Title 30—Mineral Resources--Volume 1
PART 57—SAFETY AND HEALTH STANDARDS—UNDERGROUND METAL AND NONMETAL MINES
§ 57.1   Purpose and scope.
This part 57 sets forth mandatory safety and health standards for each underground metal or nonmetal mine, including related surface operations, subject to the Federal Mine Safety and Health Act of 1977. The purpose of these standards is the protection of life, the promotion of health and safety, and the prevention of accidents.
§ 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:
Abandoned areas means areas in which work has been completed, no further work is planned, and travel is not permitted.
Abandoned mine means all work has stopped on the mine premises and an office with a responsible person in charge is no longer maintained at the mine.
Abandoned workings means deserted mine areas in which further work is not intended.
Active workings 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.
Approved means tested and accepted for a specific purpose by a nationally recognized agency.
Attended 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.
Authorized person 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.
Auxilary fan means a fan used to deliver air to a working place off the main airstream; generally used with ventilation tubing.
Barricaded means obstructed to prevent the passage of persons, vehicles, or flying materials.
Barrier means a material object, or objects that separates, keeps apart, or demarcates in a conspicuous manner such as cones, a warning sign, or tape.
Berm 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.
Blast area 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.
Blast site 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 requirement.
Blasting agent 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.
Blasting area means the area near blasting operations in which concussion or flying material can reasonably be expected to cause injury.
Blasting cap means a detonator which is initiated by a safety fuse.
Blasting circuit means the electrical circuit used to fire one or more electric blasting caps.
Blasting switch means a switch used to connect a power source to a blasting circuit.
Blowout means a sudden, violent, release of gas or liquid due to the reservoir pressure in a petroleum mine.
Booster means any unit of explosive or blasting agent used for the purpose of perpetuating or intensifying an initial detonation.
Booster fan 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.
Capped fuse means a length of safety fuse to which a blasting cap has been attached.
Capped primer means a package or cartridge of explosives which is specifically designed to transmit detonation to other explosives and which contains a detonator.
Circuit breaker 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.
Combustible means capable of being ignited and consumed by fire.
Combustible material 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 materials.
Company official means a member of the company supervisory or technical staff.
Competent person means a person having abilities and experience that fully qualify him to perform the duty to which he is assigned.
Conductor means a material, usually in the form of a wire, cable, or bus bar, capable of carrying an electric current.
Delay connector means a nonelectric short interval delay device for use in delaying blasts which are initiated by detonating cord.
Detonating cord means a flexible cord containing a solid core of high explosives.
Detonator 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.
Distribution box 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.
Electrical grounding means to connect with the ground to make the earth part of the circuit.
Employee means a person who works for wages or salary in the service of an employer.
Employer means a person or organization which hires one or more persons to work for wages or salary.
Emulsion means an explosive material containing substantial amounts of oxidizers dissolved in water droplets, surrounded by an immiscible fuel.
Escapeway means a passageway by which persons may leave a mine.
Explosive 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.
Flammable means capable of being easily ignited and of burning rapidly.
Flammable gas means a gas that will burn in the normal concentrations of oxygen in the air.
Flammable liquid a liquid that has a flash point below 100 °F (37.8 °C), a vapor pressure not exceeding 40 pounds per square inch (absolute) at 100 °F (37.8 °C), and is known as a Class I liquid.
Flash point 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.
Geological area 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.
Highway means any public street, public alley or public road.
High potential means more than 650 volts.
Hoist 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.
Igniter cord 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 desired sequence.
Insulated 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 insulated.
Insulation means a dielectric substance offering a high resistance to the passage of current and to a disruptive discharge through the substance.
Laminated partition means 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). The IME is located at 1120 19th Street NW., Suite 310, Washington, DC 20036-3605; 202-429-9280; https://www.ime.org. 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's Office of Standards, Regulations, and Variances, 201 12th Street South, Arlington, VA 22202-5452; 202-693-9440; and at all Metal and Nonmetal Mine Safety and Health District Offices, or available for inspection at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
Lay means the distance parallel to the axis of the rope in which a strand makes one complete turn about the axis of the rope.
Loading means placing explosive material either in a blasthole or against the material to be blasted.
Low potential means 650 volts or less.
Magazine means a facility for the storage of explosives, blasting agents, or detonators.
Main fan 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.
Mantrip means a trip on which persons are transported to and from a work area.
Mill includes any ore mill, sampling works, concentrator, and any crushing, grinding, or screening plant used at, and in connection with, an excavation or mine.
Mine atmosphere 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.
Mine opening means any opening or entrance from the surface into a mine.
Misfire means the complete or partial failure of a blasting charge to explode as planned.
Mobile equipment 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.
Noncombustible material 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 noncombustible materials.
Non-electric delay blasting cap means a detonator with an integral delay element and capable of being initiated by miniaturized detonating cord.
Outburst means the sudden, violent release of solids and high-pressure occluded gases, including methane in a domal salt mine.
Overburden means material of any nature, consolidated or unconsolidated, that overlies a deposit of useful materials or ores that are to be mined.
Overload means that current which will cause an excessive or dangerous temperature in the conductor or conductor insulation.
Permissible 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 permissible condition.
Potable water 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 Administration.
Powder chest means a substantial, nonconductive portable container equipped with a lid and used at blasting sites for explosives other than blasting agents.
Primer means a unit, package, or cartridge of explosives used to initiate other explosives or blasting agents, and which contains a detonator.
Reverse-current protection means a method or device used on direct-current circuits or equipment to prevent the flow of current in a reverse direction.
Rock burst 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 mine gases.
Rock fixture means any tensioned or nontensioned device or material inserted into the ground to strengthen or support the ground.
Roll protection means a framework, safety canopy or similar protection for the operator when equipment overturns.
Safety can means an approved container, of not over 5 gallons capacity, having a spring-closing lid and spout cover.
Safety fuse 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.
Safety switch means a sectionalizing switch that also provides shunt protection in blasting circuits between the blasting switch and the shot area.
Scaling 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.
Shaft means a vertical or inclined shaft, a slope, incline, or winze.
Short circuit 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.”
Storage facility 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.
Storage tank means a container exceeding 60 gallons in capacity used for the storage of flammable or combustible liquids.
Stray current means that portion of a total electric current that flows through paths other than the intended circuit.
Substantial construction 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.
Suitable means that which fits, and has the qualities or qualifications to meet a given purpose, occasion, condition, function, or circumstance.
Travelway 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.
Wet drilling 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 1.3 × 10 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.”
Working place means any place in or about a mine where work is being performed.
§ 57.1000   Notification of commencement of operations and closing of mines.
The owner, operator, or person in charge of any metal and nonmetal mine shall notify the nearest MSHA Metal and Nonmental Mine Safety and Health district office before starting operations, of the approximate or actual date mine operation will commence. The notification shall include the mine name, location, the company name, mailing address, person in charge, and whether operations will be continuous or intermittent. When any mine is closed, the person in charge shall notify the nearest district office as provided above and indicate whether the closure is temporary or permanent.
§ 57.3000   Definitions.
The following definitions apply in this subpart.
Travelway. A passage, walk, or haulageway regularly used or designated for persons to go from one place to another.
§ 57.3200   Correction of hazardous conditions.
Ground conditions that create a hazard to persons shall be taken down or supported before other work or travel is permitted in the affected area. Until corrective work is completed, the area shall be posted with a warning against entry and, when left unattended, a barrier shall be installed to impede unauthorized entry.
§ 57.3201   Location for performing scaling.
Scaling shall be performed from a location which will not expose persons to injury from falling material, or other protection from falling material shall be provided.
§ 57.3202   Scaling tools.
Where manual scaling is performed, a scaling bar shall be provided. This bar shall be of a length and design that will allow the removal of loose material without exposing the person performing the work to injury.
§ 57.3203   Rock fixtures.
(a) For rock bolts and accessories addressed in ASTM F432-95, “Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator shall—
(1) Obtain a manufacturer's certification that the material was manufactured and tested in accordance with the specifications of ASTM F432-95; and
(2) Make this certification available to an authorized representative of the Secretary and to the representative of miners.
(b) Fixtures and accessories not addressed in ASTM F432-95 may be used for ground support provided they—
(1) Have been successful in supporting the ground in an area with similar strata, opening dimensions and ground stresses in any mine; or
(2) Have been tested and shown to be effective in supporting ground in an area of the affected mine which has similar strata, opening dimensions, and ground stresses as the area where the fixtures are expected to be used. During the test process, access to the test area shall be limited to persons necessary to conduct the test.
(c) Bearing plates shall be used with fixtures when necessary for effective ground support.
(d) The diameter of finishing bits shall be within a tolerance of plus or minus 0.030 inch of the manufacturer's recommended hole diameter for the anchor used. When separate finishing bits are used, they shall be distinguishable from other bits.
(e) Damaged or deteriorated cartridges of grouting material shall not be used.
(f) When rock bolts tensioned by torquing are used as a means of ground support,
(1) Selected tension level shall be—
(i) At least 50 percent of either the yield point of the bolt or anchorage capacity of the rock, whichever is less; and
(ii) No greater than the yield point of the bolt or anchorage capacity of the rock.
(2) The torque of the first bolt, every tenth bolt, and the last bolt installed in each work area during the shift shall be accurately determined immediately after installation. If the torque of any fixture tested does not fall within the installation torque range, corrective action shall be taken.
(g) When grouted fixtures can be tested by applying torque, the first fixture installed in each work place shall be tested to withstand 150 foot-pounds of torque. Should it rotate in the hole, a second fixture shall be tested in the same manner. If the second fixture also turns, corrective action shall be taken.
(h) When other tensioned and nontensioned fixtures are used, test methods shall be established and used to verify their effectiveness.
(i) The mine operator shall certify that tests were conducted and make the certification available to an authorized representative of the Secretary.
§ 57.3360   Ground support use.
Ground support shall be used where ground conditions, or mining experience in similar ground conditions in the mine, indicate that it is necessary. When ground support is necessary, the support system shall be designed, installed, and maintained to control the ground in places where persons work or travel in performing their assigned tasks. Damaged, loosened, or dislodged timber use for ground support which creates a hazard to persons shall be repaired or replaced prior to any work or travel in the affected area.
§ 57.3400   Secondary breakage.
Prior to secondary breakage operations, the material to be broken, other than hanging material, shall be positioned or blocked to prevent movement which would endanger persons in the work area. Secondary breakage shall be performed from a location which would not expose persons to danger.
§ 57.3401   Examination of ground conditions.
Persons experienced in examining and testing for loose ground shall be designated by the mine operator. Appropriate supervisors or other designated persons shall examine and, where applicable, test ground conditions in areas where work is to be performed, prior to work commencing, after blasting, and as ground conditions warrant during the work shift. Underground haulageways and travelways and surface area highwalls and banks adjoining travelways shall be examined weekly or more often if changing ground conditions warrant.
§ 57.3430   Activity between machinery or equipment and the highwall or bank.
Persons shall not work or travel between machinery or equipment and the highwall or bank where the machinery or equipment may hinder escape from falls or slides of the highwall or bank. Travel is permitted when necessary for persons to dismount.
§ 57.3460   Maintenance between machinery or equipment and ribs.
Persons shall not perform maintenance work between machinery or equipment and ribs unless the area has been tested and, when necessary, secured.
§ 57.3461   Rock bursts.
(a) Operators of mines which have experienced a rock burst shall—
(1) Within twenty four hours report to the nearest MSHA office each rock burst which:
(i) Causes persons to be withdrawn;
(ii) Impairs ventilation;
(iii) Impedes passage; or
(iv) Disrupts mining activity for more than one hour.
(2) Develop and implement a rock burst control plan within 90 days after a rock burst has been experienced.
(b) The plan shall include—
(1) Mining and operating procedures designed to reduce the occurrence of rock bursts;
(2) Monitoring procedures where detection methods are used; and
(3) Other measures to minimize exposure of persons to areas which are prone to rock bursts.
(c) The plan shall be updated as conditions warrant.
(d) The plan shall be available to an authorized representative of the Secretary and to miners or their representatives.
§ 57.4000   Definitions.
The following definitions apply in this subpart.
Combustible liquids. Liquids having a flash point at or above 100 °F (37.8 °C). They are divided into the following classes:
Escapeway. A designated passageway by which persons can leave an underground mine.
Flash point. The minimum temperature at which sufficient vapor is released by a liquid to form a flammable vapor-air mixture near the surface of the liquid.
Main fan. A fan that controls the entire airflow of an underground mine or the airflow of one of the major air circuits of the mine.
Mine opening. Any opening or entrance from the surface into an underground mine.
Safety can. A container of not over five gallons capacity that is designed to safely relieve internal pressure when exposed to heat and has a spring-closing lid and spout cover.
§ 57.4011   Abandoned electric circuits.
Abandoned electric circuits shall be deenergized and isolated so that they cannot become energized inadvertently.
§ 57.4057   Underground trailing cables.
Underground trailing cables shall be accepted or approved by MSHA as flame resistant.
§ 57.4100   Smoking and use of open flames.
No person shall smoke or use an open flame where flammable or combustible liquids, including greases, or flammable gases are—
(a) Used or transported in a manner that could create a fire hazard; or
(b) Stored or handled.
§ 57.4101   Warning signs.
Readily visible signs prohibiting smoking and open flames shall be posted where a fire or explosion hazard exists.
§ 57.4102   Spillage and leakage.
Flammable or combustible liquid spillage or leakage shall be removed in a timely manner or controlled to prevent a fire hazard.
§ 57.4103   Fueling internal combustion engines.
Internal combustion engines shall be switched off before refueling if the fuel tanks are integral parts of the equipment. This standard does not apply to diesel-powered equipment.
§ 57.4104   Combustible waste.
(a) Waste materials, including liquids, shall not accumulate in quantities that could create a fire hazard.
(b) Waste or rags containing flammable or combustible liquids that could create a fire hazard shall be placed in the following containers until disposed of properly:
(1) Underground—covered metal containers.
(2) On the surface—covered metal containers or equivalent containers with flame containment characteristics.
§ 57.4130   Surface electric substations and liquid storage facilities.
The requirements of this standard apply to surface areas only.
(a) If a hazard to persons could be created, no combustible materials shall be stored or allowed to accumulate within 25 feet of the following:
(1) Electric substations.
(2) Unburied, flammable or combustible liquid storage tanks.
(3) Any group of containers used for storage of more than 60 gallons of flammable or combustible liquids.
(b) The area within the 25-foot perimeter shall be kept free of dry vegetation.
§ 57.4131   Surface fan installations and mine openings.
(a) On the surface, no more than one day's supply of combustible materials shall be stored within 100 feet of mine openings or within 100 feet of fan installations used for underground ventilation.
(b) the one-day supply shall be kept at least 25 feet away from any mine opening except during transit into the mine.
(c) Dry vegetation shall not be permitted within 25 feet of mine openings.
§ 57.4160   Underground electric substations and liquid storage facilities.
The requirements of this standard apply to underground areas only.
(a) Areas within 25 feet of the following shall be free of combustible materials:
(1) Electric substations.
(2) Unburied, combustible liquid storage tanks.
(3) Any group of containers used for storage of more than 60 gallons of combustible liquids.
(b) This standard does not apply to installed wiring or timber that is coated with at least one inch of shotcrete, one-half inch of gunite, or other noncombustible materials with equivalent fire protection characteristics.
§ 57.4161   Use of fire underground.
Fires shall not be lit underground, except for open-flame torches. Torches shall be attended at all times while lit.
§ 57.4200   General requirements.
(a) For fighting fires that could endanger persons, each mine shall have—
(1) Onsite firefighting equipment for fighting fires in their early stages; and
(2) Onsite firefighting equipment for fighting fires beyond their early stages, or the mine shall have made prior arrangements with a local fire department to fight such fires.
(b) This onsite firefighting equipment shall be—
(1) Of the type, size, and quantity that can extinguish fires of any class which would occur as a result of the hazards present; and
(2) Strategically located, readily accessible, plainly marked, and maintained in fire-ready condition.
§ 57.4201   Inspection.
(a) Firefighting equipment shall be inspected according to the following schedules:
(1) Fire extinguishers shall be inspected visually at least once a month to determine that they are fully charged and operable.
(2) At least once every twelve months, maintenance checks shall be made of mechanical parts, the amount and condition of extinguishing agent and expellant, and the condition of the hose, nozzle, and vessel to determine that the fire extinguishers will operate effectively.
(3) Fire extinguishers shall be hydrostatically tested according to Table C-1 or a schedule based on the manufacturer's specifications to determine the integrity of extinguishing agent vessels.
(4) Water pipes, valves, outlets, hydrants, and hoses that are part of the mine's firefighting system shall be visually inspected at least once every three months for damage or deterioration and use-tested at least once every twelve months to determine that they remain functional.
(5) Fire suppression systems shall be inspected at least once every twelve months. An inspection schedule based on the manufacturer's specifications or the equivalent shall be established for individual components of a system and followed to determine that the system remains functional. Surface fire suppression systems are exempt from these inspection requirements if the systems are used solely for the protection of property and no persons would be affected by a fire.
(b) At the completion of each inspection or test required by this standard, the person making the inspection or test shall certify that the inspection or test has been made and the date on which it was made. Certifications of hydrostatic testing shall be retained until the fire extinguisher is retested or permanently removed from service. Other certifications shall be retained for one year.
Table C-1—Hydrostatic Test Intervals for Fire Extinguishers
1 Except for stainless steel and steel used for compressed gas cylinders, all other steel shells are defined as “mild steel” shells.
§ 57.4202   Fire hydrants.
If fire hydrants are part of the mine's firefighting system, the hydrants shall be provided with—
(a) Uniform fittings or readily available adapters for onsite firefighting equipment;
(b) Readily available wrenches or keys to open the valves; and
(c) Readily available adapters capable of connecting hydrant fittings to the hose equipment of any firefighting organization relied upon by the mine.
§ 57.4203   Extinguisher recharging or replacement.
Fire extinguishers shall be recharged or replaced with a fully charged extinguisher promptly after any discharge.
§ 57.4230   Surface self-propelled equipment.
(a)(1) Whenever a fire or its effects could impede escape from self-propelled equipment, a fire extinguisher shall be on the equipment.
(2) Whenever a fire or its effects would not impede escape from the equipment but could affect the escape of other persons in the area, a fire extinguisher shall be on the equipment or within 100 feet of the equipment.
(b) A fire suppression system may be used as an alternative to fire extinguishers if the system can be manually activated.
(c) Fire extinguishers or fire suppression systems shall be of a type and size that can extinguish fires of any class in their early stages which could originate from the equipment's inherent fire hazards. Fire extinguishers or manual actuators for the suppression system shall be located to permit their use by persons whose escape could be impeded by fire.
§ 57.4260   Underground self-propelled equipment.
(a) Whenever self-propelled equipment is used underground, a fire extinguisher shall be on the equipment. This standard does not apply to compressed-air powered equipment without inherent fire hazards.
