| 2 inches |
Guard board must be below bottom of trolley wire. |
| 4 inches |
Minimum length of flanges above the cable on hoisting drum when cable is fully wound up. |
| 5 inches |
Guard boards must not be more than 5 inches apart. |
| 6 inches |
Trolley wire must be at least 6 inches outside rail. |
| 8 inches |
Trolley guard boards may exceed 5 inches on curves, but must not exceed 8 inches. |
| 12 inches |
Distance trolley wire must be kept from other power cable. |
| 18 inches |
Clearance on top of belt where men ride - speed 250 feet per minute. |
| 18 inches |
Clearance on top of belt where explosives are transported. |
| 24 inches |
Clearance on top of belt where men ride - speed 300 feet per minute. |
| 2½ feet |
Clearance from widest point of coal transportation equipment. |
| 3 feet |
Minimum height in conveyor heading if an alternate mode of transportation to take men to face is provided. |
| 3 feet |
Clearance in front of switchboard. |
| 3 feet |
Passageway clearance behind switchboard if there are any high voltage connections on back. |
| 4 feet |
Clearance in front of switchboard where there is high voltage connection on front of switchboard. |
| 4 feet |
Minimum height of a shelter hole. |
| 4 feet |
Maximum width of a shelter hole. |
| 4 feet |
Height and width of clearance along belt conveyor where belt is used as transportation for men. |
| 4½ feet |
Height of travelway if coal is 3½ feet high. |
| 5 feet |
Depth of shelter hole (at least 5 feet deep). |
| 5 feet |
Height of travelway if coal is 4 feet high. |
| 5 ft. x 3 ft. |
Passagway around a shaft. |
| 5 ft. x 5 ft. |
Passageway over or under a slope. |
| 6 feet |
Width of clearance that must be kept clear if crosscut is used as a shelter hole. |
| 6 feet |
Width of separate travelway. |
| 6½ feet |
Minimum height of trolley wire above the rail where it does not have to be guarded. |
| 8 feet |
Distance between holes drilled on 45 degree angle in rib near a body of water or other dangers. |
| 10 feet |
Width of entry to tap water. |
| 12 feet |
Distance between P-number on state approved cables. |
| 20 feet |
Distance between hangers for high voltage cable. |
| 20 feet |
Depth of holes in advance of face and on ribs when approaching an unexamined or unsurveyed area. (20 feet beyond the deepest cut to be taken) |
| 20 feet |
Height above the tipping place, a substantial structure to sustain sheaves, pulleys, ropes and loads during shaft excavation. |
| 24 feet |
Distance between trolley wire hangers. |
| 25 feet |
Depth of incombustible material used when sealing a drift. |
| 25 feet |
Distance an underground magazine must be kept from roadways and power wires. |
| 25 feet |
Distance a blow torch or fuel must be stored from any open flame. |
| 25 feet |
Minimum distance between a station ground pr primary ground at a substation.
|
| 50 feet |
Superintendent may mine to abandoned works if an accurate survey exists but cannot be examined. |
| 50 feet |
Mine foreman must drill holes near abandoned works. |
| 50 feet |
Amount of incombustible material used in sealing a shaft. |
| 50 feet |
Superintendent shall not permit mining within 50 feet of abandoned mine or any abandoned portion of any mine containing a dangerous accumulation of water until such danger has been removed. |
| 50 feet |
Minimum distance between two drifts. |
| 70 feet |
Distance to the face of each working place that all electric cables constantly kept in rooms or pillars or other working places be carried on suitable supports. |
| 80 feet |
Maximum distances between shelter holes. |
| 150 feet |
Distance from trolley wire to pillar works. |
| 150 feet |
Distance distribution centers must be kept from pillar workings unless it has an approved explosion proof enclosure. |
| 150 feet |
Minimum distance between two slopes. |
| 200 feet |
Distance magazine must be kept from mine opening unless barricaded. |
| 200 feet |
Minimum distance between 2 shafts. |
| 200 feet |
Distance mine can be advanced prior to installation of a mechanical fan. |
| 200 feet |
Distance an entry can be driven prior to an air connection. |
| 200 feet |
Distance between crossbonds on main haulage roads. |
| 200 feet |
Distance mining can advance toward an abandoned mine which cannot be examined or has an accurate survey prior to drilling. |
| 200 ft. : 1 in. |
Minimum scale of mine map. |
| 250 feet |
Distance high voltage shall be kept from pillar works. |
| 250 fpm |
Speed of belt where men are transported with 18 inches of clearance. |
| 300 fpm |
Speed of belt where men are transported with 24 inches of clearance. |
| 300 feet |
Elevations to be placed on map of adjacent mine. |
| 300 feet |
Distance magazine from face. |
| 500 feet |
Distance underground from bottom of shafts, boreholes or at other places where main power circuits enter the mine, must have disconnect switch. |
| 500 feet |
Distance rock dust sample taken in working section. |
| 500 ft. : 1 in. |
