DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
District 2
ACCIDENT INVESTIGATION REPORT
Underground Coal Mine
FATAL MACHINERY ACCIDENT
Cumberland Mine (ID 36-05018)
Cyprus Cumberland Resources Corporation
Kirby, Greene County, Pennsylvania
April 10, 1996
by
Charles W. Pogue
Coal Mine Safety and Health Inspector
and
William E. Wilson
Coal Mine Safety and Health Inspector
Originating Office - Mine Safety and Health Administration
New Stanton District Office
RR 1, Box 736, Hunker, Pennsylvania 15639
Joseph J. Garcia, District Manager
GENERAL INFORMATION
The Cumberland Mine, operated by Cyprus Cumberland Resources Corporation, a division of Cyprus Amax Coal Company, is located along State Route 2001 near Kirby, Greene County, Pennsylvania. The mine is opened by 3 shafts and 2 slopes into the Pittsburgh coal seam, which averages 84 inches in thickness. Employment is provided for 355 workers underground and 106 on the surface. The mine produces coal three shifts per day, seven days per week.
Three developing continuous-mining machine sections and one longwall section produce an average of 20,600 tons of coal daily. The coal is transported from the face by shuttle cars on developing sections and chain conveyor on the longwall section, and discharged onto belt conveyors which transport the coal to a 700-ton underground holding bin. The coal is removed from the bin by dual feeders and transported up a 2,800-foot long slope and deposited into two 7,500 ton raw coal silos. After processing at the preparation plant, clean coal is transported by overland railroad to the harbor loading facilities, discharged into barges and delivered to various customers.
The principal officers of the operation are as follows:
W. Mark Hart............................President
John M. DeMichiei.....................Vice President
Douglas R. Conklin.....................General Manager
Scott B. Langley.........................Mine Manager
The last Mine Safety and Health Administration regular Safety and Health Inspection at this mine was completed March 31, 1996.
DESCRIPTION OF THE ACCIDENT
On Wednesday, April 10, 1996, at 7:00 a.m., a longwall maintenance crew under the supervision of Randy Conklin, longwall maintenance coordinator, entered the mine and traveled to the 36 butt (011) 33A longwall panel section. The 33A panel longwall mining unit was being disassembled at No. 54 crosscut and being moved outby to No. 39 crosscut to leave coal support for the impoundment on the surface. The stageloader assembly, which weighed approximately 60 tons, was being moved as a unit. Two 900-ton Westfalia headgate shields had been installed outby the Nos. 1 and 2 shields on the longwall face and were being used to push the stageloader assembly outby in the belt conveyor entry. The assembly had been pushed approximately 120 feet from 54 crosscut to just outby No. 53 crosscut.
When the maintenance crew arrived on the section at 7:30 a.m., the headgate drive motor was against the right coal rib (looking outby). Conklin instructed Donald Beck, relief shearer operator helper, and James D'Angelo, mechanic, to use the shields to pull the stageloader assembly away from the rib. When this operation was completed, the drive motor was about 12 inches from the coal rib. A 40-ton hydraulic prop (duke jack) was positioned to keep the stageloader away from the rib as the two shields pushed the assembly outby. A notch was picked in the coal rib just above the mine floor. The duke jack was placed with the base of the jack in the notch in the coal rib and the top of the duke jack (prop head) in a 5-inch by 5-inch opening in the bottom of the frame of the stageloader crusher. The filling wand was attached to the jack with the trigger tied in the open position. The duke jack was pressurized enough to be held in place between the stageloader and the coal rib with wooden crush blocks at the base and at the prop head. Additional hydraulic pressure was then applied through a valve on the opposite side of the stageloader. D'Angelo opened the valve to fully pressurize the duke jack as Conklin and Beck used the shield controls to push the stageloader outby.
The miners completed this process three times, with notches picked in the rib approximately 30 inches apart. After each of the first two pushes, the ram jacks on the shields were extended to their approximate full stroke of 38 inches, and the duke jack was fully extended and lying free on the mine floor. When the duke jack was positioned for a third time against the coal rib and the side of the crusher, Robert Smith, crawler operator, who had been watching the positioning of the duke jack, turned and walked back toward the tailpiece crawler. Beck and Conklin then operated the two shields as D'Angelo applied the hydraulic pressure to the duke jack.
