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DEPARTMENT OF LABOR MINE SAFETY AND HEALTH ADMINISTRATION Rocky Mountain District Metal and Nonmetal Mine Safety and Health Accident Investigation Report Surface Metal/Nonmetal Mine Fatal Powered Haulage Accident S.T.S. Gravel (mine) I.D. No. 24-01501 S.T.S. Gravel (company) Livingston, Park County, Montana October 9, 1996 By Richard R. Laufenberg Supervisory Mine Safety and Health Inspector Lyle K. Marti Mine Safety and Health Inspector Rocky Mountain District Mine Safety & Health Administration P.O. Box 25367 DFC Denver, CO 80225-0367 Robert M. Friend District Manager GENERAL INFORMATION John R. Beagle, front-end loader operator, age 55, was fatally injured at about 1:00 p.m., on October 9, 1996, when the loader he was operating overturned. Beagle had a total of 15 years mining experience, 12 years as a front-end loader operator at this operation. He had not received training in accordance with 30 CFR, Part 48. Lisa Burns, S.T.S. Gravel company secretary, notified MSHA at 2:20 p.m., on the day of the accident. An investigation was started the following day. The S.T.S. Gravel mine, a multiple bench open pit sand and gravel operation, owned and operated by S.T.S. Gravel, was located near Livingston, Park County, Montana. The principal operating official was Larry J. Stands, owner. The mine was normally operated one, nine-hour shift a day, six days a week. Three persons were employed. Sand and gravel was mined, hauled and dumped into the feeder hopper of the primary crusher with a front-end loader. The finished products were stockpiled on the site and sold primarily as aggregate material to local contractors and to the public. The last regular inspection of this operation was completed on May 8, 1996. Another inspection was conducted upon completion of this accident investigation. PHYSICAL FACTORS The accident occurred on the steepest part of the haulage road between the crusher and the bottom bench of the pit. The roadway was about 600 feet long. The first 500 feet moderately declined between 4 and 5%, while the last 100 feet along the north pit wall declined 25%. The area being mined along the north pit wall was approximately 12 feet wide. The south side of the 12-feet wide cut exposed a bank approximately four feet high and the north side of the cut exposed a bank about 24-feet high. The rubber-tired, front-end loader involved in the accident was a 1977 Caterpillar, Model 980B, Serial Number 89P6699. The mine operator purchased the loader in 1989. A manufacturer's roll-over protective structure (ROPS) and seat belt were provided. Empty operating weight was about 53,400 pounds. According to the operators manual, maximum speeds of the loader were as follows:
The loader had air-actuated drum/shoe service brakes. It was equipped with an air-actuated service brake mechanism and a spring-actuated emergency parking brake mechanism in each brake chamber. There were six air brake chambers, four on the front axle (two per wheel) and two on the rear axle (one per wheel). The brake system automatically provided positive braking at all four wheels when the system air pressure dropped to approximately 40 pounds per square inch (psi). The spring-actuated mechanism could also be applied manually with a dash-mounted control valve when setting parking brakes. As a part of this investigation, measurements were taken of the distance that each air chamber push rod traveled upon brake application. The four front rods each traveled 2.5 inches, the left rear push rod traveled 2.75 inches, and the right rear push rod traveled 3 inches. The manufacturer's service manual states that brake adjustment is needed when travel of a brake chamber rod exceeds a maximum of two inches. An air pressure gauge and a low air pressure warning device were located on the instrument panel. The low pressure warning device was designed to provide a visual and audible warning when the brake system air pressure drops below 77 psi. During the accident investigation the braking system on the loader was tested and the low air pressure warning device did not function. An air leak in the right rear brake chamber was detected and the chamber was disassembled. A hole (slit) approximately one quarter inch long existed in the diaphragm. As a result, one brake application depleted the system air pressure. The defective diaphragm was replaced and the brakes were adjusted in accordance with the manufacturer's specifications. The service and park brake were capable of stopping and holding the loader with its typical load on the 25% grade after the repair and adjustments. There were no other defects affecting safety found on the loader relative to the accident. A