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Accident Investigation Report
Surface Nonmetal Mine

Fatal Machinery Accident

Oceanside/Carlsbad Quarry (mine)
Mine ID No. 04-00239-UD9 (contractor)
California Drilling and Blasting Company, Incorporated
Carlsbad, San Diego County, California

February 14, 1996


Michael J. Drussel
Mine Safety and Health Inspector

Gary L.Cook
Mine Safety and Health Inspector

Western District Office
Mine Safety and Health Administration
3333 Vaca Valley Parkway, Suite 600
Vacaville, California 95688

Fred M. Hansen
District Manager


Arthur F. Webster, a 46 year old mechanic, was fatally injured February 14, 1996 when he was backed over by a quarry drill. Webster had worked in the mining industry for 24 years, the past 15 with California Drilling and Blasting Company. He was employed as a mechanic the past 12 years.

James Ploughman, San Bernardino, California MSHA field office supervisor was notified of the accident at 8:30 a.m., February 14. An investigation was started that same day.

The accident occurred at the Oceanside/Carlsbad Quarry, an open pit, multiple bench mine owned and operated by South Coast Materials of Carlsbad, San Diego County, California. At the mine quarry rock was drilled and blasted, and then transported by truck to the plant. It was then crushed into aggregate to be used in asphalt and ready-mix cement.

South Coast Materials' Oceanside/Carlsbad Quarry operated with 37 employees working one eight-hour shift, five days a week.

California Drilling & Blasting Co., Inc. was contracted, by South Coast Materials, to do the drilling and blasting in the quarry.

Principal operating officials for California Drilling & Blasting Co., Inc. were:
Robert L. Marks, President M.E. "Skip" Marks, Operation Manager

The last regular inspection was completed on August 23, 1995.


The machine involved in the accident was a self contained, diesel powered, Gardner Denver Hydra Trac Quarry Drill, Model 3500, Serial #3511248. The drill weighted 26,000 pounds. It was 7 feet 11 inches wide, 28 feet long, and 9 feet 2 inches high. The track length was 10 feet 9 inches and the drill's tram speed was 60 feet per minute.

The operator console was on the left side, near the front of the drill. From that location, the operator's view of objects located directly behind the drill, to about 90 degrees to the right of the unit, was obstructed. The drill was not provided with a backup alarm.

Noise levels measured at the rear of the drill after the accident were 87.5 dba.

The drill backed down an uneven 16 percent slope. At the bottom, where the accident occurred, it made a 90 degree turn.

Reportedly, Webster had a history of diabetes and heart disease. It could not be determined if these conditions contributed to the accident.


On the day of the accident, Webster began work at 7:00 a.m., his regular starting time. He met with the drill operator, Earl Quinby, concerning repairs needed on a hydraulic hose that had ruptured the previous day. Because the drill was sitting on a slope, and the hose was damaged up on the mast, they decided repairs could more easily be accomplished if the machine was moved to level ground. They first installed a temporary patch on the ruptured hose. Then, while Webster went to his truck to obtain needed tools, Quinby prepared to uncouple the drill steel and move the drill. Because of low hydraulic pressure it took about two minutes to uncouple the steel. At about 7:30 a.m., Quinby went to the operator's console and began to move the drill backwards off the slope. At the bottom he turned the drill clockwise 90 degrees. When Quinby completed the turn, he saw Webster face down under the right track. Quinby immediately positioned the drill boom against the ground and lifted the track off Webster. Failing to get a response from Webster, Quinby went to the office to summon help. Operations manager E. L. "Skip" Marks called 911. Marks waited to direct the ambulance to the accident scene while Quinby returned to the drill and blocked it against possible movement.

The Carlsbad ambulance arrived at 7:43 a.m. Paramedics were unsuccessful in reviving Webster. He was pronounced dead at the scene and transported to the San Diego coroner's office where an autopsy was performed. Blunt force injuries and compression of the chest were determined to be the causes of death.


It could not be determined why the victim was in the path of the moving drill.

Because of his limited view from the operator's console, the operator moving the Hydra Trac drill was unable to determine if his path was clear.

Unless the victim was physically incapacitated, or otherwise unable to respond, a back-up alarm could have prevented this accident.


Order No.3933995
103(k) Issued to California Drilling & Blasting Co., Inc., on 2/14/96 at 1200 Hours.

An employee was fatally injured when a Gardner Denver, Model 3500, Serial #3511248, Hydra Trac drill ran over him. This order prohibits the use of this drill, and prohibits any work in the area, pending an investigation by MSHA to determine the cause of the accident.

Citation No. 3933996
104(a), 56.14132(b) Issued to California Drilling & Blasting Co., Inc., on 2/15/96 at 1500 Hours.

The Garden Denver Hydra Trac drill Model 3500, serial #3511248 was not equipped with an automatic reverse-activated signal alarm, or a wheel-mounted bell alarm, or a discriminating backup alarm, or an observer to signal when it is safe to back up. There was an obstructed view to the rear extending from the center line at the rear of the machine to the middle of the offside of the operator's station, approximately 90 degrees. On level ground this blind spot extended for more than 30 feet. A fatal accident occurred when the drill ran over an employee. This drill has never had an alarm and the condition has never been addressed with the operator. Termination of this citation requires the installation of a back-up alarm.

/s/ Michael J. Drussel
Mine Safety and Health Inspector

/s/ Gary L. Cook
Mine Safety and Health Inspector

Approved by:

Fred M. Hansen, Manager
Western District

Related Fatal Alert Bulletin:
Fatal Alert Bulletin Icon [FAB96M05]