(b) A fire suppression system may be used as an alternative to fire extinguishers if the system can be manually actuated.
(c) Fire extinguishers or fire suppression systems shall be of a type and size that can extinguish fires of any class in their early stages which could originate from the equipment's inherent fire hazards. The fire extinguishers or the manual actuator for the suppression system shall be readily accessible to the equipment operator.
§ 57.4261   Shaft-station waterlines.
Waterline outlets that are located at underground shaft stations and are part of the mine's fire protection system shall have at least one fitting located for, and capable of, immediate connection to firefighting equipment.
§ 57.4262   Underground transformer stations, combustible liquid storage and dispensing areas, pump rooms, compressor rooms, and hoist rooms.
Transformer stations, storage and dispensing areas for combustible liquids, pump rooms, compressor rooms, and hoist rooms shall be provided with fire protection of a type, size, and quantity that can extinguish fires of any class in their early stages which could occur as a result of the hazards present.
§ 57.4263   Underground belt conveyors.
Fire protection shall be provided at the head, tail, drive, and take-up pulleys of underground belt conveyors. Provisions shall be made for extinguishing fires along the beltline. Fire protection shall be of a type, size, and quantity that can extinguish fires of any class in their early stages which could occur as a result of the fire hazards present.
§ 57.4330   Surface firefighting, evacuation, and rescue procedures.
(a) Mine operators shall establish emergency firefighting, evacuation, and rescue procedures for the surface portions of their operations. These procedures shall be coordinated in advance with available firefighting organizations.
(b) Fire alarm procedures or systems shall be established to promptly warn every person who could be endangered by a fire.
(c) Fire alarm systems shall be maintained in operable condition.
§ 57.4331   Surface firefighting drills.
Emergency firefighting drills shall be held at least once every six months for persons assigned surface firefighting responsibilities by the mine operator.
§ 57.4360   Underground alarm systems.
(a) Fire alarm systems capable of promptly warning every person underground, except as provided in paragraph (b), shall be provided and maintained in operating condition.
(b) If persons are assigned to work areas beyond the warning capabilities of the system, provisions shall be made to alert them in a manner to provide for their safe evacuation in the event of a fire.
§ 57.4361   Underground evacuation drills.
(a) At least once every six months, mine evacuation drills shall be held to assess the ability of all persons underground to reach the surface or other designated points of safety within the time limits of the self-rescue devices that would be used during an actual emergency.
(b) The evacuation drills shall—
(1) Be held for each shift at some time other than a shift change and involve all persons underground;
(2) Involve activation of the fire alarm system; and
(3) Include evacuation of all persons from their work areas to the surface or to designated central evacuation points.
(c) At the completion of each drill, the mine operator shall certify the date and the time the evacuation began and ended. Certifications shall be retained for at least one year after each drill.
§ 57.4362   Underground rescue and firefighting operations.
Following evacuation of a mine in a fire emergency, only persons wearing and trained in the use of mine rescue apparatus shall participate in rescue and firefighting operations in advance of the fresh air base.
§ 57.4363   Underground evacuation instruction.
(a) At least once every twelve months, all persons who work underground shall be instructed in the escape and evacuation plans and procedures and fire warning signals in effect at the mine.
(b) Whenever a change is made in escape and evacuation plans and procedures for any area of the mine, all persons affected shall be instructed in the new plans or procedures.
(c) Whenever persons are assigned to work in areas other than their regularly assigned areas, they shall be instructed about the escapeway for that area at the time of such assignment. However, persons who normally work in more than one area of the mine shall be instructed at least once every twelve months about the location of escapeways for all areas of the mine in which they normally work or travel.
(d) At the completion of any instruction given under this standard, the mine operator shall certify the date that the instruction was given. Certifications shall be retained for at least one year.
§ 57.4400   Use restrictions.
(a) Flammable liquids shall not be used for cleaning.
(b) Solvents shall not be used near an open flame or other ignition source, near any source of heat, or in an atmosphere that can elevate the temperature of the solvent above the flash point.
§ 57.4401   Storage tank foundations.
Fixed, unburied, flammable or combustible liquid storage tanks shall be securely mounted on firm foundations. Piping shall be provided with flexible connections or other special fittings where necessary to prevent leaks caused by tanks settling.
§ 57.4402   Safety can use.
Small quantities of flammable liquids drawn from storage shall be kept in safety cans labeled to indicate the contents.
§ 57.4430   Surface storage facilities.
The requirements of this standard apply to surface areas only.
(a) Storage tanks for flammable or combustible liquids shall be—
(1) Capable of withstanding working pressures and stresses and compatible with the type of liquid stored;
(2) Maintained in a manner that prevents leakage;
(3) Isolated or separated from ignition sources to prevent fire or explosion; and
(4) Vented or otherwise constructed to prevent development of pressure or vacuum as a result of filling, emptying, or atmospheric temperature changes. Vents for storage of Class I, II, or IIIA liquids shall be isolated or separated from ignition sources. These pressure relief requirements do not apply to tanks used for storage of Class IIIB liquids that are larger than 12,000 gallons in capacity.
(b) All piping, valves, and fittings shall be—
(1) Capable of withstanding working pressures and stresses;
(2) Compatible with the type of liquid stored; and
(3) Maintained in a manner that prevents leakage.
(c) Fixed, unburied tanks located where escaping liquid could present a hazard to persons shall be provided with—
(1) Containment for the entire capacity of the largest tank; or
(2) Drainage to a remote impoundment area that does not endanger persons. However, storage of only Class IIIB liquids does not require containment or drainage to remote impoundment.
§ 57.4431   Surface storage restrictions.
(a) On the surface, no unburied flammable or combustible liquids or flammable gases shall be stored within 100 feet of the following:
(1) Mine openings or structures attached to mine openings.
(2) Fan installations for underground ventilation.
(3) Hoist houses.
(b) Under this standard, the following may be present in the hoist house in quantities necessary for the day-to-day maintenance of the hoist machinery:
(1) Flammable liquids in safety cans or in other containers placed in tightly closed cabinets. The safety cans and cabinets shall be kept away from any heat source, and each cabinet shall be labeled “flammables.”
(2) Combustible liquids in closed containers. The containers shall be kept away from any heat source and the hoist operator's work station.
§ 57.4460   Storage of flammable liquids underground.
(a) Flammable liquids shall not be stored underground, except—
(1) Small quantities stored in tightly closed cabinets away from any heat source. The small quantities shall be stored in safety cans or in non-glass containers of a capacity equal to or less than a safety can. Each cabinet shall be labeled “flammables.”
(2) Acetylene and liquefied petroleum gases stored in containers designed for that specific purpose.
(b) Gasoline shall not be stored underground in any quantity.
§ 57.4461   Gasoline use restrictions underground.
If gasoline is used underground to power internal combustion engines—
(a) The mine shall be nongassy and shall have multiple horizontal or inclined roadways from the surface large enough to accommodate vehicular traffic;
(b) All roadways and other openings shall connect with another opening every 100 feet by a passage large enough to accommodate any vehicle in the mine or alternate routes shall provide equivalent escape capabilities; and
(c) No roadway or other opening shall be supported or lined with wood or other combustible materials.
§ 57.4462   Storage of combustible liquids underground.
The requirements of this standard apply to underground areas only.
(a) Combustible liquids, including oil or grease, shall be stored in non-glass containers or storage tanks. The containers or storage tanks shall be—
(1) Capable of withstanding working pressures and stresses and compatible with the type of liquid stored;
(2) Maintained in a manner that prevents leakage;
(3) Located in areas free of combustible materials or in areas where any exposed combustible materials are coated with one inch of shotcrete, one-half inch of gunite, or other noncombustible material with equivalent fire protection characteristics; and
(4) Separated from explosives or blasting agents, shaft stations, and ignition sources including electric equipment that could create sufficient heat or sparks to pose a fire hazard. Separation shall be sufficient to prevent the occurrence or minimize the spread of fire.
(b) Storage tanks shall be vented or otherwise constructed to prevent development of pressure or vacuum as a result of filling, emptying, or atmospheric temperature changes. Vents for storage of Class II or IIIA liquids shall be isolated or separated from ignition sources.
(c) At permanent storage areas for combustible liquids, means shall be provided for confinement or removal of the contents of the largest storage tank in the event of tank rupture.
(d) All piping, valves, and fittings shall be:
(1) Capable of withstanding working pressures and stresses;
(2) Compatible with the type of liquid stored; and
(3) Maintained in a manner which prevents leakage.
§ 57.4463   Liquefied petroleum gas use underground.
Use of liquefied petroleum gases underground shall be limited to maintenance work.
§ 57.4500   Heat sources.
Heat sources capable of producing combustion shall be separated from combustible materials if a fire hazard could be created.
§ 57.4501   Fuel lines.
Fuel lines shall be equipped with valves capable of stopping the flow of fuel at the source and shall be located and maintained to minimize fire hazards. This standard does not apply to fuel lines on self-propelled equipment.
§ 57.4502   Battery-charging stations.
(a) Battery-charging stations shall be ventilated with a sufficient volume of air to prevent the accumulation of hydrogen gas.
(b) Smoking, use of open flames, or other activities that could create an ignition source shall be prohibited at the battery charging station during battery charging.
(c) Readily visible signs prohibiting smoking or open flames shall be posted at battery-charging stations during battery charging.
§ 57.4503   Conveyor belt slippage.
(a) Surface belt conveyors within confined areas where evacuation would be restricted in the event of a fire resulting from belt-slippage shall be equipped with a detection system capable of automatically stopping the drive pulley.
(b) Underground belt conveyors shall be equipped with a detection system capable of automatically stopping the drive pulley if slippage could cause ignition of the belt.
(c) A person shall attend the belt at the drive pulley when it is necessary to operate the conveyor while temporarily bypassing the automatic function.
§ 57.4504   Fan installations.
(a) Fan houses, fan bulkheads for main and booster fans, and air ducts connecting main fans to underground openings shall be constructed of noncombustible materials.
(b) Areas within 25 feet of main fans or booster fans shall be free of combustible materials, except installed wiring, ground and track support, headframes, and direct-fired heaters. Other timber shall be coated with one inch of shotcrete, one-half inch of gunite, or other noncombustible materials.
§ 57.4505   Fuel lines to underground areas.
Fuel lines into underground storage or dispensing areas shall be drained at the completion of each transfer of fuel unless the following requirements are met:
(a) The valve at the supply source shall be kept closed when fuel is not being transferred.
(b) The fuel line shall be—
(1) Capable of withstanding working pressures and stresses;
(2) Located to prevent damage; and
(3) Located in areas free of combustible materials or in areas where any exposed combustible materials are coated with one inch of shotcrete, one-half inch of gunite, or other noncombustible material with equivalent fire protection characteristics.
(c) Provisions shall be made for control or containment of the entire volume of the fuel line so that leakage will not create a fire hazard.
§ 57.4530   Exits for surface buildings and structures.
Surface buildings or structures in which persons work shall have a sufficient number of exits to permit prompt escape in case of fire.
§ 57.4531   Surface flammable or combustible liquid storage buildings or rooms.
(a) Surface storage buildings or storage rooms in which flammable or combustible liquids, including grease, are stored and that are within 100 feet of any person's work station shall be ventilated with a sufficient volume of air to prevent the accumulation of flammable vapors.
(b) In addition, the buildings or rooms shall be—
(1) Constructed to meet a fire resistance rating of at least one hour; or
(2) Equipped with an automatic fire suppression system; or
(3) Equipped with an early warning fire detection device that will alert any person who could be endangered by a fire, provided that no person's work station is in the building.
(c) Flammable or combustible liquids in use for day-to-day maintenance and operational activities are not considered in storage under this standard.
§ 57.4532   Blacksmith shops.
Blacksmith shops located on the surface shall be—
(a) At least 100 feet from fan installations used for intake air and mine openings;
(b) Equipped with exhaust vents over the forge and ventilated to prevent the accumulation of the products of combustion; and
(c) Inspected for smoldering fires at the end of each shift.
§ 57.4533   Mine opening vicinity.
Surface buildings or other similar structures within 100 feet of mine openings used for intake air or within 100 feet of mine openings that are designated escapeways in exhaust air shall be—
(a) Constructed of noncombustible materials; or
(b) Constructed to meet a fire resistance rating of no less than one hour; or
(c) Provided with an automatic fire suppression system; or
(d) Covered on all combustible interior and exterior structural surfaces with noncombustible material or limited combustible material, such as five-eighth inch, type “X” gypsum wallboard.
§ 57.4560   Mine entrances.
For at least 200 feet inside the mine portal or collar timber used for ground support in intake openings and in exhaust openings that are designated as escapeways shall be—
(a) Provided with a fire suppression system, other than fire extinguishers and water hoses, capable of controlling a fire in its early stages; or
(b) Covered with shotcrete, gunite, or other material with equivalent fire protection characteristics; or
(c) Coated with fire-retardant paint or other material to reduce its flame spread rating to 25 or less and maintained in that condition.
§ 57.4561   Stationary diesel equipment underground.
Stationary diesel equipment underground shall be—
(a) Supported on a noncombustible base; and
(b) Provided with a thermal sensor that automatically stops the engine if overheating occurs.
§ 57.4600   Extinguishing equipment.
(a) When welding, cutting, soldering, thawing, or bending—
(1) With an electric arc or with an open flame where an electrically conductive extinguishing agent could create an electrical hazard, a multipurpose dry-chemical fire extinguisher or other extinguisher with at least a 2-A:10-B:C rating shall be at the worksite.
(2) With an open flame in an area where no electrical hazard exists, a multipurpose dry-chemical fire extinguisher or equivalent fire extinguishing equipment for the class of fire hazard present shall be at the worksite.
(b) Use of halogenated fire extinguishing agents to meet the requirements of this standard shall be limited to Halon 1211 (CBrClF 2 ) and Halon 1301 (CBrF 3 ). When these agents are used in confined or unventilated areas, precautions based on the manufacturer's use instructions shall be taken so that the gases produced by thermal decomposition of the agents are not inhaled.
§ 57.4601   Oxygen cylinder storage.
Oxygen cylinders shall not be stored in rooms or areas used or designated for storage of flammable or combustible liquids, including grease.
§ 57.4602   Gauges and regulators.
Gauges and regulators used with oxygen or acetylene cylinders shall be kept clean and free of oil and grease.
§ 57.4603   Closure of valves.
To prevent accidental release of gases from hoses and torches attached to oxygen and acetylene cylinders or to manifold systems, cylinder or manifold system valves shall be closed when—
(a) The cylinders are moved;
(b) The torch and hoses are left unattended; or
(c) The task or series of tasks is completed.
§ 57.4604   Preparation of pipelines or containers.
Before welding, cutting, or applying heat with an open flame to pipelines or containers that have contained flammable or combustible liquids, flammable gases, or explosive solids, the pipelines or containers shall be—
(a) Drained, ventilated, and thoroughly cleaned of any residue;
(b) Vented to prevent pressure build-up during the application of heat; and
(c)(1) Filled with an inert gas or water, where compatible; or
(2) Determined to be free of flammable gases by a flammable gas detection device prior to and at frequent intervals during the application of heat.
§ 57.4660   Work in shafts, raises, or winzes and other activities involving hazard areas.
During performance of an activity underground described in Table C-2 or when falling sparks or hot metal from work performed in a shaft, raise, or winze could pose a fire hazard—
(a) A multipurpose dry-chemical fire extinguisher shall be at the worksite to supplement the fire extinguishing equipment required by § 57.4600; and
(b) At least one of the following actions shall be taken:
(1) Wet down the area before and after the operation, taking precaution against any hazard of electrical shock.
(2) Isolate any combustible material with noncombustible material.
(3) Shield the activity so that hot metal and sparks cannot cause a fire.
(4) Provide a second person to watch for and extinguish any fire.
Table C-2
(5) Cover or bulkhead the opening immediately below and adjacent to the activity with noncombustible material to prevent sparks or hot metal from falling down the shaft, raise, or winze. This alternative applies only to activities involving a shaft, raise, or winze.
(c) The affected area shall be inspected during the first hour after the operation is completed. Additional inspections shall be made or other fire prevention measures shall be taken if a fire hazard continues to exist.
§ 57.4760   Shaft mines.
(a) Shaft mines shall be provided with at least one of the following means to control the spread of fire, smoke, and toxic gases underground in the event of a fire: control doors, reversal of mechanical ventilation, or effective evacuation procedures. Under this standard, “shaft mine” means a mine in which any designated escapeway includes a mechanical hoisting device or a ladder ascent.
(1) Control doors. If used as an alternative, control doors shall be—
(i) Installed at or near shaft stations of intake shafts and any shaft designated as an escapeway under § 57.11053 or at other locations that provide equivalent protection;
(ii) Constructed and maintained according to Table C-3;
(iii) Provided with a means of remote closure at landings of timbered intake shafts unless a person specifically designated to close each door in the event of a fire can reach the door within three minutes;
(iv) Closed or opened only according to predetermined conditions and procedures;
(v) Constructed so that once closed they will not reopen as a result of a differential in air pressure;
(vi) Constructed so that they can be opened from either side by one person, or be provided with a personnel door that can be opened from either side; and
(vii) Clear of obstructions.
(2) Mechanical ventilation reversal. If used as an alternative, reversal of mechanical ventilation shall—
(i) Provide at all times at least the same degree of protection to persons underground as would be afforded by the installation of control doors;
(ii) Be accomplished by a main fan. If the main fan is located underground—
(A) The cable or conductors supplying power to the fan shall be routed through areas free of fire hazards; or
(B) The main fan shall be equipped with a second, independent power cable or set of conductors from the surface. The power cable or conductors shall be located so that an underground fire disrupting power in one cable or set of conductors will not affect the other; or
(C) A second fan capable of accomplishing ventilation reversal shall be available for use in the event of failure of the main fan;
(iii) Provide rapid air reversal that allows persons underground time to exit in fresh air by the second escapeway or find a place of refuge; and
(iv) Be done according to predetermined conditions and procedures.
(3) Evacuation. If used as an alternative, effective evacuation shall be demonstrated by actual evacuation of all persons underground to the surface in ten minutes or less through routes that will not expose persons to heat, smoke, or toxic fumes in the event of a fire.
(b) If the destruction of any bulkhead on an inactive level would allow fire contaminants to reach an escapeway, that bulkhead shall be constructed and maintained to provide at least the same protection as required for control doors under Table C-3.
Table C-3—Control Door Construction
1 In this table, “combustible material” does not refer to installed wiring or track support.
§ 57.4761   Underground shops.
To confine or prevent the spread of toxic gases from a fire originating in an underground shop where maintenance work is routinely done on mobile equipment, one of the following measures shall be taken: use of control doors or bulkheads, routing of the mine shop air directly to an exhaust system, reversal of mechanical ventilation, or use of an automatic fire suppression system in conjunction with an alternate escape route. The alternative used shall at all times provide at least the same degree of safety as control doors or bulkheads.