means of communication was not provided on the loader. DESCRIPTION OF ACCIDENT On the day of the accident, John R. Beagle (victim), reported for work at 7:30 a.m., his regular starting time. Beagle met with Larry J. Stands, owner, and discussed replacing the fuel filter on the Caterpillar 980B front-end loader. Beagle replaced the fuel filter and performed other routine services on the loader. It could not be determined if Beagle had performed a complete pre-operational check on the loader. At 8:00 a.m., he began his usual task of hauling gravel with the loader from the bottom bench of the pit to the crushing plant. Crushing activity was normal with no communication between Stands and Beagle. About 12:45 p.m., as Stands was hauling crushed gravel from the crusher to the stockpiles with another front-end loader, he noticed the crusher feeder hopper had run empty. He thought Beagle's loader had broken down and went to check on him. He saw the Caterpillar front-end loader on its left side at the bottom of the steep roadway next to the north pit wall. Stands parked his loader and ran down the road to the accident site. He found Beagle partially out of the left door opening of the cab. His body was wedged between the left gravel bank and the loader's hand grabrail with his knees pressed against his chest. He found the loader in first gear forward with the engine running. Stands shook the victim's arm and called his name but there was no response. He ran back up the road and drove his loader to the scale house. He told Sandra M. Johnson, scale house operator, to call the local 911, emergency assistance number. The local ambulance service arrived six minutes after receiving the call and emergency medical technicians checked the victim's vital signs. They found he was not breathing, had no pulse, and his pupils were dilated. The Park County deputy coroner, pronounced the victim dead at the scene. Extrication of the victim's body only required unbolting and removing the loader's hand grabrail. He was transported to Bozeman, Montana, where an autopsy was performed. The victim had no internal or external injuries. The official cause of death was mechanical asphyxiation. CONCLUSION Failure to maintain the front-end loader service and park brakes was the primary cause of the accident. Operating the loader on steep road gradients with defective brakes contributed to the severity of the accident. While there were no witnesses to the accident, it is apparent that the victim was unable to stop the loader as it traveled bucket first down the steep grade because of inadequate brakes. (The only brake that could have worked at all was the left rear. Single left rear brake activation on an articulating loader would cause the loader to veer right, as it did in this accident.) The loader struck the north pit wall with the right front tire causing it to ride up on one side and overturn. Because there were no internal or external injuries, it was concluded that the victim unbuckled the seat belt after the loader rolled over and while exiting the loader fell between the hand grabrail and gravel bank. Apparently the victim's left foot slipped as he stepped onto the hand grabrail and his right foot was caught inside the cab by the loader's door frame. He became wedged between the loader and the 4-foot bank, with his knees against his chest and was not able to free himself. The seat belt was clean and found hanging across the operator's seat. On days prior to the accident, individuals on the mine property had observed the victim wearing the seat belt. VIOLATIONS Order number 7900351 Issued on October 9, 1996, under the provisions of Section 103(k): Citation number 7921013 Issued on October 11, 1996 under the provisions of Section 104(a), for a violation of CFR 30 Part 56.14101(a)(1): Citation number 7921014 Issued on October 11, 1996 under the provisions of Section 104(a) for a violation of 30 CFR 30 Part 56.14101(a)(2): Citation number 7921015 Issued on October 11, 1996 under the provisions of Section 104(a), for a violation of CFR 30 Part 56.14101(a)(3): Citation number 7921016 Issued on October 11, 1996 under the provisions of Section 104(a), for a violation of CFR 30 Part 56.14100(d): RECOMMENDATATIONS Communication systems should be provided for mine haulage equipment. The victim may have been able to alert others to the emergency and help could have been requested. Mine haul roads should be designed to minimize steep road grades. /s/ Richard R. Laufenberg Supervisory Mine Safety & Health /s/ Lyle K. Marti Mine Safety & Health Inspector Approved by: Robert M. Friend, District Manager Related Fatal Alert Bulletin:  [FAB96M40]
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