The Pennsylvania Department of Environmental Protection and a crypto mining company have agreed to speed the cleanup of the company’s unpermitted coal ash dumping in northwestern Pennsylvania. The agreement was finalized in early March.
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The DEP originally ordered Stronghold Digital Mining to clean the site up by late 2027, but environmental groups sued the agency, arguing that was too lax a deadline. On March 6, the agency and the company agreed to finish the cleanup by September 1, 2026.
The company owns the Scrubgrass Power Plant in Kennerdell, Venango County. The plant burns waste coal, a lower-grade fuel left over from abandoned mining operations, to generate electricity. It uses that electricity for crypto-mining, a process where power-hungry computers generate digital currency like Bitcoin.
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The company, which didn’t respond to requests for comment, is storing ash created from the plant on a 5-acre temporary storage pad.
The coal ash pile at the Scrubgrass Power Plant, owned by the crypto mining company Stronghold Digital Mining. Image: PA EHB
“The idea was that the coal ash would be parked there for a little while while it cooled, and then it would be taken to a (permanent) disposal area,” said Charles McPhedran, an attorney for Earthjustice, which represented the plaintiffs, Scrubgrass Creek Watershed Association and PennFuture.
But the pile quickly outgrew the pad.
“It overflowed fences. It overflowed into a ditch with water on it running off the site…it just became completely out of control,” he said.
The company told the DEP it could not find suitable permanent disposal sites, according to documents filed with the Pennsylvania Environmental Hearing Board, the legal body that heard the case.
Bill Pritchard of the watershed association said he was shocked by the pile’s size, which Scrubgrass estimates is up to 325,000 tons, when he first saw it in 2023.
“It is a mountain. And so to me, it was like a blatant disregard for their stewardship,” Pritchard said.
Pritchard lives in Slippery Rock, about 20 miles south, but kayaks, hikes and bikes in nearby recreation areas along the Allegheny River. He said he was worried the coal ash, which typically contains toxic metals like mercury, cadmium and arsenic, was sitting on bare ground.
Stronghold’s Scrubgrass power plant, shown here in 2022, fuels crypto mining computers. Photo: Kara Holsopple / The Allegheny Front
The area had no containment system, and according to one expert witness hired by the plaintiff environmental groups, it is “highly probable” the site is leaching heavy metals into nearby groundwater and runoff.
“If we had a large storm, would the constituents of that coal ash enter into the Allegheny River? And then what might potentially leach out of this pile into the groundwater?” Pritchard said.
As part of the agreement, the company will reconstruct stormwater control ditches around the site and conduct groundwater and surface water sampling. In a statement, the DEP said that the company was also required to pay a $28,800 civil penalty” split between the Commonwealth of Pennsylvania Solid Waste Abatement Fund and the Clean Water Fund.
“Scrubgrass is also required to drill a monitoring well and conduct additional groundwater and surface water monitoring at the site,” the DEP said. The agency said the company will also be required to provide the DEP with quarterly progress reports, to be verified through on-site inspections.
