30 CFR § 817.11 - Signs and markers.
(a) Specifications. Signs and markers required under this part shall -
(2) Be of a uniform design throughout the activities that can be easily seen and read;
(3) Be made of durable material; and
(4) Conform to local laws and regulations.
(b) Duration of maintenance. Signs and markers shall be maintained during all activities to which they pertain.
(c) Mine and permit identification signs.
(2) Signs will show the name, business address, and telephone number of the person who conducts underground mining activities and the identification number of the current regulatory program permit authorizing underground mining activities.
(3) Signs shall be retained and maintained until after the release of all bonds for the permit area.
(d) Perimeter markers. Each person who conducts underground mining activities shall clearly mark the perimeter of all areas affected by surface operations or facilities before beginning mining activities.
(e) Buffer zone markers. Buffer zones required by § 817.57 shall be clearly marked to prevent disturbance by surface operations and facilities.