Mine Safety and Health Administration
Protecting Miners' Safety and Health Since 1978
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U.S. Department of Labor Mine Safety and Health Administration Protecting Miners' Safety and Health Since 1978 |
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PROGRAM POLICY LETTER NO. P06-V-1 FROM: RAY McKINNEY  Administrator for Coal Mine Safety and Health MARK E. SKILES  Director of Technical Support SUBJECT: Safe Use of Welding Equipment on Longwall Mining Systems- Interpretation of 30 CFR 75.1725 (a) Scope Coal mine operators, miners and miners' representatives, longwall equipment manufacturers, Mine Safety and Health Administration (MSHA) enforcement personnel, and other interested parties should have this information. Purpose This Program Policy Letter (PPL) interprets the application of Title 30 Code of Federal Regulations (30 CFR) 75.1725 (a) to welding equipment, including welding cables used on longwall systems; clarifies the scope and application of § 75.1002 to the use of welding cables on longwall mining systems; and clarifies the intent of § 75.1106 relative to § 75.1002. The policy is also intended to provide uniform and consistent enforcement with respect to the use of welding equipment on longwall mining systems. Policy This policy prohibits the permanent connection of the welding cable to the welding machine when welding is not taking place. The PPL further provides guidance to ensure that welding equipment is maintained in safe operating condition when welding is not taking place. In order to ensure that welding equipment, including welding cables, is maintained in safe operating condition, as required by § 75.1725 (a), and that miners are not exposed to shock, fire, or explosion hazards when using such equipment on longwall faces, the following must be implemented:
Questions were raised regarding the safe use of welding cables, with pigtails or connectors (couplers) that are connected to PTO of longwall controllers at all times even when welding is not taking place. Some questioned the applicability of 30 CFR § 75.1002, and recommended that such cables be prohibited. Section 75.1106 permits welding in areas of the mines where permissible equipment is otherwise required if the provisions of the standard are followed. Since the welding cable is part of the welding equipment, § 75.1002 (Installation of electrical equipment and conductors; permissibility) does not apply because § 75.1106 creates an exception to the general requirement for permissibility of electric equipment and conductors addressed by § 75.1002. The concern here is the possibility of having exposed energized conductors, or arcing at the pigtails or connectors, which would cause fire, explosion or shock hazard. 30 CFR § 75.1725 (a) requires that "[m]obile and stationary machinery and equipment shall be maintained in safe operating condition and machinery or equipment in unsafe condition shall be removed from service immediately." Section 75.1106, Welding, cutting, or soldering with arc or flame underground, requires that "[a]ll welding, cutting, or soldering with arc or flame in all underground areas of a coal mine shall, whenever practicable, be conducted in fireproof enclosures. Welding, cutting, or soldering with arc or flame in other than fireproof enclosure shall be done under the supervision of qualified person who shall make a diligent search for fire during and after such operations and shall, immediately before and during such operations, continuously test for methane with means approved by the Secretary for detecting methane. Welding, cutting, or soldering shall not be conducted in air that contains 1.0 volume per centum or more of methane. Rock dust or suitable fire extinguishers shall be immediately available during such welding, cutting, or soldering." (emphasis added) This standard allows welding, cutting, and soldering (referred to as "welding" throughout the document) at the face (in areas where permissible equipment is required) under certain prescribed conditions. In promulgating this standard, MSHA recognized that welding on some equipment, such as longwall mining systems, may be necessary in areas where permissible equipment is normally required. MSHA also recognized that welding machines and welding methods are not permissible. Consequently, the standard permits these types of activities to be performed under certain controls to prevent fires and explosions where welding is taking place. Welding machines have been historically portable stand-alone units. When welding operations were needed on the longwall face, the welding cable had to be dragged to the location where welding was to be performed. To minimize handling the long and heavy welding cable, mine operators have installed the cable along the length of the longwall face with connectors or pigtails spaced along the cable length. Also, longwall systems have been designed to include the welding machine in the explosion proof controller. The welding machine then became part of the approved longwall system; however, the welding cable is not included in the approval. When the welding machine is located in the longwall controller, some mine operators have kept the de-energized welding cable connected to the welding machine through the controller Power Take Off (PTO) at all times, even during mining operations when welding is not taking place. When the welding machine is a portable stand-alone unit, the welding cable has also been left connected to the welding machine at all times although it was de-energized. This policy is intended to prohibit such practices, as the welding cable may become energized unintentionally, presenting shock, fire or explosion hazards. Authority The Federal Mine Safety and Health Act of 1977, (30 CFR) § 75.1106, § 75.1725 and § 75.1729. Internet Availability This program policy letter may be viewed on the Internet by accessing MSHA's home page at http://www.msha.gov and choosing Compliance Info. Contact Person(s) Coal Mine Safety and Health Salwa El-Bassioni, (202) 693-9525 E-mail: el-bassioni.salwa@dol.gov Technical Support David C. Chirdon, (304) 547-2026 E-mail: chirdon.dave@dol.gov Distribution MSHA Program Policy Manual Holders Miners' Representatives Coal Mine Operators Special Interest Groups Attachments Attachment 1 Attachment 2  |
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