Section 1817.14  Casing and Sealing of Underground Openings: Temporary

a)         Each mine entry which is temporarily inactive, but has a further projected useful service under the approved permit application, shall be protected by barricades or other covering devices, fenced, and posted with signs to prevent access into the entry and to identify the hazardous nature of the opening. These devices shall be periodically inspected and maintained in good operating condition by the person who conducts the underground mining activities.

b)         Each exploration hole, other drill or borehole, shaft, well, and other exposed underground opening which have been identified in the approved permit application for use to return underground development waste, coal processing waste, or water to underground workings, or to be used to monitor ground water conditions, shall be temporarily sealed until actual use.