17.24.633    WATER QUALITY PERFORMANCE STANDARDS

(1) All surface drainage from the disturbed area, including disturbed areas that have been graded, seeded, or planted, must be treated by the BTCA before leaving the permit area. Additional BTCA practices may be required after commencement of the operation if conditions arise that were not anticipated at the time of the permit application.

(2) Sediment control through BTCA practices must be maintained until the disturbed area has been restored, the revegetation requirements of ARM 17.24.711, 17.24.713, 17.24.714, 17.24.716 through 17.24.718, 17.24.721, 17.24.723 through 17.24.726, and 17.24.731 have been met, the area meets state and federal requirements for the receiving stream, and evidence is provided that demonstrates that the drainage basin has been stabilized consistent with the approved postmining land use.

(3) All sediment control must be constructed in accordance with ARM 17.24.638 and 17.24.639 in approved locations before any strip or underground mining operations in the drainage area to be affected may begin.

(4) All discharges which include water from areas disturbed by strip or underground mining operations must be in compliance with all federal and state laws and regulations and applicable effluent limitations.

(5) In accordance with 40 CFR 434, for certain constituents as defined in the operator's MPDES permit, discharge from the disturbed areas is not subject to the effluent limitations or BTCA standards of ARM 17.24.638 if:

(a) the discharge is demonstrated by the permittee to have resulted from a precipitation event equal to or larger than a 10-year, 24-hour precipitation event, or snowmelt runoff of equivalent volume; and

(b) the discharge is from BTCA practices designed, constructed, and maintained in accordance with (1) through (4) and ARM 17.24.639.

 

History: 82-4-205, MCA; IMP, 82-4-231, MCA; NEW, 1980 MAR p. 725, Eff. 4/1/80; AMD, 1989 MAR p. 30, Eff. 1/13/89; AMD, 1994 MAR p. 2957, Eff. 11/11/94; TRANS, from DSL, 1996 MAR p. 2852; AMD, 1999 MAR p. 811, Eff. 4/23/99; AMD, 2004 MAR p. 2548, Eff. 10/22/04; AMD, 2024 MAR p. 258, Eff. 2/10/24.