(a) Control doors or bulkheads. If used as an alternative, control doors or bulkheads shall meet the following requirements:
(1) Each control door or bulkhead shall be constructed to serve as a barrier to fire, the effects of fire, and air leakage at each opening to the shop.
(2) Each control door shall be—
(i) Constructed so that, once closed, it will not reopen as a result of a differential in air pressure;
(ii) Constructed so that it can be opened from either side by one person or be provided with a personnel door that can be opened from either side;
(iii) Clear of obstructions; and
(iv) Provided with a means of remote or automatic closure unless a person specifically designated to close the door in the event of a fire can reach the door within three minutes.
(3) If located 20 feet or more from exposed timber or other combustible material, the control doors or bulkheads shall provide protection at least equivalent to a door constructed of no less than one-quarter inch of plate steel with channel or angle-iron reinforcement to minimize warpage. The framework assembly of the door and the surrounding bulkhead, if any, shall be at least equivalent to the door in fire and air-leakage resistance, and in physical strength.
(4) If located less than 20 feet from exposed timber or other combustibles, the control door or bulkhead shall provide protection at least equivalent to a door constructed of two layers of wood, each a minimum of three-quarters of an inch in thickness. The wood-grain of one layer shall be perpendicular to the wood-grain of the other layer. The wood construction shall be covered on all sides and edges with no less than 24-gauge sheet steel. The framework assembly of the door and the surrounding bulkhead, if any, shall be at least equivalent to the door in fire and air-leakage resistance, and in physical strength. Roll-down steel doors with a fire-resistance rating of 1 1/2 hours or greater, but without an insulation core, are acceptable provided that an automatic sprinkler or deluge system is installed that provides even coverage of the door on both sides.
(b) Routing air to exhaust system. If used as an alternative, routing the mine shop exhaust air directly to an exhaust system shall be done so that no person would be exposed to toxic gases in the event of a shop fire.
(c) Mechanical ventilation reversal. If used as an alternative, reversal of mechanical ventilation shall—
(1) Be accomplished by a main fan. If the main fan is located underground:
(i) The cable or conductors supplying power to the fan shall be routed through areas free of fire hazards; or
(ii) The main fan shall be equipped with a second, independent power cable or set of conductors from the surface. The power cable or conductors shall be located so that an underground fire disrupting power in one cable or set of conductors will not affect the other; or
(iii) A second fan capable of accomplishing ventilation reversal shall be available for use in the event of failure of the main fan;
(2) Provide rapid air reversal that allows persons underground time to exit in fresh air by the second escapeway or find a place of refuge; and
(3) Be done according to predetermined conditions and procedures.
(d) Automatic fire suppression system and escape route. If used as an alternative, the automatic fire suppression system and alternate escape route shall meet the following requirements:
(1) The suppression system shall be—
(i) Located in the shop area;
(ii) The appropriate size and type for the particular fire hazards involved; and
(iii) Inspected at weekly intervals and properly maintained.
(2) The escape route shall bypass the shop area so that the route will not be affected by a fire in the shop area.
§ 57.5001   Exposure limits for airborne contaminants.
The following is required until April 7, 2026. Except as permitted by § 57.5005—
(a) Except as provided in paragraph (b), the exposure to airborne contaminants shall not exceed, on the basis of a time weighted average, the threshold limit values adopted by the American Conference of Governmental Industrial Hygienists, as set forth and explained in the 1973 edition of the Conference's publication, entitled “TLV's Threshold Limit Values for Chemical Substances in Workroom Air Adopted by ACGIH for 1973,” pages 1 through 54, which are hereby incorporated by reference and made a part hereof. This publication may be obtained from the American Conference of Governmental Industrial Hygienists by writing to 1330 Kemper Meadow Drive, Attn: Customer Service, Cincinnati, OH 45240, http://www.acgih.org , or may be examined in any Metal and Nonmetal Mine Safety and Health District Office of the Mine Safety and Health Administration. Excursions above the listed thresholds shall not be of a greater magnitude than is characterized as permissible by the Conference.
(b) Asbestos standard —(1) Definitions. Asbestos is a generic term for a number of asbestiform hydrated silicates that, when crushed or processed, separate into flexible fibers made up of fibrils.
Asbestos means chrysotile, cummingtonite-grunerite asbestos (amosite), crocidolite, anthophylite asbestos, tremolite asbestos, and actinolite asbestos.
Asbestos fiber means a fiber of asbestos that meets the criteria of a fiber.
Fiber means a particle longer than 5 micrometers (µm) with a length-to-diameter ratio of at least 3-to-1.
(2) Permissible Exposure Limits (PELs) —(i) Full-shift limit. A miner's personal exposure to asbestos shall not exceed an 8-hour time-weighted average full-shift airborne concentration of 0.1 fiber per cubic centimeter of air (f/cc).
(ii) Excursion limit. No miner shall be exposed at any time to airborne concentrations of asbestos in excess of 1 fiber per cubic centimeter of air (f/cc) as averaged over a sampling period of 30 minutes.
(3) Measurement of airborne asbestos fiber concentration. Potential asbestos fiber concentration shall be determined by phase contrast microscopy (PCM) using the OSHA Reference Method in OSHA's asbestos standard found in 29 CFR 1910.1001, Appendix A, or a method at least equivalent to that method in identifying a potential asbestos exposure exceeding the 0.1 f/cc full-shift limit or the 1 f/cc excursion limit. When PCM results indicate a potential exposure exceeding the 0.1 f/cc full-shift limit or the 1 f/cc excursion limit, samples shall be further analyzed using transmission electron microscopy according to NIOSH Method 7402 or a method at least equivalent to that method.
(c) Employees shall be withdrawn from areas where there is present an airborne contaminant given a “C” designation by the Conference and the concentration exceeds the threshold limit value listed for that contaminant.
§ 57.5001T   Exposure limits for airborne contaminants.
As of April 8, 2026, except as permitted by § 57.5005—
(a) TLVs standard. Except as provided in paragraph (b) of this section and in part 60 of this chapter, the exposure to airborne contaminants shall not exceed, on the basis of a time weighted average, the threshold limit values adopted by the American Conference of Governmental Industrial Hygienists, as set forth and explained in the 1973 edition of the Conference's publication, entitled TLV's Threshold Limit Values for Chemical Substances in Workroom Air Adopted by ACGIH for 1973, pages 1 through 54. This publication is incorporated by reference into this section with the approval of the Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. This incorporation by reference (IBR) material is available for inspection at the Mine Safety and Health Administration (MSHA) and at the National Archives and Records Administration (NARA). Contact MSHA at: MSHA's Office of Standards, Regulations, and Variances, 201 12th Street South, Arlington, VA 22202-5450; (202) 693-9440; or at any Mine Safety and Health Enforcement District Office. For information on the availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email fr.inspection@nara.gov. The material may be obtained from American Conference of Governmental Industrial Hygienists, 1330 Kemper Meadow Drive, Attn: Customer Service, Cincinnati, OH 45240; www.acgih.org.
(b) Asbestos standard —(1) Definitions. Asbestos is a generic term for a number of asbestiform hydrated silicates that, when crushed or processed, separate into flexible fibers made up of fibrils.
Asbestos means chrysotile, cummingtonite-grunerite asbestos (amosite), crocidolite, anthophylite asbestos, tremolite asbestos, and actinolite asbestos.
Asbestos fiber means a fiber of asbestos that meets the criteria of a fiber.
Fiber means a particle longer than 5 micrometers (µm) with a length-to-diameter ratio of at least 3-to-1.
(2) Permissible Exposure Limits (PELs) —(i) Full-shift limit. A miner's personal exposure to asbestos shall not exceed an 8-hour time-weighted average full-shift airborne concentration of 0.1 fiber per cubic centimeter of air (f/cc).
(ii) Excursion limit. No miner shall be exposed at any time to airborne concentrations of asbestos in excess of 1 fiber per cubic centimeter of air (f/cc) as averaged over a sampling period of 30 minutes.
(3) Measurement of airborne asbestos fiber concentration. Potential asbestos fiber concentration shall be determined by phase contrast microscopy (PCM) using the OSHA Reference Method in OSHA's asbestos standard found in 29 CFR 1910.1001, Appendix A, or a method at least equivalent to that method in identifying a potential asbestos exposure exceeding the 0.1 f/cc full-shift limit or the 1 f/cc excursion limit. When PCM results indicate a potential exposure exceeding the 0.1 f/cc full-shift limit or the 1 f/cc excursion limit, samples shall be further analyzed using transmission electron microscopy according to NIOSH Method 7402 or a method at least equivalent to that method.
(c) Required action. Employees shall be withdrawn from areas where there is present an airborne contaminant given a “C” designation by the Conference and the concentration exceeds the threshold limit value listed for that contaminant.
§ 57.5002   Exposure monitoring.
Dust, gas, mist, and fume surveys shall be conducted as frequently as necessary to determine the adequacy of control measures.
§ 57.5005   Control of exposure to airborne contaminants.
The following is required until April 7, 2026. Control of employee exposure to harmful airborne contaminants shall be, insofar as feasible, by prevention of contamination, removal by exhaust ventilation, or by dilution with uncontaminated air. However, where accepted engineering control measures have not been developed or when necessary by the nature of work involved (for example, while establishing controls or occasional entry into hazardous atmospheres to perform maintenance or investigation), employees may work for reasonable periods of time in concentrations of airborne contaminants exceeding permissible levels if they are protected by appropriate respiratory protective equipment. Whenever respiratory protective equipment is used a program for selection, maintenance, training, fitting, supervision, cleaning, and use shall meet the following minimum requirements:
(a) Respirators approved by NIOSH under 42 CFR part 84 which are applicable and suitable for the purpose intended shall be furnished and miners shall use the protective equipment in accordance with training and instruction.
(b) A respirator program consistent with the requirements of ANSI Z88.2-1969, published by the American National Standards Institute and entitled “American National Standards Practices for Respiratory Protection ANSI Z88.2-1969,” approved August 11, 1969, which is hereby incorporated by reference and made a part hereof. This publication may be obtained from the American National Standards Institute, Inc., 25 W. 43rd Street, 4th Floor, New York, NY 10036; http://www.ansi.org , or may be examined in any Metal and Nonmetal Mine Safety and Health District Office of the Mine Safety and Health Administration.
(c) When respiratory protection is used in atmospheres immediately harmful to life, the presence of at least one other person with backup equipment and rescue capability shall be required in the event of failure of the respiratory equipment.
§ 57.5005T   Control of exposure to airborne contaminants.
As of April 8, 2026, the following is required. Control of employee exposure to harmful airborne contaminants shall be, insofar as feasible, by prevention of contamination, removal by exhaust ventilation, or by dilution with uncontaminated air. However, where accepted engineering control measures have not been developed or when necessary by the nature of work involved (for example, while establishing controls or occasional entry into hazardous atmospheres to perform maintenance or investigation), employees may work for reasonable periods of time in concentrations of airborne contaminants exceeding permissible levels if they are protected by appropriate respiratory protective equipment. Whenever respiratory protective equipment is used, its selection, fitting, maintenance, cleaning, training, supervision, and use shall meet the following minimum requirements:
(a) Respirators approved by NIOSH under 42 CFR part 84 which are applicable and suitable for the purpose intended shall be furnished and miners shall use the protective equipment in accordance with training and instruction.
(b) A written respiratory protection program consistent with the requirements of ASTM F3387-19, Standard Practice for Respiratory Protection, approved August 1, 2019, which is incorporated by reference into this section with the approval of the Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. This incorporation by reference (IBR) material is available for inspection at the Mine Safety and Health Administration (MSHA) and at the National Archives and Records Administration (NARA). Contact MSHA at: MSHA's Office of Standards, Regulations, and Variances, 201 12th Street South, Arlington, VA 22202-5450; (202) 693-9440; or any Mine Safety and Health Enforcement District Office. For information on the availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email fr.inspection@nara.gov. The material may be obtained from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959; www.astm.org.
(c) When respiratory protection is used in atmospheres immediately dangerous to life or health (IDLH), the presence of at least one other person with backup equipment and rescue capability shall be required in the event of failure of the respiratory equipment.
§ 57.5006   Restricted use of chemicals.
The following chemical substances shall not be used or stored except by competent persons under laboratory conditions approved by a nationally recognized agency acceptable to the Secretary.
(a) Carbon tetrachloride,
(b) Phenol,
(c) 4-Nitrobiphenyl,
(d) Alpha-naphthylamine,
(e) 4,4-Methylene Bis (2-chloroaniline),
(f) Methyl-chloromethyl ether,
(g) 3,3 Dichlorobenzidine,
(h) Bis (chloromethyl) ether,
(i) Beta-napthylamine,
(j) Benzidine,
(k) 4-Aminodiphenyl,
(l) Ethyleneimine,
(m) Beta-propiolactone,
(n) 2-Acetylaminofluorene,
(o) 4-Dimethylaminobenzene, and
(p) N-Nitrosodimethylamine.
§ 57.5015   Oxygen deficiency.
Air in all active workings shall contain at least 19.5 volume percent oxygen.
§ 57.5037   Radon daughter exposure monitoring.
(a) In all mines at least one sample shall be taken in exhaust mine air by a competent person to determine if concentrations of radon daughters are present. Sampling shall be done using suggested equipment and procedures described in section 14.3 of ANSI N13.8-1973, entitled “American National Standard Radiation Protection in Uranium Mines,” approved July 18, 1973, pages 13-15, by the American National Standards Institute, Inc., which is incorporated by reference and made a part of the standard or equivalent procedures and equipment acceptable to the Administrator, MSHA Metal and Nonmetal Mine Safety and Health district office. This publication may be examined at any Metal and Nonmetal Mine Safety and Health Subdistrict Office of the Mine Safety and Health Administration, or may be obtained from the American National Standards Institute, Inc., 25 W. 43rd Street, 4th Floor, New York, NY 10036; http://www.ansi.org. The mine operator may request that the required exhaust mine air sampling be done by the Mine Safety and Health Administration. If concentrations of radon daughters in excess of 0.1 WL are found in an exhaust air sample, thereafter—
(1) Where uranium is mined—radon daughter concentrations representative of worker's breathing zone shall be determined at least every two weeks at random times in all active working areas such as stopes, drift headings, travelways, haulageways, shops, stations, lunch rooms, magazines, and any other place or location where persons work, travel, or congregate. However, if concentrations of radon daughters are found in excess of 0.3 WL in an active working area, radon daughter concentrations thereafter shall be determined weekly in that working area until such time as the weekly determinations in that area have been 0.3 WL or less for 5 consecutive weeks.
(2) Where uranium is not mined—when radon daughter concentrations between 0.1 and 0.3 WL are found in an active working area, radon daughter concentration measurements representative of worker's breathing zone shall be determined at least every 3 months at random times until such time as the radon daughter concentrations in that area are below 0.1 WL, and annually thereafter. If concentrations of radon daughters are found in excess of 0.3 WL in an active working area radon daughter concentrations thereafter shall be determined at least weekly in that working area until such time as the weekly determinations in that area have been 0.3 WL or less for 5 consecutive weeks.
(b) If concentrations of radon daughters less than 0.1 WL are found in an exhaust mine air sample, thereafter:
(1) Where uranium is mined—at least one sample shall be taken in the exhaust mine air monthly.
(2) Where uranium is not mined—no further exhaust mine air sampling is required.
(c) The sample date, locations, and results obtained under (a) and (b) above shall be recorded and retained at the mine site or nearest mine office for at least two years and shall be made available for inspection by the Secretary or his authorized representative.
§ 57.5038   Annual exposure limits.
No person shall be permitted to receive an exposure in excess of 4 WLM in any calendar year.
§ 57.5039   Maximum permissible concentration.
Except as provided by standard § 57.5005, persons shall not be exposed to air containing concentrations of radon daughters exceeding 1.0 WL in active workings.
§ 57.5040   Exposure records.
(a) The operator shall calculate and record complete individual exposures to concentrations of radon daughters as follows:
(1) Where uranium is mined—the complete individual exposures of all mine personnel working underground shall be calculated and recorded. These records shall include the individual's time in each active working area such as stopes, drift headings, travelways, haulageways, shops, stations, lunch rooms, magazines and any other place or location where persons work, travel or congregate, and the concentration of airborne radon daughters for each active working area.
(2) Where uranium is not mined—the complete individual exposure of all mine personnel working in active working areas with radon daughter concentrations in excess of 0.3 WL shall be calculated and recorded. These records shall include the individual's time in each active working area and the concentrations of airborne radon daughters for each active working area. The operator may discontinue calculating and recording the individual exposures of any personnel assigned to work in active working areas where radon daughter concentrations have been reduced to 0.3 WL or less for 5 consecutive weeks provided that such exposure calculation and recordation shall not be discontinued with respect to any person who has accumulated more exposure than 1/12 (one-twelfth) of a WLM times the number of months for which exposures have been calculated and recorded in the calendar year in which the exposure calculation and recordation is proposed to be discontinued.
(b) The operator shall maintain the form entitled “Record of Individual Exposure to Radon Daughters” (Form 4000-9), or equivalent forms that are acceptable to the Administrator, Metal and Nonmetal Mine Safety and Health, Mine Safety and Health Administration, on which there shall be recorded the specific information required by the form with respect to each person's time-weighted current and cumulative exposure to concentrations of radon daughters.
(1) The form entitled “Record of Individual Exposure to Radon Daughters” (Form 4000-9), shall consist of an original of each form for the operator's records which shall be available for examination by the Secretary or his authorized representative.
(2) On or before February 15 of each calendar year, or within 45 days after the shutdown of mining operations for the calendar year, each mine operator shall submit to the Mine Safety and Health Administration a copy of the “Record of Individual Exposure to Radon Daughters” (Form 4000-9), or acceptable equivalent form, showing the data required by the form for all personnel for whom calculation and recording of exposure was required during the previous calendar year.
(3) Errors detected by the operator shall be corrected on any forms kept by the operator and a corrected copy of any forms submitted to the Mine Safety and Health Administration shall be submitted to the Mine Safety and Health Administration within 60 days of detection and shall identify the errors and indicate the date the corrections are made.
(4) The operator's records of individual exposure to concentrations of radon daughters and copies of “Record of Individual Exposure to Radon Daughters” (Form 4000-9) or acceptable equivalent form or true legible facsimiles thereof (microfilm or other), shall be retained at the mine or nearest mine office for a period as specified in paragraph 9.8, ANSI N13.8-1973, or shall be submitted to the Mine Safety and Health Administration. These records, if retained by the operator, shall be open for inspection by the Secretary of Labor, his authorized representative, and authorized representatives of the official mine inspection agency of the State in which the mine is located. Paragraph 9.8, ANSI N13.8-1973, is incorporated by reference and made a part of this standard. ANSI N13.8-1973 may be examined at any Metal and Nonmetal Mine Safety and Health District Office of the Mine Safety and Health Administration, and may be obtained from the American National Standards Institute, Inc., at 25 W. 43rd Street, 4th Floor, New York, NY 10036; http://www.ansi.org.
