Mine subsidence that sunk more than half an acre of an Upper St. Clair baseball field shouldn't pose further problems, engineers said.
Early in June, a collapse in the former mine 130 feet below Boyce Mayview Park sunk a 160- by 180-foot section of the park's large ballfield by about three feet.
Joe Fagan of Gateway Engineers said the subsidence occurred when two columns that had been holding up the ceiling of the mine collapsed.
“The (Department of Environmental Protection's) opinion was that the subsidence resulted in the top of the mine being in contact with the floor of the mine,” Fagan said. “The roof and the floor are touching, so there should be no more sinking.”
To fix the problem, contractors or township staff will pull up the outfield sod and some of the infield dirt, fill the hole to re-level the field, then re-sod it, said township Manager Matt Serakowski.
The ballfield likely will remain closed for the rest of the summer.
Early estimates of the cost were between $75,000 and $100,000, but that could depend on how much work can be done “in-house” by township staff, Serakowski said.
Commissioner Russell Del Re said he was concerned about collapses in other parts of the former C&F Coal Co. mine, which the DEP said closed in 1953.
“What's to say there won't be more adjacent columns doing the same thing?” he said.
Fagan said that was always a risk, given how much of the region was undermined.
Work to repair the sunken section of infield and outfield can start in early July, shortly after contractors start a separate $1.26 million project to install lighting at all the fields around Boyce Mayview Park, Serakowski said.
Contractors from Plavchak construction will install light poles and fixtures starting with the multipurpose field, then the Miracle League field, softball field and the large baseball field, and finally, lighting sidewalks around the park, he said.
The contractors will start mobilizing and bringing in materials July 6 and hope to finish by Labor Day.
Matthew Santoni is a staff writer for Trib Total Media. He can be reached at 412-380-5625 or msantoni@tribweb.com.
