Page:United States Statutes at Large Volume 66.djvu/752

 706

F a c e equipment.

Junction or distribution boxes.

T w o - c onductor trailing cables. T r o l l e y and feeder wires.

PUBLIC LAW 5 5 2 - J U L Y 16, 1952

[66 S T A T.

"(3) All underground mines, except those mines or areas of mines in which the dust is too wet or too high in incombustible content to propagate an explosion, shall be rock-dusted to within forty feet of all faces, and, if open crosscuts near such faces are less than forty feet therefrom, such crosscuts shall be rock-dusted. "(4) I n mines partially rock-dusted or in mines that are required to start rock-dusting, haulageways and parallel entries connected thereto by open crosscuts shall be rock-dusted. Back entries shall be rock-dusted for at least one thousand feet outby the junction with the first active entry. Inby this junction, the rooms, entries, and crosscuts shall be rock-dusted. "(5) Where rock dust is applied, it shall be distributed upon the top, floor, and sides of all open places and maintained in such quantity that the incombustible content of the combined coal dust, rock dust and other dust will not be less than 65 per centum. Where methane is present in any ventilating current, the 65 per centum of incombustible content of such combined dust shall be increased 1 per centum for each 0.1 per centum of methane. "(6) Paragraphs (2), (3), (4), and (5) of this subsection shall not apply to anthracite mines. "(f) ELECTRICAL EQUIPMENT.— (1) All electric face equipment used in a gassy mine shall be permissible, except that electric face equipment may be used in a gassy mine even though such equipment is not permissible if, before the effective date of this section or the date such mine became a gassy mine, whichever is later, the operator of such mine owned such equipment, or owned the right to use such equipment, or had ordered such equipment. Permissible electric face equipment in use in a gassy mine shall not be replaced by electric face equipment which is not permissible except that (A) permissible and nonpermissible electric face equipment in use in a mine may be interchanged within such mine, and (B) explosion-tested cable-reel locomotives and shuttle cars purchased before permissible cable-reel locomotives and shuttle cars became available, may be used to replace permissible cable-reel locomotives and shuttle cars. "(2) I n a gassy mine, permissible junction or distribution boxes shall be used for making multiple-power connections in working places or other places where dangerous quantities of methane may be present or may enter the air current, except that where nonpermissible junction or distribution boxes are in use, or on order, on the effective date of this section or the date such mine became a gassy mine, whichever is later, their use may be continued until such time as replacements are made. "(3) I n a gassy mine, explosion-tested cable-reel locomotives shall be equipped with two-conductor trailing cables. "(4) I n a gassy mine, trolley and feeder wires shall not extend beyond the last open crosscut and shall be kept at least one hundred and fifty feet from pillar workings. " (g) F I R E PROTECTION.—(1) Each mine shall be provided with suitable fire-fighting equipment, adequate for the size of the mine. "(2) After every blasting operation performed on shift, an examination shall be made to determine whether fires have been started. "(3) Underground storage places for lubricating oil and grease in excess of two days' supply shall be of fireproof construction. "(4) Lubricating oil and grease kept in face regions or other underground working places in a mine shall be in portable, closed, metal containers. "(5) Underground structures (transformer stations, battery-charging stations, substations, permanent pump rooms, etc.), installed in a mine after the effective date of this section shall be of fireproof construction.

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