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

Report of Investigation

Surface Nonmetal Mine
(Sand and Gravel)

Fatal Powered Haulage Accident

October 21, 2002

Wade Rathbone Pit
Wades Coal and Concrete, Inc.
Rathbone, Steuben County, New York
Mine I.D. No. 30-03215

Accident Investigators

Patrick W. Flinton
Mine Safety and Health Inspector

John B. Felichko
Mine Safety and Health Inspector

Eugene D. Hennen
Mechanical Engineer

Jon Montgomery
Educational Field Services

Originating Office
Mine Safety and Health Administration
Northeast District
Thorn Hill Industrial Park, 547 Keystone Drive, Suite 400
Warrendale, Pennsylvania 15086-7573
James R. Petrie, District Manager


OVERVIEW

On October 21, 2002, David S. Watson, Sr., loader operator, age 48, was fatally injured when the front-end loader he was operating backed over the edge of an embankment, causing it to roll over and crush him inside the cab.

The accident occurred because berms were not maintained along the elevated edge of the embankment. The lack of a Roll Over Protective Structure (ROPS) also contributed to the severity of the injuries. Watson was wearing a seatbelt at the time of the accident.

Watson had a total of 11 years mining experience, all as a loader operator at this location. He had received training in accordance with 30 CFR, Part 46.

GENERAL INFORMATION

Wade Rathbone Pit, a surface sand and gravel mine, owned and operated by Wade Coal and Concrete Inc., was located in Rathbone, Steuben County, New York. The principal operating official was Edwin A. Wade, president. The mine normally operated one, 8-hour shift per day, 5 days a week. Total employment was two persons.

Sand and gravel was extracted from the pit and hauled to the plant by front-end loader. The material was crushed, screened for size, and transported to stockpiles by conveyor belt and front-end loader. The finished product was sold or used by the company in the construction industry.

The last regular inspection of this operation was conducted on August 1, 2002. A regular inspection was conducted following the investigation.

DESCRIPTION OF THE ACCIDENT

On the day of the accident, David S. Watson, Sr., (victim) reported for work at 7:00 a.m., his normal starting time. Ronald McCaig, front-end loader operator, and Watson serviced their equipment, checked their work areas, and worked together at the primary crusher.

At about 10:00 a.m., Watson began to mine material from the pit with the Cat 988 front-end loader and haul the material to the dry screen plant. McCaig supplied material to the primary crusher with another front-end loader. The two men broke for lunch at about 12:00 p.m. and resumed their activities at 12:30 p.m. At about 2:30 p.m., McCaig noticed blue smoke coming from the area of the pit where Watson was working. McCaig traveled to the pit and found the loader overturned at the bottom of the pit. McCaig called Edwin Wade, president, for help on the radio. Wade called for emergency assistance and traveled to the pit. Wade and McCaig hooked a chain to the loader and unsuccessfully attempted to pull it off Watson.

The emergency medical assistance unit arrived a short time later and personnel were unable to detect a heartbeat. Watson was pronounced dead at the scene due to multiple injuries.

INVESTIGATION OF THE ACCIDENT

Randal Gadway, supervisory mine safety and health inspector, was notified at 4:06 p.m. on the day of the accident by a telephone call from Edwin A. Wade, president. 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, conducted a physical examination of the accident site and equipment involved in the accident, interviewed persons, and reviewed training records, conditions, and work procedures relative to the accident. MSHA conducted the investigation with the assistance of mine management and miners.

DISCUSSION

  • The accident occurred in an area of the pit that had been mined below the existing pit floor. Mining had begun in this area about 2 weeks prior to the accident, creating a new pit that was approximately 36 feet wide, 56 feet long, and 9 feet deep. Material was extracted from various locations within the new pit, hauled up a ramp, and dumped into a screening plant.


  • The screening plant was located northwest of the new pit on the existing pit floor level, about 13 feet from the edge of the new pit. Excavated material was hauled from the new pit and dumped into the screening plant hopper on the side facing the new pit. Oversized material fell to the ground in front of the screen hopper and was removed by the front-end loader. As part of the process, the loader operator would back up adjacent to the hopper, between the screen plant and the edge of the pit, and push the oversized material into a pile. The travel area between the edge of the pit and the screen plant was narrow and created a tight working area for the loader.


  • The berms along the edge of the new pit ranged from 13 to 24 inches high. Tire tracks along the edge of the pit near the screening plant indicated the loader had backed on top of the berms in several locations prior to the accident. The midaxle height of the front-end loader was 37 inches.


