30 CFR 717.12 - Signs and markers.
(a) Specifications. All signs required to be posted shall be of a standard design that can be seen and read easily and shall be made of durable material, and shall conform to local ordinances and codes. The signs and other markers shall be maintained during all operations to which they pertain.
(b) Mine and permit identification signs. Signs identifying the mine area shall be displayed at all points of access to the permit area from public highways. Signs shall show the name, business address, and telephone number of the permittee and identification numbers of current mining and reclamation permits or other authorizations to operate. Such signs shall not be removed until after release of all bonds.