Just before 10:00 a.m., when D'Angelo observed that the push had stopped, he closed the valve and crossed over the crusher to retrieve the duke jack. Moments later his co-workers heard a loud pop like a "roof bolt breaking" and then a moan from D'Angelo. Beck and Conklin reported seeing a cloud of rock dust being knocked from the coal rib. Smith ran back and observed D'Angelo sitting with his back to the rib and the duke jack lying across his lower legs. D'Angelo told Smith he could not breathe and asked him to remove the duke jack. As Smith lifted the duke jack, Beck and Conklin crossed over the crusher. Beck, a certified paramedic, attended to D'Angelo while Conklin called outside for an ambulance. Smith opened the circuit breaker on the tailpiece to deenergize the hydraulic pump.
D'Angelo told Beck that he could not get enough air, insisted on standing and pulled himself up to try to breathe easier. Beck assisted him in walking toward the tailpiece where they were met by Smith who had obtained a small first aid kit. Beck and Conklin placed D'Angelo on a stretcher, applied a cervical collar, and carried D'Angelo to the man trip for transportation to the surface. The man trip left the section at about 10:10 a.m. They were met by paramedics from EMS Southwestern Ambulance Service at the bottom of No. 3 airshaft where D'Angelo was transferred to a gurney and taken to the surface at 10:45 a.m.
When D'Angelo arrived on the surface, a Healthnet helicopter from Rostraver Airport with a nurse and physician had arrived. After being evaluated and treated at the mine site, D'Angelo was flown to Ruby Memorial Hospital in Morgantown, West Virginia. Following surgery, D'Angelo died at 5:49 p.m. The cause of death was listed as internal hemorrhage due to extensive laceration of the liver with lacerations extending into the hepatic vein and the inferior vena cava.
PHYSICAL FACTORS INVOLVED IN THE ACCIDENT
The investigation revealed the following factors relevant to the occurrence of the accident:
- The three-entry 36 butt development section was driven to
develop the 33A and 33B longwall panels. Longwall mining was
conducted in 33A panel until April 6, 1996, when the face had
been retreated to No. 54 crosscut. The longwall mining unit was
being disassembled and moved outby to No. 39 crosscut for
reassembly at the 33B panel to leave coal support for the
impoundment located on the surface. The stageloader assembly was
disconnected on Monday, April 8, and a continuous-miner puller
was used to pull the assembly outby approximately 20 feet to
install two Westfalia 900-ton headgate shields outby the Nos. 1
and 2 shields.
- The Westfalia PF4-1532 stageloader assembly weighed
approximately 60 tons. It consisted of the headdrive assembly,
four flex pans, a crusher and a cat-mounted tailpiece, with a
pressure pump and tank mounted on top to provide hydraulic
pressure for the shields. The unit measured 102 feet 6 inches
center-to-center of the chain-conveyor drive sprockets. The
overall length of the shields, the stageloader assembly and the
tailpiece crawler was 157 feet. The assembly varied in width
from 11 feet 4 inches at the crawler to about 6 feet at the flex
pans.
- The Westfalia headgate shields were capable of exerting a
maximum horizontal force of 67.8 tons. The ram jacks were
capable of extending 38 inches. At the time of the accident, the
ram jacks were only extended 18 inches. A full extension had not
been completed.
- The hydraulic prop (duke jack) model HS 40 ZL 6, Serial No.
11-4-292998, was manufactured by Salzgitter Machinen und Anlagen
AG, in the Federal Republic of Germany. It was a single-
telescope, light alloy prop jack with a nominal power rating of
400 kN (kilo-Newtons)(40 tons). The minimum yield point was
rated at 44.14 kN/cm2, (64,064 psig). The jack was equipped with
an 18-centimeter diameter (7 inches) foot plate and a 4-cam prop
head plate. The cams extended approximately 3/4 inch above the
center of the plate. The manufacturer's listed dimensions were:
2240 mm (88.2 inches) telescoped length, 1440 mm(56.7 inches)
retracted length, with 800 mm (31.5 inch) stroke and a weight of
52 kilograms (114 pounds). The jack was equipped with a 300 mm
(11.8 inches) long foot extension weighing 5.8 kilograms(12.8
pounds) for a total length of 2540 mm (100 inches) and a total
empty weight of 57.8 kilograms (127.4 pounds).
After the accident the extended jack measured 99 inches and weighed
approximately 200 pounds, indicating that it was at or near full
extension.
- The No. 3 belt conveyor entry was driven 16 feet 6 inches
wide and 78 to 84 inches high. The stageloader assembly was to
be pushed a distance of approximately 2,100 feet outby in this
entry.