  • Prior to the accident, material had been removed from the pit wall below the screen. This resulted in part of the berm along the edge of the new pit falling into the pit. While backing in the affected area, the left rear tire of the front-end loader dropped off the edge, causing the loader to roll over. Visual inspection of the loader tire tracks showed that the loader entered the pit at approximately a 30-degree angle to the edge, with the left rear tire traveling over first.


  • The machine involved in the accident was a 1966 Caterpillar front-end loader, model 988, serial number 87A1567. It was equipped with a six-cylinder diesel engine and a three-speed transmission. The loader was 25 feet long, 10 feet wide, and equipped with a 6 �-cubic yard bucket. The loader weighed approximately 64,000 pounds empty and 84,000 pounds with a full bucket of material. A fiberglass cab enclosed the operator's compartment on the loader. The cab was severely damaged when the loader rolled over.


  • The front-end loader was manufactured prior to June 30, 1969, and, therefore, was not required to be provided with a Roll Over Protective Structure (ROPS). Prior to the development of the ROPS standards, manufacturers justifiably did not address the potential frame structure loadings resulting from ROPS during a rollover since they were not a topic of design consideration. Accordingly, some front-end loaders manufactured prior to June 30, 1969, were not built with a frame of sufficient strength to accommodate a ROPS cab in the event of a rollover. At the time when this mandatory standard was developed and adopted on June 30, 1969, manufacturers were obligated to consider potential frame structure loadings to ensure operator protection in the event of a rollover. In light of this design evolution, MSHA cannot specifically prohibit the use of these front-end loaders built before June 30, 1969, unless MSHA can show that they are being used in a manner that presents a discrete safety hazard to miners.


  • The loader's service brakes consisted of a bladder style drum assembly on each wheel. Each brake assembly consisted of a spindle housing, expander tube (bladder), frame assembly, 12 brake linings, 12 lining retaining clips, and a drum. When assembled, the expanding tube was placed over the spindle housing, the frame assembly was placed over the bladder, and the 12 brake shoes were in the frame assembly. Each brake lining had a notch in the middle of the lining material where the retaining clips were installed to hold the linings in place. The brake drum, which was attached to the wheel hub, was installed over the brake linings, and the hub installed on the spindle. All the brake components remained stationary with the spindle, except the brake drum, which rotated with the wheel. When the service brake was applied, hydraulic oil expanded the bladder pushing the brake linings against the brake drum, which supplied the braking force.


  • The hydraulic flow that activated the service brakes was produced by a brake accumulator, which was supplied by two dual-section steering pumps. When the pressure in the accumulator reached 1500 to 1600 PSI, an accumulator charge valve combined the flow from both pumps. A calibrated pressure gauge was installed in the service brake accumulator system. When the machine was started, the pressure in the service brake accumulator circuit elevated to 1500 PSI. When the pressure reached 1500 PSI, the accumulator charge valve deactivated, sending the flow from the brake section of the steering pump into the steering circuit. With the machine running, the service brake pedal was depressed and released several times to reduce the accumulator pressure to check the accumulator charge valve activation pressure. When the pressure in the brake accumulator was reduced to 1100 PSI, the accumulator charge valve recharged the accumulator. The accumulator charge valve pressure settings were within the range specified in the operation and service manual.


  • With the loader engine turned off and the brake accumulator system charged to 1500 PSI, the service brake pedal was repeatedly depressed and released to determine the number of service brake applications made before the pressure in the accumulator system dropped to 0 PSI. The accumulator system pressure dropped to 0 PSI in 10 applications of the service brake. The manual for this machine specified a minimum of five service brake applications for this test.


  • The service brake was applied by depressing the foot pedal in the cab, which activated a hydraulic brake control valve. When applied, flow from the brake accumulator traveled to the expander tubes causing the brakes to be applied. Each of the four hydraulic lines between the brake control valve and expander tubes had a brake adjustment valve. The brake adjustment valve kept the brakes adjusted by limiting the amount of hydraulic oil flowing from the expander tubes when the brakes were released.


  • The parking brake was a manually applied shoe drum brake on the output side of the transmission. A lever to the left of the operator's seat controlled the brake. The lever was connected to the park brake by a push-pull cable. Examination of the parking brake revealed that the outside of the brake drum was covered with oil. The brake drum was removed and the wear surfaces of the drum and linings were visually inspected. The brake drum wear surface and the lining wear surface were soaked in oil. This oil appeared to be leaking past the seal installed on the shaft connecting the transmission to the parking brake.


