DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
Metal and Nonmetal Mine Safety and Health
Report of Investigation
Surface Nonmetal Mine
Fatal Powered Haulage Accident
May 1, 2000
Blue Circle Aggregates, Inc.
Lithonia, Dekalb County, Georgia
Mine I.D. 09-00023
Merle E. Slaton
Supervisory Mine Safety and Health Inspector
James M. McCarthy
Mine Safety and Health Inspector
Mine Safety and Health Administration
135 Gemini Circle, Suite 212; Birmingham, AL 35209
Martin Rosta, District Manager
On May 1, 2000, Wade A. West, haulage truck driver, age 42, drowned when he fell into a storm sump pond filled with about 8 feet of water. West had become disoriented and drove his loaded truck into the sump then lost his balance while attempting to dismount from the truck.
West had a total of 7 months mining experience, all with this company. He had received training in accordance with 30 CFR, Part 48.
Lithonia Quarry, a crushed limestone operation, owned and operated by Blue Circle Aggregates, Inc. was located off Rock Mountain Road in Lithonia, Dekalb County, Georgia. The principal operating official was John C. Pearson, plant manager. The pit was normally operated one, 12 hour shift a day, 5 days a week. The plant was normally operated two, 12-hour shifts a day, 5 days a week. Total employment for the mine was 29 persons.
Crushed stone was extracted from the pit by drilling and blasting multiple benches. The material was hauled to one of two primary crushers where it was crushed, screened, washed and sized. The product was then conveyed to stockpiles. The finished product was sold for use as construction aggregate.
The last regular inspection of this operation was completed April 6, 2000. A regular inspection was conducted following the investigation.
DESCRIPTION OF ACCIDENT
On the day of the accident, Wade A. West (victim) reported to work at 1:00 a.m., his normal starting time. He was assigned by Craig Fair, pit foreman, to relive the regular haulage truck driver who was on vacation for the week.
After conducting a pre-shift inspection on the Komatsu HD 465, 65-ton haul truck, West proceeded to the second bench of the pit to get material to haul to the jaw crusher. Fair fueled West's truck at about 6:30 a.m. and spoke to West during this time. Fair stated that West did not complain of any difficulties. That was the last verbal contact he had with West. Fair was called away from the mine for a family emergency at about 10:30 a.m., and Gene Owens, foreman, was left in charge.
At about 8:00 a.m., after West had finished hauling seven loads, the jaw crusher broke down and he was instructed to haul the material to the primary crusher. He hauled 16 loads to that crusher with his last one being completed at 11:45 a.m..
Walter Johnson, pit haulage truck driver, stated that he passed West as he was returning to the pit to get his last load before the end of his shift and West was headed toward the primary crusher with a full load. Johnson and West waved to each other and Johnson noted nothing unusual. After Johnson went to the crusher and dumped the load, he went to the shop area to park the truck. He saw West's truck on the top bench across the pit making short back and forward movements. He thought maybe West was taking a load of stemming up to the drill area on the bench. He asked Henry Hooten, haul truck driver, if he knew why West was there and Hooten said he did not. Both Johnson and Hooten clocked out and left the property.
At approximately 6:30 p.m., Owens noticed that West's truck was not in the parking line at the shop and inquired if anyone knew where the truck might be. No one knew and a search was initiated. After searching all of the normal haulage roads they still were unable to find the truck. Owens then began searching the other roads in the pit and eventually went to the top bench. The top bench had been stripped of overburden and in the northeast corner of the stripped area there was a storm water sump pond. Owens found West's truck in the sump with the lights and windshield wipers on. The bed of the truck was up with the load partially dumped in the water. West was not in the cab and Owen could not find any footprints indicating that West had left the truck.
Owens notified emergency personnel and a local fire and rescue team arrived and arranged for divers to search the water. When it became too dark to continue the search, it was suspended.
The search resumed the next day and two pumps were used to lower the water depth to about 4 feet. At about 2:30 p.m., divers recovered West's body in front of the left rear tires. The medical examiner pronounced him dead at the scene. Autopsy results determined that West died as a result of drowning. Circumstances leading up to the drowning could not be explained by the autopsy.
Prior to the accident, West told several co-workers that he did not bring a lunch and needed to get something from the vending machine. Although there were no witnesses, it is believed that as West was taking his last load to the primary crusher, he became disoriented and drove the truck to the non-working area of the mine. He then drove into the sump and as he attempted to dismount from his truck, he fell into the water.
INVESTIGATION OF THE ACCIDENT
At 9:50 p.m., on May 1, 2000, Harry L. Verdier, assistant district manager, was notified of the accident by a telephone call from Joe Carder, safety and health manager for the mine. An investigation was started the same day and an order was issued under the provisions of Section 103(k) of the Act to ensure the safety of the miners. MSHA conducted the investigation with the assistance of mine management and mine employees. Grady Smith, president of the United Steel Workers of America, Local #2401, was contacted and participated in the investigation.
