Skip to content
UNITED STATES
DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
COAL MINE SAFETY AND HEALTH


Report of Investigation

Underground Coal Mine

Fatal Machinery Accident
October 29, 2000

Consol Pennsylvania Coal Company
Bailey Mine
West Finley, Greene County, Pennsylvania
I.D. No. 36-07230

Accident Investigators

Joseph R. O'Donnell Jr.
Coal Mine Safety & Health Inspector

Robert A. Penigar
Coal Mine Safety & Health Inspector

Wayne M. Colley
Mechanical Engineer

Originating Office
Mine Safety and Health Administration
District 2
RR 1, Box 736, Hunker, Pennsylvania 15639
Cheryl McGill, District Manager

Release Date: March 8, 2001



OVERVIEW


On Sunday, October 29, 2000, Jeffrey Cunko, a 50-year old maintenance foreman, with 24 years mining experience, was fatally injured while performing maintenance on a chain conveyor system in the underground coal storage bunker area of the Bailey Mine. The victim was standing on the stairs leading to a catwalk when the torque arm, used to secure the chain conveyor hydraulic motor, broke loose from its anchor point. The arm rotated upward, cutting through the stairway on which Cunko was standing, striking Cunko's left leg and torso, resulting in fatal injuries.

The fatal accident occurred because a machine component with the unforeseen potential for failure under loaded conditions was installed directly beneath a walkway and control station where miners were expected to work or travel. Contributing to the accident is the fact that when the anchor was welded to the steel beam, procedures for preparing and cleaning the materials to be welded were not followed. Over time, this weld weakened until it failed.

GENERAL INFORMATION


The Bailey Mine, operated by Consol Pennsylvania Coal Company, is located near Graysville, Greene County, Pennsylvania. The mine is opened by eight shafts and one slope into the Pittsburgh coal seam which averages 69 inches in thickness. Employment is provided for 421 persons underground and 53 persons on the surface. The mine produces coal three shifts per day, six days per week. Four continuous mining machine sections and two longwall sections produce an average of 37,155 tons of coal daily. Coal is transported from the face areas to the section loading point by a chain conveyor on the longwall sections and by shuttle cars on the continuous mining machine sections. Coal is then discharged onto a series of belt conveyors, through the coal storage bunker, and then transported to the surface preparation plant. Clean coal is transported by unit train to the various customers.

The principal officials of the Consol Pennsylvania Coal Company are:
President..............................................................................D. R. Baker

Vice President......................................................................L. W. Hull

Secretary..............................................................................K. T. Skrypak

Superintendent.....................................................................David Hudson

Safety Supervisor.................................................................Lawrence Cuddy
The last complete quarterly Mine Safety and Health Administration (MSHA) regular safety and health inspection was completed on September 29, 2000. The first quarterly regular safety and health inspection for FY 2001 was ongoing, but had not been completed at the time of the accident.

DESCRIPTION OF THE ACCIDENT


On October 29, 2000, prior to the start of the midnight shift, Rob Besece, Master Mechanic, discussed the work assignments for the day with Jeffrey Cunko, Maintenance Supervisor. The first job was to remove slack from the feeder conveyor chain in the "B" side of the coal storage bunker located near the West Finley shaft bottom. Ron McNary and Tim Kusky, Mechanics, entered the mine with Cunko at approximately 12:00 a.m. and traveled to the underground coal storage bunker. They brought with them materials needed to do the job which included four chain links and four chain retaining "dogs". In order to perform their assignment, it was necessary to manually control the motion of the chain drive. Cunko traveled outby to the bunker power center and switched the operation of the chain conveyor from automatic to the control box located near the chain drive on the "B" side of the bunker so he could manually operate the chain. He then returned to the control box area.

In order to view the work being performed by Kusky and McNary, Cunko positioned himself on the stairs adjacent to where the control box was located. From this location he could control the movement of the "B" chain. Cunko performed this operation while Kusky and McNary installed the first two "dogs". Cunko pressed the START button three times to jog the chain to a point that the other two "dogs" could be inserted. Kusky was kneeling above the "A" chain facing McNary who was preparing to install the second set of "dogs".

At about 12:35 a.m., Cunko again jogged the chain when suddenly the torque arm anchoring the hydraulic chain drive motor broke loose from its mount. The torque arm rotated upwards violently, tearing through the metal stairs that Cunko was standing on and striking him. The hydraulic hoses powering the motor and an adjacent catwalk were torn from their mounts. McNary was struck by a hydraulic hose and was thrown against a metal grating but was not injured. Both Kusky and McNary heard Cunko say "Oh boy". Kusky saw Cunko at the bottom of the stairs, sitting and apparently injured. Kusky was not able to reach Cunko directly because of damage to the stairway. He ran around the front end of the bunker to reach Cunko and discovered that he was severely injured. McNary contacted Paul McManus, Foreman, by phone. He informed him of the accident and requested an ambulance and that help be sent to the bunker. McManus called the guard station, relayed the information and went to the bunker to assist.

