VOLUME V - COAL MINES
75.1714-2 Self-Rescue Devices; Use and Location
Under paragraph (c) of this Section, the determination that wearing the self-contained self-rescuer is hazardous may be made by an individual miner or by the operator. The inspector should not issue a citation unless the person is more than 25 feet from his or her self-contained self-rescuer.
The District Manager is required in paragraph (e)(1) to consider 11 factors in deciding whether to permit an operator to place a self-contained self-rescue device more than 25 feet from a miner. In order to assist the inspector when considering these factors, the following guidelines are provided to help determine whether to permit or prohibit storage, storage distances, and storage methods and procedures.
- Distance from affected sections to surface. If the deepest penetration of a working section is not farther from the surface than the travel distance listed in 3. below, the district manager may approve a plan for the operator to provide miners only with filter-type self-rescuers. However, when the deepest penetration of a working section is greater than the travel distance listed in 3., operators shall be required to provide self-contained self-rescuers.
- Pitch of seam in affected sections. In pitching seams, such as encountered in anthracite mines, self-contained self-rescuers should be stored on level travel ways.
- Height of coal seam in affected sections. The height of the travelway affects the speed of travel and consequently the distance that miners may be away from stored self-contained self-rescuers. Miners generally should not be farther from self-rescuers than a distance that they can travel at a normal pace in 5 minutes. However, the time and distance can be increased or decreased after considering all factors. Miners should never be farther from self-contained self-rescuers than a distance they can travel at a normal pace in 10 minutes. The chart should be used to convert time to travel distance (See ESCAPEWAY conversion chart ).
- Location of escapeways. Where designated escapeways are not readily available, such as during travel in remote locations of bleeders and return airways, storage of self-contained self-rescuers should be limited to not more than 5 minutes travel time.
- Proposed location of self-contained self-rescuers. The preferred locations for storage of self-contained self-rescuers are in the intake escapeways and accessible from more than one entry. In longwall mining sections, self-contained self-rescuer units should be stored near the face on the headgate and tailgate sides of the longwall unit. Enough self-contained self-rescuer units for all miners covered by the storage plan should be stored at both locations.
The environment in the storage location should be in accordance with manufacturers' recommendations. Storage plans should include provisions for segregating visitors' self-contained self-rescuers from those provided for employees at the mine. Each miner must be trained to know the specific location of the self-contained self-rescuer that is available for him/her.
- Type of work performed by affected miners. Different plans may be approved for various categories of miners, dependent primarily upon the amount of travel required to perform their work. Storage plans for section workers should rarely allow for travel times greater than 5 minutes. Storage plans for rovers may allow for travel time up to 10 minutes.
- Degree of risk to which affected miners are exposed. The amount of methane liberation and size and type of power systems, i.e., battery, electrical (a.c. or d.c.) or diesel, are some of the factors that should be considered when evaluating the degree of risk. Another factor should be the history of violations that could lead to the cause and effect of fires, explosions, and inundations.
- Potential for breaking into oxygen-deficient atmospheres. When mining near abandoned areas, as described in Section 75.1701, or into areas having a high potential for outbursts, storage of self-contained self-rescuers shall not be permitted.
- Type of risks to which affected miners are exposed. The types of risks that should be considered when evaluating storage plans are the risks associated with explosions, fires, and inundations.
- Accident history of mine. The types of accidents which should be considered are those relating to explosions, fires, inundation of gases, and outbursts.
- Other matters bearing upon the safety of miners. Storage plans should include a requirement for examination of self-contained self-rescuers during the period of the preshift examination or at the beginning of the shift. If the self-contained self-rescuers are stored in substantially constructed containers, or in another permanent manner, and located so that the units are protected from damage, inspection of the self-contained self-rescuers once each 24 hours should be sufficient to assure reliability of the units. Plans should include a provision that would permit any miner to wear or carry a self-contained self-rescuer. The tests required under the provisions of Section 75.1714-3(d) shall be made in accordance with the manufacturer's approved instructions.
The minimum number of self-contained self-rescuers underground at each mine must be equal to or greater than the number of miners underground.
