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UNITED STATES
DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
Metal and Nonmetal Mine Safety and Health

Report of Investigation

Underground Metal Mine
(Platinum)

Fatal Powered Haulage Accident

June 4, 2001

Stillwater Mine
Stillwater Mining Company
Nye, Stillwater County, Montana
ID No. 24-01490

Accident Investigators

Ronald D. Pennington
Supervisory Mine Safety and Health Inspector

David A. Huston
Mine Safety and Health Inspector

Dennis Tobin
Mine Safety and Health Specialist

F. Terry Marshall, Jr.
Mechanical Engineer

Originating Office
Mine Safety and Health Administration
Rocky Mountain District
P.O. Box 25367, DFC
Denver, CO 80225-0367
Irvin T. Hooker, District Manager


OVERVIEW

Adam Michael Viers, miner 1, age 27, was fatally injured on June 4, 2001, when he was crushed between a runaway load-haul-dump (LHD) and the rib of the drift.

The accident was caused by the failure to set the park brake or turn the wheels into the rib before exiting the operator's compartment.

Viers' had a total of 4 years, 39 weeks mining experience, 4 years at this mine with 1 year, 40 weeks as a miner 1. He had not received all the required training in accordance with 30 CFR, Part 48.

GENERAL INFORMATION

Stillwater Mine, a multi-level underground platinum mine, owned and operated by Stillwater Mining Company, was located near Nye, Stillwater County, Montana. The principal operating official was Ronald W. Clayton, vice-president of operations. The mine was normally operated two, 10-hour shifts a day, 7 days a week. Total employment was 1,084 persons; of this number 934 worked underground.

Ore was extracted using the ramp-and-fill mining method. Sub-level stoping was also done along with cut-and-fill stoping. Mine access drifts were driven at different elevations. Approximately 60 percent of the ore was transported to the mill via the 1,950-foot vertical shaft. Ore was also transported to the mill by trucks and a rail system which extended about 3 miles. The smelter and base metals refinery were located at a company-owned facility in Columbus, Montana.

The last regular MSHA inspection of the operation was completed on May 4, 2001. A regular inspection was conducted following this investigation.

DESCRIPTION OF ACCIDENT

On the day of the accident, Adam M. Viers (victim) reported for work at 5:30 p.m. He and James W. Enyeart, miner 1, were directed by Gary Lemmon, day-shift mine development foreman, to proceed to the 66 West-D7 incline ramp to install rock bolts in the recently blasted mine face. The two miners arrived at the site at 6:30 p.m. and used an LHD to back drag the muckpile at the face. The miners retrieved the bolting deck and placed it near the face and started drilling to install rock bolts using two jackleg drills. Rock bolting proceeded normally for approximately 3 hours until Viers' encountered hard ground and broke two drill steels. There were no additional drill steels at the face and Viers drove the LHD approximately 700 feet down the inclined ramp to where extra drill steels were stored. He apparently parked the LHD on a curve with the machine articulated. The engine was facing downhill and the bucket was facing uphill.

At approximately 11:20 p.m., Mickey Terry, supply man, found the victim lying in the haulage road approximately 38 feet downhill from the storage area. He had been crushed between the runaway LHD and the rib of the drift. The LHD traveled an additional 50 feet from where the victim was found and came to rest in such a manner that it blocked the drift. The engine was running, the lights were on, the park brake was not set and the bucket was in the raised position.

Terry summoned Enyeart and the two miners provided assistance to the victim and called for emergency medical personnel. The emergency response team arrived a few minutes later and transported the victim out of the mine. He was airflighted to a hospital in Billings, Montana, where he was pronounced dead at 6:53 a.m. on June 5, 2001. Death was attributed to severe blood loss due to crushing pelvic injuries.

INVESTIGATION OF THE ACCIDENT

MSHA was notified at 5:00 a.m. on June 5, 2001, by a telephone call from Michael Crum, interim manager of safety, to Jake H. DeHerrera, assistant district manager. An investigation was started the same day. An order was issued pursuant to Section 103(k) of the Mine Act to ensure the safety of miners.

MSHA's accident investigation team traveled to the mine and conducted a physical inspection of the accident site, interviewed a number of persons and reviewed information relating to the job being performed by the victim. The miners' representative participated in the investigation.

DISCUSSION

  • The fatal accident occurred in the 66 West D-7 spiral incline ramp. The spiral ramp was under development and eventually would connect the 6600 level to the drifts being developed above this level. The ramp development had progressed upward from the 6600 level on an incline grade of approximately 15 percent and the working face was approximately 900 feet from the bottom of the incline. The size of the drift averaged 12 feet wide and 11 feet high. At various places in the drift, cut-outs were made to provide areas to store supplies and to allow mobile equipment to pass. A spiral ramp in an underground mine allowed miners and materials to be transported from one level to another.

