30 CFR § 715.12 - 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. The signs and other markers shall be maintained during all operations to which they pertain and shall conform to local ordinances and codes.
(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 roads and 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.
(c) Perimeter markers. The perimeter of the permit area shall be clearly marked by durable and easily recognized markers, or by other means approved by the regulatory authority.
(d) Buffer zone markers. Buffer zones as defined in § 715.17 shall be marked in a manner consistent with the perimeter markers along the interior boundary of the buffer zone.
(e) Blasting signs. If blasting is necessary to conduct surface coal mining operations, signs reading “Blasting Area” shall be displayed conspicuously at the edge of blasting areas along access and haul roads within the mine property. Signs reading “Blasting Area” and explaining the blasting warning and all-clear signals shall be posted at all entrances to the permit area.
(f) Topsoil markers. Where topsoil or other vegetation-supporting material is segregated and stockpiled according to § 715.16(c), the stockpiled material shall be marked. Markers shall remain in place until the material is removed.