The anthracite coal producing counties of the Commonwealth shall be arranged by the secretary, with the consent of the Governor, into mine inspection districts, and the secretary may at any time, with the consent of the Governor, redistrict the anthracite coal producing districts. Each mine inspection district shall have a mine inspector. The Governor shall commission and appoint mine inspectors from among persons holding valid unexpired certificates of qualification issued by the examining board under this act or under any previous act, and each mine inspector shall hold office during good behavior or until removed from office as herein provided. It shall be the duty of the secretary to assign the mine inspectors to their respective districts and the secretary shall also designate the place of abode of each mine inspector, at a point as convenient as possible to the mines of his district.