  • Gardner Denver Model 83 pneumatic rock drills attached to jacklegs were used to drill 1-3/8 inch diameter boreholes where 5 foot long split-set roof bolts were installed.

  • The load-haul-dump (LHD) involved in the accident was an Elphinstone Model R-1300, Serial Number 6QW00891. The four-wheeled drive LHD was powered by a Caterpillar 3306 diesel engine and equipped with a four-speed transmission for both forward and reverse. Fourth gear had been locked out electronically allowing only three speeds in each direction. The LHD was 29 feet 6 inches long by 6 feet 3 inches wide, equipped with a 4 cubic yard bucket and weighed 43,440 pounds. It was equipped with articulated steering and the operator's compartment was located on the left side immediately behind the articulation.

  • The service brake system was hydraulic applied, spring- released enclosed wet disc brakes. The service brake system was tested and passed the manufacturer's recommended pull through test of 2nd gear forward, full throttle. The service brake system was also tested on a grade similar to the accident area and the service brake held the LHD.

  • The park brake system was spring applied, hydraulic-released enclosed wet disc brake controlled by a push/pull button mounted on the right side of the dash panel. The park brake system was tested and found to pass the manufacturer's recommended pull through test of 2nd gear forward, full throttle. The park brake action light functioned when the brake was applied. The park brake system was also tested on a grade similar to the accident area and the brake system held the LHD.

  • The electronic transmission controller had an interlock to prohibit the transmission from being in 1st gear with the park brake applied. This safety device was designed to automatically shift the transmission into neutral when the park brake was applied when the transmission was in 1st gear. The feature did not apply when the transmission is in 2nd or 3rd gear. The interlock device was functional.

  • The articulated steering was controlled by a STIC joystick assembly mounted on the inside of the operator's compartment door. The joystick was spring-centered and the loader would articulate in the direction that the joystick was moved. The joystick functioned properly.

  • Two types of steering interlocks were present on the LHD, a primary and a secondary. The primary interlock was a lever approximately 8-1/2 inches long and was part of the STIC joystick assembly mounted on the operator's door. It was designed to make it difficult for the operator to exit the machine without moving this lever towards the locked position. When the lever was moved to the locked position, the STIC joystick steering would be disabled and the transmission neutralized. Testing of the primary steering interlock showed that one of the adjuster screws would contact the side of the interference plate and not allow the interlock to be consistently engaged without additional force to engage the primary interlock. Tests indicated that the force to engage the interlock doubled from 3 pounds to 6 pounds and the condition was caused by wear in the steering assembly. Although the primary steering interlock was out of adjustment with the manufacturer's specifications, it was determined that the system was functional.

  • The secondary steering interlock was a hydraulic interlock that eliminated the pilot pressure to the steering joystick when the operator's door was opened. The manufacturer's service manual indicated that the secondary steering interlock should engage when the operator's door was opened within the range of 4 to 8 inches. Tests indicated the secondary steering interlock engaged when the door was opened 17-5/8 inches. Although the interlock was out of specification, it was determined that the system was functional.

  • The transmission was four speed in both forward and reverse directions; however, the electronic transmission controller was set to lock out 4th gear and 3rd gear was the highest that could be selected. The transmission gear selector could be controlled either manually or automatically. The loader was found in the manual mode. It was determined that the transmission was fully functional.

  • The front dash panel of the operator's compartment included: a tachometer, an engine temperature gauge, a transmission temperature gauge, a hydraulic oil temperature gauge and a fuel level gauge. The design is such that these gauges remain in the same position once the key has been turned off.

  • The loader was running when help arrived at the accident scene and it did not need to be started in order to move it. The key was not turned to the on position by company personnel after it was parked. All three temperature gauge readings were found to be within normal operating ranges when the machine was found after the accident.

  • Interviews with miners that had previously operated this LHD or had knowledge of its mechanical condition determined that under extreme workloads all of the LHD's temperature gauges would rise to hot and the park brake light would activate. This condition was first encountered during the Memorial Day weekend. When the mine mechanics checked the loader, the overheating conditions did not exist and they were unable to determine the cause. The company did not request diagnostic tests at this time.

  • The LHD was equipped with a Caterpillar Monitoring System (CMS) which electronically monitored several of the machine's operating parameters. Two of the CMS modes included the "tattletale" mode and the "Service" mode. A Caterpillar technician retrieved the data stored on the CMS system. The CMS service mode records events for the monitoring systems instrumentation and the power-train system instrumentation. There were no active events recorded by the CMS during the time of the accident.

  • A review of the victim's training records indicated that he had not received proper task training on the LHD. The LHD was purchased on January 8, 2001, and assigned to the 66 West D-7 spiral ramp in February 2001. The victim's last task training record was dated October 21, 2000.

