30 CFR § 57.2 Definitions.
The following definitions apply to this part. In addition
definitions contained in any subpart of part 57 apply in that subpart.
If inconsistent with the general definitions in this section, the
definition in the subpart will apply in that subpart:
means areas in which work has been completed, no
further work is planned, and travel is not permitted.
means all work has stopped on the mine premises and an office with a responsible person in charge is no longer maintained
at the mine.
means deserted mine areas in which further work is not intended.
means areas at, in, or around a mine or plant where men work or travel.
American Table of Distances
means the current edition of ``The American Table of Distances for Storage of Explosives'' published by
the Institute of Makers of Explosives.
means tested and accepted for a specific purpose by a nationally recognized agency.
means presence of an individual or continuous monitoring to prevent unauthorized entry or access. In addition, areas containing
explosive material at underground areas of a mine can be considered
attended when all access to the underground areas of the mine is
secured from unauthorized entry. Vertical shafts shall be considered
secure. Inclined shafts or adits shall be considered secure when locked
at the surface.
means a person approved or assigned by mine management to perform a specific type of duty or duties or to be at a
specific location or locations in the mine.
means a fan used to deliver air to a working place off the main airstream; generally used with ventilation tubing.
means obstructed to prevent the passage of persons, vehicles, or flying materials.
means a material object, or objects that separates, keeps
apart, or demarcates in a conspicuous manner such as cones, a warning
sign, or tape.
means a pile or mound of material along an elevated roadway capable of moderating or limiting the force of a vehicle in order to
impede the vehicle's passage over the bank of the roadway.
means the area in which concussion (shock wave), flying
material, or gases from an explosion may cause injury to persons. In
determining the blast area, the following factors, shall be considered:
(1) Geology or material to be blasted.
(2) Blast pattern.
(3) Burden, depth, diameter, and angle of the holes.
(4) Blasting experience of the mine.
(5) Delay system, powder factor, and pounds per delay.
(6) Type and amount of explosive material.
(7) Type and amount of stemming.
means the area where explosive material is handled during loading, including the perimeter formed by the loaded blastholes
and 50 feet (15.2 meters) in all directions from loaded holes. A
minimum distance of 30 feet (9.1 meters) may replace the 50-foot (15.2-
meter) requirement if the perimeter of loaded holes is demarcated with
a barrier. The 50-foot (15.2-meter) and alternative 30-foot (9.1-meter)
requirements also apply in all directions along the full depth of the
hole. In underground mines, at least 15 feet (4.6 meters) of solid rib,
pillar, or broken rock can be substituted for the 50-foot (15.2-meter)
distance. In underground mines utilizing a block-caving system or
similar system, at least 6 feet (1.8 meters) of solid rib or pillar,
including concrete reinforcement of at least 10 inches (254
millimeters), with overall dimensions of not less than 6 feet (1.8
meters) may be substituted for the 50-foot (15.2-meter) distance
means any substance classified as a blasting agent
by the Department of Transportation in 49 CFR 173.114(a) (44 FR 31182,
May 31, 1979) which is incorporated by reference. This document is
available for inspection at each Metal and Nonmetal Mine Safety and
Health District Office of the Mine Safety and Health Administration,
and may be obtained from the U.S. Government Printing Office,
Washington, DC 20402.
means the area near blasting operations in which
concussion or flying material can reasonably be expected to cause
means a detonator which is initiated by a safety fuse.
means the electrical circuit used to fire one or
more electric blasting caps.
means a switch used to connect a power source to a
means a sudden, violent, release of gas or liquid due to the reservoir pressure in a petroleum mine.
means any unit of explosive or blasting agent used for the purpose of perpetuating or intensifying an initial detonation.
means a fan installed in the main airstream or a split of the main airstream to increase airflow through a section or sections
of a mine.
means a length of safety fuse to which a blasting cap has been attached.
means a package or cartridge of explosives which is specifically designed to transmit detonation to other explosives and
which contains a detonator.
means a device designed to open and close a circuit by nonautomatic means and to open the circuit automatically on a
predetermined overcurrent setting without injury to itself when
properly applied within its rating.
means capable of being ignited and consumed by fire.
means a material that, in the form in which it
is used and under the conditions anticipated, will ignite, burn,
support combustion or release flammable vapors when subjected to fire
or heat. Wood, paper, rubber, and plastics are examples of combustible
means a member of the company supervisory or technical staff.
means a person having abilities and experience that fully qualify him to perform the duty to which he is assigned.
means a material, usually in the form of a wire, cable, or bus bar, capable of carrying an electric current.
means a nonelectric short interval delay device for use in delaying blasts which are initiated by detonating cord.
means a flexible cord containing a solid core of high explosives.
means any device containing a detonating charge that is used to initiate an explosive and includes but is not limited to
blasting caps, electric blasting caps and non-electric instantaneous or
delay blasting caps.
means a portable apparatus with an enclosure through which an electric circuit is carried to one or more cables from
a single incoming feed line; each cable circuit being connected through
individual overcurrent protective devices.
