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 19.8.36.30 - GENERAL PERFORMANCE STANDARDS: DAMS CONSTRUCTED OF WASTE MATERIAL (715.18)

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 severely 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 three 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 see-page 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)(iii) [now Subparagraph c Paragraph 3 of
				Subsection B of 19.8.36.30 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, previous 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 ten days.
(h) During
				construction of dams subject to this section, the structures shall be
				periodically inspected by a professional engineer registered in the state of
				New Mexico 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 six 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 professional engineer registered in the state of New Mexico, 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 facilitate 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 certified 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
				certification 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).