Okla. Stat. tit. 45 § 521
The fire boss shall at each entrance to the mine, or to the main intake airway, near to the mine entrance, prepare a permanent station with the proper danger signals designated as follows:
X-(DATE OF MONTH)-X
and it shall not be lawful for any person or persons, except the mine officials in cases of necessity, and such other persons as may be designated by them, to pass beyond said danger station, until the mine has been examined by the fire boss as aforesaid, and the same, or certain parts thereof, reported by him to be safe; and in all mines where operations are temporarily or indefinitely suspended, the superintendent and mine foreman shall see that a danger signal be placed at the mine entrance, or entrances, which shall be a sufficient warning to persons not to enter the mine, and if ordinary circulation of air through the mine be stopped, each entrance to said mine shall be securely fenced off and a danger signal shall be displayed upon said fence, and any workman or other person (except those persons hereinbefore provided for) passing beyond any danger signal into the mine before it has been examined and reported to be safe as aforesaid, also any person passing beyond any danger signal placed at the entrance to a working place, or any other place, in the mine without permission of the mine foreman, his assistant or his fire boss, shall be punished by a fine of not less than Fifty Dollars ($50.00) nor more than Two Hundred Dollars ($200.00), or imprisonment in the county jail not to exceed thirty (30) days, or both such fine and imprisonment; and it shall be the duty of the fire boss, mine foreman, or superintendent to forthwith prosecute such person, or persons, before the proper legal authority, or to notify the mine inspector, who shall enter proceedings against such person.
Okla. Stat. tit. 45, § 521