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MSHA - Fatal Investigation
Report

UNITED STATES DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION

Rocky Mountain District
Metal and Nonmetal Mine Safety and Health

Accident Investigation Report
Surface Nonmetal Mine
(Sand and Gravel)
Fatal Powered Haulage Accident

Paulden Sand and Rock Company
Perkins Pit
Chino Valley, Yavapai County, Arizona
I.D. 02-02786

September 18, 1998

By

Michael S. Okuniewicz
Supervisory Mine Safety and Health Inspector

Terry Marshall, Jr.
Mechanical Engineer

Originating Office
Mine Safety and Health Administration
P.O. Box 25367, DFC
Denver, Colorado 80225-0367

Robert M. Friend
District Manager

GENERAL INFORMATION
Anton H. Bisjak, Jr., loader operator, age 55, was fatally injured at 3:00 p.m. on September 18, 1998, when he was crushed inside the cab of the loader he was operating. Bisjak had a total of 40 years mining and heavy equipment operating experience, the last twelve weeks were at this mine. He had not received training in accordance with 30 CFR, Part 48.

MSHA was notified at 5:25 p.m. on the day of the accident by a telephone call from the vice president for the mining company. An investigation was started the same day.

The Perkins Pit, an open pit sand and gravel operation, owned and operated by Paulden Sand and Rock Company, was located at Chino Valley, Yavapai County, Arizona. The principle operating officials were Warren B. Dunbar, vice president, and Gerald Dunbar, president. The mine was normally operated one, 10-hour shift a day, five days a week. A total of three persons was employed.

Sand and gravel was extracted from a single bench in the pit with a front-end loader, then stockpiled near a feed hopper at the plant. A second loader fed the stockpiled material into the crusher hopper. The material was crushed, sized and stockpiled for sale as road-base aggregate.

This mine had been operating for five years. MSHA had not been notified of commencement of operations. A regular inspection was conducted following this investigation.

PHYSICAL FACTORS INVOLVED

The accident occurred at an area between the feed hopper for the crusher and the edge of the bench. Normal procedure was to fill the loader bucket from the stockpile, back approximately 50 feet, then move forward and dump the material into the hopper, back away from the hopper, then return to the stockpile for another load. This area sloped 11 percent toward the pit. A berm was not provided for a distance of 85 feet along the edge of the pit where the loader went over. The height of the bench was 15 feet.

The front-end loader involved was a 1965 Caterpillar 950, model 90A, equipped with an enclosed cab and seat belt. A roll-over protective structure was not provided. The operating weight was approximately 28,000 pounds.

The service brake system consisted of two separate air-over- hydraulic master cylinders, one for each axle. Expanding shoe drum brakes were provided on each wheel. Brakes were applied by pressing one of two foot pedals which allowed compressed air to enter air chambers. These air chambers each actuated a master cylinder stroke rod and a stroke rod indicator for the corresponding braking system. The action of the master cylinder stroke rod produced hydraulic pressure which actuated the wheel cylinder, causing brake shoe movement at the wheel assembly. Each master cylinder provided hydraulic pressure through a single brake line. A tee in each line at the axle directed pressure to individual wheel assemblies.

The effectiveness of the air chamber actuator was verified by the stroke rod indicator. Air chamber stroke rod travel at 100 psi for the rear brake system was 1 1/2 inches. The front brake system stroke rod travel was 1 7/16 inches. According to the manufacturer's service manual for this loader, the stroke travel of the indicator rods should not exceed 1 1/4 inches. Tests conducted showed that no braking force was generated by these brakes.

Other deficiencies in the service brake system were as follows:


  1. The front master cylinder hydraulic fluid reservoir was empty.
  2. The left rear wheel cylinder mounting bolt flanges were broken off the housing. This allowed the wheel cylinder to shift relative to the backing plate and caused the front plunger of the wheel cylinder to be noticeably misaligned within the brake assembly which resulted in a decrease in the effective stroke of the wheel cylinder plungers.
  3. The bleeder screw for the left rear wheel cylinder was against the backing plate and interfered with its ability to function.
  4. Malfunctions in both master cylinders allowed the hydraulic pressure generated by them to internally bypass pressure seals and return to the reservoir.
  5. The air pressure gauge was inoperative. The needle was stuck on 105 psi.

A mechanically actuated drum-type parking brake was provided on the drive line at the transmission. The linkage to the brake lever was adjusted to the maximum. Tests showed that the parking brake produced no braking force when applied.

Weather conditions at the time of the accident were clear, dry and warm.

DESCRIPTION OF ACCIDENT

On the day of the accident, Anton Bisjak (victim) reported for work at about 7:00 a.m., his regular starting time. He was instructed by Gene Baker, foreman, to move material from the stockpile, to the plant feed hopper. Kathleen Cannard, loader operator, was instructed to haul material from the pit to the plant stockpile with a second front-end loader. Baker started the plant and monitored the operation. During the course of the day , Cannard noticed that Bisjak was having problems with the loader stalling. At one time, she saw Bisjak's loader roll backwards, stopping at a small mound of dirt near the side of the pit.

