Section 75.1106-4 - Use of liquefied and nonliquefied compressed gas cylinders; general requirements(a) Persons assigned by the operator to use and work with liquefied and nonliquefied compressed gas shall be trained and designated by the operator as qualified to perform the work to which they are assigned, and such qualified persons shall be specifically instructed with respect to the dangers inherent in the use of such gases in an underground coal mine.(b) Persons who perform welding, cutting, or burning operations shall wear clothing free from excessive oil or grease.(c) Liquefied and nonliquefied compressed gas shall be used only in well-ventilated areas.(d) Not more than one liquefied or nonliquefied compressed gas unit, consisting of one oxygen cylinder and one additional gas cylinder, shall be used to repair any unit of equipment which is inby the loading point of any section.(e) Where liquefied and nonliquefied compressed gas is used regularly in underground shops or other underground structures, such shops or structures shall be on a separate split of air.(f) Where liquefied and nonliquefied compressed gas is used in any area in which oil, grease, or coal dust is present, oil and grease deposits shall, where practicable, be removed and the entire area within 10 feet of the worksite covered with a heavy coating of rock dust.(g) Liquefied and nonliquefied compressed gas cylinders shall be located no less than 10 feet from the worksite, and where the height of the coal seam permits, they shall be placed in an upright position and chained or otherwise secured against falling.(h) Liquefied and nonliquefied compressed gas shall not be used under direct pressure from the cylinder and, where such gases are used under reduced pressure, the pressure level shall not exceed that recommended by the manufacturer.(i) "Manifolding cylinders" shall only be performed in well-ventilated shops where the necessary equipment is properly installed and operated in accordance with specifications for safety prescribed by the manufacturer.36 FR 22061, Nov. 19, 1971