(5) Upon written request from a person who is a subject of these records, a statement of the year-to-date and cumulative exposure applicable to that person shall be provided to the person or to whomever such person designates.
(6) The blank form entitled “Record of Individual Exposure to Radon Daughters” (Form 4000-9) may be obtained on request from any MSHA Metal and Nonmetal Mine Safety and Health district office.
To calculate an individual's exposure to WLM for a given period of time, multiply the total exposure time (hours to the nearest half-hour) in an active working area by the average concentration of airborne radon daughters for the applicable active working area (average working level calculated to the nearest hundredth working level) and divide the product by the constant 173 hours per month.
An average airborne radon daughter concentration for a designated active working area shall be determined by averaging all sampling results for that working area during the time that persons are present. Any sample taken by Federal or State mine inspectors, which represents exposure to miners and reported to the operator within three days of being taken, shall be included in the average concentration; except that if the mine operator samples simultaneously with the inspector, he may use his own sample results.
§ 57.5041   Smoking prohibition.
Smoking shall be prohibited in all areas of a mine where exposure records are required to be kept in compliance with standard 57.5040.
§ 57.5042   Revised exposure levels.
If levels of permissible exposures to concentrations of radon daughters different from those prescribed in 57.5038 are recommended by the Environmental Protection Agency and approved by the President, no employee shall be permitted to receive exposures in excess of those levels after the effective dates established by the Agency.
§ 57.5044   Respirators.
In environments exceeding 1.0 WL, miners shall wear respirators approved by NIOSH for radon daughters prior to July 10, 1995 or under the equivalent section of 42 CFR part 84 and such respirator use shall be in compliance with § 57.5005.
§ 57.5045   Posting of inactive workings.
Inactive workings in which radon daughter concentrations are above 1.0 WL, shall be posted against unauthorized entry and designated by signs indicating them as areas in which approved respirators shall be worn.
§ 57.5046   Protection against radon gas.
Where radon daughter concentrations exceed 10 WL, respirator protection against radon gas shall be provided in addition to protection against radon daughters. Protection against radon gas shall be provided by supplied air devices or by face masks containing absorbent material capable of removing both the radon and its daughters.
§ 57.5047   Gamma radiation surveys.
(a) Gamma radiation surveys shall be conducted annually in all underground mines where radioactive ores are mined.
(b) Surveys shall be in accordance with American National Standards (ANSI) Standard N13.8-1973, entitled “Radiation Protection in Uranium Mines”, section 14.1 page 12, which is hereby incorporated by reference and made a part hereof. This publication may be examined in any Metal and Nonmetal Mine Safety and Health District Office, Mine Safety and Health Administration, or may be obtained from the American National Standards Institute, Inc., 25 W. 43rd Street, 4th Floor, New York, NY 10036; http://www.ansi.org.
(c) Where average gamma radiation measurements are in excess of 2.0 milliroentgens per hour in the working place, gamma radiation dosimeters shall be provided for all persons affected, and records of cumulative individual gamma radiation exposure shall be kept.
(d) Annual individual gamma radiation exposure shall not exceed 5 rems.
§ 57.5060   Limit on exposure to diesel particulate matter.
(a) A miner's personal exposure to diesel particulate matter (DPM) in an underground mine must not exceed an average eight-hour equivalent full shift airborne concentration of 308 micrograms of elemental carbon per cubic meter of air (308 EC µg/m 3 ). [This interim permissible exposure limit (PEL) remains in effect until the final DPM exposure limit becomes effective. When the final DPM exposure limit becomes effective, MSHA will publish a document in the Federal Register. ]
(b)(1) Effective May 20, 2006, a miner's personal exposure to diesel particulate matter (DPM) in an underground mine must not exceed an average eight-hour equivalent full shift airborne concentration of 308 micrograms of elemental carbon per cubic meter of air (308 EC µg/m 3 ).
(2) Effective January 20, 2007, a miner's personal exposure to diesel particulate matter (DPM) in an underground mine must not exceed an average eight-hour equivalent full shift airborne concentration of 350 micrograms of total carbon per cubic meter of air (350 TC µg/m 3 ).
(3) Effective May 20, 2008, a miner's personal exposure to diesel particulate matter (DPM) in an underground mine must not exceed an average eight-hour equivalent full shift airborne concentration of 160 micrograms of total carbon per cubic meter of air (160 TC µg/m 3 ).
(c)(1) If a mine requires additional time to come into compliance with the final DPM limit established in § 57.5060 (b) due to technological or economic constraints, the operator of the mine may file an application with the District Manager for a special extension.
(2) The mine operator must certify on the application that the operator has posted one copy of the application at the mine site for at least 30 days prior to the date of application, and has provided another copy to the authorized representative of miners.
(3) No approval of a special extension shall exceed a period of one year from the date of approval. Mine operators may file for additional special extensions provided each extension does not exceed a period of one year. An application must include the following information:
(i) Documentation supporting that controls are technologically or economically infeasible at this time to reduce the miner's exposure to the final DPM limit.
(ii) The most recent DPM monitoring results.
(iii) The actions the operator will take during the extension to minimize exposure of miners to DPM.
(4) A mine operator must comply with the terms of any approved application for a special extension, post a copy of the approved application for a special extension at the mine site for the duration of the special extension period, and provide a copy of the approved application to the authorized representative of miners.
(d) The mine operator must install, use, and maintain feasible engineering and administrative controls to reduce a miner's exposure to or below the applicable DPM PEL established in this section. When controls do not reduce a miner's DPM exposure to the PEL, controls are infeasible, or controls do not produce significant reductions in DPM exposures, controls must be used to reduce the miner's exposure to as low a level as feasible and must be supplemented with respiratory protection in accordance with § 57.5005(a), (b), and paragraphs (d)(1) through (d)(8) of this section.
(1) Air purifying respirators must be equipped with the following:
(i) Filters certified by NIOSH under 30 CFR part 11 (appearing in the July 1, 1994 edition of 30 CFR, parts 1 to 199) as a high efficiency particulate air (HEPA) filter;
(ii) Filters certified by NIOSH under 42 CFR part 84 as 99.97% efficient; or
(iii) Filters certified by NIOSH for DPM.
(2) Non-powered, negative-pressure, air purifying, particulate-filter respirators shall use an R- or P-series filter or any filter certified by NIOSH for DPM. An R-series filter shall not be used for longer than one work shift.
(3) The mine operator must provide a confidential medical evaluation by a physician or other licensed health care professional (PLHCP), at no cost to the miner, to determine the miner's ability to use a respirator before the miner is required to be fit tested or to use a respirator at the mine. If the PLHCP determines that the miner cannot wear a negative pressure respirator, the mine operator must make certain that the PLHCP evaluates the miner's ability to wear a powered air purifying respirator (PAPR).
(4) The mine operator must provide the miner with an opportunity to discuss their evaluation results with the PLHCP before the PLHCP submits the written determination to the mine operator regarding the miner's ability to wear a respirator. If the miner disagrees with the evaluation results of the PLHCP, the miner may submit within 30 days additional evidence of his or her medical condition to the PLHCP.
(5) The mine operator must obtain a written determination from the PLHCP regarding the miner's ability to wear a respirator, and the mine operator must assure that the PLHCP provides a copy of the determination to the miner.
(6) The miner must be reevaluated when the mine operator has reason to believe that conditions have changed which could adversely affect the miner's ability to wear the respirator.
(7) Upon written notification that the PLHCP has determined that the miner is unable to wear a respirator, including a PAPR, the miner must be transferred to work in an existing position in an area of the same mine where respiratory protection is not required. The miner must be transferred within 30 days of the final determination by the PLHCP.
(i) The miner must continue to receive compensation at no less than the regular rate of pay in the classification held by that miner immediately prior to the transfer.
(ii) Increases in wages of the transferred miner must be based upon the new work classification.
(8) The mine operator must maintain a record of the identity of the PLHCP and the most recent written determination of each miner's ability to wear a respirator for the duration of the miner's employment plus six months.
(e) Rotation of miners shall not be considered an acceptable administrative control used for compliance with the DPM standard.
§ 57.5061   Compliance determinations.
(a) MSHA will use a single sample collected and analyzed by the Secretary in accordance with the requirements of this section as an adequate basis for a determination of noncompliance with the DPM limit.
(b) The Secretary will collect samples of DPM by using a respirable dust sampler equipped with a submicrometer impactor and analyze the samples for the amount of elemental carbon using the method described in NIOSH Analytical Method 5040, except that the Secretary also may use any methods of collection and analysis subsequently determined by NIOSH to provide equal or improved accuracy for the measurement of DPM.
(c) The Secretary will use full-shift personal sampling for compliance determinations.
§ 57.5065   Fueling practices.
(a) Diesel fuel used to power equipment in underground areas must not have a sulfur content greater than 0.05 percent. The operator must retain purchase records that demonstrate compliance with this requirement for one year after the date of purchase.
(b) The operator must only use fuel additives registered by the U.S. Environmental Protection Agency in diesel powered equipment operated in underground areas.
§ 57.5066   Maintenance standards.
(a) Any diesel powered equipment operated at any time in underground areas must meet the following maintenance standards:
(1) The operator must maintain any approved engine in approved condition;
(2) The operator must maintain the emission related components of any non-approved engine to manufacturer specifications; and
(3) The operator must maintain any emission or particulate control device installed on the equipment in effective operating condition.
(b)(1) A mine operator must authorize each miner operating diesel-powered equipment underground to affix a visible and dated tag to the equipment when the miner notes evidence that the equipment may require maintenance in order to comply with the maintenance standards of paragraph (a) of this section. The term evidence means visible smoke or odor that is unusual for that piece of equipment under normal operating procedures, or obvious or visible defects in the exhaust emissions control system or in the engine affecting emissions.
(2) A mine operator must ensure that any equipment tagged pursuant to this section is promptly examined by a person authorized to maintain diesel equipment, and that the affixed tag not be removed until the examination has been completed. The term promptly means before the end of the next shift during which a qualified mechanic is scheduled to work.
(3) A mine operator must retain a log of any equipment tagged pursuant to this section. The log must include the date the equipment is tagged, the date the equipment is examined, the name of the person examining the equipment, and any action taken as a result of the examination. The operator must retain the information in the log for one year after the date the tagged equipment was examined.
(c) Persons authorized by a mine operator to maintain diesel equipment covered by paragraph (a) of this section must be qualified, by virtue of training or experience, to ensure that the maintenance standards of paragraph (a) of this section are observed. An operator must retain appropriate evidence of the competence of any person to perform specific maintenance tasks in compliance with those standards for one year after the date of any maintenance, and upon request must provide the documentation to the authorized representative of the Secretary.
§ 57.5067   Engines.
(a) Any diesel engine introduced into an underground area of a mine covered by this part after July 5, 2001, other than an engine in an ambulance or fire fighting equipment which is utilized in accordance with mine fire fighting and evacuation plans, must either:
(1) Have affixed a plate evidencing approval of the engine pursuant to subpart E of Part 7 of this title or pursuant to Part 36 of this title; or
(2) Meet or exceed the applicable particulate matter emission requirements of the Environmental Protection Administration listed in Table 57.5067-1, as follows:
Table 57.5067-1
Notes:
“g” means grams.
“hp” means horsepower.
“g/bhp-hr” means grams/brake horsepower-hour.
“kW” means kilowatt.
“g/kW-hr” means grams/kilowatt-hour.
(b) For purposes of paragraph (a):
(1) The term “introduced” means any engine added to the underground inventory of engines of the mine in question, including:
(i) An engine in newly purchased equipment;
(ii) An engine in used equipment brought into the mine; and
(iii) A replacement engine that has a different serial number than the engine it is replacing; but
(2) The term “introduced” does not include engines that were previously part of the mine inventory and rebuilt.
(3) The term introduced does not include the transfer of engines or equipment from the inventory of one underground mine to another underground mine operated by the same mine operator.
§ 57.5070   Miner training.
(a) Mine operators must provide annual training to all miners at a mine covered by this part who can reasonably be expected to be exposed to diesel emissions on that property. The training must include—
(1) The health risks associated with exposure to diesel particulate matter;
(2) The methods used in the mine to control diesel particulate matter concentrations;
(3) Identification of the personnel responsible for maintaining those controls; and
(4) Actions miners must take to ensure the controls operate as intended.
(b) An operator must retain a record at the mine site of the training required by this section for one year after completion of the training.
§ 57.5071   Exposure monitoring.
(a) Mine operators must monitor as often as necessary to effectively determine, under conditions that can be reasonably anticipated in the mine, whether the average personal full-shift airborne exposure to DPM exceeds the DPM limit specified in § 57.5060.
(b) The mine operator must provide affected miners and their representatives with an opportunity to observe exposure monitoring required by this section. Mine operators must give prior notice to affected miners and their representatives of the date and time of intended monitoring.
(c) If any monitoring performed under this section indicates that a miner's exposure to diesel particulate matter exceeds the DPM limit specified in § 57.5060, the operator must promptly post notice of the corrective action being taken on the mine bulletin board, initiate corrective action by the next work shift, and promptly complete such corrective action.
(d)(1) The results of monitoring for diesel particulate matter, including any results received by a mine operator from sampling performed by the Secretary, must be posted on the mine bulletin board within 15 days of receipt and must remain posted for 30 days. The operator must provide a copy of the results to the authorized representative of miners.
(2) The mine operator must retain for five years (from the date of sampling), the results of any samples the operator collected as a result of monitoring under this section, and information about the sampling method used for obtaining the samples.
§ 57.5075   Diesel particulate records.
(a) The table entitled “Diesel Particulate Matter Recordkeeping Requirements” lists the records the operator must maintain pursuant to §§ 57.5060 through 57.5071, and the duration for which particular records need to be retained.
Table 57.5075( a )—Diesel Particulate Recordkeeping Requirements
(b)(1) Any record listed in this section which is required to be retained at the mine site may, notwithstanding such requirement, be retained elsewhere if the mine operator can immediately access the record from the mine site by electronic transmission.
(2) Upon request from an authorized representative of the Secretary of Labor, the Secretary of Health and Human Services, or from the authorized representative of miners, mine operators must promptly provide access to any record listed in the table in this section.
(3) An operator must provide access to a miner, former miner, or, with the miner's or former miner's written consent, a personal representative of a miner, to any record required to be maintained pursuant to § 57.5071 or § 57.5060(d) to the extent the information pertains to the miner or former miner. The operator must provide the first copy of a requested record at no cost, and any additional copies at reasonable cost.
(4) Whenever an operator ceases to do business, that operator must transfer all records required to be maintained by this part, or a copy thereof, to any successor operator who must maintain them for the required period.
§ 57.6000   Definitions.
The following definitions apply in this subpart.
Blasting agent. Any substance classified as a blasting agent by the Department of Transportation in 49 CFR 173.114a(a). This document is available at any MSHA Metal and Nonmetal Safety and Health district office.
Detonating cord. A flexible cord containing a center core of high explosives which may be used to initiate other explosives.
Detonator. Any device containing a detonating charge used to initiate an explosive. These devices include electronic detonators, electric or nonelectric instantaneous or delay blasting caps, and delay connectors. The term “detonator” does not include detonating cord. Detonators may be either “Class A” detonators or “Class C” detonators, as classified by the Department of Transportation in 49 CFR 173.53 and 173.100, which is available at any MSHA Metal and Nonmetal Safety and Health district office.
Explosive. Any substance classified as an explosive by the Department of Transportation in 49 CFR 173.53, 173.88, and 173.100. This document is available at any MSHA Metal and Nonmetal Safety and Health district office.
Explosive material. Explosives, blasting agents, and detonators.
Flash point. The minimum temperature at which sufficient vapor is released by a liquid to form a flammable vapor-air mixture near the surface of the liquid.
Igniter cord. A fuse that burns progressively along its length with an external flame at the zone of burning, used for lighting a series of safety fuses in a desired sequence.
Magazine. A bullet-resistant, theft-resistant, fire-resistant, weather-resistant, ventilated facility for the storage of explosives and detonators (BATF Type 1 or Type 2 facility).
Misfire. The complete or partial failure of explosive material to detonate as planned. The term also is used to describe the explosive material itself that has failed to detonate.
Primer. A unit, package, or cartridge of explosives which contains a detonator and is used to initiate other explosives or blasting agents.
Safety switch. A switch that provides shunt protection in blasting circuits between the blast site and the switch used to connect a power source to the blasting circuit.
Slurry. An explosive material containing substantial portions of a liquid, oxidizers, and fuel, plus a thickener.
Water gel. An explosive material containing substantial portions of water, oxidizers, and fuel, plus a cross-linking agent.
§ 57.6100   Separation of stored explosive material.
(a) Detonators shall not be stored in the same magazine with other explosive material.
(b) When stored in the same magazine, blasting agents shall be separated from explosives, safety fuse, and detonating cord to prevent contamination.
§ 57.6101   Areas around explosive material storage facilities.
(a) Areas surrounding storage facilities for explosive material shall be clear of rubbish, brush, dry grass, and trees for 25 feet in all directions, except that live trees 10 feet or taller need not be removed.
(b) Other combustibles shall not be stored or allowed to accumulate within 50 feet of explosive material. Combustible liquids shall be stored in a manner that ensures drainage will occur away from the explosive material storage facility in case of tank rupture.
§ 57.6102   Explosive material storage practices.
(a) Explosive material shall be—
(1) Stored in a manner to facilitate use of oldest stocks first;
(2) Stored according to brand and grade in such a manner as to facilitate identification; and
(3) Stacked in a stable manner but not more than 8 feet high.
(b) Explosives and detonators shall be stored in closed nonconductive containers except that nonelectric detonating devices may be stored on nonconductive racks provided the case-insert instructions and the date-plant-shift code are maintained with the product.
§ 57.6130   Explosive material storage facilities.
(a) Detonators and explosives shall be stored in magazines.
(b) Packaged blasting agents shall be stored in a magazine or other facility which is ventilated to prevent dampness and excessive heating, weather-resistant, and locked or attended. Drop trailers do not have to be ventilated if they are currently licensed by the Federal, State, or local authorities for over-the-road use. Facilities other than magazines used to store blasting agents shall contain only blasting agents.
(c) Bulk blasting agents shall be stored in weather-resistant bins or tanks which are locked, attended, or otherwise inaccessible to unauthorized entry.
(d) Facilities, bins or tanks shall be posted with the appropriate United States Department of Transportation placards or other appropriate warning signs that indicate the contents and are visible from each approach.
§ 57.6131   Location of explosive material storage facilities.
(a) Storage facilities for any explosive material shall be—
(1) Located so that the forces generated by a storage facility explosion will not create a hazard to occupants in mine buildings and will not damage dams or electric substations; and
(2) Detached structures located outside the blast area and a sufficient distance from powerlines so that the powerlines, if damaged, would not contact the magazines.
(b) Operators should also be aware of regulations affecting storage facilities in 27 CFR part 55, in particular, 27 CFR 55.218 and 55.220. This document is available at any MSHA Metal and Nonmetal Safety and Health district office.