1. The accident occurred in a storm water sump located in an area of the mine that had been stripped of overburden for future mining. Mine personnel stated that none of the victim's work duties would have made it necessary for him to travel to this area. The stripped area was in the southeast corner of the mine adjacent to the south pit, 1.8 miles from the road where West had been hauling material. The truck had been carrying a load of limestone aggregate and traveled a generally level path throughout the 1.8 mile distance until it went into the sump. The terrain sloped downward, into the sump, at grades ranging from 10 percent to 30 percent for a distance of about 30 feet. The water covered an estimated 1.5 acres and was approximately 8 feet deep where the truck was found.
2. The haul truck involved in the accident was a 65-ton Komatsu, HD465, with a maximum gross weight of 211,860 pounds. The maximum rated payload was 61 tons. It had been purchased new for this mine and had been in service for three weeks. The hour meter indicated 124 hours of operation.
3. The truck was powered by a Komatsu SAA6D170E-2, six-cylinder, 23.15 liter, 715 horsepower diesel engine. The engine was not running when the truck was found. It was equipped with a fully-automatic transmission, with seven speeds forward and one reverse speed. When the truck was found, the control positions were as follows:
- The seat back was reclined to a nearly-horizontal, fully reclined position.4. The main steering system was inspected during the investigation. The hydraulic steering cylinders, steering linkage, and hydraulic steering hoses were all found to be intact. Since the truck was not operational following its recovery, no steering tests were conducted.
- The ignition key was in the "on" position. This was the normal position the key would be in while the engine was running.
- The transmission was in third gear, forward.
- The service brake pedal and accelerator pedal moved freely with no obstructions.
- The emergency brake lever was in the released position.
- The park brake lever was in the released position.
- The retarder control handle was in a partially applied position.
- The "front brake off" switch was in the deactivated position. In this position, when the service brake pedal was depressed, both the front and rear wheel brakes were applied.
- The headlight switch was in the "on" position. At the time of the investigation, none of the lights were illuminated. This could be due to dead batteries or other electrical malfunctions due to water damage to electric components.
- The engine emergency stop switch was in the "on" (travel) position. This toggle witch could be used to stop the engine when placed in the "stop" position.
- The hand-held counter used to count loads of material hauled was found on the floor of the operator's compartment.
5. An emergency steering system was provided on the truck. The operation and maintenance manual (No. SEAM05690509T) says that the steering system can be activated manually by pressing an electric button switch on the console. When the switch is "on", the red pilot lamp inside the switch lights up. The emergency steering system was also designed to automatically actuate if the engine stopped during operation or if the key switch was "on", while the engine was stopped and the parking brake switch was "off". Since the truck came to rest with the ignition in the "on" position, the engine stopped, and the parking brake was in the released position, the steering should have automatically become actuated. The red emergency steering pilot light was "on" when the truck was found. When new batteries were installed in the truck during the investigation, the emergency steering switch pilot light lit, indicating the system was actuated.
During the investigation, an attempt was made to operate the emergency steering system and it was found that it did not function. The emergency steering system depended on an electric motor to drive a hydraulic pump. The electric motor was submerged in water when the accident occurred, possibly causing damage to the motor or electronic control circuit. The electric motor for the emergency steering system, as designed, would have attempted to run continuously after the accident.
Tire tracks where the truck had maneuvered in the level area above the pond indicated the main steering system functioned at that point. The tread pattern of the tracks matched the tires on the truck. It was determined that no steering defects existed at the time of the accident and that the damage to the emergency steering system electric motor was a result of the accident.
6. The service brake system consisted of air-over-hydraulic, caliper-disc front brakes and air-over-hydraulic, oil-cooled, multiple-disc rear brakes. Cooling oil was circulated through the rear service brake disc packs. The parking brake system consisted of a spring-applied, hydraulically-released, caliper-disc on the drive shaft and provided braking at the rear wheels only. The parking brake was activated by a lever on the console between the operator's and passenger's seats. The emergency braking system consisted of the automatic application of the service brakes, at all four wheels, when tank air pressure dropped below 31 psi. An emergency brake lever on the console also allowed manual application of the emergency brake. The retarder system operated by applying the rear service brakes. It was controlled by a lever on the steering column.
7. Service brake and emergency brake drawbar pull tests were conducted. For these tests, a Caterpillar 990 wheel loader was used to provide the pulling force. The tests were conducted on a hard-packed and level surface. The truck was approximately empty when the testing was done. The truck was found in the loaded condition and the load was removed to facilitate the recovery of the truck. It was visually estimated that approximately 2 tons of material remained in the truck after it was emptied a much as reasonably possible. The tests were conducted with this residual 2 ton load in the dump body. The air system on the haul truck was changed from an external source, since the engine did not operate.
