LCT Energy has not been sharing everything they know about subsidence risks in their Rustic Ridge deep mine. LCT commissioned Barr Engineering to perform an in-depth analysis of the mine’s stability in 2021, and the report reveals some deeply concerning information about the mine’s geologic potential for subsidence.
The Barr report mostly focuses on the northernmost parts of the original Rustic Ridge #1 coal mine and the expansion area. This includes the mine’s portal and surface area, Laurel Highlands Campland, Hellein School Road, the Pennsylvania Turnpike, and segments of County Line Road and Route 31.
This area has experienced subsidence from the Rustic Ridge mine in the past. At least five documented cases of subsidence took place between 2020 and 2022. Following those cases of subsidence, LCT hired Barr Engineering to look into the Rustic Ridge’s floor and pillar stability as they were preparing materials for their application to expand the existing mine boundary.
LCT partially acknowledged the Barr report’s findings in the Revision 10 application materials, including that subsidence was caused, at least in part, due to “floor instability”. In the five documented cases of subsidence the mine voids themselves met state-minimum safety design standards, but the unstable, “soft” floor geology could not bear the pressure. Pillars, plus everything they were holding up, slowly sank and caused the earth above to subside, ultimately causing over $1.5 million in total damage to the homes.
Even with this information available, the DEP approved the Rustic Ridge I Expansion permit in April 2025, a decision that MWA immediately appealed.
When DEP approved Revision 10, it did so with incomplete information about subsidence risks. DEP knew that subsidence was caused by unstable mine geology, but LCT left out some key details from the Barr report about future subsidence. Barr concluded that the mine’s claystone floor will lose up to 60% of its strength after mine closure.
Once operators finish mining, there is no one left to pump out the groundwater that fills the mine void. Barr stated that water in the mine void will continue to further decrease the structural integrity of the mine floor and cause the supporting pillars to continually sink in the study’ area, unless extraction is limited to 40% or lower.
As MWA’s appeals move along, we can’t overstate the Barr report’s importance. This document reveals that LCT has known for at least 5 years that subsidence is likely in parts of the Rustic Ridge mine complex, and withheld that information from both DEP and our mountain communities.
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