DEP: Interboro Ave. mine subsidence work is complete | The Homepage

By Juliet Martinez, managing editor

On Nov. 7, 2023, Coastal Drilling East crews position equipment in preparation for stabilization work at the Lincoln Place Veterans of Foreign Wars post at 5132 Interboro Ave. Photo by Juliet Martinez

The mine subsidence that damaged seven Lincoln Place homes and the Veterans of Foreign Wars post in October has been stabilized, according to the Department of Environmental Protection.

The damage to the VFW post was discovered and reported on Oct. 18, 2023. The department put the job out to bid and awarded it to Mount Morris-based Coastal Drilling East LLC. on Nov. 1. The stabilization work began in earnest on Nov. 7. The area bounded by Interboro Avenue, Leaside Drive and H Way is considered stable. All it took was $600,000, 13 weeks, 39 160-foot boreholes and 479 cubic yards of grout — enough to fill five average-sized backyard swimming pools.

At a March 12 meeting with the Department of Environmental Protection at Lincoln Place Presbyterian Church, officials said they believe the subsidence to have happened underneath Interboro Avenue. Now that the four-inch-wide holes have been drilled and filled, homeowners can contact their insurers and begin repairs. It is rare for more subsidence to happen after the stabilization, they said.

Coastal Drilling East drilled at each of the spots the environmental protection department identified, said supervisor Dave Harris. Some were underneath walls or other structures, so the crew had to drill in at an angle. Once they drilled down to the mine, they discovered an open void in some places and rubble known as gob in others.

The crew lowered a camera down one of the boreholes near the VFW and saw the space was open and still supported by coal pillars that were typical in coal mines in the early 20th century. The mine did not appear to have collapsed, so Mr. Harris was unsure of what caused the subsidence at the surface. But that did not change the job.

“We found a nine-foot open void, and we filled it up,” he said. After filling the boreholes with grout, the crews restored the areas to their previous condition. They planted grass seed, replaced some shrubbery and restored a fence on one property.

Mr. Harris said some homes were severely damaged. When the ground beneath a home’s foundation moves, the harm it does may not be evident until it’s too late.

“It’s kind of like when you push something over, sometimes you can save it, but sometimes it continues to fall,” he said. “Once the slipping has occurred there, it takes a lot to stop that damage.”

Property owners who do not yet have mine subsidence insurance can visit www.dep.pa.gov/msi to find out if their home is undermined and learn about affordable policies to protect their homes. An inspector will visit the home to document its current condition. If subsidence damages the home and it needs repairs, it will be restored to the documented condition.