N.M. Admin. Code § 19.8.20.2049 - COAL PROCESSING WASTE: DAMS AND EMBANKMENTS: DESIGN AND CONSTRUCTION
A. The design of
each dam and embankment constructed of coal processing waste or intended to
impound such waste shall comply with the requirements of Subsections B through
G of 19.8.20.2017 NMAC modified as
follows:
(1) the maximum water elevation
shall be that determined by the freeboard hydrograph criteria contained in the
U.S. natural resources conservation service criteria referenced in
19.8.20.2017 NMAC;
(2) the dam and embankment shall have a
minimum safety factor of 1.5 for the partial pool with steady seepage
saturation conditions, and the seismic safety factor shall be at least
1.2;
(3) the dam or embankment
foundation and abutments shall be designed to be stable under all conditions of
construction and operation of the impoundment; sufficient foundation
investigations and laboratory testing shall be performed to determine the
safety factors of the dam or embankment for all loading conditions appearing in
Paragraph (2) of Subsection A of
19.8.20.2049 NMAC or the
publications referred to in
19.8.20.2017 NMAC and for all
increments of construction.
B. Spillways and outlet works shall be
designed to provide adequate protection against erosion and corrosion. Inlets
shall be protected against blockage.
C. Dams or embankments constructed of, or
impounding, coal processing waste shall be designed, constructed and maintained
so that at least 90 percent of the water stored during the design precipitation
event shall be removed within a 10 day period.
D. Each impounding structure constructed of
coal processing waste or intended to impound coal processing waste that meets
the criteria of
30
CFR 77.216(a) shall have
sufficient spillway capacity to safely pass, adequate storage capacity to
safely contain, or a combination of storage capacity and spillway capacity to
safely control, the probable maximum precipitation of a 6-hour precipitation
event, or greater event as specified by the director.
E. No impounding structure constructed of
coal processing waste or intended to impound coal processing waste shall be
retained as a permanent impoundment as part of the approved postmining land
use.
Notes
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