METAL AND NONMETAL MINES
METAL AND NONMETAL MINES
56/57.5001(a) Issuing Citations on the Basis of Vacuum Bottle or Bistable Gas Samples
Vacuum bottle or bistable gas samples may be used as the principal determining factor in classifying a mine as gassy (30 CFR 57.22003). However, vacuum bottle and bistable gas samples cannot be used as the basis for the issuance of citations or orders unless arrangements for special sampling bottles are made. The principal use of vacuum bottles and bistables is for rough screening to determine if potential problems exist which require more thorough evaluation.
56/57.5001(a)/.5005 Issuing and Terminating
Except where indicated, inspectors shall treat standards 56/57.5001 and 56/57.5005 as one standard when issuing citations. Issue one 56/57.5001(a)/.5005 citation for each miner whose exposure to airborne contaminant(s) exceeds the contaminant's enforcement level. The Metal and Nonmetal Health Inspection Procedures Handbook provides instructions on calculating the contaminant's enforcement level.
The body of the citation must contain all pertinent information, such as: the contaminant's permissible exposure limit (PEL) and error factor; the shift or time-weighted average (SWA/TWA); the date of the overexposure; the date of the citation; the miner's location and job description; whether an adequate respirator was provided and worn and a respiratory protection program was in place consistent with 56/57.5005; and the reason for the overexposure, such as obvious deficiencies or breakdowns in the operator's control system. The citation's initial abatement date should reflect the time needed to provide an appropriate respirator and develop a respiratory protection program consistent with 56/57.5005. Give less time if you can identify more expedient controls that will bring the miner's exposure into compliance. For highly toxic or dangerous contaminants, keep the abatement time to a minimum.
Once the operator's respiratory protection program is in place, extend the citation's abatement date to allow a reasonable time to utilize engineering or administrative controls. You do not need to modify the standard number, 56/57.5001(a)/.5005, when the operator has the respiratory protection program in place.
Initially write the citation to require feasible engineering or administrative controls provided the overexposed miner was already wearing an appropriate respirator and the operator had an appropriate respiratory protection program. The operator may use an appropriate respirator and respiratory protection program instead of such controls when the miner is installing controls or occasionally enters hazardous atmospheres to perform maintenance or investigation.
Terminate a citation when the use of administrative or engineering controls reduces the miner's exposure to the contaminant's enforcement level. If the miner's exposure exceeds the enforcement level, citations can only be terminated when the operator has used all feasible engineering and administrative controls, has an appropriate respiratory protection program, and the miner is wearing an appropriate respirator.
If the operator fails to provide an appropriate respirator and implement an appropriate respiratory protection program within the abatement time, and further extension of the abatement time is not warranted, a 104(b) order can be issued. The order can be modified, once an appropriate respirator and respiratory protection program are provided, to allow the operator to continue to operate until feasible administrative or engineering controls are established.
Where MSHA requires a respiratory protection program for compliance, inspectors can cite without resampling if the operator fails to follow the program's requirements. In such a case, cite 56/57.5005 alone as the standard violated.
56/57.5002 Dust, Gas, Mist and Fume Surveys by Mine
These standards require mine operators to conduct dust, gas, mist and fume surveys as frequently as necessary to determine the adequacy of control measures. The purpose is to help assure that the miners are not exposed to harmful concentrations of airborne contaminants.
These standards apply to those air contaminants covered under 30 C.F.R. §§ 56/57.5001(a) and (b) and do not apply to standards for radon, diesel particulate matter, or noise since those standards contain specific monitoring requirements. Mine operators must demonstrate compliance with 56/57.5002 rather than relying on enforcement interventions. MSHA emphasizes that mine operators:
- Plan - A system to survey for dust, fume, gas, and mist to determine adequacy of control measures.
- Prevent - Miners' exposure to these hazards.
- Protect - Miners from adverse health effects due to exposures to airborne contaminants.
During Agency inspections, MSHA will evaluate operator activities to verify evidence of surveys.
The term "survey" denotes any information collection method that:
- Yields information as to miners' exposures to harmful airborne contaminants, or
- Yields information as to the effectiveness of controls in reducing exposures to harmful airborne contaminants.
MSHA will determine whether the surveys being conducted are frequent enough for determining whether controls are effective in reducing exposures to airborne contaminants. Factors which may influence the frequency of inspections can include: sampling results approaching the Threshold Limit Value (TLV), changes in the mining operation (e.g., hazards or environmental agents; changes in control equipment used to reduce exposures), changes in the work schedule (e.g., if workers worked longer shifts), changes in work procedures, or whether controls need routine or special maintenance (e.g., vehicle cabs, ventilation systems, dust collection systems).
MSHA can verify whether surveys are being conducted by various means including reviewing any existing records maintained by the operator, interviewing miners and operators, or visually inspecting the work area.
