N.M. Admin. Code § 19.8.20.2057

Current through Register Vol. 36, No. 1, January 14, 2025

Section 19.8.20.2057 - BACKFILLING AND GRADING: THIN OVERBURDEN

A. The provisions of 19.8.20.2057 NMAC apply only where the overburden thickness times the swell factor, plus the thickness of other available waste materials, is less than the combined thickness of the overburden and coal bed prior to removing the coal and only when surface mining activities cannot be carried out to comply with 19.8.20.2054 NMAC to achieve the approximate original contour.

B. In surface mining activities carried out continuously in the same limited pit area for more than 1 year from the day coal-removal operations begin and where the volume of all available spoil and suitable waste materials over the permit area is demonstrated to be insufficient to achieve the approximate original contour of the lands disturbed, surface mining activities shall be conducted to meet, at a minimum, the following standards:

(1) haul or convey, backfill, and grade, using all available spoil and suitable waste materials from the entire mine area, to attain the lowest practicable stable grade, to achieve a static safety factor of 1.3, and to provide adequate drainage and long- term stability of the regraded areas and cover all acid-forming and toxic-forming materials.

(2) except as provided in Paragraph (2) of Subsection A of 19.8.20.2055 NMAC, eliminate highwalls by grading or backfilling to stable slopes not exceeding 1v:2h (50 percent), or such lesser slopes as the director may specify to reduce erosion, maintain the hydrologic balance, or allow the approved postmining land use.

(3) haul or convey, backfill, grade, and revegetate in accordance with 19.8.20.2060 through 2066 NMAC, to achieve an ecologically sound land use compatible with the prevailing use in unmined areas surrounding the permit area; and

(4) haul or convey, backfill, and grade, to ensure impoundments are constructed only where:

(a) it has been demonstrated to the director's satisfaction that all requirements of 19.8.20.2009 through 2024 NMAC have been met; and

(b) the impoundments have been approved by the director as suitable for the approved postmining land use and as meeting the requirements of 19.8.20 NMAC and all other applicable federal and state laws and regulations.

N.M. Admin. Code § 19.8.20.2057

11-29-97; 19.8.20.2057 NMAC - Rn, 19 NMAC 8.2.20.2057, 9-29-2000; A, 1-15-2002