The 46 year-old face equipment operator with 30 years mining experience was fatally injured in an electrical incident.
The victim and a qualified electrician were preparing to connect a high-voltage coupler to a receptacle labeled "FEED THROUGH" on a 7,200 VAC high-voltage switch house.
The electrician thought the receptacle was incorrectly labeled and that it was actually an output receptacle. After opening the visual disconnect and cleaning the coupler, he went to the personnel carrier.
When he heard the victim cry out, the electrician turned and saw him within arms reach of the exposed receptacle.
The victim suffered an electrical shock resulting in the fatality.
The feed through receptacle was energized because the monitor circuit was shorted in another receptacle.
MSHA have issued the following best practices:
Ensure electrical work is only performed by a qualified person or one trained to perform electrical work under the direct supervision of a qualified person.
Ensure all circuit breakers and disconnecting switches are properly marked for identification purposes.
Ensure the contacts of the appropriate visual disconnecting device are open and the device is locked out and suitably tagged by the person performing electrical work.
Use proper equipment (gloves, multimeter, etc.) when performing electrical work.
Ensure complete and thorough examinations of electrical equipment are performed and electric equipment is maintained to assure safe operating conditions.
Never assume that you know how a circuit is wired. Ask for help and/or consult a wiring diagram/schematic if you are unsure.
Use properly rated non-contact voltage testers to ensure that high-voltage circuits are de-energized.