Slurry is created when coal is washed to help it burn more cleanly. The residents say it seeped out of the old mine workings and into their aquifer, turning their well water varying shades of red, brown and black, and causing ailments ranging from learning disabilities to cancer.
For the plaintiffs, Moats said the settlement provides peace of mind.
"Resolving something yourself takes the uncertainty out of it," he said. "I tell people when they come into court, usually it's going to be more palatable than if someone reaches the agreement for you. It's definitely a good thing for the resolution to be reached."
The case would have been heard in a series of trials, with the first seven cases covering only 17 plaintiffs. That left hundreds more cases that would have tied up the courts for months.
For decades, coal companies in Appalachia have injected slurry into worked-out mines as a cheap alternative to dams and other systems that can safely store or treat it. The industry claims underground injection is safe, but critics say slurry leaches into water tables through natural and man-made cracks in the earth.
The state Department of Environmental Protection has imposed a temporary ban on new injection sites. Last year, a team of West Virginia University researchers advised lawmakers to start monitoring coal slurry, even though they could not conclusively demonstrate a hazard to public health.
The U.S. Environmental Protection Agency has long allowed states to use old mines as "backfill wells" for waste, documenting some 5,000 of them in 17 states when it last counted in 1999. But the EPA said that includes sites used to store sludge, ash, sand, cement and other materials, and it cannot identify wells by subcategories.
That means it's impossible to know how many of the sites contain coal slurry.
The plaintiffs are now mostly served by a public water system, but they argue that chronic exposure to metals and chemicals are to blame for birth defects and other health problems.
Last fall, Swope and Moats demanded every plaintiff attend first the mediation conference or risk being dropped from the lawsuit, so they piled into cars and buses and traveled from as far as Ohio and the Carolinas to Charleston.
Only a handful attended this week's session.