Paragraph (e)(3) of this Section prohibits the operator from obtaining permission from the district manager to place the self-contained self-rescuers more than 25 feet away from miners on mantrips into and out of the mine. For purposes of this Section only, miners are not considered to be on mantrips while walking into or out of the mine, or while being transported in shafts or slopes. Therefore, permission may be granted for storage of self-contained self-rescuers for miners in these situations.
Violations of the approved storage plan for self-contained self-rescuers shall be cited under Section 75.1101-23. The provisions of paragraph (e) of this Section state that the miner operator may apply to the district manager under Section 75.1101-23 for permission to place the self-contained self-rescuer 25 feet away.This provision merely informs the operator of how to apply for a storage plan and shall not be used when citations are issued for violations of the storage plan.
75.1714-3 Self-Rescue Devices; Inspection, Testing,Maintenance, Repair and Record keeping
Paragraph (b) of this Section requires that the self-rescue device be inspected for damage and for the integrity of its seal after each time it is worn or carried by a person. The term"inspected" consists of visually examining the self-rescuer. In order to make a valid visual examination of the Drager 810, the self-rescuer must be removed from the carrying pouch. The examiner shall make sure that the top and bottom of each container is not separated.
In paragraph (c) of this Section, the phrase "...except devices using vacuum containers as the only method of sealing, shall be tested... by weighing ..." applies only to Drager 810 self-rescuersnot provided with a stainless steel band to reinforce the seal. The addition of the stainless steel band requires that the Drager 810 self-rescuer be weighed to check its condition.
Extensions of approvals have been granted for modification in the periodic testing procedures for the Mine Safety Appliances Company (MSA) 60-minute self-contained self-rescuers (SCSR) and the Draeger OXY-SR 60B SCSR.
The MSA 60-minute SCSRs are not required to have an annual dry leak test of all stored units and a 90-day dry leak test for units that are worn or carried. Any unit removed from storage must be tested before the unit is returned to storage. The water immersion test may be used in lieu of the dry leak test.
The periodic test for the Draeger OXY-SR 60B SCSRs now only requires a visual examination of the unit every 90 days.
During recovery operations at a mine explosion and during an inspection of an adjacent mine, it was brought to the attention of MSHA that the release pins and bands on the self-contained self-rescuers (SCSRs) in use at these two mines had been taped.The purpose for taping was to prevent the release pins from opening accidentally.
Several miners who were injured in the explosion were unable to open the cases of their SCSRs because their hands were burned. A miner who was not injured opened the cases for the injured miners. He stated that he had a very difficult time removing the tape to free the release pins and open the cases.
MSHA inspectors should, during the course of their inspections,determine if the releases of SCSRs are fastened in a manner other than as designed by the manufacturer. In those instances where other means are used, appropriate action shall be taken to have the extra fasteners removed.
75.1718 Drinking Water
Coal mine operators are required by this Section to supply drinking water in the active workings of mines and that the water"is carried, stored, and otherwise protected in sanitary containers." Coal operators have had difficulty in maintaining water containers in a sanitary manner, especially in keeping water containers clean. To alleviate this problem, sanitary,disposable, polyethylene water container liners are available.These liners are approved for use with foods by the Food and Drug Administration and have been used by the dairy industry to line milk cans. This type of sanitary liner is acceptable for use with water containers in coal mines.
75.1719-1 Illumination in Working Places
Included in the category of self-propelled mining equipment are loading machines, cutting machines, shuttle cars, coal scoops,clean-up scoops, tractors, roof-bolting machines, face drills,longwall and shortwall installations, and supply vehicles, but rubber-tired trailers pulled by battery tractors are not included.
Technical Support tests and evaluates lighting systems in a simulated working place prior to the installation of the lighting systems underground. Each lighting system submitted is tested and evaluated to determine whether the required amount of light is provided, if the system is designed and installed to minimize discomfort glare and if the system complies with the other applicable provisions of the illumination regulations.
A Statement of Test and Evaluation (STE) is issued by Technical Support for accepted lighting systems. Each STE specifies the maximum height and width of the working place, the type and model of machine (for machine-mounted lighting systems), the location and orientation of light fixtures, the type of diffusers or louvers, and other conditions under which the lighting system must be installed and operated to provide compliance with the applicable provisions of the illumination regulations.
