The last difference between the two cases was the diminution in value of the coal companies' properties. In "Pennsylvania Coal Co. v. Mahon", "mining of 'certain coal'" was deemed "commercially impracticable" as a result of the Kohler Act. Here, the Court held that there was no "showof any deprivation significant enough to satisfy the heavy burden placed upon one alleging a regulatory taking." The Court categorized the cause of action in this case as a "facial challenge" to the Act. From the Court's perspective, the petitioners challenged the statute's possible consequences without showing that any actual injury had occurred. As the Court mentioned, there was no evidence that any of the petitioners' mines could "no longer be mined for profit."