by Jennifer Kulier, Media & Communication Resources
 

"Like Hell with the fires put out."

That's how observers describe an abandoned surface-mined site. Red, orange, even purple water. Banks devoid of vegetation. Acres devoid of wildlife. 

Throughout surface coal mining's 100-year history, its legacy had been acidic soils and water. At some sites, the acid soils precluded vegetation. The acidified water and lack of vegetation kept wildlife at bay. But decades ago, researchers at SIUC's Cooperative Wildlife Research Laboratory recognized potential for fish and wildlife habitat in the lands that others had written off as hopelessly damaged. 

Acidic conditions on abandoned mine sites are due to pyrite, a mineral form of sulfur often found mixed with coal layers. When pyritic material is disturbed and exposed to oxygen, it oxidizes, creating sulfuric acid. The federal government's answer to pyrite oxidation since 1978 has been to require companies to spread four feet of soil atop coal slurry impoundments, literally covering up the problem. 

Unfortunately, in many cases that cover soil gradually turns acidic and the underlying pyrite can still oxidize, forming insidious acid seeps that can cause problems long after a company has complied with the law. "Geochemical time bombs" is how Jack Nawrot, a senior scientist with the Wildlife Lab, describes them. 

Twenty-five years ago, Nawrot and his colleagues and students pioneered a reclamation process—still in use today—that could turn a barren, polluted former mine site into viable wildlife habitat in as little as three years. The idea was innovative, yet simple: Rather than treating the acidic remains of former coal mines as waste—as the coal industry had been doing for decades—Nawrot treated it as soil.

"In order to enhance wildlife habitat, which was our motivation, we had to solve the problem of acidity by eliminating the source rather than perpetually treating the symptoms," Nawrot says. Since acidity is merely the lack of alkalinity, he and his fellow researchers added massive amounts of agricultural limestone to the mine waste to change its geochemical makeup.

Some 50-75 tons of limestone per acre was tilled into the ground, which was then seeded with winter wheat or rye and fertilized. What happened next, to the surprise of jaded coal industry regulators, was "Instant Green," and by spring, the land was blessed with good stands of grain. The process was repeated on the site two or three more years, with each year's cover crop being incorporated into the soil. Finally, native grasses would be planted.

"People would describe areas that hadn't supported vegetation in 25 years, and say, 'You'll never get anything to grow there.' But we did," Nawrot says. "And as word got out that we had a cost-effective, environmental alternative to soil cover, the coal industry became very interested." The reclamation technique could save the industry as much as $20,000 per acre, translating into millions in total savings. 

Each strip-mine site is unique in its geochemistry, topography, and hydrology. Over the years Nawrot has tested different amounts of limestone (sometimes with an added layer of topsoil) on different slopes with different plantings. He does site characterization and provides reclamation plans to the organizations funding the work. Besides limestone treatment rates, plans can include grading, stream restoration, wetland creation, and so forth. He also monitors soil and water quality at reclaimed sites.

Even on limestone-treated sites, acid seepage can sometimes occur years after reclamation due to groundwater moving through underlying pyritic material. Nawrot calls this problem "one of the last frontiers in mined land reclamation." Recently he has used high-alkaline pools or trenches constructed upslope of problem areas to intercept water draining into the site. Adding alkaline content to the groundwater halts acid production. 

Under Nawrot’s leadership, the Wildlife Lab’s Mined Land Restoration Program has reclaimed numerous wetlands, which thousands of ducks, geese, shore and marsh birds—including the threatened least bittern—now call home. Muskrats, minks, and raccoons begin using the reclaimed wetlands during the first year after establishment, and upland portions of many reclaimed slurry sites now undulate with prairie grasses like big bluestem, Indiangrass, and switchgrass. 

Graduate students at the lab study the use of reclaimed sites by wildlife and devise ways to improve habitat. For example, many sites reclaimed by coal companies were planted to pasture grasses like tall fescue. But switching to prairie grasses, which are more difficult to establish but are hardier, provides a haven for the nesting grassland birds whose habitat is being lost to urban sprawl.

Such studies began in the mid-1950s on reclaimed land that is now Pyramid State Park in Perry County, Ill. The Wildlife Lab carried out its first demonstration projects there, to enhance fish and wildlife habitat at the site. Students recently helped reclaim acreage adjacent to Pyramid, bringing the lab’s work full-circle.

The Wildlife Lab has received many awards for its reclamation work, which has been funded by coal companies and government agencies. Many of the sites it has reclaimed are now conservation and public recreation areas. Illinois, which implemented reclamation legislation back in 1962, recently took the lab’s work into account in rewriting its regulations.

Nawrot frequently is tapped by other states to troubleshoot problem mine sites, both reclaimed and unreclaimed. But he also shares his expertise with local schools to promote "backyard" habitat establishment programs for hands-on learning. 

For instance, an 8-acre wetlands on the Du Quoin (Ill.) State Fairgrounds was created this year by Du Quoin middle-school students under Nawrot’s supervision, with help from the Illinois Department of Natural Resources and the Perry County Soil and Water Conservation District. A former strip-mine site, the tract now has a pond, wildflowers, grasses, and the beginnings of a hardwood forest.

The surest sign of success? It is already attracting deer and other wildlife.

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