§ 57.6132   Magazine requirements.
(a) Magazines shall be—
(1) Structurally sound;
(2) Noncombustible or the exterior covered with fire-resistant material;
(3) Bullet resistant;
(4) Made of nonsparking material on the inside;
(5) Ventilated to control dampness and excessive heating within the magazine;
(6) Posted with the appropriate United States Department of Transportation placards or other appropriate warning signs that indicate the contents and are visible from each approach, so located that a bullet passing through any of the signs will not strike the magazine;
(7) Kept clean and dry inside;
(8) Unlighted or lighted by devices that are specifically designed for use in magazines and which do not create a fire or explosion hazard;
(9) Unheated or heated only with devices that do not create a fire or explosion hazard;
(10) Locked when unattended; and
(11) Used exclusively for the storage of explosive material except for essential nonsparking equipment used for the operation of the magazine.
(b) Metal magazines shall be equipped with electrical bonding connections between all conductive portions so the entire structure is at the same electrical potential. Suitable electrical bonding methods include welding, riveting, or the use of securely tightened bolts where individual metal portions are joined. Conductive portions of nonmetal magazines shall be grounded.
(c) Electrical switches and outlets shall be located on the outside of the magazine.
§ 57.6133   Powder chests.
(a) Powder chests (day boxes) shall be—
(1) Structurally sound, weather-resistant, equipped with a lid or cover, and with only nonsparking material on the inside;
(2) Posted with the appropriate United States Department of Transportation placards or other appropriate warning signs that indicate the contents and are visible from each approach;
(3) Located out of the blast area once loading has been completed;
(4) Locked or attended when containing explosive material; and
(5) Emptied at the end of each shift with the contents returned to a magazine or other storage facility, or attended.
(b) Detonators shall be kept in chests separate from explosives or blasting agents, unless separated by 4 inches of hardwood or equivalent, or a laminated partition. When a laminated partition is used, operators must follow the provisions of 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). The IME is located at 1120 19th Street NW., Suite 310, Washington, DC 20036-3605; 202-429-9280; https://www.ime.org. 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's Office of Standards, Regulations, and Variances, 201 12th Street South, Arlington, VA 22202-5452; 202-693-9440; and at all Metal and Nonmetal Mine Safety and Health District Offices, or available for inspection at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
§ 57.6160   Main facilities.
(a) Main facilities used to store explosive material underground shall be located—
(1) In stable or supported ground;
(2) So that a fire or explosion in the storage facilities will not prevent escape from the mine, or cause detonation of the contents of another storage facility;
(3) Out of the line of blasts, and protected from vehicular traffic, except that accessing the facility;
(4) At least 200 feet from work places or shafts;
(5) At least 50 feet from electric substations;
(6) A safe distance from trolley wires; and
(7) At least 25 feet from detonator storage facilities.
(b) Main facilities used to store explosive material underground shall be—
(1) Posted with warning signs that indicate the contents and are visible from any approach;
(2) Used exclusively for the storage of explosive material and necessary equipment associated with explosive material storage and delivery:
(i) Portions of the facility used for the storage of explosives shall only contain nonsparking material or equipment.
(ii) The blasting agent portion of the facility may be used for the storage of other necessary equipment;
(3) Kept clean, suitably dry, and orderly;
(4) Provided with unobstructed ventilation openings;
(5) Kept securely locked unless all access to the mine is either locked or attended; and
(6) Unlighted or lighted only with devices that do not create a fire or explosion hazard and which are specifically designed for use in magazines.
(c) Electrical switches and outlets shall be located outside the facility.
§ 57.6161   Auxiliary facilities.
(a) Auxiliary facilities used to store explosive material near work places shall be wooden, box-type containers equipped with covers or doors, or facilities constructed or mined-out to provide equivalent impact resistance and confinement.
(b) The auxiliary facilities shall be—
(1) Constructed of nonsparking material on the inside when used for the storage of explosives;
(2) Kept clean, suitably dry, and orderly;
(3) Kept in repair;
(4) Located out of the line of blasts so they will not be subjected to damaging shock or flyrock;
(5) Identified with warning signs or coded to indicate the contents with markings visible from any approach;
(6) Located at least 15 feet from all haulageways and electrical equipment, or placed entirely within a mined-out recess in the rib used exclusively for explosive material;
(7) Filled with no more than a one-week supply of explosive material;
(8) Separated by at least 25 feet from other facilities used to store detonators; and
(9) Kept securely locked unless all access to the mine is either locked or attended.
§ 57.6200   Delivery to storage or blast site areas.
Explosive material shall be transported without undue delay to the storage area or blast site.
§ 57.6201   Separation of transported explosive material.
Detonators shall not be transported on the same vehicle or conveyance with other explosives except as follows:
(a) Detonators in quantities of more than 1,000 may be transported in a vehicle or conveyance with explosives or blasting agents provided the detonators are—
(1) Maintained in the original packaging as shipped from the manufacturer; and
(2) Separated from explosives or blasting agents by 4 inches of hardwood or equivalent, or a laminated partition. The hardwood or equivalent shall be fastened to the vehicle or conveyance. When a laminated partition is used, operators must follow the provisions of 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). The IME is located at 1120 19th Street NW., Suite 310, Washington, DC 20036-3605; 202-429-9280; https://www.ime.org. 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's Office of Standards, Regulations, and Variances, 201 12th Street South, Arlington, VA 22202-5452; 202-693-9440; and at all Metal and Nonmetal Mine Safety and Health District Offices, or available for examination at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
(b) Detonators in quantities of 1,000 or fewer may be transported with explosives or blasting agents provided the detonators are—
(1) Kept in closed containers; and
(2) Separated from explosives or blasting agents by 4 inches of hardwood or equivalent, or a laminated partition. The hardwood or equivalent shall be fastened to the vehicle or conveyance. When a laminated partition is used, operators must follow the provisions of 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). The IME is located at 1120 19th Street NW., Suite 310, Washington, DC 20036-3605; 202-429-9280; https://www.ime.org. 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's Office of Standards, Regulations, and Variances, 201 12th Street South, Arlington, VA 22202-5452; 202-693-9440; and at all Metal and Nonmetal Mine Safety and Health District Offices, or available for examination at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
§ 57.6202   Vehicles.
(a) Vehicles containing explosive material shall be—
(1) Maintained in good condition and shall comply with the requirements of subpart M of this part;
(2) Equipped with sides and enclosures higher than the explosive material being transported or have the explosive material secured to a nonconductive pallet;
(3) Equipped with a cargo space that shall contain the explosive material (passenger areas shall not be considered cargo space);
(4) Equipped with at least two multipurpose dry-chemical fire extinguishers or one such extinguisher and an automatic fire suppression system;
(5) Posted with warning signs that indicate the contents and are visible from each approach;
(6) Occupied only by persons necessary for handling the explosive material;
(7) Attended or the cargo compartment locked at surface areas of underground mines, except when parked at the blast site and loading is in progress; and
(8) Secured while parked by having—
(i) The brakes set;
(ii) The wheels chocked if movement could occur; and
(iii) The engine shut off unless powering a device being used in the loading operation.
(b) Vehicles containing explosives shall have—
(1) No sparking material exposed in the cargo space; and
(2) Only properly secured nonsparking equipment in the cargo space with the explosives.
(c) Vehicles used for dispensing bulk explosive material shall—
(1) Have no zinc or copper exposed in the cargo space; and
(2) Provide any enclosed screw-type conveyors with protection against internal pressure and frictional heat.
§ 57.6203   Locomotives.
Explosive material shall not be transported on a locomotive. When explosive material is hauled by trolley locomotive, covered, electrically insulated cars shall be used.
§ 57.6204   Hoists.
(a) Before explosive material is transported in hoist conveyances—
(1) The hoist operator shall be notified; and
(2) Hoisting in adjacent shaft compartments, except for empty conveyances or counterweights, shall be stopped until transportation of the explosive material is completed.
(b) Explosive material transported in hoist conveyances shall be placed within a container which prevents shifting of the cargo that could cause detonation of the container by impact or by sparks. The manufacturer's container may be used if secured to a nonconductive pallet. When explosives are transported, they shall be secured so as not to contact any sparking material.
(c) No explosive material shall be transported during a mantrip.
§ 57.6205   Conveying explosives by hand.
Closed, nonconductive containers shall be used to carry explosives and detonators to and from blast sites. Separate containers shall be used for explosives and detonators.
§ 57.6300   Control of blasting operations.
(a) Only persons trained and experienced in the handling and use of explosive material shall direct blasting operations and related activities.
(b) Trainees and inexperienced persons shall work only in the immediate presence of persons trained and experienced in the handling and use of explosive material.
§ 57.6301   Blasthole obstruction check.
Before loading, blastholes shall be checked and, wherever possible, cleared of obstructions.
§ 57.6302   Separation of explosive material.
Explosives and blasting agents shall be kept separated from detonators until loading begins.
§ 57.6303   Initiation preparation.
(a) Primers shall be made up only at the time of use and as close to the blast site as conditions allow.
(b) Primers shall be prepared with the detonator contained securely and completely within the explosive or contained securely and appropriately for its design in the tunnel or cap well.
(c) When using detonating cord to initiate another explosive, a connection shall be prepared with the detonating cord threaded through, attached securely to, or otherwise in contact with the explosive.
§ 57.6304   Primer protection.
(a) Tamping shall not be done directly on a primer.
(b) Rigid cartridges of explosives or blasting agents that are 4 inches (100 millimeters) in diameter or larger shall not be dropped on the primer except where the blasthole contains sufficient depth of water to protect the primer from impact. Slit packages of prill, water gel, or emulsions are not considered rigid cartridges and may be drop loaded.
§ 57.6305   Unused explosive material.
Unused explosive material shall be moved to a protected location as soon as practical after loading operations are completed.
§ 57.6306   Loading, blasting, and security.
(a) When explosive materials or initiating systems are brought to the blast site, the blast site shall be attended; barricaded and posted with warning signs, such as “Danger,” “Explosives,” or “Keep Out;” or flagged against unauthorized entry.
(b) Vehicles and equipment shall not be driven over explosive material or initiating systems in a manner which could contact the material or system, or create other hazards.
(c) Once loading begins, the only activities permitted within the blast site shall be those activities directly related to the blasting operation and the activities of surveying, stemming, sampling of geology, and reopening of holes, provided that reasonable care is exercised. Haulage activity is permitted near the base of bench faces being loaded or awaiting firing, provided no other haulage access exists.
(d) Loading and blasting shall be conducted in a manner designed to facilitate a continuous process, with the blast fired as soon as possible following the completion of loading. If blasting a loaded round may be delayed for more than 72 hours, the operator shall notify the appropriate MSHA district office.
(e) In electric blasting prior to connecting to the power source, and in nonelectric blasting prior to attaching an initiating device, all persons shall leave the blast area except persons in a blasting shelter or other location that protects them from concussion (shock wave), flying material, and gases.
(f) Before firing a blast—
(1) Ample warning shall be given to allow all persons to be evacuated;
(2) Clear exit routes shall be provided for persons firing the round; and
(3) All access routes to the blast area shall be guarded or barricaded to prevent the passage of persons or vehicles.
(g) Work shall not be resumed in the blast area until a post-blast examination addressing potential blast-related hazards has been conducted by a person with the ability and experience to perform the examination.
§ 57.6307   Drill stem loading.
Explosive material shall not be loaded into blastholes with drill stem equipment or other devices that could be extracted while containing explosive material. The use of loading hose, collar sleeves, or collar pipes is permitted.
§ 57.6308   Initiation systems.
Initiation systems shall be used in accordance with the manufacturer's instructions.
§ 57.6309   Fuel oil requirements for ANFO.
(a) Liquid hydrocarbon fuels with flash points lower than that of No. 2 diesel oil (125 °F) shall not be used to prepare ammonium nitrate-fuel oil, except that diesel fuels with flash points no lower than 100 °F may be used at ambient air temperatures below 45 °F.
(b) Waste oil, including crankcase oil, shall not be used to prepare ammonium nitrate-fuel oil.
§ 57.6310   Misfire waiting period.
When a misfire is suspected, persons shall not enter the blast area—
(a) For 30 minutes if safety fuse and blasting caps are used;
(b) For 15 minutes if any other type detonators are used; or
(c) For 30 minutes if electronic detonators are used, or for the manufacturer-recommended time, whichever is longer.
§ 57.6311   Handling of misfires.
(a) Faces and muck piles shall be examined for misfires after each blasting operation.
(b) Only work necessary to remove a misfire and protect the safety of miners engaged in the removal shall be permitted in the affected area until the misfire is disposed of in a safe manner.
(c) When a misfire cannot be disposed of safely, each approach to the area affected by the misfire shall be posted with a warning sign at a conspicuous location to prohibit entry, and the condition shall be reported immediately to mine management.
(d) Misfires occurring during the shift shall be reported to mine management not later than the end of the shift.
§ 57.6312   Secondary blasting.
Secondary blasts fired at the same time in the same work area shall be initiated from one source.
§ 57.6400   Compatibility of electric detonators.
All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical firing characteristics.
§ 57.6401   Shunting.
Except during testing—
(a) Electric detonators shall be kept shunted until connected to the blasting line or wired into a blasting round;
(b) Wired rounds shall be kept shunted until connected to the blasting line; and
(c) Blasting lines shall be kept shunted until immediately before blasting.
§ 57.6402   Deenergized circuits near detonators.
Electrical distribution circuits within 50 feet of electric detonators at the blast site shall be deenergized. Such circuits need not be deenergized between 25 to 50 feet of the electric detonators if stray current tests, conducted as frequently as necessary, indicate a maximum stray current of less than 0.05 ampere through a 1-ohm resistor as measured at the blast site.
§ 57.6403   Branch circuits.
(a) If electric blasting includes the use of branch circuits, each branch shall be equipped with a safety switch or equivalent method to isolate the circuits to be used.
(b) At least one safety switch or equivalent method of protection shall be located outside the blast area and shall be in the open position until persons are withdrawn.
§ 57.6404   Separation of blasting circuits from power source.
(a) Switches used to connect the power source to a blasting circuit shall be locked in the open position except when closed to fire the blast.
(b) Lead wires shall not be connected to the blasting switch until the shot is ready to be fired.
§ 57.6405   Firing devices.
(a) Power sources shall be capable of delivering sufficient current to energize all electric detonators to be fired with the type of circuits used. Storage or dry cell batteries are not permitted as power sources.
(b) Blasting machines shall be tested, repaired, and maintained in accordance with manufacturer's instructions.
(c) Only the blaster shall have the key or other control to an electrical firing device.
§ 57.6406   Duration of current flow.
If any part of a blast is connected in parallel and is to be initiated from powerlines or lighting circuits, the time of current flow shall be limited to a maximum of 25 milliseconds. This can be accomplished by incorporating an arcing control device in the blasting circuit or by interrupting the circuit with an explosive device attached to one or both lead lines and initiated by a 25-millisecond delay electric detonator.
§ 57.6407   Circuit testing.
A blasting galvanometer or other instrument designed for testing blasting circuits shall be used to test the following:
(a) In surface operations—
(1) Continuity of each electric detonator in the blasthole prior to stemming and connection to the blasting line;
(2) Resistance of individual series or the resistance of multiple balanced series to be connected in parallel prior to their connection to the blasting line;
(3) Continuity of blasting lines prior to the connection of electric or electronic detonator series; and
(4) Total blasting circuit resistance prior to connection to the power source.
(b) In underground operations—
(1) Continuity of each electric detonator series; and
(2) Continuity of blasting lines prior to the connection of electric or electronic detonators.
§ 57.6500   Damaged initiating material.
A visual check of the completed circuit shall be made to ensure that the components are properly aligned and connected. Safety fuse, igniter cord, detonating cord, shock or gas tubing, and similar material which is kinked, bent sharply, or damaged shall not be used.
§ 57.6501   Nonelectric initiation systems.
(a) When the nonelectric initiation system uses shock tube—
(1) Connections with other initiation devices shall be secured in a manner which provides for uninterrupted propagation;
(2) Factory-made units shall be used as assembled and shall not be cut except that a single splice is permitted on the lead-in trunkline during dry conditions; and
(3) Connections between blastholes shall not be made until immediately prior to clearing the blast site when surface delay detonators are used.
(b) When the nonelectric initiation system uses detonating cord—
(1) The line of detonating cord extending out of a blasthole shall be cut from the supply spool immediately after the attached explosive is correctly positioned in the hole;
(2) In multiple row blasts, the trunkline layout shall be designed so that the detonation can reach each blasthole from at least two directions;
(3) Connections shall be tight and kept at right angles to the trunkline;
(4) Detonators shall be attached securely to the side of the detonating cord and pointed in the direction in which detonation is to proceed;
(5) Connections between blastholes shall not be made until immediately prior to clearing the blast site when surface delay detonators are used; and
(6) Lead-in lines shall be manually unreeled if connected to the trunklines at the blast site.
(c) When nonelectric initiation systems use gas tube, continuity of the circuit shall be tested prior to blasting.
§ 57.6502   Safety fuse.
(a) The burning rate of each spool of safety fuse to be used shall be measured, posted in locations which will be conspicuous to safety fuse users, and brought to the attention of all persons involved with the blasting operation.
(b) When firing with safety fuse ignited individually using handheld lighters, the safety fuse shall be of lengths which provide at least the minimum burning time for a particular size round, as specified in the following table:
Table E-1—Safety Fuse—Minimum Burning Time
1 For example, at least a 36-inch length of 40-second-per-foot safety fuse or at least a 48-inch length of 30-second-per-foot safety fuse would have to be used to allow sufficient time to evacuate the area.
(c) Where flyrock might damage exposed safety fuse, the blast shall be timed so that all safety fuses are burning within the blastholes before any blasthole detonates.
(d) Fuse shall be cut and capped in dry locations.
(e) Blasting caps shall be crimped to fuse only with implements designed for that purpose.
(f) Safety fuse shall be ignited only after the primer and the explosive material are securely in place.
(g) Safety fuse shall be ignited only with devices designed for that purpose. Carbide lights, liquefied petroleum gas torches, and cigarette lighters shall not be used to light safety fuse.
(h) At least two persons shall be present when lighting safety fuse, and no one shall light more than 15 individual fuses. If more than 15 holes per person are to be fired, electric initiation systems, igniter cord and connectors, or other nonelectric initiation systems shall be used.
§ 57.6600   Loading practices.
If extraneous electricity is suspected in an area where electric detonators are used, loading shall be suspended until tests determine that stray current does not exceed 0.05 amperes through a 1-ohm resister when measured at the location of the electric detonators. If greater levels of extraneous electricity are found, the source shall be determined and no loading shall take place until the condition is corrected.
§ 57.6601   Grounding.
Electric blasting circuits, including powerline sources when used, shall not be grounded.
§ 57.6602   Static electricity dissipation during loading.
