40 CFR §434.71

1. (a)This subpart applies to pre-existing discharges that are located within or are hydrologically connected to pollution abatement areas of a coal remining operation.
2. (b)A pre-existing discharge that is intercepted by active mining or that is commingled with waste streams from active mining areas for treatment is subject to the provisions of § 434.61 Commingling of waste streams. For the purposes of this subpart, § 434.61 requires compliance with applicable BPT, BAT, BCT, and NSPS effluent limitations in subparts C, D, and F of this part. Section 434.61 applies to the commingled waste stream only during the time when the pre-existing discharge is intercepted by active mining or is commingled with active mine wastewater for treatment or discharge. After commingling has ceased, the pre-existing discharge is subject to the provisions of this part.
3. (c)In situations where coal remining operations seek reissuance of an existing remining permit with BPJ limitations and the regulatory authority determines that it is not feasible for a remining operator to re-establish baseline pollutant levels in accordance with the statistical procedures contained in appendix B of this part, pre-existing discharge limitations at existing remining operations shall remain subject to baseline pollutant levels established during the original permit application.
4. (d)The effluent limitations in this subpart apply to pre-existing discharges until the appropriate SMCRA authority has authorized bond release.