56/57.5005 Respiratory Protection
Standard 56/57.5001(a) requires that a miner's exposure shall not exceed the permissible limit of any substance on the TLV list. When the TLV is exceeded, standard 56/57.5005 mandates that operators install all feasible engineering controls to reduce a miner's exposure to the TLV. Respiratory protection is required when controls are not feasible, as well as when establishing controls, and during occasional entry into hazardous atmospheres to perform short-term maintenance or investigations. Whenever respirators are required, operators must establish a respirator program containing all elements of the standard, which incorporates ANSI Z88.2-1969. The inspector must evaluate the effectiveness of the respiratory protection in order to determine whether miners are protected from overexposure. If the operator's respiratory protection program fails to include proper selection and fit testing, the .5001(a)/.5005 violation is significant and substantial ("S and S").
Respirator selection directly affects the efficiency of the respirator. Respirators are designed to protect wearers from inhalation of hazardous atmospheres. There are many different types of respirators but each is limited in protection and application. A respirator can only protect against atmospheres for which it is designed. Without proper selection a serious health hazard may occur. A serious hazard may also occur if the respirator, even though properly selected, is not fitted as required by the standard. Fit testing is essential in order to assign the correct model and size respirator to a miner. Otherwise, it is likely that the respirator will leak and the miner will be overexposed to the toxic substance.
There are other factors that should be considered by the inspector on a case-by-case basis when determining whether the violation should be "S and S" with regard to an operator's respiratory protection program. These factors include training, cleaning and sanitizing, and maintenance of respirators.
With regard to listed nuisance particulates and silver metal overexposures between 0.01 mg/m3 and 0.1 mg/m3, operators must use engineering controls to reduce exposure to the permissible limit and comply with the respiratory protection requirements of standard 56/57.5005. However, the .5001(a)/.5005 citation for overexposure to nuisance particulates and to silver metal in the above concentration range is not "S and S." Overexposures to soluble compounds of silver, such as silver nitrate, above 0.01 mg/m3 should be considered "S and S" if adequate protection was not worn.
56/57.5005(a) Use of Certified Mercury
For mercury vapor, the use of MSHA-NIOSH certified chemical cartridge respirators is required. This is the belt-mounted Comfo II respirator with Mersorb cartridges. The purpose of the belt-mounted design is to allow the wearer to easily observe the saturation indicator on the mercury cartridge. The use of face- mounted MSA Comfo II respirators with Mersorb cartridges is only acceptable in work situations where the breathing tube of the belt-mounted respirator can become a safety hazard, the work performed causes tension on the breathing tube which can break the seal, or the breathing tube is too short for the wearer and provided that visual checks of the cartridge indicators are made every half hour. The checks on the face-mounted respirator can be made by looking into a mirror or by checking the respirator in uncontaminated air. Because leakage of mercury vapor into the respirator cannot be detected by the wearer, it is critical that a good facepiece-to-face seal be maintained and that the indicator be monitored to prevent breakthrough through the cartridges.
56/57.5005(c) Definition of Immediately Harmful to
The definition of "immediately harmful to life" in this standard is the same as that of "immediately dangerous to life or health" (IDLH) as defined by NIOSH, which is acute respiratory exposure that poses an immediate threat of loss of life, immediate or delayed irreversible adverse health effects, or acute eye exposure that would prevent escape from a hazardous atmosphere.
57.5039 Maximum Permissible Concentration (Radon
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. In enforcing this standard, the error factor for radon daughter sampling of 20% should be taken into consideration. This means that citations are to be issued when the measured radon daughter concentrations are in excess of 1.20 WL.
Also, this standard applies only to active work areas when workers are present or scheduled during the shift and, if workers are not present or scheduled, when evidence is available that other personnel normally enter the work area during the shift.
57.5040 Exposure Records (Radon
"Significant and Substantial" Violation Inadequate recordkeeping may result in excessive exposures to radiation going undetected and unremedied. Where the violation has actually or potentially contributed to this hazard, the citation will be designated "significant and substantial." Generally, such findings will be appropriate where:
- The operator fails to keep personal exposure records, or
- The operator has falsified or altered records or continuously understated the accumulated exposures.
Where such failures are the result of the operator's disregard for the recordkeeping requirements, such violation may also be considered unwarrantable.
In cases where no hazard results, a violation shall be cited
as a technical violation without "significant and substantial"
Where respiratory protection is used pursuant to 57.5044 and in compliance with 57.5005, that is, entry into hazardous areas for reasonable periods of time to establish controls or occasional entry for investigative or maintenance purposes, MSHA will allow respirator credit on mine employees' radon daughter exposure records. Respirators used for protection against radon daughters must be capable of removing 90 percent of the radon daughters from the respired air.
Credit will not be allowed for the wearing of respirators while performing any type of production work, regardless of the radiation levels.
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.
This standard applies to inactive workings (e.g., worked-out sections only). Active workings are subject to 57.5039. See 57.2 for the definition of "active workings" and 57.5040(a)(1) for examples of areas considered "active workings." Standards 57.5044 and 57.5046 for respiratory protection apply to both active and inactive workings.
57.5046 Protection Against Radon
Where radon daughter concentrations exceed 10.0 WL, respirator protection against radon gas shall be provided (in addition to protection against radon daughters).
Because of the rare special circumstances of working in atmospheres that contain radon daughters above 10.0 working levels, there are no respirators or gas masks specifically approved by NIOSH for removal of radon gas. A self-contained breathing apparatus or a continuous flow airline (pure-air) respirator would satisfy the requirements of this standard.
