Even as Pennsylvania recovers from the after-effects of the coal and logging booms, another natural resource has been discovered within the borders of the Commonwealth, the Marcellus Shale. Over the millennia, the 300 million-year-old shale has been compressed and cooked by the heat of the earth’s  core, producing natural gas trapped in the tight layers of the rock. To extract the methane from the rock, the gas industry has pioneered the use of two specific methods to extract the valuable resource from its present location approximately a mile beneath the surface of the Appalachian Plateau: horizontal drilling and hydraulic fracturing. […]