Massey’s new owner, Virginia-based Alpha Natural Resources Inc., and a court official confirmed that Circuit Judge William Thompson halted the proceedings in Madison so language in the settlement could be finalized. The terms of the agreement are confidential.

The settlement is the second major coal-slurry pollution deal Alpha has made with Southern West Virginia residents involving lawsuits it inherited when it bought Massey Energy Co. in June 2011. A previous agreement resolved claims brought by the residents of the Rawl area of Mingo County.

Thompson had consolidated 155 medical monitoring lawsuits involving about 350 people from Seth and Prenter. The plaintiffs have long argued that mining activities, including the underground injection of coal slurry, are to blame for discolored, foul-smelling well water and health problems. The lawsuit argued that decades of surface and underground mining activities fractured the geologic strata that had contained the slurry, and a network of cracks created a pathway for the slurry to contaminate the aquifer.

An environmental consultant hired by the plaintiffs said “a very toxic and pungent” hydrogen sulfide gas was evident in every home, while every water sample had apparent odor and discoloration. He said testing revealed varying levels of arsenic, lead, iron, manganese and sulfides. Several other coal companies that were initially sued have long since agreed to confidential settlements but denied any responsibility for the problems.

The plaintiffs are now served by public water lines and no longer rely on their wells for consumption, but they were demanding periodic screening for diseases they believe they could contract because of long-term exposure to toxic substances.

In January, the state Department of Environmental Protection released the findings of a yearlong groundwater study that found no evidence linking mining to widespread pollution in the area. Triad Engineering, the DEP’s consultant, sampled 33 wells and found evidence of possible links to mining activities in only two of them, neither of which is used as a drinking water supply. But Decanio has challenged Triad’s approach and methodology, arguing there were too few samples to be representative.