Electric blasting cap
means a detonator designed for and capable of being initiated by means of an electric current.
means to connect with the ground to make the earth part of the circuit.
means a person who works for wages or salary in the service of an employer.
means a person or organization which hires one or more persons to work for wages or salary.
means an explosive material containing substantial amounts of oxidizers dissolved in water droplets, surrounded by an immiscible
means a passageway by which persons may leave a mine.
means any substance classified as an explosive by the Department of Transportation in 49 CFR 173.53, 173.88 and 173.100 which
are incorporated by reference. Title 49 CFR is available for inspection
at each Metal and Nonmetal Mine Safety and Health District Office of
the Mine Safety and Health Administration, and may be obtained from the
U.S. Government Printing Office, Washington, DC 20402.
Face or bank
means that part of any mine where excavating is progressing or was last done.
Fire resistance rating
means the time, in minutes or hours, that an assembly of materials will retain its protective characteristics or
structural integrity upon exposure to fire.
Flame spread rating
means the numerical designation that indicates the extent flame will spread over the surface of a material during a
specified period of time.
means capable of being easily ignited and of burning rapidly.
means a gas that will burn in the normal concentrations of oxygen in the air.
a liquid that has a flash point below 100 ºF (37.8 ºC), a vapor pressure not exceeding 40 pounds per square inch
(absolute) at 100 ºF (37.8 ºC), and is known as a Class I
means the minimum temperature at which sufficient vapor is released by a liquid or solid to form a flammable vapor-air mixture
at atmospheric pressure.
means an area characterized by the presence of the same ore bodies, the same stratigraphic sequence of beds, or the same
ore-bearing geological formation.
means any public street, public alley or public road.
means more than 650 volts.
means a power driven windlass or drum used for raising ore, rock, or other material from a mine, and for lowering or raising
persons and material.
means a fuse, cordlike in appearance, which burns progressively along its length with an external flame at the zone of
burning, and is used for lighting a series of safety fuses in the
means separated from other conducting surfaces by a dielectric substance permanently offering a high resistance to the
passage of current and to disruptive discharge through the substance.
When any substance is said to be insulated, it is understood to be
insulated in a manner suitable for the conditions to which it is
subjected. Otherwise, it is, within the purpose of this definition,
uninsulated. Insulating covering is one means for making the conductor
means a dielectric substance offering a high resistance to the passage of current and to a disruptive discharge through the
a partition composed of the following material and minimum nominal dimensions: \1/2\-inch-thick plywood, \1/2\-inch-
thick gypsum wallboard, \1/8\-inch-thick low carbon steel, and \1/4\-
inch-thick plywood, bonded together in that order (IME-22 Box). A
laminated partition also includes alternative construction materials
described in the Institute of Makers of Explosives (IME) Safety Library
Publication No. 22, ``Recommendations for the Safe Transportation of
Detonators in a Vehicle with other Explosive Materials,'' (May 1993),
and the ``Generic Loading Guide for the IME-22 Container,'' (October
1993). This incorporation by reference has been approved by the
Director of the Federal Register in accordance with 5 U.S.C. 552(a) and
1 CFR part 51. Copies are available at MSHA, 1100 Wilson Blvd., Room
2436, Arlington, Virginia 22209-3939, and at all Metal and Nonmetal
Mine Safety and Health district offices, or available for inspection at
the Office of the Federal Register, 800 North Capitol Street, NW., 7th
Floor, suite 700, Washington, DC.
means the distance parallel to the axis of the rope in which a strand makes one complete turn about the axis of the rope.
means placing explosive material either in a blasthole or against the material to be blasted.
means 650 volts or less.
means a facility for the storage of explosives, blasting agents, or detonators.
means a fan that controls the entire airflow of the mine, or the airflow of one of the major air circuits.
