83 STAT. ]
PUBLIC LAW 91-173-DEC. 30, 1969
775
(c) All underground areas of a coal mine, except those areas 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 working faces, unless such areas are inaccessible or unsafe to enter or unless the Secretary or his authorized representative permits an exception upon his finding that such exception will not pose a hazard to the miners. All crosscuts that are less than forty feet from a working face shall also be rock dusted. (d) Where rock dust is required to be applied, it shall be distributed upon the top, floor, and sides of all underground areas of a coal mine and maintained in such quantities that the incombustible content of the combined coal dust, rock dust, and other dust shall be not less than 65 per centum, but the incombustible content in the return aircourses shall be no less than 80 per centum. Where methane is present in any ventilating current, the per centum of incombustible content of such combined dusts shall be increased 1.0 and 0.4 per centum for each 0.1 per centum of methane where 65 and 80 per centum, respectively, of incombustibles are required. (e) Subsections (b) through (d) of this section shall not apply to hiu""^^^^^* bility. underground anthracite mines. ELECTRICAL EQUIPMENT—GENERAL
SEC. 305. (a)(1) Effective one year after the operative date of this title— (A) all junction or distribution boxes used for making multiple power connections inby the last open crosscut shall be permissible; (B) all handheld electric drills, blower and exhaust fans, electric pumps, and such other low horsepower electric face equipment as the Secretary may designate within two months after the operative date of this title which are taken into or used inby the last open crosscut of any coal mine shall be permissible; (C) all electric face equipment which is taken into or used inby the last open crosscut of any coal mine classified under any provision of law as gassy prior to the operative date of this title shall be permissible; and (D) all other electric face equipment which is taken into or used inby the last crosscut of any coal mine, except a coal mine referred to in paragraph (2) of this subsection, which has not been classified under any provision of law as a gassy mine prior to the operative date of this title shall be permissible. (2) Effective four years after the operative date of this title, all ^^^^'il'^^^^""°"" electric face equipment, other than ec[uipment referred to in para- ""'^ la^ce. graph (1)(B) of this subsection, which is taken into or used inby the last open crosscut of any coal mine which is operated entirely in coal seams located above the watertable and which has not been classified under any provision of law as a gassy mine prior to the operative date of this title and in which one or more openings were made prior to the date of enactment of this Act, shall be permissible, except that any operator of such mine who is unable to comply with the provisions of this paragraph on such effective date may file with the^ Panel an application tor a permit for noncompliance ninety days prior to such date. If the Panel determines, after notice to all interested persons and an opportunity for a public hearing under section 5 of this Act, ^"*^'?• 744. that such application satisfies the provisions of paragraph (10) of this
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