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

REPORT OF INVESTIGATION
August 9, 2000

Surface Nonmetal Mine
(Stone Mining, Dimension)
Fatal Powered Haulage Accident

at

Rocky Mountain Quartzite Quarry
Northern Stone Supply, Inc.
Oakley, Cassia County, Idaho
ID No. 10-00648

John Widows
Supervisory Mine Safety and Health Inspector

Robert V. Montoya
Mine Safety and Health Inspector

Lawrence Wilson
Civil Engineer

F. Terry Marshall
Mechanical Engineer

John C. Kathmann
Mine Safety and Health Specialist

Originating Office
Mine Safety and Health Administration
Western District
2060 Peabody Road, Suite 610
Vacaville, CA 95687
Lee D. Ratliff, District Manager





OVERVIEW


On August 9, 2000, Wesley Dimick, mechanic, age 42, was fatally injured when he apparently lost control of a front-end loader he was driving down a haulroad. The loader overturned and the roll-over protective structure collapsed, pinning Dimick in the operators station. Reportedly, Dimick was wearing a seat belt at the time.

The accident occurred as a result of the loader not having an adequate service braking system capable of stopping and holding the loader on the grade it was traveling. Contributing to the severity of the accident was the lack of structural strength of the roll-over protective structure.

Dimick was the co-owner of a business that had repaired equipment for the mine operator.

GENERAL INFORMATION


The Rocky Mountain Quartzite Quarry, a building stone quarry, owned by Northern Stone Supply, Inc., was located eight miles south of Oakley, Cassia County, Idaho. The principal operating officials were Gary Mullard, president, and Garth Greenwell, foreman. The mine operated on a seasonal basis, employing up to 67 miners during peak demand periods. The mine did not have scheduled work hours or work days. Generally, mining activities occurred during daylight hours, six days a week. All the miners lived in cabins at the mine.

At the mine, excavators stripped away the overburden, exposing bedded layers of quartzite. The exposed quartzite was mined by hand to extract the various sizes and desired thickness of flagstone. Larger pieces of stone were broken or split with chisels and hammers. Individual pieces of flagstone were hand stacked onto pallets, secured with "chicken" wire, then loaded with fork lifts onto flatbed trucks. The pallets were trucked off-site to storage and/or shipped to customers.

Wesley Dimick (victim) was the nephew of Garth Greenwell, foreman, Northern Stone Supply, Inc. Dimick was employed full time as a mechanic for the Boise Cascade Container Plant in Burley, Idaho. He was also the co-owner of Wescom, an electronics repair company, located in Oakley, Idaho. Wescom had repaired home appliances at cabins housing the miners and had repaired mining equipment for the mine operator. Greenwell was listed on the MSHA Legal Identity form for Northern Stone Supply, Inc., as the foreman; however, he was also the sole owner of Rocky Mountain Quarry and Service Company, an independent contractor who supplied miners to and performed other services at the mine site. His company had been assigned MSHA contractor identification number GGW some time prior to the accident

The last regular inspection of this operation was completed on July 1, 1999. Another inspection was conducted following this investigation.

DESCRIPTION OF ACCIDENT


On the day of the accident, Wesley Dimick (victim) completed working a 12-hour graveyard shift at the Boise Cascade Burley Container Plant at 7:00 a.m., then went home and slept for several hours. Shortly before noon, he drove to the Rocky Mountain Quartzite Quarry accompanied by George Richardson, his father-in-law. They arrived at the mine at about 12:00 p.m. There, they met Garth Greenwell, foreman, and discussed the days activities at the mine.

During the conversation, Greenwell mentioned that a maintenance overhaul was due on the Caterpillar 922B front-end loader, to include replacement of the service brakes. Dimick and Richardson told Greenwell they would help him with the overhaul. Rather than overhauling the loader at the mine site, they decided to take the machine to a shop in Oakley, Idaho, where it would be more convenient to do the repairs. Dimick started to drive the loader to the shop, approximately eight miles from the mine, while Greenwell and Richardson went to another section of the mine.

Dimick drove the loader approximately 900 feet down the steep, curved haul road, before apparently losing control of the loader. The machine overturned and landed next to the left hand berm of the road. The force of the impact collapsed the ROPS, pinning Dimick in the operator's cab.

