons of limestone in 2020, the presentation showed.

Mapes also cited a study from the U.S. Department of the Interior that found an all-wood structure would have to be subjected to the force of two nearby explosions daily for 28 years before any damage would appear.

"That's many more shots than we will ever do," he said.

He said the quarry's operating permit covers nearly 1,000 acres, and future limestone will be produced from deposits below areas already worked and north of the pit toward Route 36.

That's enough stone for the quarry to operate another 50 to 100 years, depending on market conditions, he said.

The National presentation said the company operates 14 quarries and sand and gravel plants in Ohio, and it purchased the Delaware quarry in 1961 from Scioto Lime and Stone Co. Doll said the local quarry has operated since the 1800s.

Quarries are turned into lakes once their long lifespan comes to an end, Mapes said.

He showed photos of three such lakes at former National quarry sites. One – Lake Cascades at Findlay – has residential and commercial property nearby, he said.

Homan asked Doll about the possibility of notifying the public in advance of quarry explosions.

Doll said some neighbors have been notified in the past.

"I don't know how we would be able to go about communicating that to a mass group," he said.

Mapes said the company has an extensive list of people it calls.

At other locations in the past, a whistle announcing an upcoming blast drew spectators to the quarries, raising safety concerns, he said.

Mapes said the company fields questions by telephone and email at its website, natlime.com.

editorial@thisweeknews.com

@ThisWeekNews