COLUMBIA — More than 3,700 acres of mined land await clean-up in Missouri, a legacy of Missouri's unregulated coal mining past.
Coal mining started in Missouri during the 1840s, but only one active coal mine, located in Hume, remains. Emission restrictions have made the state's high-sulfur coal less desirable. Now, the state must grapple with the thousands of acres of abandoned mines, 35 of which began to be cleaned up in early July.
In Boone and Callaway counties, 20 reclamation projects have been completed since the act was passed.
By 1971, when Missouri began regulation, more than 100,000 acres had been affected by mining. The first reclamation project in the state was finished in 1982.
Coal reclamation projects are ranked by priority, from I to III. The Millersburg mine is ranked a Level II priority site. According to the Department of Natural Resources website priority II sites are those whose reclamation contribute to the "protection of public health, safety and general welfare from the adverse effects of past coal mining practices that do not constitute extreme danger." Level I sites are considered an extreme danger, and restoration of Level III sites address resources and environments that have been "previously degraded by the adverse effects of past coal mining practices."
Although coal mining has waned in the state, extraction of industrial minerals has not. More than 1,000 acres are permitted for mining each year, according to the DNR website.
The 35-acre project underway near Millersburg is expected to be completed in October. It is divided in two sections, a roughly 25-acre area north of Route F and another 10-acre area to the south. Both sites are on private land.
A 1977 law established national requirements for the reclamation of active and future mines as well as funding the reclamation of abandoned mines. The program is funded by a federal tax on coal to help clean-up mines that were abandoned before the law was enacted.
A survey conducted in 1985 by the Division of Geology and Land and cited in the project summary indicated that mining at the Millersburg site ended in 1947.
The mines exploited the Bevier-Wheeler coal beds and were mined by the Jennings and Crowson Coal Co., according to a project summary from the Missouri Department of Natural Resources. The coal was used locally or sold to nearby towns.
Photos and satellite images of the north section before restoration began show long bare ridges of material, called overburden or spoil, excavated from the mines. The images show these sparsely vegetated hills and ravines that ran north to south and were flanked on both sides by narrow lakes — pits created by mining that gradually filled with rainwater. The south section was smaller, with ridges of overburden running parallel to a long water-filled pit.
This year, the Department of Natural Resources awarded a $630,000 contract to the St. Louis-based Pangea Group to carry out the reclamation, or clean-up. Randy LaChance, field superintendent for Pangea Group, said a team of seven to eight people began working on the project in early July.
Out at the site a few weeks ago the reclamation process was underway. An enormous tractor traversed acres of bare earth and dragged soil in two dirt pans, each capable of holding 17 cubic yards. Roiling columns of dust cloaked the machinery in a beige haze.
The overburden left at the site after mining ceased contains numerous acid-forming materials. Because some of the most acidic materials lay directly over the coal seam, they are often extracted last and left on top of the piles of the overburden.
These acid-forming materials — likely a shale — resist vegetation and can cause water-quality problems. For more than 60 years, the Millersburg mines remained without significant vegetation. The contaminated lakes became pits filled with rainwater and were emptied as part of the clean-up.
While driving a truck beside a healthy lake near the reclamation site, LaChance explained that the lakes his team drained were inhospitable to life.
"This lake has lots of vegetation growing on it," he said. "The ones we pumped didn't have a weed or moss or nothing growing on it."
Before filling in the pits, LaChance's team pumped out the water and treated it with hydrated lime to neutralize the pH. The water was then released into a creek.
To neutralize the acidic soil, about 50 tons per acre of agricultural lime will be incorporated into the graded soil before it is covered by 18 inches of uncontaminated soil — called select material — and an additional 25 tons per acre of lime, LaChance said.
Finally, grasses and trees will be planted at the site.
Soon the bare earth will be carpeted in grass, and the unresolved legacy of unregulated mining that for decades lay raw near Millersburg will be settled. But underground, below the select material, below the lime and overburden, there still linger traces of the substance that drove people to turn the earth upside down.
"Every once in a while in a pile of dirt you'll find some old coal," LaChance said.
Supervising editor is John Schneller.