Artino Narvaez and Marcos Verdin, mechanics' helpers, and Jerry Stanger, mechanic, were working nearby, heard the loader's impact, and saw a cloud of dust. They immediately went to the scene of the accident. Narvaez shut off the engine and first aid was provided to the victim. Other miners arrived to assist Dimick and a call was placed to emergency response personnel. A local emergency medical unit and a search and rescue team arrived at the mine a short time later. Dimick was pronounced dead at the scene. Death was attributed to injuries sustained in the accident.

INVESTIGATION OF THE ACCIDENT


MSHA was notified of the accident on August 10, 2000, at 7:40 a.m., by a telephone call from Garth Greenwell to Inspector Robert Montoya at the Boise, Idaho MSHA field office. An investigation was started on August 10, 2000. An order was issued pursuant to Section 103(k) of the Mine Act to ensure the safety of miners. An MSHA team conducted a physical inspection of the accident site with the assistance of mine management. The miners did not request, nor have, representation during the investigation.

DISCUSSION


� The victim was taking the loader from a location known as the "Top Quarry" in the mine to a maintenance shop in Oakley, Idaho, approximately eight miles away. Prior to the accident, the loader was parked on a 3% grade at the "Top Quarry." Along the route taken by the victim, the road grade changed to 12% downgrade for a distance of 220 feet, followed by an 11% downgrade for the next 385 feet. On this 11% grade, a sharp turn to the right occurred with the grade then steepening to 17%.

� The width of the haul road varied from approximately 38 feet near the "Top Quarry" to approximately 26� feet at the accident site. The widest piece of equipment regularly traveling this haul road was a Caterpillar 950B front-end loader. This loader was approximately 8� feet wide.

� The berm at the accident site was approximately 38 inches high with periodic breaks in it for drainage. There was a V-shaped drainage hole in the berm immediately next to the location of the accident site but it did not contribute to the accident.

� The general condition of the road surface was good. The road had been recently surfaced with a decomposed granite material and it was well compacted. There had not been any rain in the area for several weeks prior to the accident, nor was there any spilled material which could have reduced traction. There were no large holes, rutting, or irregularities in the road. The haul road was slightly crowned in the center for drainage.

� The loader involved in the accident was a 1965 Caterpillar, Model 922B, Traxcavator front-end loader, serial number 94A1103. It was equipped with a Roll-Over-Protective-Structure (ROPS). The loader's bucket had been removed and replaced with forks. No identification tags or markings could be found on the fork lift attachment. The engine's hour-meter indicated the machine had been operated 3261 hours.

� The loader was powered by an 80-horsepower Caterpillar, Model D330, four-cylinder, diesel engine. The machine was of rigid-frame construction with hydraulic-boosted steering provided to the rear wheels. The loader was not carrying a load at the time of the accident. Empty loader weight was estimated to be approximately 17,000 pounds.

� A power-shift transmission provided two speeds to the "work" range (four wheel drive) and the "travel" range (two wheel drive). The loader's maximum forward speed was 3.8 miles per hour and 6.8 miles per hour, first and second gear, respectively, in the work range. Maximum forward speed was 11.8 miles per hour and 18.9 miles per hour, first and second gear, respectively, in the travel range. The gears were not synchronized between four and two-wheel drive which required the operator to stop the loader then shift from one range to the other. The transmission lever was found in the neutral position after the accident.

� The loader was equipped with service brakes and a parking brake. The service brakes consisted of four internal-expanding, shoe drum brakes, one at each wheel of each axle. The service brakes were wheel-hydraulic, air-actuated, with separate systems for the front and rear axles. They were actuated by either of two foot pedals in the cab. The right foot pedal applied the service brakes. The left foot pedal applied the service brakes and actuated the power-shift transmission's neutralizer function which removed power to the drive wheels before the brakes were applied. A third foot pedal in the cab controlled the loader's acceleration. All pedal controls moved freely and returned to the upward most position when foot pressure was released.

� The fluid level of the rear axle master cylinder reservoir was measured to be approximately 9/16 of an inch below the top of the reservoir. This amount was 1/16 of an inch below the level recommended in Caterpillar's service manual for the machine. The air chamber indicator rod stroke for the rear service brake system was measured to be 1 inches. The service manual stated that adjustment of the service brake's manual adjusters was required when the air chamber stroke indicator rod extends 1� inches.

