(a) Haulage roads on entries developed after August 12, 1949, shall have a continuous unobstructed clearance of at least 24 inches from the farthest projection of moving equipment, on the clearance side.

(b) On haulage roads where trolley lines are used, the clearance shall be on the side opposite the trolley lines.

(c) On the trolley wire or "tight" side, there shall be six inches of clearance on track haulages developed prior to March 30, 1970, and 12 inches of clearance on track haulages developed after that date.

(d) After August 12, 1949, all new sidetracks, partings, or entries equipped with more than one track shall have a clearance of at least 24 inches between the outermost projection of moving traffic.

(e) The clearance space on all haulage roads on entries driven before or after August 12, 1949, shall be kept free of loose rock, coal, supplies, or other materials; provided, that not more than 24 inches need be kept free of such obstructions.

(f) In those exceptional instances where extremely thin seams of coal entail taking more rock than coal, the provisions of subsections (a) and (e) of this section shall be modified for room entries, such modification to be by the chief in writing; provided, that all persons shall be instructed to and required to use shelter holes when trips or cars are passing.

(g) In those exceptional instances where extremely bad roof conditions in thin seams require special timbering, the unobstructed clearance provided for in subsections (a) and (e) of this section may be regarded as measured from the rib or gob line, collar legs notwithstanding.

(h) Ample clearance shall be provided at all points where supplies are loaded or unloaded along haulage roads or conveyors.

(i) Where it is necessary for men to cross conveyors regularly and where the width of conveyors or low roof introduces a hazard, suitable crossover bridges shall be provided.

(j) Shelter holes shall be provided along haulage entries driven after August 12, 1949, where locomotive, rope, or animal haulage is used. Such shelter holes shall be spaced not more than 80 feet apart. Except where the trolley wire is six feet six inches or more above the roadbed or guarded effectively at the shelter holes, they shall be on the side of the entry opposite the trolley wire.

(k) Shelter holes made after August 12, 1949, shall be at least five feet in depth, not more than four feet in width and six feet in height or as high as the traveling space if the traveling space is less than six feet high. Room necks and cross cuts may be used as shelter holes even though their width exceeds four feet.

(l) Shelter holes shall be kept clear of refuse and other obstructions.

(m) Shelter holes shall be provided at switch throws, except where more than six feet of clearance is maintained and at room switches.

(n) At each landing of a slope where men are passing and cars are handled, a shelter hole at least 10 feet deep, four feet wide, and six feet high shall be provided.

(o) Where the only travelway to or from work is an incline plane, rope, or locomotive roads on which men travel on foot while such incline planes, rope, or locomotive roads are used for hoisting or haulage, shelter holes as specified in subsection (k) of this section shall be provided at not more than 80 foot intervals. These shelter holes shall be provided even though the travelway was driven prior to August 12, 1949; except, that they will not be required on locomotive roads where six feet or more clearance exists from the outermost projection of moving traffic, nor in those cases where adequate safeguards have been provided to secure men against exposure to danger from wrecks and such safeguards are approved by the division.