Mineral Resources. Part71:Mandatory health standards—surface coal mines and surface work areas of underground coal mines. Section71.205:Approved sampling devices; operation; air flowrate.
(a) Sampling devices approved in accordance with part 74 (Coal Mine Dust Personal Sampler Units) of this title shall be operated at the flowrate of 2.0 liters of air per minute, or at a different flowrate as prescribed by theSecretary and the Secretary of Health and Human Services for the particular device.