Lighting system manufacturers are furnishing a 3-by-5-inch metal plate with each accepted machine-mounted lighting system. The metal plate contains pertinent information about the lighting system and should be attached to the machine near the permissibility plate. The 3-by-5-inch metal plate is not required by regulation; however, the plate must be present on the machine to consider the system as one for which an STE has been issued.
The operator is not required to have an STE; therefore, acitation shall not be issued for failure to comply with an STE.If the STE is not being complied with, and in order to issue acitation, the inspector must take measurements to determine if the failure to comply with the STE results in a reduction of li below the 0.06 footlamberts required by paragraph (d) of this Section.
When an inspector observes self-propelled mining equipment being operated in a working place, a lighting system has been installed in accordance with an STE, and all of the provisions of the STE are being complied with as recorded on the metal plate, the lighting system shall be acceptable as being in compliance with paragraph (d) of this Section and the inspector shall not take light measurements.
Experience with STEs has shown that flexibility in the application of STEs is needed. Due to differences in machine design, manufacturers' mechanical design changes, and mine operators' modifications of mining machines, it is, at times,impossible to install a light fixture exactly as specified in the STE. In other instances, if a light fixture is installed in the specified location, the light source is in direct view of the operator or helper and objectionable glare is created.Therefore, it has become necessary to establish procedures which will permit coal mine operators to make application to the district manager in the district in which the mine is located for approval of a modification of an STE.
The term "a miner's normal field of vision," as contained in paragraph (e), means surfaces that can be readily seen by a miner from any position in the working place that his/her duties require him/her to be while self-propelled mining equipment is being operated. Not included are floor surfaces under the machine or surfaces behind line curtains or ventilation tubing.
Paragraph (g) requires that light fixtures be designed and installed to minimize discomfort glare. There are some locations on board certain mining machines in thin coal seams in which it is impossible to install presently available fixtures without creating discomfort glare to miners.
Extremely bright lights are required to light the area from rib to rib in thin coal seams (less than 42 inches in thickness), and these light fixtures of necessity are installed at the miner's eye level which compounds the glare problem. To combat this glare problem in seams with mining heights less than 42 inches,it is necessary to reduce the area in which light measurements are made to not more than 5 feet from the machine and to specify other locations in which light measurements are not to be taken.The intent of this policy is not to allow a reduction in the number of light fixtures used, but to permit better locations,diffusing, and guarding of light fixtures as a method of reducing or eliminating discomfort glare.
This policy recognizes the technical problems involved in reducing glare and defines locations within the area specified in paragraph (e)(1) through paragraph (e)(6) in which light measurements are to be taken.
When the mining height is less than 42 inches, light measurements shall be made within an area the perimeter of which is 5 feet from any part of continuous-mining machines, loading machines,coal drills, and cutting machines when measured parallel to the mine floor.
Headlights on continuous-mining machines and loading machines should be oriented so that the maximum amount of light is provided on the coal face. This improves the ability of the machine operator to see the location of the cutting bits or gathering arms. Therefore, to allow the most efficient utilization of the available light, light measurements shall not be taken of the floor area between the cutter boom hinge pin or gathering head hinge pin and the coal face.
Scoops used as load/haul/dump vehicles, clean-up, or supply vehicles shall be illuminated in accordance with paragraph (e)(6)while such vehicles are being operated in the working place.
Auger-Type Continuous Miners
Most auger-type continuous-mining machines are operated with jack setters and timbermen working inby the miner operator in close proximity to rotating cutting bits or the machine. These miners must be able to communicate with the miner operator by means of signaling with their cap lamps and even small amounts of glare can be extremely hazardous.
Present technology will not permit installation of light fixtures on rope-propelled, auger-type continuous-mining machines in which miners are required to be inby the machines to set jacks or timbers without creating discomfort glare to the jack setters or timbermen. Therefore, illumination will not be required in working places in which rope-propelled, auger-type continuous-mining machines are operated if jack setters or timbermen are required to work inby the machine operator pending the development of glare-free illumination systems for these machines.Illumination is not required in a working place in which a roof bolting machine is being operated if a rope-propelled, auger-type continuous-mining machine is also being operated in the same working place.
