When written charges of neglect of duty, incompetency, or malfeasance in office against any deputy mine inspector are made and filed with the chief of the division of mineral resources management, signed by not less than fifteen employees, or an owner, lessee, or agent of a mine, the chief shall promptly investigate such charges and advise in writing the complainant whose name appears first in the charges, the result of such investigation.
If the mine employs less than fifteen employees, such charges shall be filed and signed by not less than fifty per cent of the employees.