| (a) General requirements.
(1) Blasting shall be conducted in a manner that will
prevent injury to persons, damage to public or private property outside
the permit area, adverse impacts on any underground mine, and change
in the course, channel, or availability of ground or surface waters
outside the permit area.
(2) Except where lesser distances are approved by the
Commission, based upon a pre-blasting survey, seismic investigation,
and an approved blast design submitted in accordance with the requirements
of §12.357(d) of this title (relating to Use of Explosives: General
Requirements), blasting shall not be conducted within:
(A) 1,000 feet of any building used as a dwelling,
public building, school, church, hospital, nursing facility, or community
or institutional building outside the permit area; and
(B) 500 feet of facilities including, but not limited
to, disposal wells, petroleum or gas storage facilities, active and
abandoned underground mines, fluid-transmission pipelines, gas or
oil-collection lines, or water and sewage lines.
(b) Scheduled blasting. All blasting shall be conducted
between sunrise and sunset, unless otherwise approved by the Commission
upon a showing by the operator that the public will be protected from
adverse noise and other impacts.
(1) The Commission may limit the area covered, timing
and sequence of blasting as listed in the blasting schedule if such
limitations are reasonable and necessary in order to protect the
public health, safety or welfare.
(2) Blasting may be conducted between sunset and sunrise
if:
(A) a blast that has been prepared during the afternoon
must be delayed due to the occurrence of an unavoidable hazardous
condition and cannot be delayed until the next day because a potential
safety hazard could result that cannot be adequately mitigated;
(B) in addition to the required warning signals, oral
notices are provided to persons within 1/2 mile of the blasting site;
and
(C) a complete written report of blasting at night
is filed by the operator with the Commission not later than three
days after the night blasting. The report shall include a description
in detail of the reasons for the delay in blasting including why
the blast could not be held over to the next day, when the blast was
actually conducted, the warning notices given, and a copy of the blast
report required by §12.362 of this title (relating to Use of
Explosives: Records of Blasting Operations).
(c) Unscheduled blasting. Unscheduled blasting may
be conducted only where public or operator health and safety so require,
and for emergency blasting actions. The operator shall use audible
signals to notify residents within 1/2 mile of the blasting site prior
to conducting unscheduled blasting, and shall document the reason
for the unscheduled blasting in accordance with §12.362 of this
title (relating to Use of Explosives: Records of Blasting Operations).
(d) Warnings. All blasting shall require blasting
signs, warnings, and access control.
(1) Blasting signs shall meet the specifications of
§12.330 of this title (relating to Signs and Markers). The operator
shall:
(A) conspicuously place signs reading, "Blasting Area",
along the edge of any blasting area that comes within 100 feet of
any public road right-of-way, and at the point where any other road
provides access to the blasting area; and
(B) conspicuously place at all entrances to the permit
area from public roads or highways, signs reading, "Warning! Explosives
in Use". The signs shall clearly list and describe the meaning of
the audible blast warning and all-clear signals that are in use, and
shall explain the marking of the blasting areas and charged holes
awaiting firing within the permit area.
(2) Warning and all-clear signals of different character
or pattern that are audible within a range of 1/2 mile from the blasting
site shall be given. The operator shall notify each person within
the permit area and each person who resides or regularly works within
1/2 mile of the permit area regarding the meaning of the signals in
the blasting schedule.
(e) Access control. Access to the blasting area shall
be controlled to prevent the presence of livestock or unauthorized
persons during blasting and until an authorized representative of
the operator has reasonably determined that:
(1) no unusual hazards, such as imminent slides or
undetonated charges, exist; and
(2) access to and travel within the blasting area can
be safely resumed.
(f) Airblast.
(1) Limits.
(A) Airblast shall not exceed the maximum limits specified
below at the location of any dwelling, public building, school, church,
or community or institutional building outside the permit area, except
as provided in subsection (i) of this section.
Attached Graphic
(B) In all cases except the C-weighted, slow-response,
the measuring systems used shall have a flat frequency response of
at least 200 Hz at the upper end. The C-weighted shall be measured
with a Type 1 sound-level meter that meets the standard American National
Standards Institute (ANSI) S1.4-1971 specifications. ANSI S1.4-1971
is on file and available for inspection at the offices of the Commission,
170l N. Congress Avenue, Austin, Texas.
(C) If necessary to prevent damage, the Commission
shall specify lower maximum allowable airblast levels than those of
subparagraph (A) of this paragraph for use in the vicinity of a specific
blasting operation.
(2) Monitoring.
(A) The operator shall conduct periodic monitoring
to ensure compliance with the airblast standards. The Commission may
require airblast measurement of any or all blasts, and may specify
the locations at which the measurements are to be taken.
(B) The measuring systems shall have an upper-end flat
frequency response of at least 200 Hz.
(g) Flyrock. Flyrock traveling in the air or along
the ground shall not be cast from the blasting site:
(1) more than one half the distance to the nearest
dwelling or other occupied structure;
(2) beyond the area of control required under subsection
(e) of this section; or
(3) beyond the permit boundary.
(h) Ground vibration.
(1) General. In all blasting operations, except as
otherwise authorized in subsection (i) of this section, the maximum
ground vibration shall not exceed the values approved in the blasting
plan required under §12.141 of this title (relating to Operation
Plan: Blasting). The maximum ground vibration for protected structures
listed in paragraph (2)(A) of this subsection shall be established
in accordance with the maximum peak-particle-velocity limits of paragraph
(2) of this subsection, the scaled-distance equation of paragraph
(3) of this subsection, the blasting-level chart of paragraph (4)
of this subsection, or by the Commission under paragraph (5) of this
subsection. All structures in the vicinity of the blasting area, not
listed in paragraph (2)(A) of this subsection, such as water towers,
pipelines and other utilities, tunnels, dams, impoundments, and underground
mines, shall be protected from damage by establishment of a maximum
allowable limit on the ground vibration, submitted by the operator
in the blasting plan and approved by the Commission.
(2) Maximum peak particle velocity.
(A) The maximum ground vibration shall not exceed
the following limits at the location of any dwelling, public building,
school, church, or community or institutional building outside the
permit area:
Attached Graphic
(B) A seismographic record shall be provided for each
blast.
(3) Scaled-distance equation.
(A) An operator may use the scaled-distance equation,
W = (D/Ds )2 ,
to determine the allowable charge weight of explosives to be detonated
in any 8-millisecond period, without seismic monitoring; where W =
the maximum weight of explosives, in pounds; D = the distance, in
feet, from the blasting site to the nearest protected structure; and
Ds = the scaled-distance factor, which
may initially be approved by the Commission using the values for
the scaled-distance factor listed in paragraph (2)(A) of this subsection.
(B) The development of a modified scaled-distance factor
may be authorized by the Commission on receipt of a written request
by the operator, supported by seismographic records of blasting at
the mine site. The modified scaled-distance factor shall be determined
such that the particle velocity of the predicted ground vibration
will not exceed the prescribed maximum allowable peak particle velocity
of paragraph (2)(A) of this subsection, at a 95% confidence level.
(4) Blasting-level chart.
Cont'd... |
