UNITED STATES
DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
Northeastern District
ACCIDENT INVESTIGATION REPORT
SURFACE NONMETAL MINE
FATAL ELECTROCUTION ACCIDENT
Dell Conractors Material Inc. - ID. No. 28-00035
Dell Contractors Materials Inc.
Clifton, Passaic County, New Jersey
December 8, 1995
By
Carl W. Liddeke
Supervisory Mine Safety and Health Inspector
Carl A. Onder
Mine Safety and Health Inspector
Gustave E. Paul
Mine Safety and Health Inspector (Electrical)
Northeastern District
Mine Safety and Health Administration
230 Executive Drive, Suite 2
Cranberry Township, Pennsylvania 16066-6415
James R. Petrie
District Manager
GENERAL INFORMATION
David McNaught, primary crusher operator, age 34, was
electrocuted on December 8, 1995, at approximately 11:00 a.m.
when the metal walkway on which he was standing
became energized. McNaught was employed by Dell Contractors
Materials Inc. He had worked 1 week as a primary crusher
operator for this company and 1 year 4 months
operating their concrete recrush plant. He had a total of 10
years mining experience.
Dell Contractors Materials Inc. was a crushed stone mining
operation located in Clifton, Passaic County, New Jersey. The
principle operating officials were John Gilham, general
manager, and Bruce P. Pascale, superintendent. The mine normally
operated one 8-10 hour shift a day, 6 days a week. A total of 18
persons was employed at the minesite.
Stone was mined by drilling and blasting multiple benches.
Broken stone was loaded by front-end loaders into haul trucks
which transported the material to the primary crushing
and screening plant. Crushed stone products were stockpiled for
sale to customers.
The last regular inspection of this operation was completed by
MSHA on October 18, 1995.
Pascale notified James Petrie, MSHA Northeastern district
manager, of the accident on December 8, 1995, at 1:00 p.m. by
telephone. Mine Safety and Health Inspector Carl A.
Onder arrived at the mine site on December 9, 1995, and started
the accident investigation. Electrical Mine Safety and Health
Inspector Gustave E. Paul and Supervisory Mine Safety and Health
Inspector Carl W. Liddeke also participated in this
investigation.
PHYSICAL FACTORS INVOLVED
A galvanized water pipe, 1-inch outside diameter by 3/4-inch
inside diameter by 18 feet in length, which provided water for
the dust control sprays on the primary crusher, extended out of
the ground adjacent to the walkway. A 2-inch wide strap of
conveyor belting was fastened to the walkway railing to support
the pipe. Another piece of conveyor belting was taped to the
first vertical metal support of the railing to prevent the
water pipe from rubbing against it. This piece of conveyor
belting was worn through, and allowed the water pipe to make
contact with the metal support. Evidence of arcing was
observed where the 1-inch water pipe had made contact with the
first vertical support. Electrical conduits, which provided
electrical power from the main electrical control room to various
electrical junction boxes within the primary plant, also extended
out of the ground near the water pipe.
A portable generator provided power (480 volts-3 phase) to
operate the plant. Frame grounding was used as the primary means
to ground equipment and metal electrical enclosures. Circuit
breakers were used to provide overload protection.
Approximately 2 to 3 weeks prior to the accident, Willie
Roberson, laborer, reported to Timothy Dupree, electrician, that
he had observed electrical arcing between an abandoned electrical
conduit and the frame of the No.2 conveyor near the trash metal
magnet. According to Dupree, about 10 days prior to the
accident, he had also observed arcing in this general area. It
was raining at the time. Dupree investigated the source of
the arcing and found that a bare wire was touching the conduit,
which he subsequently taped. He did not, however, conduct a
ground continuity test to determine why the arcing had not
tripped a circuit breaker.
During its accident investigation, MSHA also found a ground fault
inside the electrical disconnect box which was used as a junction
box that supplied power (480 volts-3 phase) to the No.2 conveyor.
The junction box was located on the frame of the primary
crusher, in the area of the primary discharge conveyor head
pulley, 5 feet from ground level. The junction box contained
three, 3-phase conductors. Each conductor connection was
insulated with rubber and plastic tape. One of the phase
conductors was positioned against the backside of the junction
box. Vibration had caused the insulation to wear through,
causing a fault current. The junction box was not adequately
grounded and, as a result, the fault current energized the metal
walkway outside the crusher control booth.
DESCRIPTION OF THE ACCIDENT
David McNaught reported for work at 6:30 a.m., his normal
starting time. As part of the regular work practice, every 2
hours McNaught was to alternate the primary crushing
duties with Willie Roberson, laborer. At approximately 11:00
a.m., McNaught and Roberson had just switched duties, with
McNaught operating the primary crusher.
