16 Tex. Admin. Code § 12.528 - Use of Explosives: Control of Adverse Effects
(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 §
12.526(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; or
(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 would 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 3 days after the night blasting. The report shall include a
description in detail of the reason for the delay in blasting including why the
blasting 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 §
12.530 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 §
12.530 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 §
12.500 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 the 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 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) Airblasts 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.
(B) In
all cases except the C-weighted, slow response, the measuring systems used must
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 office of the
Commission, 1701 North 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 1/2 the distance to the nearest
dwelling or other occupied structure;
(2) beyond the area of control required under
subsection (i) of this section; or
(3) beyond the permit boundary.
(h) Ground vibration.
(1) General. In all blasting operations,
except as otherwise authorized in subsection (h) of this section, the maximum
ground vibration shall not exceed the values approved by the Commission. 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 ground vibration, submitted by the operator 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:
(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/D[sub]s[/sub])[sup]2[/sup], 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 D[sub]s[/sub] = 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.
(A) An operator may use the ground vibration
limits in Figure 1 to determine the maximum allowable ground vibration.
Attached Graphic
(B) If
the Figure 1 limits are used, a seismographic record, including both
particle-velocity and vibration-frequency levels, shall be provided for each
blast. The method for the analysis of the predominant frequency contained in
the blasting records shall be approved by the Commission before application of
this alternative blasting criterion.
(5) The maximum allowable ground vibration
shall be reduced by the Commission beyond the limits otherwise provided by this
section, if determined necessary to provide damage protection.
(6) The Commission may require an operator to
conduct seismic monitoring of any or all blasts or may specify the locations at
which the measurements are taken and the degree of detail necessary in the
measurement.
(i) The
maximum airblast and ground vibration standards of subsections (f) and (h) of
this section shall not apply at the following locations:
(1) at structures owned by the permittee and
not leased to another person; and
(2) at structures owned by the permittee and
leased to another person, if a written waiver by the lessee is submitted to the
Commission before blasting.
Notes
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