New Mexico Administrative Code › Title 19 - NATURAL RESOURCES AND WILDLIFE › Chapter 8 - COAL MINING › Part 36 - NEW MEXICO COAL SURFACE MINING REGULATIONS [CSMC 1979-1] › Section 19.8.36.42 - UNDERGROUND MINING GENERAL PERFORMANCE STANDARDS: DAMS CONSTRUCTED OF WASTE MATERIAL (717.18)

Current through Register Vol. 35, No. 13, July 16, 2024
A.
				General. No waste material shall be used in existing or new dams without the
				approval of the regulatory authority. The permittee shall design, locate,
				construct, operate, maintain, modify and abandon or remove all dams (used
				either temporarily or permanently) constructed of waste materials in accordance
				with the requirements of this Section.
B. Construction of dams.
(1) Waste shall not be used in the
				construction of dams unless demonstrated through appropriate engineering
				analysis to have no adverse effect on stability.
(2) Plans for dams subject to this Section,
				and also including those dams that do not meet the size or other criteria of
				Section 77.216(a)of this title, shall be approved by the regulatory authority
				before construction and shall contain the minimum plan requirements established
				by the mining enforcement and safety administration pursuant to Section
				77.216-2 of this title.
(3)
				Construction requirements are as follows:
(a)
				Design shall be based on the flood from the probable maximum precipitation
				event unless the permittee shows that the failure of the impounding structure
				would not cause loss of life or severly damage property or the environment, in
				which case, depending on site conditions, a design based on a precipitation
				event of no less than 100-year frequency may be approved by the regulatory
				authority.
(b) The design freeboard
				distance between the lowest point on the embankment crest and the maximum water
				elevation shall be at least 3 feet to avoid overtopping by wind and wave
				action.
(c) Dams shall have minimum
				safety factors as follows:
_________________________________________________________________________________________
Case Loading condition Minimum safety factor
_________________________________________________________________________________________
I _ _ _ _ _ _ _ _ _ _ End of construction _ _ _ _ _ _ _ _
				  1.3
II _ _ _ _ _ _ _ _ _ _ Partial pool with steady seep-age
				  saturation 1.5
III _ _ _ _ _ _ _ _ _ _ Steady seepage from spillway or
				  decant crest 1.5
IV _ _ _ _ _ _ _ _ _ _ Earthquake (cases II and III with
				  seismic loading) 1.0
_________________________________________________________________________________________
(d) The dam, foundation and
				abutments shall be stable under all conditions of construction and operation of
				the impoundment. Sufficient foundation investigations and laboratory testing
				shall be performed to determine the factors of safety of the dam for all
				loading conditions in Paragraph (b)(3)(ii) [now Subparagraph b of Paragraph 3
				of Subsection B of 19.8.36.42 NMAC] of this Section and for all increments of
				construction.
(e) Seepage through
				the dam, foundation and abutments shall be controlled to prevent excessive
				uplift pressures, internal erosion, sloughing, removal of material by solution
				or erosion of material by loss into cracks, joints and cavities. This may
				require the use of impervious blankets, pervious drainage zones or blankets,
				toe drains, relief wells or dental concreting of jointed rock surface in
				contact with embankment materials.
(f) Allowances shall be made for settlement
				of the dams and the foundation so that the freeboard will be
				maintained.
(g) Impoundments
				created by dams of waste materials shall be subject to a minimum drawdown
				criteria that allows the facility to be evacuated by spillways or decants of 90
				percent of the volume of water stored during the design precipitation event
				within 10 days.
(h) During
				construction of dams subject to this Section, the structures shall be
				periodically inspected by a registered professional engineer to ensure
				construction according to the approved design. On completion of construction
				the structure shall be certified by a professional engineer registered in the
				State of New Mexico, experienced in the field of dam construction as having
				been constructed in accordance with accepted professional practice and the
				approved design.
(i) A permanent
				identification marker, at least 6 feet high that shows the dam number assigned
				pursuant to Section 77.216-1 of this title and the name of the person operating
				or controlling the dam, shall be located on or immediately adjacent to each dam
				within 30 days of certification of design pursuant to this Section.
(4) All dams, including those not
				meeting the size or other criteria of Section 77.216(a) of this title, shall be
				routinely inspected by a registered professional engineer, or someone under the
				supervision of a registered professional engineer, in accordance with mining
				enforcement and safety administration regulations pursuant to Section 77.216-3
				of this title.
(5) All dams shall
				be routinely maintained. Vegetative growth shall be cut where necessary to
				facilitiate inspection and repairs. Ditches and spillways shall be cleaned. Any
				combustible materials present on the surface, other than that used for surface
				stability such as mulch or dry vegetation shall be removed and any other
				appropriate maintenance procedures followed.
(6) All dams subject to this section shall be
				recertified annually as having been constructed and modified in accordance with
				current prudent engineering practices to minimize the possibility of failures.
				Any changes in the geometry of the impounding structure shall be highlighted
				and included in the annual recertification report. These certifications shall
				include a report on existing and required monitoring procedures and
				instrumentation, the average and maximum depths and elevations of any impounded
				waters over the past year, existing storage capacity of impounding structures,
				any fires occurring in the material over the past year and any other aspects of
				the structures affecting their stability.
(7) Any enlargements, reductions in size,
				reconstruction or other modification of the dams shall be approved by the
				regulatory authority before construction begins.
(8) All dams shall be removed and the
				disturbed areas regraded, revegetated and stabilized before the release of bond
				unless the regulatory authority approves retention of such dams as being
				compatible with an approved postmining land use (Section 715.13).