(by a 4-3 majority, court overturned portions of new PA law that regulates Marcellus Shale development on basis the offending portions that gave the state decision-making authority over local drilling decisions violated constitutional due process requirements and impermissibly gave PA Dept. of Environmental Protection power to make legislative policy judgments; court noted that 150 unconventional wells had been drilled inside boundaries of several municipalities and portions of law prevented local governments from taking action to protect health and safety of citizens, and required localities to amend existing zoning laws; distinctions in law that treated oil and gas differently from other extraction industries constitutional because distinction based on legitimate differences that justified different zoning classifications).