After talking to McManus, McNary went to get first aid equipment. Bernie Kirkpatrick, August LaSalvia, George Joseph, Steve Edgehouse, and Brian Allen heard the call for help and proceeded to the accident site. When LaSalvia arrived at the accident site, he found Cunko unconscious and held him until McManus arrived with a stretcher. Cunko was placed on the stretcher. McManus attempted to stop the bleeding on Cunko's left upper leg. After surveying the severity of the injuries, he called outside requesting life flight. Cunko was transported to the surface where Emergency Medical Technicians from West Finley Volunteer Fire Department began advanced life support procedures. Washington Ambulance & Chair arrived at the mine at 1:28 a.m. The STAT Medevac life flight helicopter arrived a few minutes later. Cunko was flown to UPMC Hospital, Pittsburgh, Pennsylvania, by the STAT Medevac helicopter where he was pronounce dead at 1:42 a.m. The Allegheny County Coroner's Office listed the cause of death as blunt force trauma.

INVESTIGATION OF THE ACCIDENT


At approximately 2:30 a.m. on October 29, 2000, James Bandish, MSHA Ruff Creek Field Office Supervisor, was notified by Larry Cuddy, Safety Supervisor, that a fatal accident had occurred. An MSHA accident investigation team was assembled. The team consisted of Coal Mine Safety and Health inspectors, a training specialist from Educational Field Services and engineers from Technical Support. A representative of the Office of the Solicitor provided assistance during the investigation. A 103(k) order was issued to ensure the safety of the miners until an investigation could be conducted. MSHA and the Pennsylvania Department of Environmental Protection jointly conducted the investigation with the assistance of mine management and miners. Interviews were conducted at the mine site. The on-site investigation was completed on November, 6, 2000. The miners chose not to have representation during the investigation.

DISCUSSION OF THE ACCIDENT


The following is a discussion of the relevant factors identified during the accident investigation:
  • The West Finley underground coal storage bunker is located near the West Finley Shaft bottom. The bunker is 165 feet long, 13 feet wide, and 12 feet high. The bunker was installed in 1994 and modified in 1996, increasing the storage capacity from 400 tons to approximately 650 tons. The bunker system acts as a surge bin and maintains a constant flow of coal to the mainline belt at a rate of 4,000 tons per hour. The bunker feed conveyor system utilizes two 34 mm longwall-type chains, 164 feet in length, to move coal into and out of the bunker as needed. The chains are driven by twin Flender Elgin Hydrex hydraulic motors. The chain drive motors are powered by two hydraulic pumps located remotely from the bunker.


  • There are three operator control stations which can be used to control the operation of the "A" and "B" chain conveyors. One control station is located near the bunker power center. Another control station is located at the bunker operator's normal work area (the cage) at the front end of the bunker, and a third is located at the tail end of the bunker, on the "B" side. Only one control station can be enabled for control at a given time. The selection of which control station is used can only be made at the control station near the power center.


  • The control station at the tail end of the bunker is an electrical control box located on the "B" side of the bunker approximately 5 feet above the bottom step of the cat walk stairs where the victim was located at the time of the accident. The electrical switches in the control box include three rotary switches and one momentary pushbutton switch. The three rotary switches are used to select one of the available functions which include: AUTO/JOG, REVERSE/FORWARD, and JOG A/ JOG B. The momentary START pushbutton switch is used to activate the solenoids that control the jog operation of the hydraulic motor. When the START switch is depressed, hydraulic fluid is supplied from the hydraulic pump to the hydraulic motor. When the START switch is released, the supply of hydraulic fluid from the pump to the motor is terminated.


  • Testing of the electrical switches indicated that all switches opened and closed properly. A forward movement of the "B" side conveyor chain when depressing the START switch indicated that the associated solenoid effectively controlled the "B" side hydraulic motor operation.


  • The bunker feeder chains are replaced every two years as part of a preventive maintenance program. The "B" side conveyor chain was put in place approximately ten months prior to the accident. The chains are checked periodically for wear and slack conditions. The links in the new chain stretch after being used for a period of time. This stretching of the chain links and lengthening of the chain results in slack. The slack is reduced by removing links and flights. To accomplish this, the chain is blocked in position and moved toward the blocked side by jogging the chain in short movements which causes the slack in the chain to be gathered. The chain is then blocked in place to retain the gathered links. The necessary work can then be performed. This same procedure is often used on longwall face conveyors to remove slack in the conveyor chain.


  • Each of the two feeder chains is driven by a hydraulic motor attached to the chain through a planetary gear box. Each hydraulic motor is mounted with a torque arm to prevent the motor housing from turning due to the torque developed by the motor under load. The other end of the torque arm is anchored to the floor. Each torque arm measured 6 feet in length and 1-3/4 inches thick. The torque arm varies from 10" wide at the floor mounting to 36" wide at the hydraulic motor housing. The torque arm was connected to the floor anchor (see sketch in Appendix 3) by two steel links, each measuring 1" thick x 5" wide x 23" long. The steel links are attached to the torque arm and to the floor anchor using two 2-1/2" diameter steel pins. The floor anchor is a steel plate measuring 8-1/2" high x 11" wide x 1-1/2" thick, which was welded to an H-beam buried horizontally in the concrete floor. The floor anchor mountings were installed in 1994 when the bunker was built and had not been modified.


