WY Stat § 30-3-501 (2021)
2021 Wyoming Statutes|Title 30 - Mines and Minerals|Chapter 3 - Mining Safety|Article 5 - Ventilation and Dust Control|Section 30-3-501 - Ventilation Regulations Generally; Quantity of Air Required; Record of Measurements.

30-3-501. Ventilation regulations generally; quantity of air required; record of measurements.| (a) The operator shall provide and maintain, at all times, for all persons in every working place, a good and sufficient amount of ventilation circulating an adequate quantity of fresh air sufficient to dilute and render harmless any noxious gases or powder smoke that may be present.  (b) The number of men on a split shall be no more than the ventilation system can support. Where dust or fumes in harmful quantities result from mining, milling or processing operations, some mechanical or other means which will alleviate this condition shall be used wherever and whenever practical. The operator shall furnish and encourage the use of personal protective devices for alleviating harmful effects of dust and fumes. Each person shall use the devices furnished by the operator.  (c) The quantity of air reaching the last open crosscut in any pair or set of entries shall not be less than nine thousand (9,000) cubic feet a minute. However, the quantity of air reaching the last open crosscut in any pair or set of entries in pillar sections may be less than nine thousand (9,000) cubic feet of air a minute, if at least nine thousand (9,000) cubic feet of air a minute is being delivered to the intake end of the pillar line. In any underground mine, the operator shall provide on the surface or underground a fan or other mechanical means for producing and controlling air circulation within the mine.  (d) The air current at working faces shall under any condition have a sufficient volume and velocity to dilute and carry away smoke from blasting and any flammable or harmful gases.  (e) At least once each week, the mine foreman or other certified persons designated by him, shall measure the volume of air near the main intake or main return, the amount passing through the last open crosscut of entries, and the volume of air in each split. A record of these measurements shall be kept in a book on the surface and shall be open for inspection by interested persons.  (f) The main-intake and main-return air currents in mines shall be in separate openings.  (g) All slopes or entries in coal mines shall be driven in sets of two (2) or more.  (h) In gassy mines haulage roads shall be in intake air.  (j) Battery-charging stations and transformer stations containing liquid-filled transformers shall be well ventilated by separate splits of air conducted through vents to the return air courses and returning direct to the surface.  (k) Changes in ventilation that materially affect the main air current or any split thereof shall be made when the mine is idle and with no men in the mine, other than those engaged in changing the ventilation.  (m) In gassy mines air that has passed through abandoned sections or that has been used to ventilate pillar lines shall not be reused to ventilate live workings.  (n) The inspector shall establish by rule ventilation requirements for mines and associated surface facilities. The rules may be generally applicable to all mines or promulgated for specific types of mines or mining operation and may:  (i) Establish minimum and maximum volumes of air required for specified areas of mines;  (ii) Specify the means for ventilation, including the use, installation and operation of main mine fans, booster fans, blower fans, exhausting and other fans, and associated equipment including warning and monitoring devices;  (iii) Specify the use, placement and construction of crosscuts, doors and line brattice needed to provide ventilation;  (iv) Specify personal protective devices to be used to alleviate the effects of dust and harmful gases;  (v) Specify areas of the mine and times for monitoring, and training requirements for persons monitoring ventilation and associated equipment or providing ventilation in accordance with this act or rules adopted under this act;  (vi) Establish appropriate procedures for making changes in ventilation;  (vii) Specify required actions in response to hazards due to inadequate ventilation, including the existence of specified levels of dust or gases; and  (viii) Require recordkeeping in accordance with applicable federal law.