� The fluid level of the front axle master cylinder reservoir was about �-inch below the top of the master cylinder reservoir. This amount was at the manufacturer's recommended level. The air chamber stroke indicator rod was missing on the front master cylinder assembly. During the investigation, a temporary stroke indicator rod was fabricated to measure the air chamber stroke for this master cylinder assembly. The air chamber indicator rod stroke for the front service brake system was measured to be 1 -inch, -inch over the specified maximum limit in the service manual.

� The right-side front brake's wheel cylinder was visibly leaking brake fluid. Fluid also drained from the wheel cylinder when the rear dust boot was pulled away from the cylinder. Past leakage of fluid from the cylinder had contaminated the entire brake assembly and a greasy, wet, black-colored, material was observed on all surfaces. The brake shoe linings were fluid-soaked with the lining-to-drum friction contact surfaces being wet. The front and rear brake shoe lining thickness of the brake assembly was measured to be 0.11 and 0.14 inches, front and rear, respectively, at the center of the lining. The front brake shoe had four worn rivets and the rear shoe had three worn rivets contacting the drum during brake application.

� The left side front brake wheel cylinder had brake fluid seeping past the front dust boot. The lining-to-drum friction contact surfaces were dry. The front and rear brake shoe lining thickness of the brake assembly was measured to be 0.15 and 0.14 inches, front and rear, respectively, at the center of the lining. Both the front and rear brake shoes had two worn rivets contacting the drum during brake application.

� The right side rear brake wheel cylinder was leaking brake fluid. Fluid drained from the wheel cylinder when the rear dust boot was pulled away from the wheel cylinder. A buildup of black-colored material was observed on the backing plate, the wheel cylinder, and the inside of the brake shoes. This material was visibly wet on the back side of the wheel cylinder rear dust boot area and the rear adjuster cam. The brake lining-to-drum friction contact surfaces were dry. The front and rear brake shoe lining thickness of this brake assembly was measured to be 0.20 and 0.18 inches, front and rear, respectively, at the center of the lining.

� The left side rear brake wheel cylinder was seeping brake fluid past the front dust boot. The brake lining-to-drum friction contact surfaces were dry. The front and rear brake shoe lining thickness was measured to be 0.17 and 0.16 inches, front and rear, respectively, at the center of the lining.


� Leaking brake fluid observed behind the dust boots of the wheel cylinders and in both the front and the rear master cylinder reservoirs had a grayish-black tint. All wheel cylinder pistons moved freely within their respective bores and the cylinder walls showed no signs of rust.

� Other hydraulic or air leaks were not detected within either the front or rear axle brake systems until the air chamber for the rear brake system failed during hydraulic pressure tests.

� All four service brake drums had an inner diameter of 16 2/32 inches and a nominal diameter of approximately 16 inches. The three-inch wide contact surfaces were very smooth and shiny, with the right rear surface showing slight discoloration. This discoloration included two �-inch bands going around the entire inner diameter's circumference. One �-inch wide band was light brown in color starting about 1-inch from the edge of the drum and the other band was light to dark blue in color starting approximately 2 -inches from the edge of the drum.

� The manual adjusters on the service brakes were eccentric cams that turned using a six-sided bolt head. There was one adjuster for each of the eight shoes. The 6-flats on the bolt head represented one full turn of the cam from the least to the maximum adjustment position. By design, if the brake linings or brake drums were excessively worn and the adjustment was turned past the maximum position, the "cam over" position would be reached and the cam would return to the point of least adjustment. During the investigation, the forward manual adjusters of the front service brakes were found to be adjusted 3� and 4 flats from the "cam over" position on the left and right brakes, respectively. The rear manual adjusters of the front service brakes were found to be adjusted at 1 and 3� flats, respectively, from the "cam over" position on the left and right side brakes. The forward manual adjusters of both the left rear and right rear service brakes were found to be adjusted 3 flats from the "cam over" position. The rear manual adjusters of the rear service brakes were found to be adjusted 4 and 3 flats, respectively, from the "cam over" position on the left and right side brakes.

