ABSTRACT
Pennsylvania Coal v. Mahon, 260 US 393, was the principal US Supreme Court case to establish what was required for governmental regulation to be classified as a "taking." US Industry was driven by energy, and the primary energy source of the times was coal. Pennsylvania was underlain by vast coal deposits. Mining coal in Pennsylvania was problematic, however, because removal of it caused subsidence of the surface area. Significant parts of Pennsylvania were sinking. The coal companies conventionally sold the surface rights to land while retaining the mineral rights. In Mahon, the owners of surface rights sued Pennsylvania Coal to prevent the company from exercising its option to remove the coal from beneath their property because it would cause subsidence, requiring them to vacate their home. Pennsylvania Coal was decided on the basis of the Fifth and Fourteenth Amendments to the US Constitution.
