25 Pa. Code § 87.135
(a) Surface coal mining activities, except support activities, may not be conducted closer than 500 feet to any point of either an active or abandoned underground mine, except to the extent that:
The provisions of this § 87.135 amended under the Surface Mining Conservation and Reclamation Act (52 P. S. § § 1396.1—1396.19a); The Clean Streams Law (35 P. S. § § 691.1—691.1001); and section 1920-A of The Administrative Code of 1929 (71 P. S. § 510-20).
The provisions of this § 87.135 adopted December 19, 1980, 10 Pa.B. 4789, effective July 31, 1982, 12 Pa.B. 2382; amended July 30, 1982, 12 Pa.B. 2473, effective July 31, 1982, 12 Pa.B. 2382; amended June 15, 1990, 20 Pa.B. 3383, effective July 27, 1991, 21 Pa.B. 3316; amended December 15, 1995, effective December 16, 1995, 25 Pa.B. 5821. Immediately preceding text appears at serial pages (198988) to (198989).
This section cited in 25 Pa. Code § 87.76 (relating to surface mining near underground mining); and 25 Pa. Code § 87.176 (relating to auger mining).