Remotely-Controlled Continuous Miner
When the mining height is less than 42 inches and remotely-controlled continuous-mining machines are operated in the working place, light measurements shall not be made of the area on the right side of the machine and outby the center of the main frame.
Shortwall Mining Equipment
- When either chain conveyors or extensible belt conveyors are used to transport the coal from the continuous miner to the section loading point, the following areas shall be illuminated:
- The face;
- The area for the length of the self-advancing roof support system and all surfaces within the miner's normal field of vision between the gob-side of the travelway and the side of the block of coal from which coal is being extracted; and
- The control station and the headpiece and tail piece of the conveyor, and all surfaces within 5 feet horizontally from the control station, head piece and tailpiece.
- When shuttle cars are used to transport the coal from the continuous miner to the section loading point, illumination shall be provided in accordance with the following:
- The face, ribs, roof, floor, and exposed surfaces of mining equipment between the face and the outby edge of the rear bumper of the continuous-mining machine shall be illuminated by the stationary lighting fixtures in accordance with the requirements of paragraph (e)(4) or by lighting fixtures installed on the continuous-mining machine in accordance with the requirements of paragraph (e)(1).
- The shuttle car roadway shall be illuminated by stationary lighting fixtures in accordance with the requirements of paragraph (e)(4) or by lighting fixtures installed on the shuttle car in accordance with the requirements of paragraph (e)(6).
Problems have been encountered in illuminating the coal face and face conveyor to 0.06 footlamberts in longwall mining installations operating in coal seams under 42 inches in thickness. The problems have been caused by the lack of sufficient clearance between the bottom of the roof support chocks and the side of the face conveyor, leaving little or no space through which light fixtures installed on the chocks can cast light on the face conveyor or the coal face. Therefore, in determining compliance with the illumination requirements for longwall mining installations operating in coal seams less than 42 inches in thickness, measurements shall not be taken on the face conveyor or the coal face. Measurements shall be taken the entire length of the travelway and the area within a distance of 5 feet horizontally from the control station, headpiece, and tailpiece.
High spill boards are installed on many longwall face conveyors so that the coal will be retained on the face conveyor to prevent spillage. These spill boards are necessary to prevent spilled coal and coal dust from accumulating along the travelway and between the roof-support shields or chocks. In some instances,the roof-support shields or chocks barely clear the spill boards.
The spill boards on longwall face conveyors are considered"other obstructions necessary to insure safe mining conditions,"as provided in Section 75.1719-3(b)(8). Consequently, in determining compliance with the illumination regulations for longwall mining installations, light measurements shall not be made of areas where shadows are cast by spill boards installed on the longwall face conveyors.
When the mining height is less than 42 inches, measurements shall not be taken of the area in front of and to the side of the roof-bolting machine operator(s) position(s). This does not apply to roof drills that are an integral part of a continuous mining machine.
Light fixtures installed adjacent to supply trays on dual-head roof-bolting machines create objectionable glare to the operator and helper. Therefore, to allow removal or repositioning of these light fixtures, the lighting system shall be considered to be in compliance if the required level of light is provided as determined by illumination measurements made with the drill heads either together or separated approximately 8 feet and in position to drill holes or install roof bolts.
Shuttle Cars and Other Self-Propelled Equipment
The requirements of paragraph (e)(6) apply at all times when shuttle cars are being trammed in the working place even though a continuous-mining machine or loading machine is also being operated in the same working place. However, this does not prevent the shuttle car operator from turning the headlights out while the shuttle car is under the boom of the continuous mining machine or loading machine.
When determining the height and width of the coal surface to be illuminated as provided in paragraph (e)(6)(ii), the maximum height of the equipment (including sideboards, cabs, and canopies) and the maximum width of the equipment (including bumpers, tires, cabs, and canopies) shall be used. The height and width of the coal surface that is required to be illuminated will be the same in both directions of travel.
When the mining height will not permit installation of light fixtures at a location that will light the area directly in front of shuttle cars, tractors, maintenance vehicles, scoops,load/haul/dump vehicles, etc., the unshaded areas outlined on the illustration may be lighted and measurements taken accordingly.(See illustration)