  • Oil was observed on the inside bottom of the left front tire. The oil had drained out of the bottom of the brake drum after the machine was uprighted. After the loader was moved from the accident scene, the oil no longer ran out of the bottom of the brake drum. When the service brake was applied, the brake linings did not move. The hydraulic line connecting to the expander tube was removed to determine why the brake linings did not move when the service brake was applied. Examination revealed that a metal plate had been placed between the hydraulic line and the expander tube. The plate prevented hydraulic oil from entering the expander tube, resulting in no braking force on the wheel. The metal plate was removed and the hydraulic line was reconnected to the expander tube. When the service brake was applied, hydraulic oil leaked out of the top of the expander tube, revealing that the expander tube was defective.


  • When the service brake was applied to the right front wheel, all 12 of the brake linings moved. The outside edge of the backing plates of the 12 brake linings made contact with the retaining clips. According to the maintenance manual, the brake linings should be replaced before the outside edge of the backing plate comes in contact with the retaining clips when the brakes are applied. A feeler gauge was used to determine if the brake linings were making full contact with the brake drum when the service brake was applied. Five of the 12 linings were not making full contact with the brake drum revealing that the braking force was compromised by the worn brake linings. When the service brake was released, the brake linings remained close to the brake drum, indicating the brake adjustment valve was operating properly. The brake linings and brake drum were clean. No oil or other signs of contamination were present.


  • The brake linings on the rear wheels had adequate lining material and all made full contact with the drums when the service brake was applied. When the brakes were released, the brake linings remained close to the brake drum, indicating the brake adjustment valves were operating properly. No defects were found on the service brake assemblies on the rear wheels.


  • When the left rear wheel traveled over the edge of the pit, only the right rear wheel could effectively apply braking force to stop or slow the loader because the front brakes were defective.


  • Pulling the loader with another loader while the brakes were applied tested the force supplied by the service brake and parking brake systems. A load cell was placed between the machines to determine the braking force supplied by the brakes on the loader involved in the accident. The tests were conducted in ideal conditions on a level area with the loader bucket empty. The tires rolled (i.e., tires did not slide) during the pull tests. When the loader was pulled, it took 26,000 pounds of force to pull the loader through the applied service brake. The grade holding capacity of the loader service brake system with a fully loaded bucket was calculated to be approximately a 32 percent grade. It took 6,000 pounds of force to pull the loader through the applied park brake. The grade holding capacity of the loader park brake system with a fully loaded bucket was calculated to be approximately a 7-percent grade.


  • When the loader was uprighted and the engine was started, the machine would not steer. Visual inspection revealed that the steering column was pushed against the top of the steering box in the accident. To test the steering, the steering column was unbolted to relieve the pressure on the top of the steering box. After the pressure was relieved, the steering functioned properly.


  • An evaluation of the operator's visibility was conducted in the area of the accident. With an employee sitting in the operator's seat of the loader, the employee could not see the contact area between the loader tires and road, and was unable to judge the location of the rear tires relative to the edge of the pit. Mirrors were installed on the machine, but were damaged in the accident and could not be reinstalled for an evaluation of the visibility.


  • Reportedly, emergency response personnel had to remove the victim's seat belt to extricate him from the machine.
  • ROOT CAUSE ANALYSIS

    A root cause analysis was conducted. The following causal factors were identified:

    Causal Factor: The berm was removed as material was taken from the pit to feed the plant.

    During development of the pit, there was no interaction by the supervisor and the loader operator to ensure that adequate berms were maintained along the elevated edge of the pit. The material mined from the new pit was loaded from numerous areas of the pit wall. This mining procedure continually depleted material that provided a base to the roadway on the perimeter of the pit, and the material used as berms for the roadway.

    Corrective Action: Mining practices and procedures should be reviewed to ensure that the extraction process does not create hazards to persons that are required to work near it. Berms should be located as to accommodate the extraction process, while providing protection to persons that are required to travel on the elevated roadway above the affected area.

    Causal Factor: The front-end loader backed over the elevated edge of the pit.

    While performing routine work cycle activities, the front-end loader backed over the elevated edge of the pit. While positioned in the operator's seat, the equipment operator could not visually identify that he was at the edge, or judge the location of the rear tires, as he backed the front-end loader. Tire tracks along the edge of the pit near the screening plant indicated the loader had backed on top of the berms in several locations prior to the accident.

    Corrective Action: Where the equipment operator has a restricted view to the rear, mirrors or other visual devices should be installed and maintained to ensure the operator's safety. Where the extraction process affects the haulage cycle of mobile equipment, workplace examinations should be conducted frequently to evaluate for changes affecting safe operation.

    Causal Factor: The travel area between the plant hopper and the elevated edge of the pit was narrow creating a tight working area.

