Pennsylvania Coal Co. v. Mahon 260 U.S. 393 (1922) Pennsylvania Coal sold off some deeds to land. But they only sold the surface of the land, and kept the right to mine under the surfaces. The deeds also gave Pennsylvania Coal immunity for any damage caused to the surface from their mining activities. Pennsylvania has complex property laws. Under Pennsylvania law there are three different layers of property; the surface, the subsidence layer, and the coal layer. It's possible to sell off one layer of property and keep the rest. The subsidence layer is the layer just under the surface where mining could cause the surface to collapse. 40 years later, Mahon owned a home on one of the plots originally sold by Pennsylvania Coal. Mining was causing subsidence and damaging Mahon's home, so he sued for an injunction. The Trial Court found for Pennsylvania Coal. Mahon appealed. Mahon argued that Pennsylvania had passed The Kohler Act (P.L. 1198), which took away Pennsylvania Coal's mining rights. The Kohler Act forbid the mining of coal in the subsidence layer in such a way to cause damage to buildings on the surface. Pennsylvania Coal argued that if the Kohler Act were applied in this case, it would be an illegal taking under the Constitution. They argued that it should only apply to subsidence damage on land that they didn't have a property right to. The Pennsylvania Supreme Court reversed. Pennsylvania Coal appealed. The Pennsylvania Supreme Court found that the Kohler Act was a legitimate exercise of the police power. The US Supreme Court reversed and found for Pennsylvania Coal. The US Supreme Court found that under the 5th Amendment, the government has a right to take land, but it must be for the public good and there must be compensation. The Kohler Act couldn't be a legitimate taking, because there was no "public" good, and there is no compensation. In fact, it was argued that since the coal was valuable and supported many jobs, it was more in the public's interest to mine the coal even at the expense of a single homeowner. The Court found that, while property may be regulated to a certain extent, if regulation goes too far it will be recognized as a taking. In order to determine whether or not the regulation goes too far, you have to look at the average reciprocity of advantage. Average reciprocity of advantage basically says that the aggregate amount of benefit that comes from a regulation is approximately equal to the amount of burden the regulation causes. Of course, you have to consider the fact that the burden can completely fall on one person and the benefits could fall on a different segment of the community. The Court felt that since Mahon only purchased the surface of the land, and had indemnified Pennsylvania Coal from damage resulting from subsidence, he took a risk and has to live with the consequences. In a dissent, it was argued that coal is, while in place, land. You aren't allowed to use your land to create a nuisance, or disturb other people's land. The government has a right to regulate public nuisances, so what's special about coal? The dissent felt that the restriction was not a taking at all but was instead a prohibition of a noxious use, which is perfectly within the bounds of the law. Pennsylvania Coal argued that they had lost 100% of the value of the coal in the subsidence layer, and a 100% loss was going too far. However, the dissent argued that they hadn't lost 100% of their coal, they'd only lost a small percentage of their coal since they still could mine all the coal in the lower layers. The idea that losing 100% of part of an investment is not the same as losing a small percentage of the overall investment is known as conceptual severance. The general rule for takings had been that permanent physical occupations are always considered takings, while nuisance control measures are never considered takings. But this case modified the rule a bit. Here it was held that if the nuisance control measure creates too much of a burden on the property owner, it is considered a taking. Although never overruled, the Courts have been unable to develop any set formula for determining if a regulation went so far as to be a taking.