Chapter 1. STATE MINE INSPECTOR

The discharge of any exhaust pipe for an internal combustion engine used for fans, power plant or engine driven compressor shall be located and so arranged that the exhaust fumes from this engine cannot under any conditions get into the intake air of the mine or the intake air of…

Dust suspected of being explosive shall be tested for explosability. If tests prove positive, appropriate control measures shall be taken. Historical Note Former Rule 4:02.

The air intake of all compressors must be located so that no hazardous fumes or smoke can get into the air intake. The use of compressors that have a common crankcase with the internal combustion engine used to drive it is prohibited except for modern machines specifically design…

Except as permitted by R11-1-406: 1. Except as provided in subsection (2) 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. Excursio…

Dust, gas, mist, and fume surveys shall be conducted as frequently as necessary to determine the adequacy of control measures. Historical Note Former Rule 4:05.

Control of employees’ 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 w…

Air at all active underground working places shall contain at least 19.5 volume percent oxygen. Historical Note Adopted effective April 7, 1976 (Supp. 76-2). Former Section R11-1-407 repealed, new Section R11-1-407 adopted effective August 18, 1980 (Supp. 80-4).

Ventilation doors shall be: 1. Substantially constructed. 2. Covered with fire-retardant materials, if constructed of wood. 3. Maintained in good condition. 4. Self-closing, if manually operated. 5. Equipped with audible or visual warning devices, if mechanically operated. Histor…

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. Historical Note Adopted effective August 18, 1980 (Supp. 80-4).

Fan housings and air ducts connecting main fans to underground openings shall be fire resistant. Historical Note Former Section R11-1-333 renumbered as Section R11-1-412 effective August 18, 1980 (Supp. 80-4).

Pursuant to A.R.S. § 27-365, the underground use of any internal combustion engine is unlawful unless the Inspector has approved the equipment. In addition to the approval of the Inspector for use of the equipment, the equipment shall conform in all respects to the requirements o…

Underground diesel-powered equipment shall be equipped with a stainless steel exhaust system including conditioner and satisfactory diluting device, which will reduce toxic gases to a minimum before they are released into the mine atmosphere. (Except if limestone and water are us…

The conditioner must not increase the engine back pressure above 18 inches of water or 1 1/2 inches of mercury when the diesel equipment is developing its rated horsepower. The conditioner must hold sufficient water for four hours of operation without replenishing and at the end …

At least once each week an inspection of the diesel engine and the gas conditioner MUST be made and a written report of its condition be put on file for examination by the Mine Inspector or his deputies. Historical Note Former Rule 4:24.

When flexible tubing is used on exhaust from diesel motor to the air conditioner or scrubber, it must be the type that will withstand back pressure and not leak. Historical Note Former Rule 4:25.

The use of diesel-powered equipment shall be restricted to haulageway or other working places where positive ventilation is maintained by mechanical means. If possible, the ventilation in places where diesel equipment is used shall be arranged so that the air carrying exhaust gas…

Diesel engines must not be operated when the atmosphere adjacent to its engine contains toxic gases above the tolerance set by the United States Bureau of Mines as listed below: Carbon dioxide 0.5% by vol. Carbon monoxide 0.01% by vol. Nitrogen dioxide 0.0005% by vol. Oxygen must…

When a diesel engine is used in underground mine operations, all dead-end headings shall be separately ventilated by auxiliary ventilation with a minimum air velocity of not less than 50 linear feet per minute in the working face itself. The intake of the auxiliary system must be…

If diesel equipment other than that approved by U.S. Bureau of Mines is utilized, 150 C.F.M. per brake horsepower is the required ventilating air for safe operation. Historical Note Former Rule 4:29.

Historical Note Former Rule 4:30; Amended effective April 7, 1976 (Supp. 76-2). Repealed effective August 18, 1980 (Supp. 80-4).

Suitable lights and audible warning devices shall be installed and maintained in good working condition on all mobile diesel equipment operated underground. Historical Note Former Rule 4:31.

All diesel equipment must be checked for fuel leaks and any leaks found must be noted and reported. Historical Note Adopted effective April 7, 1976 (Supp. 76-2).

All connections and tubing from air cleaner to the intake manifold must be closely checked for cracks, breaks, or loose connections. The intake manifold must be secure and properly gasketed to cylinder heads and be free of holes and cracks. Historical Note Adopted effective April…

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