The following definitions apply in this part.

Act. The Federal Mine Safety and Health Act of 1977, Public Law 91-173, as amended by Public Law 95-164 and Public Law 109-236.

Active workings. Any place in a surface coal mine or the surface work area of an underground coal mine where miners are normally required to work or travel.

Approved sampling device. A sampling device approved by the Secretary and Secretary of Health and Human Services (HHS) under part 74 of this title.

Certified person. An individual certified by the Secretary in accordance with §71.202 to take respirable dust samples required by this part or certified in accordance with §71.203 to perform maintenance and calibration of respirable dust sampling equipment as required by this part.

Coal mine dust personal sampler unit (CMDPSU). A personal sampling device approved under part 74, subpart B, of this title.

Concentration. A measure of the amount of a substance contained per unit volume of air.

Continuous personal dust monitor (CPDM). A personal sampling device approved under part 74, subpart C, of this title.

Designated work position (DWP). A work position in a surface coal mine and surface work area of an underground coal mine designated for sampling to measure respirable dust generation sources in the active workings. Each DWP will be assigned a four-digit number assigned by MSHA identifying the specific physical portion of the mine that is affected, followed by a three-digit MSHA coal mining occupation code describing the location to which a miner is assigned in the performance of his or her regular duties.

District Manager. The manager of the Coal Mine Safety and Health District in which the mine is located.

Equivalent concentration. The concentration of respirable coal mine dust, including quartz, expressed in milligrams per cubic meter of air (mg/m3) as measured with an approved sampling device, determined by dividing the weight of dust in milligrams collected on the filter of an approved sampling device by the volume of air in cubic meters passing through the filter (sampling time in minutes (t) times the sampling airflow rate in cubic meters per minute), and then converting that concentration to an equivalent concentration as measured by the Mining Research Establishment (MRE) instrument. When the approved sampling device is:

(1) The CMDPSU, the equivalent concentration is determined by multiplying the concentration of respirable coal mine dust by the constant factor prescribed by the Secretary.

(2) The CPDM, the device shall be programmed to automatically report end-of-shift concentration measurements as equivalent concentrations.

MRE instrument. The gravimetric dust sampler with a four channel horizontal elutriator developed by the Mining Research Establishment of the National Coal Board, London, England.

MSHA. The Mine Safety and Health Administration of the U.S. Department of Labor.

Normal work shift. (1) A shift during which the regular duties of the DWP are performed while routine day-to-day mining activities are occurring in the rest of the mine and

(2) A shift during which there is no rain, or, if rain occurs, the rain does not suppress the respirable dust to the extent that sampling results will be measurably lower, in the judgment of the person certified under this part to conduct sampling.

Quartz. Crystalline silicon dioxide (SiO2) not chemically combined with other substances and having a distinctive physical structure.

Representative sample. A respirable dust sample, expressed as an equivalent concentration, that reflects typical dust concentration levels in the working environment of the DWP when performing normal duties.

Respirable dust. Dust collected with a sampling device approved by the Secretary and the Secretary of HHS in accordance with part 74 (Coal Mine Dust Sampling Devices) of this title.

Secretary. The Secretary of Labor or a delegate.

Surface area. A specific physical portion of a surface coal mine or surface area of an underground coal mine. These areas are assigned a four-digit identification number by MSHA.

Surface coal mine. A surface area of land and all structures, facilities, machinery, tools, equipment, excavations, and other property, real or personal, placed upon or above the surface of such land by any person, used in, or to be used in, or resulting from, the work of extracting in such area bituminous coal, lignite, or anthracite from its natural deposits in the earth by any means or method, and the work of preparing the coal so extracted, including custom coal preparation facilities.

Surface installation. Any structure in which miners work at a surface coal mine or surface work area of an underground coal mine.

Surface work area of an underground mine. The surface areas of land and all structures, facilities, machinery, tools, equipment, shafts, slopes, excavations, and other property, real or personal, placed in, upon or above the surface of such land by any person, used in, or to be used in, or resulting from, the work of extracting bituminous coal, lignite, or anthracite from its natural deposits underground by any means or method, and the work of preparing the coal so extracted, including custom coal preparation facilities.

Surface worksite. Any area in which miners work at a surface coal mine or surface work area of an underground coal mine.

Valid respirable dust sample. A respirable dust sample collected and submitted as required by this part, including any sample for which the data were electronically transmitted to MSHA, and not voided by MSHA.

Work position. An occupation identified by an MSHA three-digit code number describing a location to which a miner is assigned in the performance of his or her normal duties.