Minimum scale of electrical map. |
| 1,000 feet |
Distance that can be mined toward another mine prior to that mine being put on the mine map. |
| 1,000 feet |
Distance in dry section where rock dust shall be applied back from the face or water the runways down. |
| 2,000 feet |
Minimum distance between trolley cutout switches. |
| 2,000 feet |
Distance between rock dust samples on main haulages. |
| 3,000 feet |
When distance between 2 mines became 3000 feet, a barrier pillar must be left. |
| Barrier Pillar Formula |
10 feet + 2 feet (for every foot and part of a foot of the coal seam) + 5 feet (for every 100 feet and part of a 100 feet off cover). |
| 900 fpm |
Maximum speed for hoisting men. |
| 1,500 feet |
Maximum distance a mine can advance prior to establishing communications. |
| 5,000 feet |
Every new gassy mine with main entries projected to exceed 5000 feet, shall have at least 5 main entries. |
| 5,000 feet |
Every new non-gassy mine with main entries projected to exceed 5000 feet shall have at least 3 main entries. |
| 2,000 feet |
If mine is non-gassy and becomes gassy and has less than 5 entries and the main entries are projected in excess of 2000 feet, if the inspector feels it is necessary, an addition entry shall be driven. |
| 3,000 feet |
An operator or superintendent may mine out to the boundary as long as no other mine in the same seam is within 3000 feet of said mine. |
| 1,000 feet |
Distance for shut off-valves on compressed air lines. |
| 50 feet |
Distance from face for blowdown valves. |
| 5 feet |
Distance in non-gassy mine flame safety lamp shall be kept from explosives. |
| 5 feet |
Distance between underground boxes or magazines of explosives if kept separately. |
| 4 inches |
Thickness of partition in box or magazine separating powder and caps. |
| 2 inches |
Thickness of wood on inside or door on surface magazine. |
| 3/8 inch |
Thickness of metal on door of surface magazine. |
| 25 feet |
Distance around surface magazine to be kept free of combustible material. |
| 125 feet |
Minimum length of blasting cable. |
| 3 ft. x 5 ft. |
Minimum walkway dimensions around bottom of elevator shaft. |
| 5 ft. x 5 ft. |
Minimum walkway dimensions around both sides of a slope. |
| 1/32 inch |
Distance between grinding wheel and tool rest. |
| 300 feet |
Length of hose on tank car of 1,000 gallon for fire fighting. |
| 250 feet |
Length of hose on rock duster for use for fire fighting. |
| 1,000 feet |
Length of fire hose available with fittings suitable for connection to water lines. |
| 600 feet |
Distance back from face for one Class A fire extinguisher or rock dust or barrel of water if water is not piped to the faces of working places. |
| 100 feet |
Depth of shaft when persons are lowered and hoisted by means of machine unless the second opening is a drift or a slope. |
| 10 inches |
Tread size on steps in a shaft. |
| 9 inches |
Riser height of steps in a shaft. |
| 2 ft. x 4 ft. |
Size of landings for steps in a shaft. |
| 1,000 feet |
Men lowered and hoisted on slope if slope exceeds 15 degrees descent and its length exceeds 1000 feet and is used as a means of ingress and egress. |
| 3,000 feet |
Men lowered and hoisted on slope if slope averages 5 degrees to 15 degrees descent and its length exceeds 3,000 feet and is used as a means of ingress and egress. |
| 80 feet |
A passage area laid out for a mine opening of a mine on someone elses property for drainage or ventilation. |
| 15 feet |
Width of a right of way for any such mine opening, as stated in the previous statement above, to any public road. |
| 10 feet and 60 degrees |
Requirements for permanently installed ladders that are more than 10 feet in length and set at a 60 degree angle shall have backguards. |
| 12 inches |
Distance cables and feed wires shall be kept from mine cars and locomotives. |
| 50 feet |
Minimum distance a splice can be to the machine for trailing cables on equipment without reels. |
| 1/8 inch |
Thickness of incombustible structure for housing electrical equipment, except room hoists and gathering pumps, which remain in the same location for a period of one year or more. |
Other Measurements |
| 0.004 |
Feeler gauge maximum on flanged surfaces. |
| Not less than 1/8 inch |
Tolerance for packing glands. |
| 0.491 lbs./sq.in. |
1 inch of Mercury will create pressure of .491 psi. |
| 29.92 |
Barometric pressure at sea level. |
| 8.3 lbs. |
Weight of a gallon of water. |
| 7.5 gals. |
Gallons of water in a cubic foot. |
| 62.5 lbs. |
Weight of a 1 cubic foot of water. |
| 5.2 lbs./sq.ft. |
1 inch of water gauge creates a pressure of 5.2 lbs./sq. ft. |
| 1.3273 lbs. |
Weight of 1 cubic foot of air at absolute zero. |
| 18 |
Molecular weight of water. |
| 32 |
Molecular weight of Oxygen. |
| 1 |
Atomic weight of Hydrogen. |
| C2H2 |
Chemical Symbol for Acetylene. |
| TLV |
Threshold Limit Value |
| PEL |
Permissible Exposure Level |
| PPM |
Parts per Million |