In Centre Lime & Stone Co., Inc. v. Spring Township Board of Supervisors, 787 A.2d 1105 (Pa. Cmwlth. 2001), the township ordinance permitted underground mining activity in Forest Districts and surface mining in Industrial (I-1) Districts. Applicant owned land in a Forest District that contained substantial reserves of skid-resistant stone. Applicant filed a curative amendment to create an overlay district that would permit surface mining on its land. The board of supervisors denied applicant's request. On appeal to this Court, applicant argued the court should recognize a separate mineral estate, like coal, for skid-resistant stone. In denying the appeal, the Court emphasized the coal industry's prominence in Pennsylvania and held skid-resistant stone does not enjoy the same status. Thus, a separate mineral estate for skid-resistant stone was unwarranted.