With the air system pressure at 120 psi, all four wheels slid when the service brake was applied. The parking brake, emergency brake, and the retarder controls were kept fully released during these tests. The air pressure was lowered to 70 psi and the same test was conducted. Again, all four wheels slid. The air pressure was further lowered to 40 psi and all the tires slid except the front left, which rolled. The front left disc was oily which would reduce braking capacity. The source of the oil was very likely to be from a nearby hydraulic steering hose that had been disconnected during the recovery to allow the front wheels to be turned straight. At the time of the accident, the front left brake would have provided somewhat higher braking force had the oil not been present. No hydraulic leaks or air leaks were found in the brake system. When all brake controls were in the released position, the tires rolled freely when the truck was pulled.
Komatsu personnel stated that the normal governed air pressure is 100 psi +/- 4 psi. Braking torque was proportional to the application pressure so testing at 40 psi would have reduced available braking torque by a factor of 40/100, or more than one half. Even at this reduced pressure, the service brake had the capability to slide the tires, except for the front left. Calculations based on these tests showed that the service brake system could have slid the tires of a fully loaded truck, with the exception of the front left tire. (This was the wheel where the brake disc had been contaminated with oil during the recovery.) Tire skid marks were observed on the exposed rock surfaces on the hillside leading to the pond. No service brake defects were found.
8. The emergency brake was tested with the air system at 70 psi. With the emergency brake applied, and the service brake, parking brake and retarder released, all four wheels slid during the tests. When the emergency brake was released, the wheels rolled freely when the truck was pulled. No emergency brake defects were found.
The hydraulic brake pressure at the rear wheels was measured when the service brake was applied and the following was found: left rear brake disc pack - 575 psi, right rear brake disc pack - 575 psi. These tests were conducted with the air system pressure set at 95 psi to 105 psi. These air and hydraulic pressures corresponded to the normal pressures as specified by Komatsu. Information from Komatsu indicated the air to hydraulic pressure ratio was 5.4 to 1, which was approximately the ratio determined in the tests.
9. The two rear air-over-hydraulic brake chambers on the truck were equipped with a pin indicator that would protrude from the end of the unit if a brake system defect caused it to over stroke. None of the over stroke pins were found to be protruding. The brake chambers for the front brakes did not have over stroke indicators.
10. The truck remained upright throughout the entire distance, including when it came to rest in the pond. The dump body was found partially raised, and part of the load was found behind the truck.
11. According to his family, the victim had a history of diabetes and was on insulin to control his medical condition. The autopsy report did not address the victim's insulin levels.
12. The victim had approximately 7 months experience at this mine as a floater, which included part-time haulage truck driver. He received new employee, inexperienced miner training starting on October 8, 1999. He also received emergency medical training in hazard recognition, transport and communications systems, roof/ground control/ventilation, mine map, escape way, emergency evacuation, barricading, explosives, and fire safety training on December 17, 1999. According to the pit foreman, West had been provided task training on the truck's operational functions on the day of the accident, prior to West operating the truck.
13. While the truck was in the pond, the highest water level in the operator's compartment was approximately one foot above the operator's seat cushion. The instrument panel had been completely submerged.
14. The accident occurred during daylight hours. Visibility was not impaired by rain or other weather factors.
The accident occurred when the victim lost his balance and fell into the water while dismounting the haul truck. The investigation was unable to determine why the victim became disoriented and drove in the wrong direction into a non-working area of the mine and into a water-filled sump.
Order No. 6074537 was issued on May 2, 2000, under provisions of Section 103(k) of the Mine Act:
An accident occurred at the Blue Circle Aggregates, Inc., Lithonia Quarry when a 60-ton Komatsu haulage truck was driven into approximately eight feet of water. This order is issued to assure the safety of personnel 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 operator shall obtain approval from an authorized representative for all actions to recover persons, equipment and/or restore operations in the affected area.
This order was terminated on May 5, 2000. Conditions that contributed to the accident have been corrected and normal mining operations can resume.
Related Fatal Alert Bulletin:
A. Persons Participating in the Investigation
B. Persons Interviewed
C. Accident Investigation Data (Form 7000-50a)
D. Accident Investigation Data - Victim Information (Form 7000-50b)
Persons Participating in the Investigation
Blue Circle Aggregates, Inc.
John C. Pearson, plant managerUnited Steel Workers of America, Local #2401
Joe Carder, safety director
Michael Holden, safety coordinator
Gene Owens, plant foreman
Grady Smith, presidentMine Safety and Health Administration
Merle E. Slaton, supervisory mine inspector
James M. McCarthy, mine safety and health inspector
Ronald Medina, mechanical engineer
Blue Circle Aggregates, Inc.
John C. Pearson, plant manager
Gene Owens, plant foreman
Craig Fair, pit foreman
Charles Robinson, floater
Albert Harris, loader operator
Walter Johnson, haulage truck driver
Henry Hooten, haulage truck driver
Howard Hooten, primary crusher operator