� Drawbar pull tests were conducted to quantify the service brake performance of the loader with a main air system application pressure at approximately 100 psi. These tests measured an average braking force equivalent to that required to be developed to counter the effects of an approximate 5.2% grade, including the rolling resistance. This value represented the approximate maximum grade at which the loader could have been held at a constant velocity for a time period prior to the development of brake fade. The test demonstrated that the service brakes on the loader would not have stopped nor held the loader on the road it was traveling at the time of the accident.

� When the investigation team turned the adjusters to produce a more effective braking force, all eight adjusters went into the "cam over" position. The manual adjusters were again placed at the maximum adjustment positions and drawbar tests were re-conducted to quantify the service brake performance of the loader. In this condition, the tests measured an average braking force equivalent to that required to be developed to counter the effects of approximately a 22.8% grade, including the rolling resistance. This value represented the approximate maximum grade at which the loader could have been held at a constant velocity for a time period prior to the development of brake fade. The test demonstrated that, after appropriate adjustments were made, the loader's service brakes would stop and/or hold the loader on the road it was traveling on at the time of the accident.

� The parking brake was an internal-expanding shoe drum that acted on the front drive shaft. It was mechanically controlled by a lever located on the right side of the operator's seat. Application of this lever also actuated the power-shift transmission's neutralizer function. Drawbar pull tests were conducted on the loader's parking brake system to quantify it's performance. The tests resulted in a static braking force equating to the ability to hold the machine stationary on an approximate 34% grade, including rolling resistance. This test demonstrated that the parking brake would have held the loader stationary on the maximum grade it was operating on at the time of the accident.

� Photographs taken by a local sheriff's investigator indicated that the loader's air gauge on the dash read approximately 120 psi shortly after the accident. The gauge was marked with two ranges of main air system pressures, red and green; the red range was from 0 to 75 psi and the green range was from 75 psi to 150 psi.

� Functional testing could not be performed on the loader's power-shift transmission and the transfer case due to the damage sustained in the accident. All transmission and transfer case linkages were visually intact. According to a local sheriff's report, the loader's transmission range control lever was found in neutral and the speed control lever was found in second gear after the accident.

� Testing of the steering system could not be conducted due to the damaged engine. A visual inspection of the system after the accident indicated that the hydraulic plumbing was intact with no leaks or broken hoses. The steering column was broken at its mounting area within the operator's compartment, which placed the steering wheel into the seat area. A section of the steering wheel had been cut out, reportedly to extricate the victim. However, the remainder of the steering systems mechanical linkages were intact.

� Functional testing could not be performed on the fork lift attachment's hydraulic functions due to the damaged engine. However, the unloaded attachment was tested by raising it above the ground, removing the lifting mechanism, and looking for movement (leak down) of the cylinders. Visual downward movement of the fork lift attachment was not observed when tested in this manner.

� The ROPS tag identified the structure as having been manufactured in May 1985 by Saf-T-Cab, serial number 17698. The tag stated that the structure was designed to meet OSHA Standard 1926-1000 for a Caterpillar 922B machine. It also stated that the structure was rated for a gross vehicle weight of 20,000 pounds. The structure was mounted to the loader with 1-inch (outer diameter) SAE grade, number 8, steel bolts. One bolt was located on each bottom end of the four vertical structural members of the structure and they were installed perpendicular to the machine's longitudinal axis. The ROPS collapsed under load induced during the accident with the fabricated metal structure undergoing a significant failure. The four ROPS attachment points on the bottom corners of the structure remained intact; however, the fabricated metal structure failed at the top four corners of the ROPS. The failures in these corner areas were observed to be a combination of weld failures and cross-section failures of the structural members. Safety defects which might have contributed to the accident were not observed in the ROPS by the investigation party.

� The loader's seat belt was reportedly being worn by the victim at the time of the accident. The belt's 2-inch wide webbing had been cut near the male portion of the latch, reportedly by rescue crews for extrication purposes. A Firestone model no. 1771 tag was sewn on the seat belt webbing. The female portion of the latch had a push-button release stamped with "GM" and "Firestone RCF-67" markings.

� Prior to MSHA's arrival at the mine, the loader had been removed from the accident site and taken to the "Red's Middle Quarry" level. The left front tire had been replaced to facilitate moving the machine since the original tire had deflated when the machine was being up-righted during recovery activities. At the time of the accident, all tires on the loader were Michelin 17.5R25 XHA. Air pressure for the right side tires was measured at 56 psi for the front and 53 psi for the rear. The left rear tire had debris in the bead seat area, apparently from the accident, and air pressure was measured to be 20 psi.

