The petitioners challenged two sections of the Subsidence Act. First, they challenged Section 4, which "mining that causes subsidence damage to three categories of structures . . . : [1. public buildings and noncommercial buildings generally used by the public; dwellings used for human habitation; and [3. cemeteries." Second, the petitioners challenged Section 6 of the Act. This section "the DER to revoke a mining permit if the removal of coal causes damage to a structure or area protected by Section 4 and the operator has not . . . [done any of the following within six months: 1. repaired the damage, satisfied any claim arising [from the damage, or [3.] deposited a sum equal to the reasonable cost of repair with the DER as security."