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

REPORT OF INVESTIGATION

Surface Nonmetal Mine
(Sand and Gravel)

Fatal Other Accident (Drowning)
May 16, 2002

Lawrence Gravel, Inc. No. 2
Lawrence Gravel, Inc.
Palestine, Crawford County, Illinois
I.D. No. 11-01081


Accident Investigators


Thomas J. Pavlat
Mine Safety and Health Specialist

Fred H. Tisdale
Mine Safety and Health Inspector

Terence M. Taylor
Senior Civil Engineer


Originating Office
Mine Safety and Health Administration
North Central District
515 West First Street, Room 333
Duluth, MN 55802-1302
Felix A. Quintana, District Manager


OVERVIEW

On May 16, 2002, Dane E. Lawrence, vice president, age 43, drowned when the bulldozer he was operating fell into a water-filled pit. At the time of the accident, Lawrence was leveling material at the end of the wet screen plant's waste material discharge pipe. The bulldozer was in front of the discharge pipe, on top of ground formed by waste sand, when the material gave way and the bulldozer fell into the pond. The accident occurred because the waste sand delta shear strength was incapable of maintaining a stable slope with the added dynamic bulldozer loading.

Lawrence had a total of 25 years' experience as an equipment operator. He had received training in accordance with 30 CFR, Part 46.

GENERAL INFORMATION

Lawrence Gravel, Inc. No. 2, a dredging operation, was owned and operated by Lawrence Gravel, Inc. The operation was located 4 miles south of Hutsonville, Crawford County, Illinois. The principal operating official was Dane E. Lawrence, vice president. The mine operated one, 8-hour shift, five days a week. A total of five persons worked at the mine.

Sand and gravel was dredged to a depth of 40 to 50 feet from a pond approximately 10 acres in size. The material was piped to a wet screen plant where it was sized and conveyed to stockpiles. The finished products were used in the construction industry. Waste material from the plant was piped and deposited into the pond.

The last regular inspection of this operation was completed on December 6, 2000. Another inspection was conducted following the investigation.

DESCRIPTION OF ACCIDENT

On the day of the accident, Dane E. Lawrence reported for work at approximately 6:30 a.m., his regular starting time. Lawrence was in his office when James B. Cooper, Jr., front-end loader operator, arrived at the mine at 6:45 a.m. Cooper informed Lawrence the screen plant's waste material discharge pipe needed to be extended, and a pile of material had formed at the discharge end of the pipe. Lawrence informed Cooper that, due to poor traction in the area, he would use the bulldozer to level the area at the end of the pipe. Cooper was to use a front-end loader to raise and position the pipe extension.

Lawrence drove the bulldozer north along the east side of the pipe to the discharge end. When he neared the end of the pipe, Lawrence used the bulldozer blade to level the material along the east side of the pipe. Lawrence then proceeded around the end of the pipe. Immediately after the bulldozer was turned, the ground gave way and the bulldozer fell into the pond.

Cooper and Charles F. Dorn, dredge operator, were located approximately 200 feet southwest of the end of the discharge and observed the bulldozer fall into the pond. The material slide created a backwash of water, causing Cooper and Dorn to initially retreat from the area. After a few moments, Cooper and Dorn returned to the pipe end and communicated with Lawrence, who had surfaced. Attempts to rescue Lawrence failed.

The County Sheriff's Department and local emergency personnel, including the Crawford County Rescue Squad Dive Team, arrived a short time later and recovered the victim. He was pronounced dead, and death was attributed to drowning.

INVESTIGATION OF THE ACCIDENT

MSHA was notified at 8:00 a.m. on May 16, 2002, by a telephone call from DiAnna S. McNair, office manager, Lawrence Gravel, Inc., to Felix A. Quintana, North Central district manager. An investigation began the same day. An order was issued pursuant to Section 103(k) of the Mine Act to ensure the safety of miners.

MSHA's investigation team conducted a physical inspection of the accident site, interviewed a number of persons, and reviewed procedures performed by the crew and victim at the time of the accident. Management and miners assisted in the investigation. The miners did not request, nor have, representation during the investigation.

DISCUSSION
  • The mine operator used a dredge to mine sand and gravel from below the water level. The dredge was capable of mining approximately 50 feet deep. The pit was approximately 3 miles west of the Wabash River. The mine pit had a surface area of approximately 10 acres and a normal depth of approximately 50 feet. The dredging operation was located to the west of the waste sand discharge pipeline.


  • The mine produced four primary products: FA 1 sand (minus 1/8 inch), CA 16 gravel (1/8 to 3/8 inch), CA 7 gravel (3/8 to 1-1/4 inches), and oversize gravel (1-1/4 to 3 inches). The operator could not sell all the mined FA 1 sand, therefore the wasted sands were returned to the pit.


  • A portion of the pit was filled with waste sands that had been discharged into the pit and the remaining disturbed area consisted of ponded water. Gradation test results on the waste sand material were: 99.25% passed 1/4 inch; 98% passed #4; 81.7% passed #10; 51% passed #20; 17.7% passed #40; 8% passed #100; and 5% passed #200. The Unified soil classification was that of a poorly-graded sand (SP). There were very little fine size particles within the sand.