Roberson was standing on the ground, near the No. 1 conveyor,
when he noticed that the crusher feeder was jammed. Thinking
that something was wrong, he walked up to the crusher control
booth where he found McNaught laying on the walkway with his left
leg over the midrail. Roberson used two fingers to check
McNaught's carotid artery for a pulse; none was found. He then
went to get help. Roberson located DuPree and told him
that McNaught was badly injured. DuPree and Roberson then
proceeded to the accident site where Dupree also checked McNaught
for vital signs, finding none. Dupree then went to the quarry
office and called the Clifton Fire Rescue Squad, then ran back to
the accident scene.
Anthony Ferri, truckdriver, was backing his truck up the ramp to
dump into the crusher feeder when he saw Dupree running toward
the crusher. Ferri jumped out of his vehicle and hurried down
the ramp to meet Dupree. Dupree told Ferri that McNaught was
hurt and they both went to assist him.
When Ferri started to move McNaught's leg off of the midrail, he
received a severe electrical shock. Ferri yelled to Dupree "I'm
getting shocked." Dupree told Ferri to let go and get away.
Ferri replied, "I can't." Dupree then grabbed Ferri's clothing
and pulled him away. Dupree stated that when he pulled on Ferri,
he received a mild shock. Dupree told Ferri not to move. He
then shut off the generator eliminating all electrical
power to the plant.
At 11:38 a.m., the Clifton New Jersey Police arrived and started
CPR on McNaught. At 11:41 a.m., the Clifton New Jersey Fire
Rescue Squad arrived. They continued to perform CPR on McNaught
and transported him and Ferri, in separate units, to St. Joseph
Hospital, Paterson, New Jersey. McNaught was pronounced dead on
arrival. Ferri was treated and released. The State of New
Jersey Medical Examiner's report indicated the cause of
McNaught's death was electrocution.
CONCLUSION
The primary cause of the accident was the lack of an adequate
ground on the junction box providing electrical power to the No.
2 conveyor. A contributing factor was an electrical fault which
occurred within this box. When the electrical fault occurred,
the grounding protection was not sufficient to trip the circuit
breaker controlling electrical power to the box. As a result,
the fault current energized the metal structure of the walkway on
which McNaught was standing. Although there were no eyewitnesses
to the accident, evidence indicated that McNaught was
electrocuted when he attempted to move the water pipe (which
acted as a ground) away from the handrail on the energized
walkway. This provided a path for the fault current to travel
through McNaught's body.
VIOLATIONS
Order No. 4426509 was issued under the provisions of the Act of
1977 103(k) on 12/8/95:
An accident, caused by a possible exectrocution, occurred at the
area of the primary crusher/feeder, on the walkway adjacent to
the feed hopper bin leading to the crusher control booth, from
the truck ramp. This order prohibits the use of any electrical
power, supplied or generated to the plant until the source or
cause of the accident can be determined.
This order was terminated on 12/14/95, after completion of the
accident investigation.
Citation No. 4426517 was issued under the provisions of Section
104(d)1 on 12/8/95, for a violation of 30 CFR 56.12025:
A fatal accident occurred at this operation on 12/ 8/ 95, when
the crusher operator was electrocuted due to a phase to ground
fault inside a disconnect box which served as a junction box.
The box provided power (480 volts-3 phase) to the No.2 conveyor
and was located on the primary crusher frame. The taped
insulation on a power conductor inside the box had worn through
which energized the metal walkway on which the crusher
operator was standing. The metal box enclosing the circuit was
not grounded. This violation is an unwarrantable failure to
comply with a mandatory safety standard.
This citation was terminated on 2/28/96, after the electrical
contractor had removed all preexisting wiring, and will replace
with new up-dated systems. The company/contractor will conduct a
continuity and resistance test of the grounding system prior to
start up, and the results shall be forwarded to the Manchester,
NH field office, and Wyomissing, PA field office.
Citation No. 4426518 was issued under the provisions of Section
104(a) on 12/8/95, for a violation of 30 CFR 56.12030:
A fatal accident occurred at this operation on 12/8/95, when the
crusher operator was electrocuted due to a phase to ground fault
inside a disconnect box which served as a junction box. The box
provided power (480 volts-3 phase) to the No. 2-conveyor and
was located on the primary crusher frame. The taped insulation on
a power conductor inside the box had worn through which energized
the metal walkway on which the crusher operator was standing.
Arcing, due to the worn insulation, has occurred several
weeks prior to the accident. The company had attempted to find
the fault but continued to operate the plant.
This order was terminated on 2/8/96, after the hazard no longer
existed. The electrical contractor had removed all preexisting
wiring, and will replace with new updated systems. The company
will conduct a continuity and resistance test of the grounding
system prior to start up, and the results shall be forwarded to
the Manchester, NH field office and Wyomissing, PA field office.
Respectfully submitted by:
/s/ Carl W. Liddeke
Supervisory Mine Safety and health Inspector
/s/ Carl A. Onder
Mine Safety and Health Inspector
/s/ Gustave E. Paul
Mine Safety and Health Inspector (Electrical)
Approved by:
James R. Petrie
District Manager
Related Fatal Alert Bulletin: [FAB95M44]
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