Former mine pit swallowing more fill than estimated

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March 7, 2008

Anonymous The Joplin Globe Fri Mar 07, 2008, 08:36 PM CST

By Wally Kennedy

wkennedy@joplinglobe.com

CARTERVILLE, Mo. — It was a big, deep hole in the ground. They knew when they started it would take a lot to fill it up.

But, it’s going to take a lot more than they thought.

“That thing really sucked up a lot of material,’’ said Mark Doolan, project manager in charge of the cleanup of the Jasper County Superfund Site.

The former mining pit is part of a 75-acre tract west of Carterville that the U.S. Environmental Protection Agency is reclaiming with heavy equipment at a cost of $1.9 million.

A survey by Black & Veatch, an engineering and consulting firm based in Kansas City, calculated there was enough fill material on the tract to fill the hole. The calculation suggested 350,000 cubic yards of fill material would do the job.

So far, 400,000 cubic yards have been dumped into the hole. Doolan estimates another 100,000 cubic yards will be needed to finish the project.

Doolan and Jim Zerkel, project manager for Synder Construction Co., Joplin, the contractor, believe underground voids connected to the hole have swallowed some of the fill.

Said Zerkel: “It’s flowing back inside the caverns and the rooms. We have checked some depths. There was a 2-to-1 slope in the water, but it’s starting to level itself out now. It’s obviously going to hold more than what they figured.’’

Zerkel said the fact that more material has been needed to fill the hole is not necessarily a bad thing.

“There’s a shortage of holes to dispose of this stuff,” he said. “The more it takes to fill these holes, the better.’’

Doolan said a change order is being drafted by the EPA to create a new contract to get more fill from a nearby area to complete the job.

“We’ll go onto another piece of property to finish the pit,’’ he said. “The property is south of Lewis Street (old Route 66) and north of Highway 171. It was part of the next phase of the cleanup anyway.’’

A crossing with flagmen will be constructed over Lewis Street. Haul roads will be built on each side of the crossing.

The agency is working up a cost estimate for the additional fill for the pit.

Despite icy and rainy weather, Snyder Construction crews are ahead of schedule and could be finished in a month or so.

A miners’ ditch that was constructed through the mining field is now elevated because of the excavation that has taken place on both sides of it. The project will rechannel the creek to a point west of its existing location. When that is finished, workers will remove contaminated sediment from the ditch and place it in a mine opening.

“The miners’ ditch is like we have excavated a Roman aqueduct,” Doolan said. “The creek is higher than the surrounding land.’’

The water flow in the ditch will be recreated as a natural stream by the Missouri Department of Conservation and the U.S. Fish and Wildlife Service. It will meander with deep pools and ripples. It will not be a rip-rapped ditch.

“It’s an old miners’ ditch that will be turned into a natural creek with willows and creek-side vegetation,’’ Doolan said. “We want to re-establish it with fish and wildlife.’’

The EPA, in this first phase, plans to restore 75 acres on the west side of the city. Eventually, more than 300 acres between Webb City and Carterville will be reclaimed. The contract calls for Snyder to dig up mine wastes and contaminated soil and place the materials in mine pits.

The waste comes from a variety of lead mining, milling and smelting operations, some dating back to the 1800s. The wastes have contaminated groundwater, surface water and surface soil with cadmium, lead and zinc.

The EPA has installed six monitoring wells around the pits that are being filled at Carterville. When the second phase, which will be closer to Webb City, starts next year, the EPA will drill 12 monitoring wells.

“We are monitoring to make sure we are not having a groundwater problem,” Doolan said. “If we do have a problem, we will cease and desist, and do something else with the chat.”

The site will be cleaned up to a standard that will allow mostly unrestricted development in the future.

Carterville Mayor Dale Davenport said, “It’s changed everything about the way it looks. You can actually see the contour of the land, now. Once they get it all done, it’s really going to look nice.’’

Long-term project

The contract is the first in a series to be bid for cleanups that will cover about 7,000 acres over a 10-year period. The EPA estimates it will cost $57 million to reclaim and restore all the land. The state of Missouri recently agreed to fund 10 percent of the cleanup, which is required under the federal Superfund law. The EPA also will attempt to recover costs from mining and chemical companies that have been identified as potentially responsible parties for the contamination.