At about 3:00 p.m., Cannard saw smoke coming from the pit. Baker heard the screen plant run dry and also spotted smoke coming from the pit area. Upon arriving at the edge of the bench he saw Bisjak's loader upside down in the pit. Baker instructed Cannard to call the main office to report the accident and then went to render first aid. The office manager called for emergency assistance and personnel from the local fire department arrived a short time later. Bisjak was pronounced dead at the scene.

CONCLUSION

The accident was caused by failure to maintain the brakes on the front-end loader. Failure to provide a berm along the edge of the pit was a contributing factor.

VIOLATIONS

Order No. 4652341 was issued on September 18, 1998, under the provisions of Section 103(k) of the Mine Act:

A fatal accident occurred at this mine as the result of a roll-over of a Caterpillar, Model 950, front-end loader. This order prohibits the operation of the plant feed hopper and ramp areas as well as the pit access road nearest the overturned loader and the area surrounding the overturned loader. No further work of any kind is to be done in these areas or with this equipment until the mine or affected areas can be returned to normal mining operations as determined by an authorized representative of the Secretary. The operator shall obtain approval from an authorized representative for all actions to recover equipment, and/or restore operations in the affected area.

This order was terminated on October 20, 1998, after it was determined that the mine could safely resume normal operation.

Citation No. 7907214 was issued on October 20, 1998, under provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR 56.14101(a)(1):

A front-end loader operator was fatally injured at this mine on September 18, 1998, when the loader he was operating backed over a 15-ft highwall. The service brakes were not capable of stopping and holding the loader. Both master cylinders were inoperative; both front wheel cylinders were seeping brake fluid; the air pressure side of the service brake system leaked; and the left rear wheel cylinder could not be bled. Warren Dunbar, vice president, knew for several months that the service brakes were inoperative, yet directed that the loader be regularly used for production work. Failure to repair the brakes is a serious lack of reasonable care which constitutes more than ordinary negligence and is an unwarrantable failure to comply with a mandatory safety standard.

This citation was terminated on October 28, 1998. The Caterpillar 950 wheel loader was severely damaged and will not be repaired. The mine operator implemented a program to inspect all mobile equipment prior to use and directed that safety defects be corrected before placing the equipment in service.

Order No. 7907215 was issued on October 20, 1998, under provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR 56.14101(a)(2):

A front-end loader operator was fatally injured at this mine on September 18, 1998, when the loader he was operating backed over a 15-ft highwall. The parking brake was defective in that it was out of adjustment and was not capable of holding the loader. Warren Dunbar, vice president, knew for several months that the parking brake system was inoperative, yet directed that the loader be used regularly for production work. Failure to repair the brakes is a lack of reasonable care which constitutes more than ordinary negligence and is an unwarrantable failure to comply with a mandatory safety standard.

This order was terminated on October 28, 1998. The Caterpillar 950 wheel loader was severely damaged and will not be repaired. The mine operator implemented a program to inspect all mobile equipment prior to use and directed that safety defects be corrected before placing the equipment in service.

Order No. 7907216 was issued October 20, 1998, under provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR 56.9300:

A front-end loader operator was fatally injured at this mine on September 18, 1998, when the loader he was operating backed over a 15-ft highwall. A berm or guardrail had not been provided along the elevated outer edge of the pit which was located approximately 35 yards from the feed hopper where the loader was dumping. Failure to provide a berm or guardrail is lack of reasonable care which constitutes more than ordinary negligence and is an unwarrantable failure to comply with a mandatory safety standard.

This order was terminated on October 20, 1998. A berm has been provided along the pit edge near the plant feed hopper.

Order No. 7907217 was issued on October 20, 1998, under provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR 56.14100(a):

A front-end loader operator was fatally injured at this mine on September 18, 1998, when the loader he was operating backed over a 15-ft highwall. The following defects affecting safety had not been corrected: both master cylinders were inoperative; both front wheel cylinders were seeping; the brake system air pressure gauge was defective; the left rear brake cylinder could not be bled; the parking brake was out of adjustment rendering it ineffective, and the engine foot-pedal linkage was worn beyond acceptable limits. Failure to conduct pre-shift inspections of the loader to identify and promptly correct safety defects is a lack of reasonable care which constitutes more than ordinary negligence and is a unwarrantable failure to comply with a mandatory standard.

This order was terminated on October 20, 1998, after the mine operator implemented a program to inspect all mobile equipment prior to use and directed that safety defects be corrected before placing the equipment in service.

Citation No. 7907221 was issued on September 19, 1998, under provisions of Section 104(a) of the Mine Act for violation of 30 CFR 56.1000:

The operator of the Perkins Pit failed to notify MSHA prior to commencement of operation. The Perkins Pit had operated for five years in conjunction with another pit and the mine operator knew or should have known of the regulations pertaining to notification.



Related Fatal Alert Bulletin:
FAB98M41