66 S T A T. ]
PUBLIC LAW 552-JULY 16, 1952
705
place he examines. If such mine examiner, in making his examine"Danger" sign. tion, finds a condition which he considers to be dangerous to persons who may enter or be in such area, he shall indicate such dangerous place by posting a 'DANGER' sign conspicuously at a point which persons entering such dangerous place would be required to pass. No person, other than Federal or State mine inspectors or persons authorized by the mine operator to enter such place for the purpose of eliminating the dangerous condition therein, shall enter such place while such sign is so posted. Upon completing his examination such mine examiner shall report the result of his examination to a person designated by the mine operator to receive such reports, at a designated station on the surface of the premises of the mine or underground, before other persons enter the underground areas of such mine to work in such coal-producing shift. Each such mine examiner shall also record the results of his examination with ink or indelible pencil in a book kept for such purpose at a place on the surface of the mine designated by the mine operator. No person (other than a certified person designated under this paragraph) shall enter any underground area in a gassy mine, except during a coal-producing shift, unless an examination of such area as prescribed in this paragraph has been made within twelve hours immediately preceding his entrance into such area. "(8) I n nongassy mines, an examination as prescribed in paragraph (7) shall be made at least once in each calendar day during which coal ^ is produced. Such examination shall be made within four hours immediately preceding the beginning of the first coal-producing shift on such day. "(9) The underground working places in all mines shall be examined for hazards by certified persons designated by the mine operator to do so, at least once during each coal-producing shift, or oftener if necessary for safety. I n a gassy mine, such examinations shall include tests with a permissible flame safety lamp for methane, and oxygen deficiency. I n all underground face workings in a gassy mine where electrically driven equipment is operated, examinations for methane shall be made with a permissible flame safety lamp by a person trained in the use of such lamp before such equipment is taken into or operated in face regions, and frequent examinations for methane shall be made during such operations. "(10) I n a gassy mine, immediately before a roof fall is made in pillar workings, such workings shall be examined to ascertain whether methane is present. If in such examination methane is found in amounts that can be detected with a permissible flame safety lamp, a roof fall shall not be made until such gas is removed. "(11) I n a gassy mine, all workings which are abandoned after the effective date of this section or the date such mine became a gassy mine, whichever is later, shall be sealed or ventilated. If such workings are sealed, the sealing shall be done in a substantial manner with incombustible material. One or more of the seals of every sealed area shall be fitted with a pipe and cap or valve to permit the sampling of gases and the measuring of hydrostatic pressure behind such seals. For the purposes of this paragraph, workings within a panel shall not be deemed to be abandoned until such panel is abandoned. "(e) COAL D U S T AND ROCK DITST.—(1) Coal dust, loose coal, and other combustible materials shall not be permitted to accumulate in dangerous quantities in active underground workings of a mine, "(2) Where underground mining operations raise an excessive amount of dust into the air, water, or water with a wetting agent added to it, or other effective method shall be used to allay such dust at its source.
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