Program Policy Manual - VOLUME V - Mine Safety and Health ...

MSHA PROGRAM POLICY MANUAL VOLUME V
made in paragraphs (b)(1) through (b)(8) of this Section.
77.215-3 Refuse Piles; Certification
Paragraphs (a) and (b) do not require specific wording for
certification. However, the registered engineer should
incorporate the wording in paragraph (a) as part of the
certification. In addition, the certification should include
statements describing the remedial work performed at the site
that has minimized the hazardous condition(s).
77.216 Water, Sediment, or Slurry Impoundments and
Impounding Structures; General
For the purpose of determining the elevation to which water,
sediment or slurry can be impounded, measurements should be
taken from the upstream toe of the structure to the lowest
point on the crest of the structure. If the lowest point on
the crest of the structure is the invert of a properly designed
open channel spillway, then that point is the proper location
for the upper measurement. Where decant pipes and pipe
spillways are used, the elevation must still be measured to the
lowest point on the crest of the structure, not to the invert
of the decant riser or spillway pipe.
As the emphasized language above makes clear, the impoundment
capacity of a structure may be based on a measurement to the
invert of the spillway only if two contingencies are satisfied.
The spillway must be an open channel configuration, and it must
be properly designed. Where either of these requirements is
lacking, the impoundment capacity of a structure must be
determined based on a measurement made to the lowest point on
the crest of the structure, without reference to the spillway.
To assure that the requirement of a properly designed spillway
is satisfied when the impoundment capacity of a structure is to
be determined by measurement to the invert of the spillway,
district managers are advised to adopt the following
procedures:
1. For impounding structures completed after August 6,
1981, the District Manager should notify the operator
that, in order to rely on a measurement to the invert
of the spillway for determining impoundment
capacity,the operator must supply the information and
analyses necessary for the district manager to make a
meaning-ful evaluation of whether the spillway is
properly designed. If this information is not made
available to the district manager, then measurements
should be made to the crest of the structure when
determining impoundment capacity.
February 2003 (Release V-33) 165