30 CFR § 75.337 Construction and repair of seals.
(a) The mine operator shall maintain and repair seals to protect
miners from hazards of sealed areas.
(b) Prior to sealing, the mine operator shall--
(1) Remove insulated cables, batteries, and other potential
electric ignition sources from the area to be sealed when constructing
seals, unless it is not safe to do so. If ignition sources cannot
safely be removed, seals must be constructed to at least 120 psi;
(2) Remove metallic objects through or across seals; and
(3) Breach or remove all stoppings in the first crosscut inby the
seals immediately prior to sealing the area.
(c) A certified person designated by the mine operator shall
directly supervise seal construction and repair and--
(1) Examine each seal site immediately prior to construction or
repair to ensure that the site is in accordance with the approved
(2) Examine each seal under construction or repair during each
shift to ensure that the seal is being
constructed or repaired in accordance with the approved ventilation
(3) Examine each seal upon completion of construction or repair to
ensure that construction or repair is in accordance with the approved
(4) Certify by initials, date, and time that the examinations were
(5) Make a record of the examination at the completion of any shift
during which an examination was conducted. The record shall include
each deficiency and the corrective action taken. The record shall be
countersigned by the mine foreman or equivalent mine official by the
end of the mine foreman's or equivalent mine official's next regularly
scheduled working shift. The record shall be kept at the mine for one
(d) Upon completion of construction of each seal a senior mine
management official, such as a mine manager or superintendent, shall
certify that the construction, installation, and materials used were in
accordance with the approved ventilation plan. The mine operator shall
retain the certification for as long as the seal is needed to serve the
purpose for which it was built.
(e) The mine operator shall--
(1) Notify the District Manager between two and fourteen days prior
to commencement of seal construction;
(2) Notify the District Manager, in writing, within five days of
completion of a set of seals and provide a copy of the certification
required in paragraph (d) of this section; and
(3) Submit a copy of quality control results to the District
Manager for seal material properties specified by § 75.335 within
30 days of completion of quality control tests.
(f) Welding, cutting, and soldering. Welding, cutting, and
soldering with an arc or flame are prohibited within 150 feet of a
seal. An operator may request a different location in the ventilation
plan to be approved by the District Manager. The operator's request
must address methods the mine operator will use to continuously monitor
atmospheric conditions in the sealed area during welding or burning;
the airflow conditions in and around the work area; the rock dust and
water application methods; the availability of fire extinguishers on
hand; the procedures to maintain safe conditions, and other relevant
(g) Sampling pipes. (1) For seals constructed after April 18, 2008,
one non-metallic sampling pipe shall be installed in each seal that
shall extend into the center of the first connecting crosscut inby the
seal. If an open crosscut does not exist, the sampling pipe shall
extend one-half of the distance of the open entry inby the seal.
(2) Each sampling pipe shall be equipped with a shut-off valve and
appropriate fittings for taking gas samples.
(3) The sampling pipes shall be labeled to indicate the location of
the sampling point when more than one sampling pipe is installed
through a seal.
(4) If a new seal is constructed to replace or reinforce an
existing seal with a sampling pipe, the sampling pipe in the existing
seal shall extend through the new seal. An additional sampling pipe
shall be installed through each new seal to sample the area between
seals, as specified in the approved ventilation plan.
(h) Water drainage system. For each set of seals constructed after
April 18, 2008, the seal at the lowest elevation shall have a
corrosion-resistant, non-metallic water drainage system. Seals shall
not impound water or slurry. Water or slurry shall not accumulate
within the sealed area to any depth that can adversely affect a seal.