(a) It is the duty of the fire boss, or a certified person acting as such, to prepare a danger signal (a separate signal for each shift) with red color at the mine entrance at the beginning of his or her shift or prior to his or her entering the mine to make his or her examination and, except for those persons already on assigned duty, no person except the mine owner, operator or agent, and only then in the case of necessity, shall pass beyond this danger signal until the mine has been examined by the fire boss or other certified person and the mine or certain parts thereof reported by him or her to be safe. When reported by him or her to be safe, the danger sign or color thereof shall be changed to indicate that the mine is safe in order that employees going on shift may begin work. Each person designated to make the fire boss examinations shall be assigned a definite underground area of the mine, and, in making his or her examination shall examine all active working places in the assigned area and make tests with an approved device for accumulations of methane and oxygen deficiency; examine seals and doors; examine and test the roof, face and ribs in the working places and on active roadways and travelways, approaches to abandoned workings, accessible falls in active sections and areas where any person is scheduled to work or travel underground. He or she shall place his or her initials and the date at or near the face of each place he or she examines. Should he or she find a condition which he or she considers dangerous to persons entering the areas, he or she shall place a conspicuous danger sign at all entrances to the place or places. Only persons authorized by the mine management may enter the places while the sign is posted and only for the purpose of eliminating the dangerous condition. Upon completing his or her examination he or she shall report by suitable communication system or in person the results of this examination to a certified person trained as a certified miner with at least two years mining experience designated by mine management to receive and record the report, at a designated station on the surface of the premises of the mine or underground, before other persons enter the mine to work in coal-producing shifts. He or she shall also record the results of his or her examination with ink or indelible pencil in a book prescribed by the director, kept for the purpose at a place on the surface of the mine designated by mine management. All records of daily and weekly reports, as prescribed herein, shall be open for inspection by interested persons.

(b) Supplemental examination. - When it becomes necessary to have workers enter areas of the mine not covered during the preshift examination, a supplemental examination shall be performed by a fire boss or certified person acting as such within three hours before any person enters the area. The fire boss or certified person acting as such shall examine the area for hazardous conditions, determine if air is traveling in its proper direction and test for oxygen deficiency and methane.

(c) Each examined area shall be certified by date, time and the initials of the examiner.

(d) The results of the examination shall be recorded with ink or indelible pencil by the examiner in the book referenced in subsection (a) of this section before he or she leaves the mine on that shift.