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PUBLIC LAW 552-JULY 16, 1952
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[66 S T A T.
1.5 per centum. However, in virgin territory in mines ventilated by exhaust fans, where methane is liberated in large amounts, if the quality of air in a split ventilating the workings in such territory equals or exceeds twice the minimum volume of air prescribed in paragraph (1) of this subsection and if only permissible electric equipment is used in such workings and the air in the split returning from such workings does not pass over trolley or other bare power wires, and if a certified person designated by the mine operator IS continually testing the gas content of the air in such split during mining operations in such workings, it shall be necessary to withdraw the employees and cut off all power from the portion of the mine endangered by such methane only when the quantity thereof in the air returning from such workings exceeds 2 per centum, as determined by a permissible methane detector, a permissible flame safety lamp, air analysis, or other recognized means of accurately detecting such gas. "(5) In a gassy mine, air which has passed by an opening of any unsealed, abandoned area shall not be used to ventilate any active face area in such mine if such air contains 0.25 per centum or more of methane; but if this sentence cannot be complied with in such mine on the effective date of this section, such mine may continue to be operated after such date as it was operated immediately prior to such date, for a reasonable time until future mine development and ventilation of such mine can be changed to comply with this sentence. In no event shall such air be used to ventilate any area in such mine in which men work or travel if such air contains more than 1 per centum of methane. For the purposes of this paragraph, an area within a panel shall not be deemed to be abandoned until such panel is abandoned. "(6) I n a gassy mine, air that has passed through an abandoned panel which is inaccessible for inspection, or air that has passed through a similar abandoned area which is inaccessible for inspection, or air which has been used to ventilate a pillar line, or air which has been used to ventilate an area from which the pillars have been removed, shall not be used to ventilate any active face area in such mine; but if this sentence cannot be complied with in such mine on the effective date of this section, such mine may continue to be operated after such date as it was operated immediately prior to such date, for a reasonable time until future mine development and ventilation of such mine can be changed to comply with this sentence. In no event shall such air be used to ventilate any area in such mine in which men work or travel if such air contains more than 1 per centum of methane. "(7) In a gassy mine, within four hours immediately preceding the beginning of a coal-producing shift, and before any worKmen in such shift other than those who may be designated to make the examinations prescribed in this paragraph enter the underground areas of such mine, certified persons designated by the operator of such mine to do so shall make an examination, as prescribed in this paragraph, of such areas. Each person designated to act as such a mine examiner shall be directed to examine a definite underground area of such mine, and, in making his examination, such examiner shall inspect every active working place in such area and make tests therein with a permissible flame safety lamp for accumulations of methane and oxygen deficiency in the air therein; examine seals and doors to determine whether they are functioning properly; inspect and test the roof, face, and rib conditions in the working places and on active roadways and travel ways; inspect active roadways, travel ways, approaches to abandoned workings and accessible falls in active sections for explosive gas and other hazards; and inspect to determine whether the air in each split is traveling in its proper course and in normal volume. Such mine examiner shall place his initials and the date at or near the face of each
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