When explosive material is loaded pneumatically into a blasthole in a manner that generates a static electricity hazard—
(a) An evaluation of the potential static electricity hazard shall be made and any hazard shall be eliminated before loading begins;
(b) The loading hose shall be of a semiconductive type, have a total of not more than 2 megohms of resistance over its entire length and not less than 1000 ohms of resistance per foot;
(c) Wire-countered hoses shall not be used;
(d) Conductive parts of the loading equipment shall be bonded and grounded and grounds shall not be made to other potential sources of extraneous electricity; and
(e) Plastic tubes shall not be used as hole liners if the hole contains an electric detonator.
§ 57.6603   Air gap.
At least a 15-foot air gap shall be provided between the blasting circuit and the electric power source.
§ 57.6604   Precautions during storms.
During the approach and progress of an electrical storm—
(a) Surface blasting operations shall be suspended and persons withdrawn from the blast area or to a safe location; or
(b) Underground electronic or electrical blasting operations that are capable of being initiated by lightning shall be suspended and all persons withdrawn from the blast area or to a safe location.
§ 57.6605   Isolation of blasting circuits.
Lead wires and blasting lines shall be isolated and insulated from power conductors, pipelines, and railroad tracks, and shall be protected from sources of stray or static electricity. Blasting circuits shall be protected from any contact between firing lines and overhead powerlines which could result from the force of a blast.
§ 57.6700   Nonsparking tools.
Only nonsparking tools shall be used to open containers of explosive material or to punch holes in explosive cartridges.
§ 57.6701   Tamping and loading pole requirements.
Tamping and loading poles shall be of wood or other nonconductive, nonsparking material. Couplings for poles shall be nonsparking.
§ 57.6800   Storage facilities.
When repair work which could produce a spark or flame is to be performed on a storage facility—
(a) The explosive material shall be moved to another facility, or moved at least 50 feet from the repair activity and monitored; and
(b) The facility shall be cleaned to prevent accidental detonation.
§ 57.6801   Vehicle repair.
Vehicles containing explosive material and oxidizers shall not be taken into a repair garage or shop.
§ 57.6802   Bulk delivery vehicles.
No welding or cutting shall be performed on a bulk delivery vehicle until the vehicle has been washed down and all explosive material has been removed. Before welding or cutting on a hollow shaft, the shaft shall be thoroughly cleaned inside and out and vented with a minimum 1/2 -inch diameter opening to allow for sufficient ventilation.
§ 57.6803   Blasting lines.
Permanent blasting lines shall be properly supported. All blasting lines shall be insulated and kept in good repair.
§ 57.6900   Damaged or deteriorated explosive material.
Damaged or deteriorated explosive material shall be disposed of in a safe manner in accordance with the instructions of the manufacturer.
§ 57.6901   Black powder.
(a) Black powder shall be used for blasting only when a desired result cannot be obtained with another type of explosive, such as in quarrying certain types of dimension stone.
(b) Containers of black powder shall be—
(1) Nonsparking;
(2) Kept in a totally enclosed cargo space while being transported by a vehicle;
(3) Securely closed at all times when—
(i) Within 50 feet of any magazine or open flame;
(ii) Within any building in which a fuel-fired or exposed-element electric heater is operating; or
(iii) In an area where electrical or incandescent-particle sparks could result in powder ignition; and
(4) Opened only when the powder is being transferred to a blasthole or another container and only in locations not listed in paragraph (b)(3) of this section.
(c) Black powder shall be transferred from containers only by pouring.
(d) Spills shall be cleaned up promptly with nonsparking equipment. Contaminated powder shall be put into a container of water and shall be disposed of promptly after the granules have disintegrated, or the spill area shall be flushed promptly with water until the granules have disintegrated completely.
(e) Misfires shall be disposed of by washing the stemming and powder charge from the blasthole, and removing and disposing of the initiator in accordance with the requirement for damaged explosives.
(f) Holes shall not be reloaded for at least 12 hours when the blastholes have failed to break as planned.
§ 57.6902   Excessive temperatures.
(a) Where heat could cause premature detonation, explosive material shall not be loaded into hot areas, such as kilns or sprung holes.
(b) When blasting sulfide ores where hot holes occur that may react with explosive material in blastholes, operators shall—
(1) Measure an appropriate number of blasthole temperatures in order to assess the specific mine conditions prior to the introduction of explosive material;
(2) Limit the time between the completion of loading and the initiation of the blast to no more than 12 hours; and
(3) Take other special precautions to address the specific conditions at the mine to prevent premature detonation.
§ 57.6903   Burning explosive material.
If explosive material is suspected of burning at the blast site, persons shall be evacuated from the endangered area and shall not return for at least one hour after the burning or suspected burning has stopped.
§ 57.6904   Smoking and open flames.
Smoking and use of open flames shall not be permitted within 50 feet of explosive material except when separated by permanent noncombustible barriers. This standard does not apply to devices designed to ignite safety fuse or to heating devices which do not create a fire or explosion hazard.
§ 57.6905   Protection of explosive material.
(a) Explosive material shall be protected from temperatures in excess of 150 degrees Fahrenheit.
(b) Explosive material shall be protected from impact, except for tamping and dropping during loading.
§ 57.6960   Mixing of explosive material.
(a) The mixing of ingredients to produce explosive material shall not be conducted underground unless prior approval of the MSHA district manager is obtained. In granting or withholding approval, the district manager shall consider the potential hazards created by—
(1) The location of the stored material and the storage practices used;
(2) The transportation and use of the explosive material;
(3) The nature of the explosive material, including its sensitivity;
(4) Any other factor deemed relevant to the safety of miners potentially exposed to the hazards associated with the mixing of the bulk explosive material underground.
(b) Storage facilities for the ingredients to be mixed shall provide drainage away from the facilities for leaks and spills.
§ 57.7002   Equipment defects.
Equipment defects affecting safety shall be corrected before the equipment is used.
§ 57.7003   Drill area inspection.
The drilling area shall be inspected for hazards before starting the drilling operations.
§ 57.7004   Drill mast.
Persons shall not be on a mast while the drill-bit is in operation unless they are provided with a safe platform from which to work and they are required to use safety belts to avoid falling.
§ 57.7005   Augers and drill stems.
Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a moving stem or auger.
§ 57.7008   Moving the drill.
When a drill is being moved from one drilling area to another, drill steel, tools, and other equipment shall be secured and the mast placed in a safe position.
§ 57.7009   Drill helpers.
If a drill helper assists the drill operator during movement of a drill to a new location, the helper shall be in sight of, or in communication with, the operator at all times.
§ 57.7010   Power failures.
In the event of power failure, drill controls shall be placed in the neutral position until power is restored.
§ 57.7011   Straightening crossed cables.
The drill stem shall be resting on the bottom of the hole or on the platform with the stem secured to the mast before attempts are made to straighten a crossed cable on a reel.
§ 57.7012   Tending drills in operation.
While in operation, drills shall be attended at all times.
§ 57.7013   Covering or guarding drill holes.
Drill holes large enough to constitute a hazard shall be covered or guarded.
§ 57.7018   Hand clearance.
Persons shall not hold the drill steel while collaring holes, or rest their hands on the chuck or centralizer while drilling.
§ 57.7028   Hand clearance.
Persons shall not rest their hands on the chuck or centralizer while drilling.
§ 57.7032   Anchoring.
Columns and the drills mounted on them shall be anchored firmly before and during drilling.
§ 57.7050   Tool and drill steel racks.
Receptacles or racks shall be provided for drill steel and tools stored or carried on drills.
§ 57.7051   Loose objects on the mast or drill platform.
To prevent injury to personnel, tools and other objects shall not be left loose on the mast or drill platform.
§ 57.7052   Drilling positions.
Persons shall not drill from—
(a) Positions which hinder their access to the control levers;
(b) Insecure footing or insecure staging; or
(c) Atop equipment not suitable for drilling.
§ 57.7053   Moving hand-held drills.
Before hand-held drills are moved from one working area to another, air shall be turned off and bled from the hose.
§ 57.7054   Starting or moving drill equipment.
Drill operators shall not start or move drilling equipment unless all miners are in the clear.
§ 57.7055   Intersecting holes.
Holes shall not be drilled where there is a danger of intersecting a misfired hole or a hole containing explosives, blasting agents, or detonators.
§ 57.7056   Collaring in bootlegs.
Holes shall not be collared in bootlegs.
§ 57.7801   Jet drills.
Jet piercing drills shall be provided with:
(a) A system to pressurize the equipment operator's cab, when a cab is provided; and
(b) A protective cover over the oxygen flow indicator.
§ 57.7802   Oxygen hose lines.
Safety chains or other suitable locking devices shall be provided across connections to and between high pressure oxygen hose lines of 1-inch inside diameter or larger.
§ 57.7803   Lighting the burner.
A suitable means of protection shall be provided for the employee when lighting the burner.
§ 57.7804   Refueling.
When rotary jet piercing equipment requires refueling at locations other than fueling stations, a system for fueling without spillage shall be provided.
§ 57.7805   Smoking and open flames.
Persons shall not smoke and open flames shall not be used in the vicinity of the oxygen storage and supply lines. Signs warning against smoking and open flames shall be posted in these areas.
§ 57.7806   Oxygen intake coupling.
The oxygen intake coupling on jet piercing drills shall be constructed so that only the oxygen hose can be coupled to it.
§ 57.7807   Flushing the combustion chamber.
The combustion chamber of a jet drill stem which has been sitting unoperated in a drill hole shall be flushed with a suitable solvent after the stem is pulled up.
§ 57.8518   Main and booster fans.
(a) All mine main and booster fans installed and used to ventilate the active workings of the mine shall be operated continuously while persons are underground in the active workings. However, this provision is not applicable during scheduled production-cycle shutdowns or planned or scheduled fan maintenance or fan adjustments where air quality is maintained in compliance with the applicable standards of subpart D of this part and all persons underground in the affected areas are advised in advance of such scheduled or planned fan shutdowns, maintenance, or adjustments.
(b) In the event of main or booster fan failure due to a malfunction, accident, power failure, or other such unplanned or unscheduled event:
(1) The air quality in the affected active workings shall be tested at least within 2-hours of the discovery of the fan failure, and at least every 4-hours thereafter by a competent person for compliance with the requirements of the applicable standards of subpart D of this part until normal ventilation is restored, or
(2) All persons, except those working on the fan, shall be withdrawn, the ventilation shall be restored to normal and the air quality in the affected active workings shall be tested by a competent person to assure that the air quality meets the requirements of the standards in subpart D of this part, before any other persons are permitted to enter the affected active workings.
§ 57.8519   Underground main fan controls.
All underground main fans shall have controls placed at a suitable protected location remote from the fan and preferably on the surface.
§ 57.8520   Ventilation plan.
A plan of the mine ventilation system shall be set out by the operator in written form. Revisions of the system shall be noted and updated at least annually. The ventilation plan or revisions thereto shall be submitted to the District Manager for review and comments upon his written request. The plan shall, where applicable, contain the following:
(a) The mine name.
(b) The current mine map or schematic or series of mine maps or schematics of an appropriate scale, not greater than five hundred feet to the inch, showing:
(1) Direction and quantity of principal air flows;
(2) Locations of seals used to isolate abandoned workings;
(3) Locations of areas withdrawn from the ventilation system;
(4) Locations of all main, booster and auxiliary fans not shown in paragraph (d) of this standard.
(5) Locations of air regulators and stoppings and ventilation doors not shown in paragraph (d) of this standard;
(6) Locations of overcasts, undercasts and other airway crossover devices not shown in paragraph (d) of this standard;
(7) Locations of known oil or gas wells;
(8) Locations of known underground mine openings adjacent to the mine;
(9) Locations of permanent underground shops, diesel fuel storage depots, oil fuel storage depots, hoist rooms, compressors, battery charging stations and explosive storage facilities. Permanent facilities are those intended to exist for one year or more; and
(10) Significant changes in the ventilation system projected for one year.
(c) Mine fan data for all active main and booster fans including manufacturer's name, type, size, fan speed, blade setting, approximate pressure at present operating point, and motor brake horsepower rating.
(d) Diagrams, descriptions or sketches showing how ventilation is accomplished in each typical type of working place including the approximate quantity of air provided, and typical size and type of auxiliary fans used.
(e) The number and type of internal combustion engine units used underground, including make and model of unit, type of engine, make and model of engine, brake horsepower rating of engine, and approval number.
§ 57.8525   Main fan maintenance.
Main fans shall be maintained according to either the manufacturer's recommendations or a written periodic schedule adopted by the operator which shall be available at the operation on request of the Secretary or his authorized representative.
§ 57.8527   Oxygen-deficiency testing.
Flame safety lamps or other suitable devices shall be used to test for acute oxygen deficiency.
§ 57.8528   Unventilated areas.
Unventilated areas shall be sealed, or barricaded and posted against entry.
§ 57.8529   Auxiliary fan systems.
When auxiliary fan systems are used, such systems shall minimize recirculation and be maintained to provide ventilation air that effectively sweeps the working places.
§ 57.8531   Construction and maintenance of ventilation doors.
Ventilation doors shall be—
(a) Substantially constructed;
(b) Covered with fire-retardant material, if constructed of wood;
(c) Maintained in good condition;
(d) Self-closing, if manually operated; and
(e) Equipped with audible or visual warning devices, if mechanically operated.
§ 57.8532   Opening and closing ventilation doors.
When ventilation control doors are opened as a part of the normal mining cycle, they shall be closed as soon as possible to re-establish normal ventilation to working places.
§ 57.8534   Shutdown or failure of auxiliary fans.
(a) Auxiliary fans installed and used to ventilate the active workings of the mine shall be operated continuously while persons are underground in the active workings, except for scheduled production-cycle shutdowns or planned or scheduled fan maintenance or fan adjustments where air quality is maintained in compliance with the applicable standards of subpart D of this part, and all persons underground in the affected areas are advised in advance of such scheduled or planned fan shutdowns, maintenance, or adjustments.
(b) In the event of auxiliary fan failure due to malfunction, accident, power failure, or other such unplanned or unscheduled event:
(1) The air quality in the affected active workings shall be tested at least within 2 hours of the discovery of the fan failure, and at least every 4 hours thereafter by a competent person for compliance with the requirements of the applicable standards of subpart D of this part until normal ventilation is restored, or
(2) All persons, except those working on the fan, shall be withdrawn, the ventilation shall be restored to normal and the air quality in the affected active workings shall be tested by a competent person to assure that the air quality meets the requirements of the standards in subpart D of this part, before any other persons are permitted to enter the affected active workings.
§ 57.8535   Seals.
Seals shall be provided with a means for checking the quality of air behind the seal and a means to prevent a water head from developing unless the seal is designed to impound water.
§ 57.9100   Traffic control.
To provide for the safe movement of self-propelled mobile equipment—
(a) Rules governing speed, right-of-way, direction of movement, and the use of headlights to assure appropriate visibility, shall be established and followed at each mine; and
(b) Signs or signals that warn of hazardous conditions shall be placed at appropriate locations at each mine.
§ 57.9101   Operating speeds and control of equipment.
Operators of self-propelled mobile equipment shall maintain control of the equipment while it is in motion. Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility, and traffic, and the type of equipment used.
§ 57.9102   Movement of independently operating rail equipment.
Movement of two or more pieces of rail equipment operating independently on the same track shall be controlled for safe operation.
§ 57.9103   Clearance on adjacent tracks.
Railcars shall not be left on side tracks unless clearance is provided for traffic on adjacent tracks.
§ 57.9104   Railroad crossings.
Designated railroad crossings shall be posted with warning signs or signals, or shall be guarded when trains are passing. These crossings shall also be planked or filled between the rails.
§ 57.9160   Train movement during shift changes.
During shift changes, the movement of underground trains carrying rock or material shall be limited to areas where the trains do not present a hazard to persons changing shifts.
§ 57.9200   Transporting persons.
Persons shall not be transported—
(a) In or on dippers, forks, clamshells, or buckets except shaft buckets during shaft-sinking operations or during inspection, maintenance and repair of shafts.
(b) In beds of mobile equipment or railcars, unless—
(1) Provisions are made for secure travel, and
(2) Means are taken to prevent accidental unloading if the equipment is provided with unloading devices;
(c) On top of loads in mobile equipment;
(d) Outside cabs, equipment operators' stations, and beds of mobile equipment, except when necessary for maintenance, testing, or training purposes, and provisions are made for secure travel. This provision does not apply to rail equipment.
(e) Between cars of trains, on the leading end of trains, on the leading end of a single railcar, or in other locations on trains that expose persons to hazards from train movement.
(1) This paragraph does not apply to car droppers if they are secured with safety belts and lines which prevent them from falling off the work platform.
(2) Brakemen and trainmen are prohibited from riding between cars of moving trains but may ride on the leading end of trains or other locations when necessary to perform their duties;
(f) To and from work areas in overcrowded mobile equipment;
(g) In mobile equipment with materials or equipment unless the items are secured or are small and can be carried safely by hand without creating a hazard to persons; or
(h) On conveyors unless the conveyors are designed to provide for their safe transportation.
§ 57.9201   Loading, hauling, and unloading of equipment or supplies.
Equipment and supplies shall be loaded, transported, and unloaded in a manner which does not create a hazard to persons from falling or shifting equipment or supplies.
§ 57.9202   Loading and hauling large rocks.
Large rocks shall be broken before loading if they could endanger persons or affect the stability of mobile equipment. Mobile equipment used for haulage of mined material shall be loaded to minimize spillage where a hazard to persons could be created.
§ 57.9260   Supplies, materials, and tools on mantrips.
Supplies, materials, and tools, other than small items that can be carried by hand, shall not be transported underground with persons in mantrips. Mantrips shall be operated independently of ore or supply trips.
§ 57.9261   Transporting tools and materials on locomotives.
Tools or materials shall not be carried on top of locomotives underground except for secured rerailing devices located in a manner which does not create a hazard to persons.
§ 57.9300   Berms or guardrails.
(a) Berms or guardrails shall be provided and maintained on the banks of roadways where a drop-off exists of sufficient grade or depth to cause a vehicle to overturn or endanger persons in equipment.
(b) Berms or guardrails shall be at least mid-axle height of the largest self-propelled mobile equipment which usually travels the roadway.
(c) Berms may have openings to the extent necessary for roadway drainage.
(d) Where elevated roadways are infrequently traveled and used only by service or maintenance vehicles, berms or guardrails are not required when all of the following are met:
(1) Locked gates are installed at the entrance points to the roadway.
(2) Signs are posted warning that the roadway is not bermed.
(3) Delineators are installed along the perimeter of the elevated roadway so that, for both directions of travel, the reflective surfaces of at least three delineators along each elevated shoulder are always visible to the driver and spaced at intervals sufficient to indicate the edges and attitude of the roadway.
(4) A maximum speed limit is posted and observed for the elevated unbermed portions of the roadway. Factors to consider when establishing the maximum speed limit shall include the width, slope and alignment of the road, the type of equipment using the road, the road material, and any hazardous conditions which may exist.