    Oversized material fell to the ground in front of the screen hopper and was removed by the front-end loader. As part of the process, the loader operator would back up adjacent to the hopper, between the screen plant and the edge of the pit, and push the oversized material into a pile. The travel area between the edge of the pit and the screen plant was narrow and created a tight working area for the loader. As the material was removed from the pit walls, the working area was reduced even further.

    There was no interaction between the supervisor and the loader operator to identify this narrow work area as a hazard and restrict access to it.

    Corrective Action: Mining practices and procedures should be reviewed to ensure that the extraction process does not create hazards to persons that are required to work near it. Where the extraction process affects the haulage cycle and work practices of mobile equipment, workplace examinations should be conducted frequently to evaluate for changes affecting safe operation and prompt correction of hazards observed.

    Causal Factor: The left front brake line was blocked and the right front brake linings were excessively worn, rendering the front brakes of the front-end loader inoperative.

    There was no documentation that maintenance had been performed on the loader's brakes for several years. It could not be determined if the left front brake line had been blocked prior to the company's purchase of the loader in 1995.

    Corrective Action: Establish procedures requiring periodic examinations of mobile equipment brakes and the prompt repair of brake defects.

    CONCLUSION

    The cause of the accident was failure to maintain adequate berms along the elevated edge of the roadway above the pit. A contributing cause was the failure to properly maintain the front brakes of the loader. Root causes included the following: failure to follow established procedures that required berms to be maintained along the elevated edges of roadways, failure to identify the narrow work area as a hazard and restrict access to it, and failure to establish procedures requiring periodic examinations of mobile equipment brakes and the prompt repair of brake defects.

    ENFORCEMENT ACTIONS

    Order No. 7745671 was issued on October 21, 2002, under the provisions of Section 103(k) of the Mine Act:
    A fatal accident occurred at this operation on October 21, 2002, when a front-end loader operator backed the loader over a 10-foot high bench and was crushed in the machine. This order is issued to assure the safety of persons at this operation and prohibits work in the affected area until MSHA determines that it is safe to resume normal operations as determined by an authorized representative of the Secretary of Labor. The mine operator shall obtain approval from an authorized representative for all actions to recover and/or restore operations in the affected area.
    Citation No. 6003646 was issued on November 25, 2002, under the provisions of Section 104(a) of the Mine Act for violation of 30 CFR 56.9300(b):
    A fatal accident occurred at this operation on October 21, 2002, when a Caterpillar front-end loader over-traveled the elevated edge of a work area and overturned. Berms at least midaxle height were not maintained along the elevated edge of the roadway between the power screen unit and the pit. The existing berms ranged from 13 to 24 inches and the midaxle height of the front-end loader was 37 inches.
    This citation was terminated on November 25, 2002. Berms of at least midaxle height have been installed along the elevated edge of the roadway between the power screen unit and the pit.

    Citation No. 6003647 was issued on November 25, 2002, under the provisions of Section 104(a) of the Mine Act for violation of 30 CFR 56.14101(a)(3):
    A fatal accident occurred at this operation on October 21, 2002, when a Caterpillar front-end loader over-traveled the elevated edge of a work area and overturned. All braking systems on the front-end loader were not maintained in functional condition. The defects included, but were not limited to, a metal plate was found in the brake hose fitting for the left front wheel which blocked off the oil flow to the brake bladder, rendering this brake inoperative; all 12 brake linings on the right front wheel were worn past the manufacturer's replacement criteria; and five of the linings were excessively worn and only making partial contact with the brake drum.
    Related Fatal Alert Bulletin:
    Fatal Alert Bulletin Icon FAB02M33




    APPENDIX A


    Persons Participating in the Investigation

    Wades Coal and Concrete Inc.

    Edwin A. Wade ............. president
    Ronald A. McCaig, Jr. ............. front-end loader operator
    Robert F. Wagner ............. mechanic


    Steuben County Office of the Sheriff

    Lorri Kashorek ............. investigator
    Eric Tyner ............. investigator
    Al Burchard ............. deputy


    Mine Safety and Health Administration

    Patrick W. Flinton ............. mine safety and health inspector
    John B. Felichko ............. mine safety and health inspector
    Eugene D. Hennen ............. mechanical engineer (Technical Support)
    Jon Montgomery ............. educational field services


    APPENDIX B

    Persons Interviewed

    Wades Coal and Concrete Inc.

    Edwin A. Wade ............. president
    Ronald A. McCaig, Jr. ............. front-end loader operator
    Robert F. Wagner ............. mechanic