Article 3. Air Quality, Radiation and Physical Agents
4VAC25-40-3160. Oxygen content in mines.
Air in all active areas shall contain at least 19.5% volume oxygen as measured by an acceptable oxygen analyzer.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.40, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-3170. Ventilation.
Main fans shall be installed on the surface; if it is necessary to locate them underground, they shall be in fire-resistant areas and shall be provided with remote controls.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.41, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-3180. Fan housings and air ducts.
Fan housings and air ducts connecting main fans to underground openings shall be fire resistant.
Statutory Authority
§§ 45.1-161.3 and 45.1-161.294 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.42, eff. July 19, 1989.
4VAC25-40-3190. Air intakes and returns.
Separate mine openings shall be provided for main intake and return air currents except during early stages of development. A multiple compartment shaft is a single opening for the purpose of this standard.
Statutory Authority
§§ 45.1-161.3 and 45.1-161.294 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 5.43, eff. July 19, 1989.
4VAC25-40-3200. Air current effectiveness.
The air current passing through the mine shall have a sufficient volume and velocity to dilute or remove dangerous amounts of noxious impurities and explosive gases.
Statutory Authority
§§ 45.1-161.3 and 45.1-161.294 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.44, eff. July 19, 1989.
4VAC25-40-3210. Fan maintenance.
Main fans shall be inspected and maintained properly.
Statutory Authority
§§ 45.1-161.3 and 45.1-161.294 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.45, eff. July 19, 1989.
4VAC25-40-3220. Mine atmosphere test instruments.
Instruments shall be provided to test the mine atmosphere quantitatively for carbon monoxide, nitrogen dioxide, and other gases that occur in the mine. Tests shall be conducted as frequently as necessary by the operator to ensure that the required quality of air is maintained.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.46, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-3230. (Repealed.)
Historical Notes
Derived from VR480-05-1.2 § 15.47, eff. July 19, 1989; repealed, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-3240. Access to inadequately ventilated areas.
Access to inadequately ventilated areas shall be sealed, or barricaded and posted against entry.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.48, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-3250. Installation of ventilation tubing.
When used, ventilation tubing shall be installed so that the air current sweeps the face areas effectively. Maximum distance of the end of the tubing from the face generally shall be 30 feet for blowing and six feet for exhausting.
Statutory Authority
§§ 45.1-161.3 and 45.1-161.294 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.49, eff. July 19, 1989.
4VAC25-40-3260. Ventilation door operation.
Ventilation doors not operated mechanically shall be designed and installed so that they are self-closing and will remain closed regardless of the direction of the air movement.
Statutory Authority
§§ 45.1-161.3 and 45.1-161.294 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.50, eff. July 19, 1989.
4VAC25-40-3270. Requirements for ventilation doors.
Ventilation doors shall be:
1. Substantially constructed;
2. Covered with fire-retardant material, if constructed of wood;
3. Maintained in good condition;
4. Self-closing, if manually operated; and
5. Equipped with audible or visual warning devices, if mechanically operated.
Statutory Authority
§§ 45.1-161.3 and 45.1-161.294 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.51, eff. July 19, 1989.
4VAC25-40-3280. Ventilation door closing.
When ventilation control doors are opened as a part of the normal mining cycle, they shall be closed as soon as possible to reestablish normal ventilation to active areas.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.52, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-3290. Sampling for radon gas.
Mine atmospheres shall be sampled to determine if hazardous concentrations of radon gas are present. Where potentially hazardous concentrations are found, or known sources of radon exist, each active area shall be sampled as often as necessary by a competent person.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.53, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-3300. Maximum annual exposure.
No person shall be permitted to receive an exposure to radon gas in excess of four working level months in any calendar year.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.54, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-3310. Maximum concentrations.
Persons shall not be exposed to air containing concentrations of radon gas exceeding 1.0 working level in active areas.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.55, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.
4VAC25-40-3320. Changes in permissible exposures.
If levels of permissible exposures to concentrations of radon gas differ from those prescribed in this chapter are recommended by the Environmental Protection Agency and approved by the President of the United States, no employee shall be permitted to receive exposures in excess of those levels after the effective dates established by the director.
Statutory Authority
§§ 45.1-161.3, 45.1-161.294 and 45.1-161.305 of the Code of Virginia.
Historical Notes
Derived from VR480-05-1.2 § 15.56, eff. July 19, 1989; amended, Virginia Register Volume 14, Issue 17, eff. July 1, 1998.