Cracking Dam And Moving Bridge

Greene County, Pa (United States):
A mysterious force that has caused cracks through a Greene County dam since July also is causing a bridge downstream to move, the state departments of Environmental Protection and Conservation and Natural Resources announced Monday.
About two weeks ago, workers noticed a slight movement in the access bridge near the dam in Ryerson Station State Park. No structural damage is evident and the bridge is still being used, officials said. Officials drained the lake behind the dam July 28 after water began leaking at the rate of 80 gallons a minute.
Several possible causes -- including flood damage, mine subsidence, earthquakes and landslides -- are being investigated, said natural resources department spokeswoman Chris Novak.
"Nothing has been ruled out," she said.
Consol Energy also is investigating, said Tom Hoffman, a spokesman for the Upper St. Clair coal-mining company. The closest mine to the dam is 2,500 feet away, Hoffman said.
"We don't think we've seen any evidence to date that would lead you to conclude that mining was the cause of this," Hoffman said.
Because the 45-year-old dam has been breached and the 62-acre lake has been drained, there is no risk to nearby residents, Novak said. There are 12 homes and one restaurant downstream of the dam.
The dam will not be repaired or rebuilt and the lake will not be refilled until the movement stops, Novak said.
Sept 13, 2005
Allison M. Heinrichs ,Tribune Review