SECTION 460:15-1-25. Ventilation

(a)   Main fans shall be:

(1)   Installed on the surface;

(2)   Installed in fireproof housings and connected to the mine opening with fireproof air ducts; and

(3)   Equipped with a pressure-recording gauge and an automatic signal device designed to give alarm should the fan slow or stop. The signal from this device should be placed so that it will be seen or heard by a responsible person who is always on duty and can hear or will observe such alarm when men are underground and who shall take appropriate action immediately.

(b)   To protect main fans from forces coming out of the mine should an explosion occur:

(1)   Main fans should be offset not less than fifteen (15) feet from the nearest side of the mine opening, and explosion doors or a weak wall having a cross sectional area equal to or greater than the connection entry should be provided in direct line with possible explosion forces; or

(2)   Main fans may be installed in line with diversion entry, slope, or shaft (fan entry) driven from the mine air courses to the surface.

(3)   The surface opening of the fan entry should be no less than fifteen (15) feet nor more than one hundred (100) feet from the surface opening of the connected mine air course (pressure relief entry). The pressure relief entry opening should be provided with a weak wall or explosion doors in direct line with forces of an explosion originating underground and such weak wall or explosion doors should have a cross-sectional area of the pressure relief entry not be less than that of the fan entry. The underground intersection of the fan entry and pressure relief entry should be no less than fifteen (15) feet nor more than one hundred (100) feet from the surface opening of the pressure relief entry. The pillar of coal between the pressure relief entry and the fan entry should, regardless of coal bed height, contain not less than two thousand five hundred (2,500) square feet.

(c)   Main fans may be driven either by electric motors or internal combustion engines.

(1)   When electric motors are used, they should be provided with a separate power circuit independent of any other mine circuit.

(2)   When an internal combustion engine is used, the engine should be installed in a fireproof housing, located so as to be protected from possible fuel supply fire or explosions. The engine and exhaust should be located out of direct line with the airstream produced by the fan and be vented to the atmosphere in such a manner that the exhaust gases cannot contaminate the mine intake airstream or any enclosure.

(d)   In mines ventilated by multiple force or multiple exhaust main fans, each main fan installation should be equipped with fireproof doors, so positioned that in the event of the failure of a main fan, the doors at the fan will automatically close and prevent air reversal through the fan.

(e)   In mines ventilated by a combination of force and exhaust fans, fireproof automatic closing doors will automatically close to prevent air reversal that would affect the safety of the miners.

(f)   The area surrounding all main fans should be kept free of flammable material for at least one hundred (100) feet in all directions.

(g)   The minimum quantity of air reaching the last open crosscut in any pair or set of rooms shall be nine thousand (9,000) cubic feet per minute, and the minimum quantity of air reaching the intake end of a pillar line shall be nine thousand (9,000) cubic feet per minute. The minimum quantity of air in any coal mine reaching any face where coal is being mined shall be three thousand (3,000) cubic feet per minute. The Department of Mines or the mine inspector may require in any coal mine a greater quantity and velocity of air when he or she determines it necessary to protect the health and safety of the miners. The quantity of air shall be measured in the last open crosscut in each pair or set of developing entries. The ventilation shall be conducted through all accessible entries, rooms and all working places, in such manner and with such velocity as to dilute and render harmless inflammable, noxious and poisonous gases.

(h)   In the event of interruption of the ventilation current, employees shall be immediately withdrawn to the assembly points as designated by the operator, and the power to the faces disconnected. If the ventilation current cannot be restored in fifteen (15) minutes, all employees shall not return to work until the ventilation current has been restored and the area examined and reported safe.

(i)   All ventilating fans shall be operated continuously unless:

(1)   Repair or maintenance is needed.

(2)   Mine is to be permanently closed and is in the process of being sealed.

(3)   If the ventilating fan has been temporarily stopped for more than fifteen (15) minutes and the employees are withdrawn from the mine. No person shall be allowed underground except for the purpose of inspection until the mine has been reported free of accumulations of explosive gases and other dangers.

(j)   The fan shall be inspected at least daily and recorded in an approved book.

(k)   All main stoppings, overcasts, or undercasts between main intakes and returns shall be substantially built of non-combustible material. Stoppings between intake and return air courses shall be maintained not more than three (3) crosscuts from the face. A suitable man door shall be provided as per the ventilation plan, but not more than six hundred (600) feet apart. Man doors shall have a minimum opening of nine hundred (900) square inches. All mines liberating any dangerous, explosive or noxious gases shall be kept free of standing gas in all working places and roadways. No accumulation of explosive gas shall be allowed to exist in any open, worked out, orabandoned parts of the mine. It shall be removed as soon as possible after its discovery, and no miners or other persons who are not employed in the removal of the dangerous accumulation shall be allowed to remain in any mine or part of mine during the time that a dangerous accumulation of explosive gas is being removed from any part of this mine. All worked out places or abandoned areas shall be either properly ventilated or examined, sealed, or maintained as a bleeder system.

(l)   In all mines it shall be the duty of the operator to employ one or more persons holding certificates of competency from the Oklahoma Mining Commission as mine foremanor fire-boss to examine the mine and who shall examine every working place, all places adjacent to live working, every roadway and traveling way, all seals, every road to abandoned workings, and over all falls in the mine, for inflammable, noxious and poisonous gases and other dangerous or unsafe conditions such as falls of roof, dangerous tracks, timbering, or water. Such examination shall begin within three (3) hours prior to the appointed time for each shift to enter the mine and shall be made with an approved methane detection device and flame-safety lamp. The fire-boss shall examine for all dangers in all portions of the mine under his charge and after each examination he shall leave at each place examined the date, time and initials of his examinations. He shall place a danger signal at every place, where inflammable, noxious and poisonous gas has been discovered, or where immediate danger is found to exist from any other cause. The fire-boss shall report to the mine foreman all places where dangerous accumulations of gas have been found, and the nature and location of any other existing danger, and shall record the results of his inspection in a book kept for that purpose. No person shall enter any portion of a mine falling within the above classification until the fire-bosses have completed their examination and have reported that the mine is in a safe condition for the employees to enter.

(m)   Combustible material shall not be stockpiled or stored within 300 feet of any surface mine opening.

[Source: Amended at 31 Ok Reg 2092, eff 9-12-14]