UNITED STATES
DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION


NORTH CENTRAL DISTRICT
Metal and Nonmetal Mine Safety and Health


Accident Investigation Report
Surface Nonmetal Mine
(Limestone)

Fatal Falling/Sliding Material Accident

Jack Gray Transport, Inc. (Contractor)
(I.D. No. 6WJ)

Located at
Thornton Quarry
Material Service Corporation
Thornton, Cook County, Illinois
(I.D. No. 11-00066)


August 18, 1997


By

Fred H. Tisdale
Mine Safety and Health Inspector (Electrical)
and
Steven M. Richetta
Supervisory Mine Safety and Health Inspector


Originating Office
Mine Safety and Health Administration
Federal Building, U.S. Courthouse
515 W. First Street, #228
Duluth, MN 55802-1302

John K. Radomsky
Acting District Manager

GENERAL INFORMATION

Charles E. Street Jr., contract truck driver, age 36, was fatally injured at about 11:15 a.m. on August 18, 1997, when he was buried in a slide from a stockpile of crushed limestone. He had a total of two years, ten months of experience as a contract truck driver delivering product. He had not received training in accordance with 30 CFR Part 48.

Randall Mucha, safety manager, Material Service Corporation, notified the MSHA office in Peru, IL of the accident by telephone at 12:10 p.m. on August 18, 1997. An investigation was started the same day.

The Thornton Quarry, an open pit limestone operation owned and operated by Material Service Corporation, was located at Thornton, Cook County, Illinois. The principal operating official was John Halloran, area manager. The mine normally operated three shifts, eight hours a day, five days a week. One hundred and thirty persons were employed. Limestone was quarried, crushed, sized, and stockpiled using dump trucks and stacker conveyors. The limestone was used for building and construction.

Jack Gray Transport, Inc. was a trucking firm that was contracted to haul material from the Thornton Quarry and other operations in the area. The principal operating official was John S. Gray, president. Charles E. Street, Jr. was an employee of this cartage company.

MSHA's last regular safety and health inspection of Thornton Quarry was conducted from February 10 through February 13, 1997.

PHYSICAL FACTORS INVOLVED

The vehicle involved in the accident was a Peterbilt, highway-type semi-tractor with a Ravens 24 foot aluminum dump trailer. The dump trailer was equipped with a tailgate at the rear of the trailer that hinged at the top and had a latch mechanism at the bottom to secure it. The tailgate was equipped with "spreader chains" to control the distance that the tailgate would open in order to regulate the flow of material from the trailer. The tailgate could be unlatched from the operator's cab, but changes to the spreader chain's adjustment were done by hand at the tailgate.

The accident occurred at the base of the grade eight limestone stockpile. The stockpile was about 75 feet high and 150 feet long by 160 feet wide and contained limestone which varied in size from 1-1/2 inches to dust-sized particles. The pile of crushed stone was fed from a 36 inch wide radial stacker conveyor that received material from the bin loadout system. This system was designed to automatically convey material away from the loadout bins when they were full and to dump the material on the stockpile. As this pile gained material at the top, it would occasionally slide down to the angle of repose. There were no procedures in place to trim this stockpile.

Over-the-road contract trucks entered the stockpile area and backed their trucks to the stockpile where company front-end loaders loaded them. As the material was taken from the bottom of the pile by front-end loaders, the void created was intermittently filled in by sliding material from higher on the pile. This sliding action was a result of the loose material seeking its angle of repose. Measurements taken at the scene indicated the angle of the stockpile was approximately 37 degrees. It was estimated that the angle of this stockpile prior to the accident was approximately 39 degrees.

Two contract truck drivers witnessed the accident, along with the company employee who operated the Hough 560 front-end loader.

Rain showers had moved through the area earlier that morning but, at the time of the accident, the weather was clear and cool.

DESCRIPTION OF THE ACCIDENT

On the day of the accident, Charles E. Street, Jr. (victim) started his work day at about 5:30 a.m. hauling crushed limestone from the mine to customers. Work progressed normally until about 11:00 a.m. After receiving his seventh load, Street drove to the scales where he was notified by the scale operator that they had been told his load had been canceled. The scale operator directed him to return that load to the grade eight stockpile but he wasn't given specific instructions where to dump the material at the stockpile.

Street returned to the stockpile and backed his trailer up to the base of the pile. Joe Molnar and James McCauley, contract truck drivers for Brites Cartage, were in the process of being loaded by Mike O'Donnell who was operating the Hough 560 front-end loader at this stockpile.

As Street attempted to dump his load, he unlatched his tailgate, partially raised his dump bed and apparently realized that the spreader chains, still attached to the tailgate, would inhibit the unloading process. He left the dump bed about a third of the way up and walked to the driver's side of the tailgate and unhooked the chain on that side. He then walked behind the trailer and moved up about 2 feet onto the pile of grade eight material and attempted to unhook the chain at the right side. As Street was reaching for the right hand spreader chain, the pile suddenly sloughed off and knocked him down. He was trapped behind the trailer's right rear tires and completely covered by the sliding material.

Seeing the pile slough onto the victim, all three men jumped from their vehicles and ran to his aid. As they attempted to dig him out, the material kept sloughing over him.

John Halloran, area manager for Material Service Corporation, heard the radio calls for help, requested an ambulance, and proceeded to the scene to help dig. The ambulance was called at 11:14 a.m. and arrived at 11:18 a.m. Area rescue personnel arrived and assisted in the rescue attempts.

After several tons of material had been removed, the rescuers were able to grasp Street and pull him free. Street had no vital signs and resuscitation efforts were not successful. The victim was transported to St. James Hospital where he was pronounced dead at 12:20 p.m. The cause of death was asphyxiation.

CONCLUSION

The accident was caused by failing to trim the unstable stockpile or to ensure that persons were not exposed near the base of the stockpile.

VIOLATIONS

Order No. 7817149

Issued on August 18, 1997, at 1430 hours under the provisions of Section 103(K) of the Mine Act:

The order was issued to prevent persons from entering the area until a determination could be made that there was no longer a hazard in the area.

This order was terminated on August 19, 1997 at 1015 hrs.

The following citation was issued to Jack Gray Transport, Inc. on 09/11/97 at 0800 hours:

Citation No. 7824526

Part/Section of Title 30 CFR: 56.9314; Type of Action: 104a

On August 18, 1997, a contract truck driver was fatally injured when the grade eight stockpile sloughed, covering him as he was removing the spreader chains from his truck's tailgate. He had backed the truck against the base of the approximately 75 foot high stockpile, and had walked between the truck and the stockpile, when the stockpile sloughed.

The following citation was issued to Material Service Corporation on 09/11/97 at 0805 hours:

Citation No. 7824527

Part/Section of Title 30 CFR: 56.9314; Type of Action: 104a

On August 18, 1997, a contract truck driver was fatally injured when the grade eight stockpile sloughed, covering him as he was removing the spreader chains from his truck's tailgate. He had backed the truck against the base of the approximately 75 foot high stockpile, and had walked between the truck and the stockpile, when the stockpile sloughed.

[FAB97M44]