(a) The operator shall take five valid respirable dust samples for
each part 90 miner within 15 calendar days after:
(1) The 20-day period specified for each part
90 miner in §90.100 (Respirable
dust standard);
(2) Receipt of notification from MSHA that any respirable
dust sample taken in accordance with §90.208 (Bimonthly
sampling) exceeds 1.0 milligram per cubic meter of air or the respirable
dust standard established by §90.101 (Respirable
dust standard when quartz is present); and
(3) Implementing any transfer after the twentieth calendar
day following receipt of notification from MSHA that a part 90 miner is employed at the mine.
