The Mine Safety and Health Administration has issued an electrical safety alert after miners' burn and shock incidents. The accidents resulted in miners being transported to the hospital.
One incident occurred when a miner received flash burns to his eyes when he was working near a 480VAC scoop charger circuit breaker. Another miner was shocked while repositioning a 575VAC permissible water pump when he grabbed the pump cable. A mine foreman was shocked when he attempted to pull a roof bolter trailing cable out from under a rock fall. A fourth miner was shocked when an electrician contacted an energized component in the control panel of a 995VAC continuous mining machine.
MSHA stressed the following best practices:
• Do not perform any electrical work until the circuit is de-energized, locked, and tagged out. Remember, electrical work is installing or maintaining electrical equipment or conductors.
• Be knowledgeable of the hazards of electricity and NEVER touch any ungrounded electrical component until you are sure it is de-energized.
• Identify all hazards then develop and follow a safe plan to perform work or troubleshoot to ensure the safety of all miners. Always de-energize equipment except when necessary for trouble shooting or testing.
• Always handle de-energized cable instead of energized cable, or wear properly rated and well maintained electrical gloves when handling energized cables.
• Protect electrical cables from damage by mobile equipment and falling roof. When cable damage is suspected, IMMEDIATELY notify a qualified electrician so a potentially dangerous condition can be corrected.
• Install sensitive ground fault relays with instantaneous trip setting of 125mA or less on all face equipment. Use trailing cables with a grounded metallic shield.
• Wear properly rated PPE to protect against electrical shock, arc blast, and arc flash by following NFPA 70E Standard for Electrical Safety in the Workplace.