  • Some miners stated that when the operator's door was opened on the LHD the park brake would automatically set. The investigation revealed that such a device did not exist on this LHD. This misconception may have influenced persons operating this LHD.

    CONCLUSION

    The accident was caused by the failure to set the park brake and to turn the wheels of the LHD into the rib before exiting the operator's compartment. Failure to require that the victim received task training on this model LHD was a root cause of this accident.

    ENFORCEMENT ACTIONS
     Order No. 6267229 was issued on June 5, 2001, under the provisions of Section 103(k) of the Mine Act:
    A serious accident occurred at this operation on June 4, 2001, resulting in a fatality on June 5, 2001. The equipment operator of the Elphinstone 4 yard LHD, Model R-1300, Company No. 92536 was struck by the LHD when attempting to retrieve supplies for his work area. This order is issued to ensure the safety of persons at this operation until the mine or affected areas can be returned to normal operations as determined by an authorized representative of the Secretary. The mine operator shall obtain approval from an authorized representative for all actions to recover persons, equipment, and/or return affected areas of the mine to normal operations.
    This order was terminated on June 8, 2001, when it was determined that the mine could safely resume normal operations.

    Citation No. 7935411 was issued on August 2, 2001, under the provisions of Section 104(a) of the Mine Act for violation of 30 CFR 57.14207:
    An accident resulting in fatal injuries occurred at this operation on June 4, 2001, when a miner was crushed between his runaway LHD and the rib of the drift. The victim had parked the LHD on a grade and had not set the park brake, chocked the wheels or set the wheels into the rib before exiting the operator's compartment.
    This citation was terminated on August 27, 2001. The mine operator conducted safety stand-down meetings with all miners. A specific task training module was developed for the Elphinstone LHD's and the miners were instructed in the safe operation of the R-1300 and R-1500 loaders.

    Citation No. 7935412 was issued on August 2, 2001, under the provisions of Section 104(a) of the Mine Act for violation of 30 CFR 48.7(a)(3):
    An accident resulting in fatal injuries occurred at this operation on June 4, 2001, when a miner was crushed between a runaway LHD and the rib of the drift. A review of the victim's training records indicated that he was not properly tasked trained on the Elphinstone Model R-1300 LHD that he was operating. The mine operator was aware of the training requirements and failed to provide the training. The Federal Mine Safety and Health Act of 1977 declares an untrained miner a hazard to himself and others.
    This citation was terminated on August 2, 2001. All miners assigned to operate the Elphinstone LHD's have been instructed in safe operating procedures.

    Related Fatal Alert Bulletin:
    Fatal Alert Bulletin Icon FAB01M14

    APPENDIX A


    Persons Participating in the Investigation

    Stillwater Mining Company
    Ronald W. Clayton .............. Vice-President of Operations
    Daniel A. St. Don .............. Superintendent of Development
    Leonard C. Campbell .............. General Mine Foreman 1
    Daniel R. Hickman .............. Manager of Human Resources
    Steven D. Wood .............. Corporate Safety Director
    Michael W. Crum .............. Interim Manager of Safety
    Jonathan J. Leak .............. Safety Coordinator
    Rick Pauling .............. Maintenance Superintendent
    PACE International Union
    Deborah K. Hayes .............. National Accident Coordinator
    Steven H. Gentry .............. Regional Director
    Brad A. Shorey .............. President, Local 8-0001
    Sharon McCave .............. Secretary/Treasurer, Local 8-0001
    Carroll Sparks .............. Steward, Miner's Rep, Local 8-0001
    Tractor and Equipment Company, Billings, Montana
    Ronald Guerechit .............. Caterpillar Electronic Technician
    Mine Safety and Health Administration
    Ronald D. Pennington .............. Supervisory Mine Safety & Health Inspector
    David A. Huston .............. Mine Safety and Health Inspector
    Dennis Tobin .............. Mine Safety and Health Specialist
    F. Terry Marshall, Jr. .............. Mechanical Engineer
    APPENDIX B


    Persons Interviewed

    Stillwater Mining Company
    Leonard C. Campbell .............. General Mine Foreman 1
    Michael W. Crum .............. Interim Manager of Safety
    Steven D. Wood .............. Corporate Safety Director
    Robert S. Weigel .............. Leadman, Upper West
    James W. Enyeart .............. Miner 1
    Jeffery S. McGinnis .............. Leadman,66 Footwall & Ramp
    Mickey S. Terry .............. Supplyman
    Linda L. Holmquist .............. Operator 1, & EMT
    Christopher C. Sorenson .............. Leadman, Beat C, Lower Country
    Leonard L. Clayton .............. Beat Mechanic, 66 West
    Brian R. Johnson .............. Mechanic II
    Carroll Sparks .............. Miners' Representative