- On the April 9 day shift, the stageloader assembly was
pushed as a unit outby approximately 30 feet using the two newly-
installed shields as "walking shields." The stageloader assembly
could not be adequately steered with the walking shields and
consequently had been pushed close to the left rib (looking
outby). A duke jack was used approximately four times during
this shift to steer the assembly away from the rib. Each time the
duke jack was used, it could be seen by the crew members. In
at least one instance, when the duke jack failed to fall free of
the stageloader assembly, the shield operators initiated an
additional push until the duke jack was free. On the afternoon
shift, the assembly was moved an additional 30 feet. Only wooden
crib blocks were used to maintain alignment. On the midnight
shift the assembly was moved an additional 40 feet. A duke jack
was used three to four times on the right side (looking outby) to
push against the spill plate. The spill plate is located inby
the drive motor, near the No. 1 shield. Therefore, the duke jack
was in view of the No. 1 shield operator at all times. The duke
jack fell free with each push.
- On the April 10 day shift, Conklin and his crew arrived on
the section and found that the stageloader assembly was left in
contact with the right rib (looking outby) at the end of the
midnight shift. Using the shields and duke jack, they moved the
stageloader assembly away from the rib. They had completed the
third advance when the accident occurred. This was the first
shift Conklin and this crew had performed this work.
- At a point beginning 32 inches from the base of the duke
jack, a gouge measuring from 1/2 inch to 1-1/4 inches wide by
8-inches long was found on the side of the duke jack. Metal
shavings were found on the mine floor and on the edge of the
frame of the headgate drive motor. It was concluded that this
gouge resulted from the frame of the motor being forced against
the duke jack as the stageloader assembly was pushed. When this
occurred, a lateral force was applied to the duke jack which
resulted in permanent damage to the duke jack such that the
piston would not fully retract when the fluid was released.
The prop head plate of the duke jack was wedged against the metal frame of the stageloader in a 5-inch by 5-inch opening at the base of the crusher with two of the cams inside the opening. After the accident, the bottom cam was missing from the head plate. The cast metal was bent back where the cam separated from the plate. The longwall maintenance crew reported that all four cams were intact on the crown head-plate before the accident.
With the top of the duke jack wedged against the metal frame of the stageloader and the bottom of the duke jack set in a notch in the coal rib, the two ends of the duke jack were restrained from moving. As the stageloader assembly was pushed using the "walking shields," the motor contacted the duke jack, placing significant lateral forces on the duke jack which caused the duke jack to act as a spring waiting to release this stored energy.
- The duke jack was positioned against the stageloader with
the wand wired open. During each push the duke jack was
pressurized by opening a valve on the opposite side of the
stageloader. The victim closed the valve before crossing the
stageloader to retrieve the duke jack.
- The duke jack was capable of being released remotely. A
releasing key could be attached to a rope or chain to actuate the
operating valve to let fluid escape from the cylinder. However,
this key could not be used while the wand was attached to the
duke jack. The wand must be removed from the duke jack to allow
fluid to escape from the cylinder through the port when the
operating valve is actuated.
- The wand was held in place on the duke jack by a locking
element. The wand was removed by sliding the locking element
back. Immediately after the accident, the wand was found
disconnected from the duke jack and lying next to it on the mine
floor.
- The investigation revealed through discussions with both
mine management and labor that it was common practice to use duke
jacks in various modes whenever heavy equipment needed to be
moved.
- A small pick hammer that the victim normally carried tucked
under his belt was found on the mine floor. The pick hammer was
last seen on top of the stageloader. The handle was split
lengthwise for 2-inches and broken into two pieces which were
found lying on the ground near the victim.
- Three notches had been picked in the right coal rib (looking
outby) just above the mine floor, about 30 inches apart, to allow
for a place to set the bottom of the duke jack. The rib coal
between the notches was found to be crushed out after the
accident. Witnesses said that this condition did not exist
before the accident.
- Mine management and labor had discussed the complete longwall mining unit move and had agreed on a plan which included moving the stageloader assembly as a unit. The 44 page written plan did not specifically address the use of the duke jacks or the issue of controlling the stageloader assembly as it was pushed.
CONCLUSION
The accident occurred because management failed to foresee the problem of controlling the stageloader assembly as it was pushed as a unit and the necessity of using duke jacks to assist in steering it. As a result of the high lateral force placed on the duke jack, the duke jack sprang free, striking the victim, when one or more of the following occurred: Coal around the notch in the rib crushed out, the cam broke away from the prop head plate of the duke jack or the victim attempted to remove the wand.
ENFORCEMENT ACTIONS
-
A 103 (K) Order was issued to ensure the safety of the
miners until an investigation could be conducted.
Respectfully submitted by:
Charles W. Pogue
Coal Mine Safety and Health Inspector
William E. Wilson
Coal Mine Safety and Health Inspector
Approved by:
Joseph J. Garcia
District Manager
Related Fatal Alert Bulletin:
FAB96C12