52 Pa. Stat. § 70-201
It shall not be lawful, neither shall it be permitted, for any person or persons to act as mine foreman, assistant mine foreman or mine examiner of any coal mine or colliery, unless they are registered as a holder of a certificate of qualification or service under this act. The mine foreman shall have full charge of all the inside workings and the persons employed therein, subject, however, to the supervision and control of the operator or the superintendent, in order that all the provisions of this act, so far as they relate to his duties, shall be complied with and the regulations prescribed for each class of workmen under his charge carried out in the strictest manner possible. Nothing in this article shall prevent a mine foreman or assistant mine foreman from acting as a mine examiner in case of an emergency. Upon the effective date of this act and after an examination has been given for the certification of mine foremen, assistant mine foremen, and mine examiner, it shall be unlawful for any operator or superintendent to employ a mine examiner who has not been certified as such by the Department of Mines and Mineral Industries.
52 P.S. § 70-201