(a) Sampling.

1. (1) Mine operators shall commence sampling by the compliance date in § 60.1 to assess the full shift, 8-hour TWA exposure of respirable crystalline silica for each miner who is or may reasonably be expected to be exposed to respirable crystalline silica.

2. (2) If the sampling under paragraph (a)(1) of this section is:

   1. (i) Below the action level, the mine operator shall take at least one additional sampling within 3 months.
   2. (ii) At or above the action level but at or below the PEL, the mine operator shall take another sampling within 3 months.
   3. (iii) Above the PEL, the mine operator shall take corrective actions and sample pursuant to § 60.12(b).
3. (3) Where the most recent sampling indicates that miner exposures are at or above the action level but at or below the PEL, the mine operator shall continue to sample within 3 months of the previous sampling.
4. (4) The mine operator may discontinue sampling when two consecutive samplings indicate that miner exposures are below the action level. The second of these samplings must be taken after the operator receives the results of the prior sampling but no sooner than 7 days after the prior sampling was conducted.

(c) Periodic evaluation. At least every 6 months after commencing sampling under 60.12(a)(1) or whenever there is a change in: production; processes; installation or maintenance of engineering controls; installation or maintenance of equipment; administrative controls; or geological conditions; mine operators shall evaluate whether the change may reasonably be expected to result in new or increased respirable crystalline silica exposures. Once the evaluation is completed, the mine operator shall:

1. (1) Make a record of the evaluation, including the evaluated change, the impact on respirable crystalline silica exposure, and the date of the evaluation; and
2. (2) Post the record on the mine bulletin board and, if applicable, by electronic means, for the next 31 days.

(e) Sampling requirements.

1. (1) Sampling shall be performed for the duration of a miner's regular full shift and during typical mining activities, including shaft and slope sinking, construction, and removal of overburden.

2. (2) The full-shift, 8-hour TWA exposure for such miners shall be measured based on:

   1. (i) Personal breathing-zone air samples for metal and nonmetal operations; or
   2. (ii) Occupational environmental samples collected in accordance with § 70.201(c), § 71.201(b), or § 90.201(b) of this chapter for coal operations.
3. (3) Where several miners perform the same tasks on the same shift and in the same work area, the mine operator may sample a representative fraction (at least two) of these miners to meet the requirements in paragraphs (a) through (e) of this section. In sampling a representative fraction of miners, the mine operator shall select the miners who are expected to have the highest exposure to respirable crystalline silica.
4. (4) The mine operator shall use respirable-particle-size-selective samplers that conform to ISO 7708:1995(E) to determine compliance with the PEL. ISO 7708:1995(E), Air quality—Particle size fraction definitions for health-related sampling, First Edition, 1995-04-01, is incorporated by reference into this section with the approval of the Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. This incorporation by reference (IBR) material is available for inspection at the Mine Safety and Health Administration (MSHA) and at the National Archives and Records Administration (NARA). Contact MSHA at: MSHA's Office of Standards, Regulations, and Variances, 201 12th Street South, Arlington, VA 22202-5450; (202) 693-9440; or any Mine Safety and Health Enforcement District Office. For information on the availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email fr.inspection@nara.gov. The material may be obtained from the International Organization for Standardization (ISO), CP 56, CH-1211 Geneva 20, Switzerland; phone: + 41 22 749 01 11; fax: + 41 22 733 34 30; website: www.iso.org.

(f) Methods of sample analysis.

1. (1) The mine operator shall use a laboratory that is accredited to ISO/IEC 17025 “General requirements for the competence of testing and calibration laboratories” with respect to respirable crystalline silica analyses, where the accreditation has been issued by a body that is compliant with ISO/IEC 17011 “Conformity assessment—Requirements for accreditation bodies accrediting conformity assessment bodies.”
2. (2) The mine operator shall ensure that the laboratory evaluates all samples using respirable crystalline silica analytical methods specified by MSHA, the National Institute for Occupational Safety and Health (NIOSH), or the Occupational Safety and Health Administration (OSHA).