(5) Road surface traction is not impaired by weather conditions, such as sleet and snow, unless corrective measures, such as the use of tire chains, plowing, or sanding, are taken to improve traction.
(e) This standard is not applicable to rail beds.
§ 57.9301   Dump site restraints.
Berms, bumper blocks, safety hooks, or similar impeding devices shall be provided at dumping locations where there is a hazard of overtravel or overturning.
§ 57.9302   Protection against moving or runaway railroad equipment.
Stopblocks, derail devices, or other devices that protect against moving or runaway rail equipment shall be installed wherever necessary to protect persons.
§ 57.9303   Construction of ramps and dumping facilities.
Ramps and dumping facilities shall be designed and constructed of materials capable of supporting the loads to which they will be subjected. The ramps and dumping facilities shall provide width, clearance, and headroom to safely accommodate the mobile equipment using the facilities.
§ 57.9304   Unstable ground.
(a) Dumping locations shall be visually inspected prior to work commencing and as ground conditions warrant.
(b) Where there is evidence that the ground at a dumping location may fail to support the mobile equipment, loads shall be dumped a safe distance back from the edge of the unstable area of the bank.
§ 57.9305   Truck spotters.
(a) If truck spotters are used, they shall be in the clear while trucks are backing into dumping position or dumping.
(b) Spotters shall use signal lights to direct trucks where visibility is limited.
(c) When a truck operator cannot clearly recognize the spotter's signals, the truck shall be stopped.
§ 57.9306   Warning devices for restricted clearances.
Where restricted clearance creates a hazard to persons on mobile equipment, warning devices shall be installed in advance of the restricted area and the restricted area shall be conspicuously marked.
§ 57.9307   Design, installation, and maintenance of railroads.
Roadbeds and all elements of the railroad tracks shall be designed, installed, and maintained to provide safe operation consistent with the speed and type of haulage used.
§ 57.9308   Switch throws.
Switch throws shall be installed to provide clearance to protect switchmen from contact with moving trains.
§ 57.9309   Chute design.
Chute-loading installations shall be designed to provide a safe location for persons pulling chutes.
§ 57.9310   Chute hazards.
(a) Prior to chute-pulling, persons who could be affected by the draw or otherwise exposed to danger shall be warned and given time to clear the hazardous area.
(b) Persons attempting to free chute hangups shall be experienced and familiar with the task, know the hazards involved, and use the proper tools to free material.
(c) When broken rock or material is dumped into an empty chute, the chute shall be equipped with a guard or all persons shall be isolated from the hazard of flying rock or material.
§ 57.9311   Anchoring stationary sizing devices.
Grizzlies and other stationary sizing devices shall be securely anchored.
§ 57.9312   Working around drawholes.
Unless platforms or safety lines are used, persons shall not position themselves over drawholes if there is danger that broken rock or material may be withdrawn or bridged.
§ 57.9313   Roadway maintenance.
Water, debris, or spilled material on roadways which creates hazards to the operation of mobile equipment shall be removed.
§ 57.9314   Trimming stockpile and muckpile faces.
Stockpile and muckpile faces shall be trimmed to prevent hazards to persons.
§ 57.9315   Dust control.
Dust shall be controlled at muck piles, material transfer points, crushers, and on haulage roads where hazards to persons would be created as a result of impaired visibility.
§ 57.9316   Notifying the equipment operator.
When an operator of self-propelled mobile equipment is present, persons shall notify the equipment operator before getting on or off that equipment.
§ 57.9317   Suspended loads.
Persons shall not work or pass under the buckets or booms of loaders in operation.
§ 57.9318   Getting on or off moving equipment.
Persons shall not get on or off moving mobile equipment. This provision does not apply to trainmen, brakemen, and car droppers who are required to get on or off slowly moving trains in the performance of their work duties.
§ 57.9319   Going over, under, or between railcars.
Persons shall not go over, under, or between railcars unless—
(a) The train is stopped; and
(b) The train operator, when present, is notified and the notice acknowledged.
§ 57.9330   Clearance for surface equipment.
Continuous clearance of at least 30 inches from the farthest projection of moving railroad equipment shall be provided on at least one side of the tracks at all locations where possible or the area shall be marked conspicuously.
§ 57.9360   Shelter holes.
(a) Shelter holes shall be—
(1) Provided at intervals adequate to assure the safety of persons along underground haulageways where continuous clearance of at least 30 inches cannot be maintained from the farthest projection of moving equipment on at least one side of the haulageway; and
(2) At least four feet wide, marked conspicuously, and provide a minimum 40-inch clearance from the farthest projection of moving equipment.
(b) Shelter holes shall not be used for storage unless a 40-inch clearance is maintained.
§ 57.9361   Drawholes.
To prevent hazards to persons underground, collars of open drawholes shall be free of muck or materials except during transfer of the muck or material through the drawhole.
§ 57.9362   Protection of signalmen.
Signalmen used during slushing operations underground shall be located away from possible contact with cables, sheaves, and slusher buckets.
§ 57.10001   Filling buckets.
Buckets shall not be overloaded, and feed shall be regulated to prevent spillage.
§ 57.10002   Inspection and maintenance.
Inspection and maintenance of carriers (including loading and unloading mechanisms), ropes and supports, and brakes shall be performed by competent persons according to the recommendations of the manufacturer.
§ 57.10003   Correction of defects.
Any hazardous defects shall be corrected before the equipment is used.
§ 57.10004   Brakes.
Positive-action-type brakes and devices which apply the brakes automatically in the event of a power failure shall be provided on aerial tramways.
§ 57.10005   Track cable connections.
Track cable connections shall not obstruct the passage of carriage wheels.
§ 57.10006   Tower guards.
Towers shall be suitably protected from swaying buckets.
§ 57.10007   Falling object protection.
Guard nets or other suitable protection shall be provided where tramways pass over roadways, walkways, or buildings.
§ 57.10008   Riding tramways.
Persons other than maintenance persons shall not ride aerial tramways unless the following features are provided.
(a) Two independent brakes, each capable of holding the maximum load;
(b) Direct communication between terminals;
(c) Power drives with emergency power available in case of primary power failure; and
(d) Buckets equipped with positive locks to prevent accidental tripping or dumping.
§ 57.10009   Riding loaded buckets.
Persons shall not ride loaded buckets.
§ 57.10010   Starting precautions.
Where possible, aerial tramways shall not be started until the operator has ascertained that everyone is in the clear.
§ 57.11001   Safe access.
Safe means of access shall be provided and maintained to all working places.
§ 57.11002   Handrails and toeboards.
Crossovers, elevated walkways, elevated ramps, and stairways shall be of substantial construction, provided with handrails, and maintained in good condition. Where necessary, toeboards shall be provided.
§ 57.11003   Construction and maintenance of ladders.
Ladders shall be of substantial construction and maintained in good condition.
§ 57.11004   Portable rigid ladders.
Portable rigid ladders shall be provided with suitable bases and placed securely when used.
§ 57.11005   Fixed ladder anchorage and toe clearance.
Fixed ladders shall be anchored securely and installed to provide at least 3 inches of toe clearance.
§ 57.11006   Fixed ladder landings.
Fixed ladders shall project at least 3 feet above landings, or substantial handholds shall be provided above the landings.
§ 57.11007   Wooden components of ladders.
Wooden components of ladders shall not be painted except with a transparent finish.
§ 57.11008   Restricted clearance.
Where restricted clearance creates a hazard to persons, the restricted clearance shall be conspicuously marked.
§ 57.11009   Walkways along conveyors.
Walkways with outboard railings shall be provided wherever persons are required to walk alongside elevated conveyor belts. Inclined railed walkways shall be nonskid or provided with cleats.
§ 57.11010   Stairstep clearance.
Vertical clearance above stair steps shall be a minimum of seven feet, or suitable warning signs or similar devices shall be provided to indicate an impaired clearance.
§ 57.11011   Use of ladders.
Persons using ladders shall face the ladders and have both hands free for climbing and descending.
§ 57.11012   Protection for openings around travelways.
Openings above, below, or near travelways through which persons or materials may fall shall be protected by railings, barriers, or covers. Where it is impractical to install such protective devices, adequate warning signals shall be installed.
§ 57.11013   Conveyor crossovers.
Crossovers shall be provided where it is necessary to cross conveyors.
§ 57.11014   Crossing moving conveyors.
Moving conveyors shall be crossed only at designated crossover points.
§ 57.11016   Snow and ice on walkways and travelways.
Regularly used walkways and travelways shall be sanded, salted, or cleared of snow and ice as soon as practicable.
§ 57.11017   Inclined fixed ladders.
Fixed ladders shall not incline backwards.
§ 57.11025   Railed landings, backguards, and other protection for fixed ladders.
Fixed ladders, except on mobile equipment, shall be offset and have substantial railed landings at least every 30 feet unless backguards or equivalent protection such as safety belts and safety lines, are provided.
§ 57.11026   Protection for inclined fixed ladders.
Fixed ladders 70 degrees to 90 degrees from the horizontal and 30 feet or more in length shall have backguards, cages or equivalent protection, starting at a point not more than seven feet from the bottom of the ladders.
§ 57.11027   Scaffolds and working platforms.
Scaffolds and working platforms shall be of substantial construction and provided with handrails and maintained in good condition. Floorboards shall be laid properly and the scaffolds and working platform shall not be overloaded. Working platforms shall be provided with toeboards when necessary.
§ 57.11036   Ladderway trap doors and guards.
Trap doors or adequate guarding shall be provided in ladderways at each level. Doors shall be kept operable.
§ 57.11037   Ladderway openings.
Ladderways constructed after November 15, 1979, shall have a minimum unobstructed cross-sectional opening of 24 inches by 24 inches measured from the face of the ladder.
§ 57.11038   Entering a manway.
Before entering a manway where persons may be working or traveling, a warning shall be given by the person entering the manway and acknowledged by any person present in the manway.
§ 57.11040   Inclined travelways.
Travelways steeper than 35 degrees from the horizontal shall be provided with ladders or stairways.
§ 57.11041   Landings for inclined ladderways.
Fixed ladders with an inclination of more than 70 degrees from the horizontal shall be offset with substantial landings at least every 30 feet or have landing gates at least every 30 feet.
§ 57.11050   Escapeways and refuges.
(a) Every mine shall have two or more separate, properly maintained escapeways to the surface from the lowest levels which are so positioned that damage to one shall not lessen the effectiveness of the others. A method of refuge shall be provided while a second opening to the surface is being developed. A second escapeway is recommended, but not required, during the exploration or development of an ore body.
(b) In addition to separate escapeways, a method of refuge shall be provided for every employee who cannot reach the surface from his working place through at least two separate escapeways within a time limit of one hour when using the normal exit method. These refuges must be positioned so that the employee can reach one of them within 30 minutes from the time he leaves his workplace.
§ 57.11051   Escape routes.
Escape routes shall be—
(a) Inspected at regular intervals and maintained in safe, travelable condition; and
(b) Marked with conspicuous and easily read direction signs that clearly indicate the ways of escape.
§ 57.11052   Refuge areas.
Refuge areas shall be—
(a) Of fire-resistant construction, preferably in untimbered areas of the mine;
(b) Large enough to accommodate readily the normal number of persons in the particular area of the mine;
(c) Constructed so they can be made gastight; and
(d) Provided with compressed air lines, waterlines, suitable handtools, and stopping materials.
§ 57.11053   Escape and evacuation plans.
A specific escape and evacuation plan and revisions thereof suitable to the conditions and mining system of the mine and showing assigned responsibilities of all key personnel in the event of an emergency shall be developed by the operator and set out in written form. Within 45 calendar days after promulgation of this standard a copy of the plan and revisions thereof shall be available to the Secretary or his authorized representative. Also, copies of the plan and revisions thereof shall be posted at locations convenient to all persons on the surface and underground. Such a plan shall be updated as necessary and shall be reviewed jointly by the operator and the Secretary or his authorized representative at least once every six months from the date of the last review. The plan shall include:
(a) Mine maps or diagrams showing directions of principal air flow, location of escape routes and locations of existing telephones, primary fans, primary fan controls, fire doors, ventilation doors, and refuge chambers. Appropriate portions of such maps or diagrams shall be posted at all shaft stations and in underground shops, lunchrooms, and elsewhere in working areas where persons congregate;
(b) Procedures to show how the miners will be notified of emergency;
(c) An escape plan for each working area in the mine to include instructions showing how each working area should be evacuated. Each such plan shall be posted at appropriate shaft stations and elsewhere in working areas where persons congregate;
(d) A fire fighting plan;
(e) Surface procedure to follow in an emergency, including the notification of proper authorities, preparing rescue equipment, and other equipment which may be used in rescue and recovery operations; and
(f) A statement of the availability of emergency communication and transportation facilities, emergency power and ventilation and location of rescue personnel and equipment.
§ 57.11054   Communication with refuge chambers.
Telephone or other voice communication shall be provided between the surface and refuge chambers and such systems shall be independent of the mine power supply.
§ 57.11055   Inclined escapeways.
Any portion of a designated escapeway which is inclined more than 30 degrees from the horizontal and that is more than 300 feet in vertical extent shall be provided with an emergency hoisting facility.
§ 57.11056   Emergency hoists.
The procedure for inspection, testing and maintenance required by standard 57.19120 shall be utilized at least every 30 days for hoists designated as emergency hoists in any evacuation plan.
§ 57.11058   Check-in, check-out system.
Each operator of an underground mine shall establish a check-in and check-out system which shall provide an accurate record of persons in the mine. These records shall be kept on the surface in a place chosen to minimize the danger of destruction by fire or other hazards. Every person underground shall carry a positive means of being identified.
§ 57.11059   Respirable atmosphere for hoist operators underground.
For the protection of operators of hoists located underground which are part of the mine escape and evacuation plan required under standard 57.11053, the hoist operator shall be provided with a respirable atmosphere completely independent of the mine atmosphere. This independent ventilation system shall convert, without contamination, to an approved and properly maintained 2-hour self-contained breathing apparatus to provide a safe means of escape for the hoist operator after the hoisting duties have been completed as prescribed in the mine escape and evacuation plan for that hoist. The hoist operator's independent ventilation system shall be provided by one of the following methods:
(a) A suitable enclosure equipped with a positive pressure ventilation system which may be operated continuously or be capable of immediate activation from within the enclosure during an emergency evacuation. Air for the enclosure's ventilation system shall be provided in one of the following ways:
(1) Air coursed from the surface through a borehole into the hoist enclosure directly or through a metal pipeline from such borehole; or
(2) Air coursed from the surface through metal duct work into the hoist enclosure, although this duct work shall not be located in timber-supported active workings; or
(3) Air supplied by air compressors located on the surface and coursed through metal pipe into the hoist enclosure.
A back-up system shall be provided for a hoist enclosure ventilation system provided by either of the methods set forth in paragraphs (a) (2) and (3) of this section. This back-up system shall consist of compressed air stored in containers connected to the enclosure. This back-up system shall provide and maintain a respirable atmosphere in the enclosure for a period of time equal to at least twice the time necessary to complete the evacuation of all persons designated to use that hoist as prescribed in the mine escape and evacuation plan required under standard 57.11053; or
(b) An approved and properly maintained self-contained breathing apparatus system which shall consist of a mask connected to compressed air stored in containers adjacent to the hoist controls. The self-contained breathing system shall provide a minimum of 24 hours of respirable atmosphere to the hoist operator. In addition, the self-contained breathing system shall be capable of a quick connect with the approved 2-hour self-contained breathing apparatus above.
§ 57.12001   Circuit overload protection.
Circuits shall be protected against excessive overloads by fuses or circuit breakers of the correct type and capacity.
§ 57.12002   Controls and switches.
Electric equipment and circuits shall be provided with switches or other controls. Such switches or controls shall be of approved design and construction and shall be properly installed.
§ 57.12003   Trailing cable overload protection.
Individual overload protection or short circuit protection shall be provided for the trailing cables of mobile equipment.
§ 57.12004   Electrical conductors.
Electrical conductors shall be of a sufficient size and current-carrying capacity to ensure that a rise in temperature resulting from normal operations will not damage the insulating materials. Electrical conductors exposed to mechanical damage shall be protected.
§ 57.12005   Protection of power conductors from mobile equipment.
Mobile equipment shall not run over power conductors, nor shall loads be dragged over power conductors, unless the conductors are properly bridged or protected.
§ 57.12006   Distribution boxes.
Distribution boxes shall be provided with a disconnecting device for each branch circuit. Such disconnecting devices shall be equipped or designed in such a manner that it can be determined by visual observation when such a device is open and that the circuit is deenergized, and the distribution box shall be labeled to show which circuit each device controls.
§ 57.12007   Junction box connection procedures.
Trailing cable and power-cable connections to junction boxes shall not be made or broken under load.
§ 57.12008   Insulation and fittings for power wires and cables.
Power wires and cables shall be insulated adequately where they pass into or out of electrical compartments. Cables shall enter metal frames of motors, splice boxes, and electrical compartments only through proper fittings. When insulated wires, other than cables, pass through metal frames, the holes shall be substantially bushed with insulated bushings.
§ 57.12010   Isolation or insulation of communication conductors.
Telephone and low-potential signal wire shall be protected, by isolation or suitable insulation, or both, from contacting energized power conductors or any other power source.
§ 57.12011   High-potential electrical conductors.
High-potential electrical conductors shall be covered, insulated, or placed to prevent contact with low potential conductors.
§ 57.12012   Bare signal wires.
The potential on bare signal wires accessible to contact by persons shall not exceed 48 volts.
§ 57.12013   Splices and repairs of power cables.
Permanent splices and repairs made in power cables, including the ground conductor where provided, shall be—
(a) Mechanically strong with electrical conductivity as near as possible to that of the original;
(b) Insulated to a degree at least equal to that of the original, and sealed to exclude moisture; and,
(c) Provided with damage protection as near as possible to that of the original, including good bonding to the outer jacket.
§ 57.12014   Handling energized power cables.
Power cables energized to potentials in excess of 150 volts, phase-to-ground, shall not be moved with equipment unless sleds or slings, insulated from such equipment, are used. When such energized cables are moved manually, insulated hooks, tongs, ropes, or slings shall be used unless suitable protection for persons is provided by other means. This does not prohibit pulling or dragging of cable by the equipment it powers when the cable is physically attached to the equipment by suitable mechanical devices, and the cable is insulated from the equipment in conformance with other standards in this part.
§ 57.12016   Work on electrically-powered equipment.
Electrically powered equipment shall be deenergized before mechanical work is done on such equipment. Power switches shall be locked out or other measures taken which shall prevent the equipment from being energized without the knowledge of the individuals working on it. Suitable warning notices shall be posted at the power switch and signed by the individuals who are to do the work. Such locks or preventive devices shall be removed only by the persons who installed them or by authorized personnel.
§ 57.12017   Work on power circuits.
