The Pennsylvania Department of Environmental Protection rejected a proposal to change size requirements for coal mine pillars and allow alternative methods for constructing natural gas wells where coal is mined underground.

"Natural gas extraction is increasingly intersecting with longwall mining, particularly in southwestern Pennsylvania," said DEP Acting Secretary Patrick McDonnell in a Jan. 19 news release. "While new drilling methods may make extraction more efficient, coal miners' safety remains our primary concern. For this reason, DEP stands by the established regulatory benchmarks that we believe better protect miner safety and maintain the integrity of gas wells."

DEP reviewed a study and field tests conducted at CONSOL Energy Inc.'s Enlow Fork Mine to determine if 1957 standards for the dimensions of coal mine pillars, columns of coal or rock left in place in the mine to support overlying rock and furnish protection for gas wells drilled in the permitted area of a mine, should be revised in light of modern longwall mining methods.

The results showed that subsidence-related deformation could occur if a support pillar is not suitably sized, the release said.