If, based upon samples taken, analyzed, and recorded pursuant to section
842
(a) of this title, or samples taken during an inspection by an authorized representative of the Secretary, the applicable limit on the concentration of respirable dust required to be maintained under this chapter is exceeded and thereby violated, the Secretary or his authorized representative shall issue a citation fixing a reasonable time for the abatement of the violation. During such time, the operator of the mine shall cause samples described in section
842
(a) of this title to be taken of the affected area during each production shift. If, upon the expiration of the period of time as originally fixed or subsequently extended, the Secretary or his authorized representative finds that the period of time should not be further extended, he shall determine the extent of the area affected by the violation and shall promptly issue an order requiring the operator of such mine or his agent to cause immediately all persons, except those referred to in subsection (c) of this section, to be withdrawn from, and to be prohibited from entering, such area until the Secretary or his authorized representative has reason to believe, based on actions taken by the operator, that such limit will be complied with upon the resumption of production in such mine. As soon as possible after an order is issued, the Secretary, upon request of the operator, shall dispatch to the mine involved a person, or team of persons, to the extent such persons are available, who are knowledgeable in the methods and means of controlling and reducing respirable dust. Such person or team of persons shall remain at the mine involved for such time as they shall deem appropriate to assist the operator in reducing respirable dust concentrations. While at the mine, such persons may require the operator to take such actions as they deem appropriate to insure the health of any person in the coal or other mine.