480 U.S. 470 (1987)
In 1966 the Pennsylvania Legislature enacted the Bituminous Mine Subsidence and Land Conservation Act to address land subsidence caused by underground coal mining.1 The Act authorizes the Department of Environmental Resources to implement and enforce a comprehensive program preventing or minimizing subsidence and consequent damage to surface structures.2 Section 4 prohibits mining that causes subsidence damage to public buildings, dwellings used for human habitation, and cemeteries, and generally requires that 50 percent of the coal beneath such structures remain in place to provide surface support.3
Petitioners are an association of coal producers and several of its member corporations engaged in underground bituminous coal mining in western Pennsylvania.4 They own, lease, or control substantial coal reserves and associated support estates beneath surface properties affected by the Subsidence Act.5 Many of these interests were severed from the surface estate between 1890 and 1920, and petitioners or their predecessors typically acquired waivers of liability for subsidence damage along with rights to deposit wastes, provide drainage and ventilation, and erect surface facilities.6
In 1982 petitioners filed a civil rights action in the United States District Court for the Western District of Pennsylvania against the Secretary of the Department of Environmental Resources and other officials.7 They sought to enjoin enforcement of the Subsidence Act and its implementing regulations, alleging that Section 4 and Section 6 effected a taking of their property without compensation and that Section 6 impaired their contractual obligations.8 The parties entered a stipulation of facts concerning the facial challenge and filed cross-motions for summary judgment.9
The District Court granted summary judgment in favor of the Department officials.10 The Court of Appeals for the Third Circuit affirmed.11 The Supreme Court granted certiorari to consider the constitutional challenges to the Subsidence Act.12
Petitioners have never claimed that the Subsidence Act makes it commercially impracticable for them to continue mining their bituminous coal interests in western Pennsylvania, nor have they identified any specific mine rendered unprofitable by the statute.13 The evidence in the record shows that enforcement of the 50 percent rule has required petitioners to leave less than 27 million tons of coal in place.14 This applies across 13 mines containing over 1.46 billion tons.15 It amounts to less than 2 percent of the total coal in those operations.16
Whether the Pennsylvania Bituminous Mine Subsidence and Land Conservation Act effects a taking of petitioners' property without just compensation in violation of the Fifth and Fourteenth Amendments?17
A land use regulation effects a taking if it does not substantially advance legitimate state interests or denies an owner economically viable use of his land.18
No. The Subsidence Act substantially advances the Commonwealth's legitimate interests in protecting the public from the devastating effects of land subsidence caused by underground coal mining.19 Petitioners own or control substantial coal reserves and support estates beneath surface properties affected by the Act. Petitioners have not claimed that the Act makes it commercially impracticable to mine their coal.20 The Act therefore does not deny petitioners economically viable use of their property.21
The Subsidence Act does not effect a taking of petitioners' property without just compensation.22
Related opinions on this issue
Joined by Justice Powell, Justice O'connor, And Justice Scalia
Chief Justice Rehnquist dissents from the majority's conclusion that the Subsidence Act does not effect a taking.23 He argues that the Act requires petitioners to leave 50 percent of their coal in the ground to support the surface.24 This requirement constitutes a permanent physical occupation of petitioners' property.25
Under the decisions in Loretto v. Teleprompter Manhattan CATV Corp. and Pennsylvania Coal Co. v. Mahon, such a requirement constitutes a taking.26 The majority attempts to distinguish Pennsylvania Coal on the ground that only a small percentage of petitioners' coal is affected.27 But the proper inquiry is not the percentage of coal affected but whether the Act destroys the value of petitioners' property rights.28
In Pennsylvania Coal the Court held that the Kohler Act took the coal operators' property because it made it commercially impracticable to mine the coal.29 Here the Subsidence Act has the same effect on the coal that must be left in place.30 He would reverse the judgment of the Court of Appeals.31
Whether the Subsidence Act violates the Contracts Clause by substantially impairing petitioners' contractual obligations?32
The Contracts Clause prohibits states from passing laws that substantially impair contractual obligations unless the law serves a significant and legitimate public purpose and the adjustment of rights is reasonable and appropriate to that purpose.33
No. The Subsidence Act does not operate as a substantial impairment of the contractual obligations at issue.34 The parties to the contracts executed after the passage of earlier legislation were aware of the additional restrictions on mining that the Commonwealth could impose.35 The Commonwealth has a strong public interest in preventing subsidence.36 The Act is justified by that public interest even if the impairment is substantial.37
The Subsidence Act does not violate the Contracts Clause.38