  • According to Joy Mining Machinery, the Flender hydraulic motor will see a maximum operating hydraulic pressure of 5000 psi which can produce a maximum torque of 336,252 foot-pounds. This would result in a calculated compressive or tensile force of 56, 042 pounds-force being produced at the weld used to attach the anchor to the "H" beam.


  • According to information provided by Joy Mining Machinery, the original weldment specification for attachment of the anchor plate to the "H" beam was a 13mm ( � inch) fillet weld using a semi-automatic welder and flux core wire weld material having a 70,000 psi minimum tensile strength. The perimeter of the anchor weld pattern for the anchor was calculated to be 25 inches. According to accepted welding industry standards, a 25 inch (the perimeter of the anchor weld pattern) weld of this type and size, using a conservative ultimate strength derating factor of 0.3, would effectively hold 190,050 pounds-force. The potential holding ability of 190,050 pounds-force would provide a 3.4 factor of safety for the 56,042 pounds-force, calculated to be the maximum tensile force capable of being delivered by the torque arm on the anchor.


  • The torque arm anchor was removed from the mine and taken by MSHA for analysis. The analysis of the anchor's welded and fractured surfaces was conducted by Touchtone Research Laboratory. The analysis revealed that the approximately 1.9 square inches of total weld material and anchor parent metal (approximately 21 percent of that specified in the original weldment specification) showed signs of recent fracture. This indicated that only a part of the weld was available to withstand the tensile force at the time of the accident. The surface of the base of the anchor, which did not show signs of recent failure, was covered with a residue containing high temperature scale identified as black iron oxide. Black iron oxide developed as a result of a cutting process. This residue was not cleaned from the anchor before it was welded to the H beam.


  • Calculations conducted indicated that a competent weld having an effective weld (root) area of 1.9 square inches could only withstand approximately 71 percent of the estimated 56,042 pounds-force capable of being produced by the torque arm.
  • CONCLUSION


    The fatal accident occurred because a machine component with the unforeseen potential for failure under loaded conditions was installed directly beneath a walkway and control station where miners were expected to work or travel. Contributing to the accident is the fact that when the anchor was welded to the steel beam, procedures for preparing and cleaning the materials to be welded were not followed. Over time, this weld weakened until it failed.

    ENFORCEMENT ACTIONS


    The following order was issued due to conditions revealed during the investigation:

    1. A 103(k) order was issued to ensure the safety of all persons in the mine until an investigation was completed and all areas and equipment were deemed safe.

    Related Fatal Alert Bulletin:
     FAB00C32




    APPENDIX 1

    The following persons provided information and/or were present during the investigation: Consol. PA Coal Co. Officials
    David Hudson .......... Superintendent
    Tom Blaskovich .......... Manager of Safety
    Elizabeth S. Chamberlin .......... Director of Safety
    Dan Anderson .......... Assistant Superintendent
    Lawrence Cuddy .......... Safety Supervisor
    Rob Besece .......... Master Mechanic
    William Tolliner .......... Corporate Safety
    Jack Holt .......... Vice President Safety
    Pennsylvania Department of Environmental Protection
    Joseph Sbaffoni .......... Division Chief
    Robert Ceschini .......... Electrical Inspector Field Supervisor
    Jerome Grashien .......... Mine Inspector
    Donald W. Dean .......... Electrical Inspector
    William Garay .......... Mine Inspector Field Supervisor
    Mine Safety and Health Administration
    Joseph R. O'Donnell Jr. .......... Coal Mine Safety and Health Inspector
    Robert Penigar .......... Coal Mine Safety and Health Inspector
    Wayne Colley .......... Mechanical Engineer, Technical Support
    Donald W. Conrad .......... Mine Safety and Health Specialist (Training)
    Carl F. Kubincanek .......... Coal Mine Safety and Health Inspector
    Phillip McCabe .......... Mechanical Engineer, Technical Support
    Theresa Timlin .......... Attorney, Office of the Solicitor
    David Lewetag .......... Coal Mine Safety and Health Inspector - Electrical
    County of Allegheny
    Dennis King .......... Assistant Coroner
    Washington Ambulance and Chair
    Marlene Reed .......... Paramedic Supervisor
    West Finley Volunteer Fire Department
    Steve Emery .......... Emergency Medical Technician

    APPENDIX 2

    List of Persons Interviewed Consol. PA Coal Co.
    August LaSalvia .......... Maintenance
    Ronald McNary .......... Maintenance
    Tim Kusky .......... Maintenance
    Rob Besece .......... Master Mechanic