  • The steel discharge pipe had an 8 inch inside diameter and was approximately 663 feet long. The discharge line consisted of multiple sections of steel pipe of various lengths that were mechanically fastened by conveyor belt-type couplings. The pipe was oriented in a northern direction and was filling in the northeast portion of the pit. It was lying across a previously deposited hydraulic sand fill. The pipe was relatively flat except for the last three sections from the discharge end that were sloped upward to allow the discharged waste sand to spew outward into the pond. The last three sections were supported by sand mounds. The invert of the pipe at the discharge end was located approximately 3-1/2 feet above the elevation of the pit water. Reportedly, with the length of the pipe and the power of the pump, the discharge sands could spew out as much as 15 feet.


  • Reportedly, this was one of the wettest spring seasons for this operation. In the month of May prior to the accident, there had been 9.45 inches of rain. At the time of the accident, there was local flooding in the communities near the mine. The water level in the pit was approximately 8 to 10 feet higher than normal. The northern portion of the discharged waste sand was saturated approximately 1 foot below the surface.


  • A front-end loader was normally used to move the discharge pipeline and to clear away any sand buildup out in front of the pipeline. It was estimated that within the last six months, there were only three other instances where a bulldozer had been used on the sand delta to clear away sand buildup from the front of the discharge pipeline.


  • The bulldozer that the victim was operating was not recovered after the accident. It was an International TD-20 that was purchased during 1965. There were no owner's manuals at the site containing equipment specifications. Since International's bulldozers were later acquired by Dresser, equipment specifications are believed to be similar to a Dresser TD-20G dozer. The overall weight would have been approximately 52,000 pounds with 26 inch wide tracks. The track ground pressures were specified as 9.9 pounds per square inch. The bulldozer was not equipped with a cab.


  • The discharge pipeline had been extended by one section and was moved in an easternly direction to its present location two days prior to the accident. Prior to the accident, witnesses estimated that there was a sand delta of up to 150 to 200 feet out beyond the discharge end of the pipe. The delta was estimated to be 150 feet to the west of the pipe and 135 feet to the east of the pipe.


  • According to the witnesses, the slope failure was sudden. The bulldozer and a large section of the sand delta beyond the discharge end of the pipe dropped into the water. The surface area of the failed section of the sand delta would have been roughly 150 to 200 feet wide and 285 feet long. At the failure edge (scarp) of the delta, the water depth appeared to drop off rapidly. According to recovery divers, the delta sunk approximately 22 feet.


  • Although the dredge was capable of mining to a depth of 50 feet, depending on the relative pit water levels from the time the delta area had been previously mined and the depth at the time of the failure, the top of the sand delta may have been over 60 feet above the pit bottom.


  • The dynamic loading of the moving bulldozer weight on the saturated sand delta would have caused the pore water pressures to increase within the sand in the vicinity of the bulldozer. The combination of the elevated seasonal water level within the sand delta and the increased pore water pressures caused by the bulldozer loading would have resulted in a lowered overall shear strength for the sand delta. The sand delta's reduced strength was incapable of maintaining a stable slope, thereby allowing the delta to shear off immediately behind the bulldozer and rotate out into the water.


  • Laboratory test results performed by Geotechnics, an independent testing laboratory, indicate that the soil had a specific gravity of 2.72, a shear strength total friction angle of 41.5 degrees, and an underwater angle of repose (slope) equal to 40.7 degrees.

  • CONCLUSION

    The root cause of the accident was a failure to recognize the instability of the saturated sand delta under the load of a moving bulldozer.

    ENFORCEMENT ACTIONS


    Order No. 7849183 was issued on May 16, 2002, under the provision of Section 103(k) of the Mine Act:
    A fatal accident occurred at the Lawrence Gravel, Inc. No. 2 sand and gravel operation when a dozer operator's International TD-20 fell into approximately 18 feet of water. This order is issued to assure the safety of all persons at this operation. It prohibits all activity at the pipeline discharge area until MSHA has determined that it is safe to resume normal mining operations. The mine operator shall obtain prior approval from MSHA for all actions to recover and/or restore operations at the pipeline discharge area.
    This order was terminated on July 2, 2002 after the conditions that contributed to the fatal accident no longer existed.

    Related Fatal Alert Bulletin:
    Fatal Alert Bulletin Icon FAB02M15




    APPENDIX A


    Persons Participating in the Investigation


    Lawrence Gravel, Inc.
    Robert D. Hackney ......... foreman
    Roger G. Hodge ......... front-end loader operator
    Charles F. Dorn ......... dredge operator
    James B. Cooper, Jr. ......... front-end loader operator
    DiAnna S. McNair ......... office manager
    Crawford County Coroner's Office
    Earl L. Deckard ......... coroner
    Mine Safety and Health Administration
    Thomas J. Pavlat ......... mine safety and health specialist
    Fred H. Tisdale ......... mine safety and health inspector
    Gene W. Upton ......... supervisory mine safety and health inspector
    Terence M. Taylor ......... senior civil engineer

    APPENDIX B

    Persons Interviewed

    Lawrence Gravel, Inc.
    Roger G. Hodge ......... front-end loader operator
    Charles F. Dorn ......... dredge operator
    James B. Cooper, Jr. ......... front-end loader operator

    Drawing of Accident

    Drawing of Accident

    Photo of Scene

    Photo of Scene