1. A. During on-shift examinations required by § 45.2-827 of the Code of Virginia, a mine foreman authorized by the operator shall determine the concentration of carbon monoxide (CO) and nitrogen dioxide (NO₂).

   1. 1. In the return of each working section where diesel equipment is used inby the loading point at a location which represents the contribution of all diesel equipment on such section.
   2. 2. At a point inby the last piece of diesel equipment on a longwall or shortwall when mining equipment is being installed or removed. This examination shall be made at a time which represents the contribution of all diesel equipment used for this activity including the diesel equipment used to transport longwall or shortwall equipment to and from the section.
   3. 3. In any other area designated by the chief where diesel equipment is operated in a manner which can result in significant concentrations of diesel exhaust emissions.

   4. 4. The concentrations of carbon monoxide (CO) and nitrogen dioxide (NO₂) shall not exceed the following threshold limit values:

      Threshhold Limit Values (TLV)
      Carbon Monoxide (CO)	25 ppm
      Nitrogen Dioxide (NO2)	3 ppm

2. B. Samples of CO and NO₂ shall be collected and analyzed:

   1. 1. By appropriate instrumentation that has been maintained and calibrated in accordance with the manufacturer's recommendations;
   2. 2. In a manner that makes the results available immediately to the person collecting the samples; and
   3. 3. During periods that are representative of conditions during normal operations.

3. C. The results of these tests shall be:

   1. 1. Recorded in a secure book that is not susceptible to alteration, or recorded electronically in a computer system that is secure and not subject to alteration; and
   2. 2. Retained at a surface location at the mine for at least one year and made available for inspection by interested persons.

Statutory Authority

§ 45.2-103 of the Code of Virginia.

Historical Notes

Derived from Virginia Register Volume 17, Issue 20, eff. July 18, 2001; amended, Virginia Register Volume 38, Issue 13, eff. March 31, 2022.