57.5047 Gamma Radiation Exposure Records
"Significant and Substantial" Violation
Inadequate gamma radiation exposure records may result in undetected and unremedied excessive exposures (see 57.5047(d)). Where the violation of 57.5047 has actually or potentially contributed to this hazard, the resulting citations will be designated "significant and substantial." Generally, such findings will be appropriate where:
- The operator fails to keep personal exposure records, or
- The operator has falsified or altered records or continuously understated the accumulated exposures.
Where such failures are the result of the operator's disregard for the recordkeeping requirements, such violation may be considered unwarrantable.
In cases where no hazard results, a violation shall be cited as a technical violation without "significant and substantial" findings.
56/57.14213 Ventilation for Welding
This is a work practice standard intended to reduce the concentration of airborne contaminants from welding below levels which may cause health impairment. In ventilation for welding fume control, local exhaust ventilation is better than dilution ventilation, and general dilution ventilation is better than natural ventilation.
This standard should be cited whenever welding is performed in a confined area without any detectable ventilation. For the health field notes, collect information on the number of persons exposed, type of welding being used, type of rod used, surface welding performed on, description of work area, length of time welding was done, type and use of personal protective equipment, and any other pertinent information.
Subpart J Travelways and Escapeways
This standard requires two or more separate escapeways to the surface at every underground mine. However, a second escapeway is recommended, but not required, during the exploration or development of an ore body. In this application, "exploration or development of an ore body" should be used in its narrowest sense, i.e., while an ore body is being initially developed, or development or exploration work is being conducted as an extension of a currently producing mine. Where mining occurs along a mineralized zone and production and development are indistinguishable as separate activities, the standard must be applied as it would to a producing mine.
A violation of 30 CFR 57.11050(a) exists and a citation must be issued whenever fewer than two functional escapeways out of an underground metal or nonmetal mine are available to miners working underground, even if the mine operator has started correcting the condition which caused the second escapeway to be nonfunctional. No violation of 30 CFR 57.11050(a) exists, however, if, upon there being fewer than two functional escapeways, the mine operator immediately initiates a continuous withdrawal of miners to the surface.
A "properly maintained" escapeway is an escapeway that is functional, providing the miners with a safe means of egress to the surface during a mine evacuation. There may be temporary periods when an escapeway is not immediately available however, the functionality is still intact.
The following examples demonstrate situations that the Agency would consider to be functional escapeways. No violation of 30 CFR 57.11050(a) would exist in these circumstances:
1) When maintenance, repairs, or other interruption of service, and the removal from service does not affect the functional ability of the escapeway to enable miners to reach the surface in an emergency. For example, an interruption of service that would not usually affect the functioning of the escapeway would include the lubricating of hoist ropes, adjustment of hoist gates, replacement of bolts on the shaft guides, or the inspection of shafts, adits, or conveyances. If the functioning escapeway would not be impaired or affected in any way, i.e., if the work being performed or the inspection of the escapeway can immediately be terminated and the miners can resume using the escapeway, the Agency would consider the escapeway to be "properly maintained."
2) When it is necessary to use the escapeway to lower mining equipment into, or retrieve mining equipment from the mine, and only miners facilitating the lowering or retrieving of mining equipment remain underground. As in the situation of miners working underground to perform maintenance or repair on the escapeway itself, in this situation the escapeway can be rapidly returned to service and only a few miners are stationed underground. The Agency believes that this policy interpretation reflects a reasonable accommodation of the concern for miners stationed underground to have a second escapeway out of the mine and the need to lower and retrieve mining equipment.
In setting an abatement time for any violation described above, an inspector or other authorized agency representative should, at a minimum, consider the following factors: the hazard(s) to miners, the time required to safely evacuate all but necessary maintenance personnel from the mine, the type of self-rescue devices available, the notification of all miners underground of the unavailability of the nonfunctional escapeway (including the instructions for use of the remaining escapeway in the case of an emergency), and the time required to return the affected escapeway to operation. The violation is abated when at least two escapeways are again fully functional or miners are no longer underground.
The second paragraph of this standard directs the positioning of a refuge within 30 minutes of a working place, where an employee cannot safely reach the surface within an hour.
57.11055 Inclined Escapeways
This standard requires an emergency hoisting facility only for that portion of a designated escapeway which is inclined more than 30 degrees and that is more than 300 feet in vertical extent. The vertical extent refers only to a continuous portion of a designated escapeway, and not to a composite of portions each less than 300 feet but more than 300 feet when combined.
Subpart K Electricity
56/57.12006 Distribution Boxes
This standard requires that distribution boxes be provided with a disconnecting device for each branch circuit. Such a disconnecting device 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. The distribution box shall be labeled to show which circuit each device controls.
A distribution box is defined under "Definitions" in 56/57.2. Many distribution boxes or power centers have a window at each individual circuit where it can be visually determined whether the circuit is deenergized or not. Where plugs are used at the distribution box to provide current for individual circuits, it can be visually determined when these plugs are not connected. When plugs are used, they shall conform to the requirements of standard 56/57.12084.