Major electrical installation
means an assemblage of stationary electrical equipment for the generation, transmission, distribution, or
conversion of electrical power.
means a trip on which persons are transported to and from a work area.
includes any ore mill, sampling works, concentrator, and any crushing, grinding, or screening plant used at, and in connection with,
an excavation or mine.
means any point at least 12 inches away from the back, face, rib, and floor in any mine; and additionally, in a Category
IV mine, at least 3 feet laterally away from the collar of a borehole which releases gas into a mine.
means any opening or entrance from the surface into a mine.
means the complete or partial failure of a blasting charge to explode as planned.
means wheeled, skid-mounted, track-mounted, or rail-mounted equipment capable of moving or being moved.
Multipurpose dry-chemical fire extinguisher
means an extinguisher having a rating of at least 2-A:10-B:C and containing a nominal 4.5
pounds or more of dry-chemical agent.
means a material that, in the form in which it is used and under the conditions anticipated, will not ignite, burn,
support combustion, or release flammable vapors when subjected to fire
or heat. Concrete, masonry block, brick, and steel are examples of
Non-electric delay blasting cap
means a detonator with an integral delay element and capable of being initiated by miniaturized detonating
means the sudden, violent release of solids and high-pressure occluded gases, including methane in a domal salt mine.
means material of any nature, consolidated or unconsolidated, that overlies a deposit of useful materials or ores
that are to be mined.
means that current which will cause an excessive or dangerous temperature in the conductor or conductor insulation.
means a machine, material, apparatus, or device which has been investigated, tested, and approved by the Bureau of Mines or
the Mine Safety and Health Administration, and is maintained in
means water which shall meet the applicable minimum health requirements for drinking water established by the State or
community in which the mine is located or by the Environmental
Protection Agency in 40 CFR part 141, pages 169-182 revised as of July
1, 1977. Where no such requirements are applicable, the drinking water
provided shall conform with the Public Health Service Drinking Water
Standards, 42 CFR part 72, subpart J, pages 527-533, revised as of
October 1, 1976. Publications to which references are made in this
definition are hereby made a part hereof. These incorporated
publications are available for inspection at each Metal and Nonmetal
Mine Safety and Health District Office of the Mine Safety and Health
means a substantial, nonconductive portable container equipped with a lid and used at blasting sites for explosives other
than blasting agents.
means a unit, package, or cartridge of explosives used to initiate other explosives or blasting agents, and which contains a
means a method or device used on direct-current circuits or equipment to prevent the flow of current in a
means a sudden and violent failure of overstressed rock resulting in the instantaneous release of large amounts of accumulated
energy. Rock burst does not include a burst resulting from pressurized
means any tensioned or nontensioned device or material inserted into the ground to strengthen or support the ground.
means a framework, safety canopy or similar protection for the operator when equipment overturns.
means an approved container, of not over 5 gallons capacity, having a spring-closing lid and spout cover.
means a flexible cord containing an internal burning medium by which fire is conveyed at a continuous and uniform rate for
the purpose of firing blasting caps or a black powder charge.
means a sectionalizing switch that also provides shunt protection in blasting circuits between the blasting switch and
the shot area.
means removal of insecure material from a face or highwall.
Secondary safety connection
means a second connection between a conveyance and rope, intended to prevent the conveyance from running
away or falling in the event the primary connection fails.
means a vertical or inclined shaft, a slope, incline, or winze.
means an abnormal connection of relatively low
resistance, whether made accidentally or intentionally, between two
points of difference potential in a circuit.
Slurry (as applied to blasting)
. See ``Water gel.''
means the entire class of structures used to store explosive materials. A ``storage facility'' used to store blasting
agents corresponds to a BATF Type 4 or 5 storage facility.
means a container exceeding 60 gallons in capacity used for the storage of flammable or combustible liquids.
means that portion of a total electric current that flows through paths other than the intended circuit.
means construction of such strength, material, and workmanship that the object will withstand all reasonable
shock, wear, and usage to which it will be subjected.
means that which fits, and has the qualities or qualifications to meet a given purpose, occasion, condition, function,
means a passage, walk or way regularly used and designated for persons to go from one place to another.
Water gel or Slurry (as applied to blasting)
means an explosive or blasting agent containing substantial portions of water.
means the continuous application of water through the central hole of hollow drill steel to the bottom of the drill hole.
Working level (WL)
means any combination of the short-lived radon daughters in one liter of air that will result in ultimate emission of
1.3x10\5\ MeV (million electron volts) of potential alpha energy, and
exposure to these radon daughters over a period of time is expressed in
terms of ``working level months'' (WLM). Inhalation of air containing a
radon daughter concentration of 1 WL for 173 hours results in an
exposure of 1 WLM.''
means any place in or about a mine where work is being performed.