Reprinted with permission
Upper St. Clair baseball field sinks more than 3 feet because of mine subsidence
By Matthew Santoni
Wednesday, June 10, 2015, 11:30 p.m.
Part of an Upper St. Clair baseball field in Boyce Mayview Park has sunk more than 3 feet, a result of mine subsidence that will close the field the rest of the summer, the township manager said.
Starting last week, a 60-square-yard area between first base, second base and the outfield in the park's large baseball field sank between 3 and 3 1/2 feet, Manager Matthew Serakowski said. Representatives of the state Department of Environmental Protection's bureau of mines have helped the township's geotechnical engineering consultants evaluate the site.
"They believe it's due to mine subsidence or a mine shaft failure," Serakowski said. "Pretty much all of Western Pennsylvania is undermined."
The agencies and township will monitor the site for the next seven to 10 days to make sure it does not sink deeper or spread, but for now there doesn't appear to be any risk to the nearby grandstands or the large Community and Recreation Center, Serakowski said.
DEP spokesman John Poister said his bureau's engineers are cautiously optimistic that the subsidence won't worsen. As long as no structures are threatened, it will be up to the township and its contractors to pump concrete underground to stabilize the mine and fill in the sunken part of the surface.
"Typically, if an area (subsides), it goes in a larger area at once," Poister said. "But I don't think anybody is making any predictions at this point."
Poister said the mine that collapsed was the Mayview Mine, operated by the C&F Coal Co. and closed about 1953. It wasn't clear exactly how far the mine spread under the park, he said, but Serakowski said the township made sure the recreation center would be safe from subsidence when it was built.
Serakowski said five or six organized teams — mostly teenage and adult teams, because the field is so large — normally are scheduled to use the affected site, but they have been relocated to use Baker Field or other diamonds nearby.