(a) Each operator shall take one valid respirable dust sample from
each designated area on a production shift during each bimonthly period
beginning with the bimonthly period of December 1, 1980. The bimonthly
February 1-March 31
April 1-May 31
June 1-July 31
August 1-September 30
October 1-November 30
December 1-January 31.
(b) When the respirable dust standard is changed in accordance with
§70.101 (Respirable dust standard when quartz is
present), respirable dust sampling of designated areas shall begin on the
first production shift during the next bimonthly period following
notification of such change from MSHA.
(c) Upon notification from MSHA that any respirable dust sample taken
from a designated area to meet the requirements of paragraph (a) or (b) of
this section exceeds the applicable standard in §70.100 (Respirable dust standards) or §70.101 (Respirable
dust standard when quartz is present), the operator shall take five
valid respirable dust samples from that designated area within 15
calendar days. The operator shall begin such sampling on the first day on
which there is a production shift following the day of receipt of
(d) Upon issuance of a citation for a violation of §70.100 (Respirable dust standards) or §70.101 (Respirable
dust standard when quartz is present) involving a designated
area, paragraphs (a), (b) and (c) of this section shall not apply to that
designated area until the violation is abated in accordance with
§70.201(d) (Sampling; general requirements).
(e) Designated area samples shall be collected at locations to
measure respirable dust generation sources in the active workings. The
approved mine ventilation plan contents required by §75.371(t) of this chapter shall show the specific locations where
designated area samples will be collected. Each designated area will be
assigned a four-digit identification number by MSHA.
(f) MSHA approval of the operator's ventilation system and methane
and dust control plan may be revoked based on samples taken by MSHA or in
accordance with this part 70.