� The victim had received training on forklift operation from his employer, Boise Cascade Paper Division, for maintenance operation of forklifts in their maintenance shop. MSHA was told that Dimick was not certified to operate forklifts in production at their Burley Container plant.

� Dimick had received verbal task training in operating the loader involved in the accident by mine personnel prior to the accident.

CONCLUSION


The cause of the accident was the failure to ensure that the loader had an adequate service braking system capable of stopping and holding the loader on the grade it was traveling. Contributing to the severity of the injuries was the lack of structural strength of the ROPS.

ENFORCEMENT ACTIONS


Northern Stone Supply, Inc.

Order No. 7982660 was issued on August 10, 2000, under the provisions of Section 103(k) of the Mine Act:
A powered haulage accident occurred at the Rocky Mountain Quartzite Quarry haul road which fatally injured the independent contractor employee operating the Caterpillar 922B forklift. This order prohibits the use of the forklift and the section of the haul road where the accident occurred until MSHA determines if any other potential hazards exist. This order is issued to assure the safety of persons at this operation until the mine or affected areas can be returned to normal mining operations as determined by an authorized representative of the Secretary. The mine operator shall obtain permission from an authorized representative for all actions to recover persons, equipment and/or restore operations in the affected area.
This order was terminated on August, 24, 2000, when the on-site investigation was concluded and the loader removed from the mine site.

Citation No. 7994252 was issued on August 23, 2000, under the provisions of Section 104(a) of the Mine Act for a violation of 30 CFR 56.14101(a)(1):
A fatal accident occurred at this mine on August 9, 2000, when the person operating a Caterpillar front-end loader, model 922B, serial no. 94A1103, lost control of the machine while descending a haul road, overturned, and fatally injured the operator. The service braking system on the front-end loader was not capable of stopping and holding the loader on the grade it was traveling.
This citation was terminated on August, 23, 2000, when the loader was removed from the mine property. The service braking system was repaired, tested, and is now effective.

Rocky Mountain Quarry & Service Co.

Citation No. 7978375 was issued on August 23, 2000, under the provisions of Section 104(a) of the Mine Act for a violation of 30 CFR 56.14101(a)(1):
A fatal accident occurred at this mine on August 9, 2000, when the person operating a Caterpillar front-end loader, model 922B, serial no. 94A1103, lost control of the machine while descending a haul road, overturned, and fatally injured the operator. The service braking system on the front-end loader was not capable of stopping and holding the loader on the grade it was traveling.
This citation was terminated on August, 23, 2000, when the loader was removed from the mine property. The service braking system was repaired, tested, and is now effective.

Related Fatal Alert Bulletin:
Fatal Alert Bulletin Icon FAB2000M32

APPENDIX A
Persons Participating in the Investigation

Northern Stone Supply, Inc.
Garth Greenwell .......... foreman
Mine Safety and Health Administration
John Widows .......... supervisory mine safety and health inspector
Robert Montoya .......... mine safety and health inspector
Lawrence Wilson .......... civil engineer
F. Terry Marshall.......... mechanical engineer
John Kathmann .......... mine safety and health specialist
APPENDIX B

Persons Interviewed

Northern Stone Supply, Inc.
Gary Mullard .......... president
Garth Greenwell .......... foreman
Cameron Smith .......... foreman
Michael Mullard .......... truck driver
Jerry Stanger .......... mechanic
Marcos Verdin .......... mechanic's helper
Silvano Villanuava .......... miner
Artenio Narvaez .......... mechanic's helper
Enrique Villanuvea .......... miner
Trevor Stanger .......... truck driver
Jose Sarreon .......... miner
Cassia County Sheriff Department
Billy Crystal .......... sheriff
Quick Response Unit (Oakley, Idaho)
Wayne Mullen .......... emergency medical technician
Cassia County Search and Rescue Unit
Mark Welch .......... emergency medical technician
Boise Cascade Paper Division (Burley Container Plant)
Virgil Cole .......... safety director
Columbia Claims Service, Inc.
Jack Oyler .......... owner
No Affiliation
George Richardson .......... retired