Power circuits shall be deenergized before work is done on such circuits unless hot-line tools are used. Suitable warning signs shall be posted by the individuals who are to do the work. Switches shall be locked out or other measures taken which shall prevent the power circuits from being energized without the knowledge of the individuals working on them. Such locks, signs, or preventive devices shall be removed only by the person who installed them or by authorized personnel.
§ 57.12018   Identification of power switches.
Principal power switches shall be labeled to show which units they control, unless identification can be made readily by location.
§ 57.12019   Access to stationary electrical equipment or switchgear.
Where access is necessary, suitable clearance shall be provided at stationary electrical equipment or switchgear.
§ 57.12020   Protection of persons at switchgear.
Dry wooden platforms, insulating mats, or other electrically-nonconductive material shall be kept in place at all switchboards and power-control switches where shock hazards exist. However, metal plates on which a person normally would stand and which are kept at the same potential as the grounded, metal, non-current-carrying parts of the power switches to be operated may be used.
§ 57.12021   Danger signs.
Suitable danger signs shall be posted at all major electrical installations.
§ 57.12022   Authorized persons at major electrical installations.
Areas containing major electrical installations shall be entered only by authorized persons.
§ 57.12023   Guarding electrical connections and resistor grids.
Electrical connections and resistor grids that are difficult or impractical to insulate shall be guarded, unless protection is provided by location.
§ 57.12025   Grounding circuit enclosures.
All metal enclosing or encasing electrical circuits shall be grounded or provided with equivalent protection. This requirement does not apply to battery-operated equipment.
§ 57.12026   Grounding transformer and switchgear enclosures.
Metal fencing and metal buildings enclosing transformers and switchgear shall be grounded.
§ 57.12027   Grounding mobile equipment.
Frame grounding or equivalent protection shall be provided for mobile equipment powered through trailing cables.
§ 57.12028   Testing grounding systems.
Continuity and resistance of grounding systems shall be tested immediately after installation, repair, and modification; and annually thereafter. A record of the resistance measured during the most recent test shall be made available on a request by the Secretary or his duly authorized representative.
§ 57.12030   Correction of dangerous conditions.
When a potentially dangerous condition is found it shall be corrected before equipment or wiring is energized.
§ 57.12032   Inspection and cover plates.
Inspection and cover plates on electrical equipment and junction boxes shall be kept in place at all times except during testing or repairs.
§ 57.12033   Hand-held electric tools.
Hand-held electric tools shall not be operated at high potential voltages.
§ 57.12034   Guarding around lights.
Portable extension lights, and other lights that by their location present a shock or burn hazard, shall be guarded.
§ 57.12035   Weatherproof lamp sockets.
Lamp sockets shall be of a weatherproof type where they are exposed to weather or wet conditions that may interfere with illumination or create a shock hazard.
§ 57.12036   Fuse removal or replacement.
Fuses shall not be removed or replaced by hand in an energized circuit, and they shall not otherwise be removed or replaced in an energized circuit unless equipment and techniques especially designed to prevent electrical shock are provided and used for such purpose.
§ 57.12037   Fuses in high-potential circuits.
Fuse tongs or hotline tools, shall be used when fuses are removed or replaced in high-potential circuits.
§ 57.12038   Attachment of trailing cables.
Trailing cables shall be attached to machines in a suitable manner to protect the cable from damage and to prevent strain on the electrical connections.
§ 57.12039   Protection of surplus trailing cables.
Surplus trailing cables to shovels, cranes and similar equipment shall be—
(a) Stored in cable boats;
(b) Stored on reels mounted on the equipment; or
(c) Otherwise protected from mechanical damage.
§ 57.12040   Installation of operating controls.
Operating controls shall be installed so that they can be operated without danger of contact with energized conductors.
§ 57.12041   Design of switches and starting boxes.
Switches and starting boxes shall be of safe design and capacity.
§ 57.12042   Track bonding.
Both rails shall be bonded or welded at every joint and rails shall be crossbonded at least every 200 feet if the track serves as the return trolley circuit. When rails are moved, replaced, or broken bonds are discovered, they shall be rebonded within three working shifts.
§ 57.12045   Overhead powerlines.
Overhead high-potential powerlines shall be installed as specified by the National Electrical Code.
§ 57.12047   Guy wires.
Guy wires of poles supporting high-voltage transmission lines shall meet the requirements for grounding or insulator protection of the National Electrical Safety Code, part 2, entitled “Safety Rules for the Installation and Maintenance of Electric Supply and Communication Lines” (also referred to as National Bureau of Standards Handbook 81, Nov. 1, 1961), and Supplement 2 thereof issued March 1968, which are hereby incorporated by reference and made a part hereof. These publications and documents may be obtained from the National Institute of Science and Technology, 100 Bureau Drive, Stop 3460, Gaithersburg, MD 20899-3460. Telephone: 301-975-6478 (not a toll free number); http://ts.nist.gov/nvl; or from the Government Printing Office, Information Dissemination (Superintendent of Documents), P.O. Box 371954, Pittsburgh, PA 15250-7954; Telephone: 866-512-1800 (toll free) or 202-512-1800; http://bookstore.gpo.gov , or may be examined in any Metal and Nonmetal Mine Safety and Health District Office of the Mine Safety and Health Administration.
§ 57.12048   Communication conductors on power poles.
Telegraph, telephone, or signal wires shall not be installed on the same crossarm with power conductors. When carried on poles supporting powerlines, they shall be installed as specified by the National Electrical Code.
§ 57.12050   Installation of trolley wires.
Trolley wires shall be installed at least seven feet above rails where height permits, and aligned and supported to suitably control sway and sag.
§ 57.12053   Circuits powered from trolley wires.
Ground wires for lighting circuits powered from trolley wires shall be connected securely to the ground return circuit.
§ 57.12065   Short circuit and lightning protection.
Powerlines, including trolley wires, and telephone circuits shall be protected against short circuits and lightning.
§ 57.12066   Guarding trolley wires and bare powerlines.
Where metallic tools or equipment can come in contact with trolley wires or bare powerlines, the lines shall be guarded or deenergized.
§ 57.12067   Installation of transformers.
Transformers shall be totally enclosed, or shall be placed at least 8 feet above the ground, or installed in a transformer house, or surrounded by a substantial fence at least 6 feet high and at least 3 feet from any energized parts, casings, or wiring.
§ 57.12068   Locking transformer enclosures.
Transformer enclosures shall be kept locked against unauthorized entry.
§ 57.12069   Lightning protection for telephone wires and ungrounded conductors.
Each ungrounded conductor or telephone wire that leads underground and is directly exposed to lightning shall be equipped with suitable lightning arrestors of approved type within 100 feet of the point where the circuit enters the mine. Lightning arrestors shall be connected to a low resistance grounding medium on the surface and shall be separated from neutral grounds by a distance of not less than 25 feet.
§ 57.12071   Movement or operation of equipment near high-voltage powerlines.
When equipment must be moved or operated near energized high-voltage powerlines (other than trolley lines) and the clearance is less than 10 feet, the lines shall be deenergized or other precautionary measures shall be taken.
§ 57.12080   Bare conductor guards.
Trolley wires and bare power conductors shall be guarded at mantrip loading and unloading points, and at shaft stations. Where such trolley wires and bare power conductors are less than 7 feet above the rail, they shall be guarded at all points where persons work or pass regularly beneath.
§ 57.12081   Bonding metal pipelines to ground return circuits.
All metal pipelines, 1,000 feet or more in length running parallel to trolley tracks, that are used as a ground return circuit shall be bonded to the return circuit rail at the ends of the pipeline and at intervals not to exceed 500 feet.
§ 57.12082   Isolation of powerlines.
Powerlines shall be well separated or insulated from waterlines, telephone lines and air lines.
§ 57.12083   Support of power cables in shafts and boreholes.
Power cables in shafts and boreholes shall be fastened securely in such a manner as to prevent undue strain on the sheath, insulation, or conductors.
§ 57.12084   Branch circuit disconnecting devices.
Disconnecting switches that can be opened safely under load shall be provided underground at all branch circuits extending from primary power circuits near shafts, adits, levels and boreholes.
§ 57.12085   Transformer stations.
Transformer stations shall be enclosed to prevent persons from unintentionally or inadvertently contacting energized parts.
§ 57.12086   Location of trolley wire.
Trolley and trolley feeder wire shall be installed opposite the clearance side of haulageways. However, this standard does not apply where physical limitations would prevent the safe installation or use of such trolley and trolley feeder wire.
§ 57.12088   Splicing trailing cables.
No splice, except a vulcanized splice or its equivalent, shall be made in a trailing cable within 25 feet of the machine unless the machine is equipped with a cable reel or other power feed cable payout-retrieval system. However, a temporary splice may be made to move the equipment for repair.
§ 57.13001   General requirements for boilers and pressure vessels.
All boilers and pressure vessels shall be constructed, installed, and maintained in accordance with the standards and specifications of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code.
§ 57.13010   Reciprocating-type air compressors.
(a) Reciprocating-type air compressors rated over 10 horsepower shall be equipped with automatic temperature-actuated shutoff mechanisms which shall be set or adjusted to the compressor when the normal operating temperature is exceeded by more than 25 percent.
(b) However, this standard does not apply to reciprocating-type air compressors rated over 10 horsepower if equipped with fusible plugs that were installed in the compressor discharge lines before November 15, 1979, and designed to melt at temperatures at least 50 degrees below the flash point of the compressors' lubricating oil.
§ 57.13011   Air receiver tanks.
Air receiver tanks shall be equipped with one or more automatic pressure-relief valves. The total relieving capacity of the relief valves shall prevent pressure from exceeding the maximum allowable working pressure in a receiver tank by not more than 10 percent. Air receiver tanks also shall be equipped with indicating pressure gages which accurately measure the pressure within the air receiver tanks.
§ 57.13012   Compressor air intakes.
Compressor air intakes shall be installed to ensure that only clean, uncontaminated air enters the compressors.
§ 57.13015   Inspection of compressed-air receivers and other unfired pressure vessels.
(a) Compressed-air receivers and other unfired pressure vessels shall be inspected by inspectors holding a valid National Board Commission and in accordance with the applicable chapters of the National Board Inspection Code, a Manual for Boiler and Pressure Vessel Inspectors, 1979. This code is incorporated by reference and made a part of this standard. It may be examined at any Metal and Nonmetal Mine Safety and Health District Office of the Mine Safety and Health Administration, and may be obtained from the publisher, the National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Avenue, Columbus, Ohio 43229.
(b) Records of inspections shall be kept in accordance with requirements of the National Board Inspection Code, and the records shall be made available to the Secretary or his authorized representative.
§ 57.13017   Compressor discharge pipes.
Compressor discharge pipes where carbon build-up may occur shall be cleaned periodically as recommended by the manufacturer, but no less frequently than once every two years.
§ 57.13019   Pressure system repairs.
Repairs involving the pressure system of compressors, receivers, or compressed-air-powered equipment shall not be attempted until the pressure has been bled off.
§ 57.13020   Use of compressed air.
At no time shall compressed air be directed toward a person. When compressed air is used, all necessary precautions shall be taken to protect persons from injury.
§ 57.13021   High-pressure hose connections.
Except where automatic shutoff valves are used, safety chains or other suitable locking devices shall be used at connections to machines of high-pressure hose lines of 3/4 -inch inside diameter or larger, and between high-pressure hose lines of 3/4 -inch inside diameter or larger, where a connection failure would create a hazard.
§ 57.13030   Boilers.
(a) Fired pressure vessels (boilers) shall be equipped with water level gauges, pressure gauges, automatic pressure-relief valves, blowdown piping, and other safety devices approved by the American Society of Mechanical Engineers to protect against hazards from overpressure, flameouts, fuel interruptions and low water level, all as required by the appropriate sections, chapters and appendices listed in paragraphs (b) (1) and (2) of this section.
(b) These gauges, devices and piping shall be designed, installed, operated, maintained, repaired, altered, inspected, and tested by inspectors holding a valid National Board Commission and in accordance with the following listed sections, chapters and appendices:
(1) The ASME Boiler and Pressure Vessel Code, 1977, published by the American Society of Mechanical Engineers.
(2) The National Board Inspection Code, a Manual for Boiler and Pressure Vessel Inspectors, 1979, published by the National Board of Boiler and Pressure Vessel Inspectors.
(c) Records of inspections and repairs shall be kept in accordance with the requirements of the ASME Boiler and Pressure Vessel Code and the National Board Inspection Code. The records shall be made available to the Secretary or his authorized representative.
(d) Sections of the ASME Boiler and Pressure Vessel Code, 1977, listed in paragraph (b)(1) of this section, and chapters and appendices of the National Board Inspection Code, 1979, listed in paragraph (b)(2) of this section, are incorporated by reference and made a part of this standard. These publications may be obtained from the publishers, the American Society of Mechanical Engineers, 22 Law Drive, P.O. Box 2900, Fairfield, New Jersey 07007, Phone: 800-843-2763 (toll free); http://www.asme.org , and the National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Avenue, Columbus, Ohio 43229. The publication may be examined at any Metal and Nonmetal Mine Safety and Health District Office of the Mine Safety and Health Administration.
§ 57.14000   Definitions.
The following definitions apply in this subpart.
Travelway. A passage, walk, or way regularly used or designated for persons to go from one place to another.
§ 57.14100   Safety defects; examination, correction and records.
(a) Self-propelled mobile equipment to be used during a shift shall be inspected by the equipment operator before being placed in operation on that shift.
(b) Defects on any equipment, machinery, and tools that affect safety shall be corrected in a timely manner to prevent the creation of a hazard to persons.
(c) When defects make continued operation hazardous to persons, the defective items including self-propelled mobile equipment shall be taken out of service and placed in a designated area posted for that purpose, or a tag or other effective method of marking the defective items shall be used to prohibit further use until the defects are corrected.
(d) Defects on self-propelled mobile equipment affecting safety, which are not corrected immediately, shall be reported to, and recorded by, the mine operator. The records shall be kept at the mine or nearest mine office from the date the defects are recorded, until the defects are corrected. Such records shall be made available for inspection by an authorized representative of the Secretary.
§ 57.14101   Brakes.
(a) Minimum requirements. (1) Self-propelled mobile equipment shall be equipped with a service brake system capable of stopping and holding the equipment with its typical load on the maximum grade it travels. This standard does not apply to equipment which is not originally equipped with brakes unless the manner in which the equipment is being operated requires the use of brakes for safe operation. This standard does not apply to rail equipment.
(2) If equipped on self-propelled mobile equipment, parking brakes shall be capable of holding the equipment with its typical load on the maximum grade it travels.
(3) All braking systems installed on the equipment shall be maintained in functional condition.
(b) Testing. (1) Service brake tests shall be conducted on surface-operated equipment at underground mines when an MSHA inspector has reasonable cause to believe that the service brake system does not function as required, unless the mine operator removes the equipment from service for the appropriate repair;
(2) The performance of the service brakes shall be evaluated according to Table M-1.
Table M-1
Stopping distances are computed using a constant deceleration of 9.66 FPS 2 and system response times of .5.1, 1.5, 2, 2.25 and 2.5 seconds for each of increasing weight category respectively. Stopping distance values include a one-second operator response time.
Table M-2—The Speed of a Vehicle Can Be Determined by Clocking It Through a 100-Foot Measured Course at Constant Velocity Using Table M-2. When the Service Brakes Are Applied at the End of the Course, Stopping Distance Can Be Measured and Compared to Table M-1.
(3) Service brake tests shall be conducted under the direction of the mine operator in cooperation with and according to the instructions provided by the MSHA inspector as follows:
(i) Equipment capable of traveling at least 10 miles per hour shall be tested with a typical load for that particular piece of equipment. Front-end loaders shall be tested with the loader bucket empty. Equipment shall not be tested when carrying hazardous loads, such as explosives.
(ii) The approach shall be of sufficient length to allow the equipment operator to reach and maintain a constant speed between 10 and 20 miles per hour prior to entering the 100 foot measured area. The constant speed shall be maintained up to the point when the equipment operator receives the signal to apply the brakes. The roadway shall be wide enough to accommodate the size of the equipment being tested. The ground shall be generally level, packed, and dry in the braking portion of the test course. Ground moisture may be present to the extent that it does not adversely affect the braking surface.
(iii) Braking is to be performed using only those braking systems, including auxiliary retarders, which are designed to bring the equipment to a stop under normal operating conditions. Parking or emergency (secondary) brakes are not to be actuated during the test.
(iv) The tests shall be conducted with the transmission in the gear appropriate for the speed the equipment is traveling except for equipment which is designed for the power train to be disengaged during braking.
(v) Testing speeds shall be a minimum of 10 miles per hour and a maximum of 20 miles per hour.
(vi) Stopping distances shall be measured from the point at which the equipment operator receives the signal to apply the service brakes to the final stopped position.
(4) Test results shall be evaluated as follows:
(i) If the initial test run is valid and the stopping distance does not exceed the corresponding stopping distance listed in Table 1, the performance of the service brakes shall be considered acceptable. For tests to be considered valid, the equipment shall not slide sideways or exhibit other lateral motion during the braking portion of the test.
(ii) If the equipment exceeds the maximum stopping distance in the initial test run, the mine operator may request from the inspector up to four additional test runs with two runs to be conducted in each direction. The performance of the service brakes shall be considered acceptable if the equipment does not exceed the maximum stopping distance on at least three of the additional tests.
(5) Where there is not an appropriate test site at the mine or the equipment is not capable of traveling at least 10 miles per hour, service brake tests will not be conducted. In such cases, the inspector will rely upon other available evidence to determine whether the service brake system meets the performance requirements of this standard.
§ 57.14102   Brakes for rail equipment.
Braking systems on railroad cars and locomotives shall be maintained in functional condition.
§ 57.14103   Operators' stations.
(a) If windows are provided on operators' stations of self-propelled mobile equipment, the windows shall be made of safety glass or material with equivalent safety characteristics. The windows shall be maintained to provide visibility for safe operation.
(b) If damaged windows obscure visibility necessary for safe operation, or create a hazard to the equipment operator, the windows shall be replaced or removed. Damaged windows shall be replaced if absence of a window would expose the equipment operator to hazardous environmental conditions which would affect the ability of the equipment operator to safely operate the equipment.
(c) The operators' stations of self-propelled mobile equipment shall—
(1) Be free of materials that may create a hazard to persons by impairing the safe operation of the equipment; and
(2) Not be modified, in a manner that obscures visibility necessary for safe operation.
§ 57.14104   Tire repairs.
(a) Before a tire is removed from a vehicle for tire repair, the valve core shall be partially removed to allow for gradual deflation and then removed. During deflation, to the extent possible, persons shall stand outside of the potential trajectory of the lock ring of a multi-piece wheel rim.
(b) To prevent injury from wheel rims during tire inflation, one of the following shall be used:
(1) A wheel cage or other restraining device that will constrain all wheel rim components during an explosive separation of a multi-piece wheel rim, or during the sudden release of contained air in a single piece rim wheel; or
(2) A stand-off inflation device which permits persons to stand outside of the potential trajectory of wheel components.