Kentucky Revised Statutes Title XXVIII. Mines and Minerals § 352.371.Boreholes in advance of working face required

Whenever any working place approaches within fifty (50) feet of abandoned areas in the mine as shown by surveys made and certified by a registered engineer, or within two hundred (200) feet of any other abandoned areas of the mine which cannot be inspected and which may contain dangerous accumulations of water or gas, or within two hundred (200) feet of any workings of an adjacent mine, a borehole or boreholes shall be drilled to a distance of at least twenty (20) feet in advance of the working face of the working place and shall be continually maintained to a distance of at least ten (10) feet in advance of the advancing working face. When there is more than one (1) borehole, they shall be drilled sufficiently close to each other to insure that the advancing working face will not accidentally hole through into abandoned areas or adjacent mines. Boreholes shall also be drilled not more than eight (8) feet apart in the rib of the working place to a distance of at least twenty (20) feet and at an angle of forty-five (45) degrees before additional cuts are taken. Rib holes shall be drilled in one (1) or both ribs of the working place as may be necessary for adequate protection of miners in such place. Alternative plans which afford equal or greater protection may be approved by the commissioner or his authorized representative.