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Southeastern District
Metal and Nonmetal Mine Safety and Health

Accident Investigation Report
Surface Nonmetal Mine

Fatal Hand Tools Accident

Benton County Quarry
Thompson Machinery Commerce Corporation
Vulcan Materials Company
Holladay, Benton County, Tennessee
Mine I.D. 40-00098-DD3

April 21, 1997


William L. Wilkie
Supervisory Mine Inspector


Terry G. Lingenfelter
Mine Safety and Health Inspector(Electrical)

Originating Office
Mine Safety and Health Administration
135 Gemini Circle, Suite 212
Birmingham, Alabama 35209

Martin Rosta
District Manager


Scott E. Mayer, contractor mechanic, age 45, was fatally injured at about 10:40 a.m. on April 21, 1997, when he was crushed between the bucket lifting arms and the frame of a Caterpillar 990 front-end loader. The victim had a total of 12-1/2 years experience as a heavy equipment mechanic with this contractor company. He had not received training in accordance with 30 CFR, Part 48.

William Huffman, manager, safety and health, Midsouth Division, Vulcan Materials Company, notified the MSHA District office in Birmingham, Alabama, of the accident at 11:00 a.m. on April 21, 1997. An investigation was started the same day.

The Benton County Quarry, a crushed limestone operation, owned and operated by Vulcan Materials Company, was located in Holladay, Benton County, Tennessee. The mine normally operated one 10-hour shift per day, five days a week and employed 25 persons. The principal operating official was E. W. Wayne Hollis, superintendent.

Limestone was mined by conventional multiple-bench method. The material was drilled and blasted, then loaded by front-end-loaders into trucks and hauled to the primary crusher located in the quarry. It was transported by conveyor to the main plant where it was further crushed, sized and stockpiled and sold for use in the construction industry and as agricultural lime.

The victim was employed by Thompson Machinery Commerce Corporation, an independent contractor located in Camden, Benton County, Tennessee. Thompson Machinery Commerce Corporation was contracted by Vulcan Materials Company to service and repair heavy equipment on the mine site. The principal operating official was James B. Ezzell, executive vice president/CEO.

The last regular inspection of this operation was conducted January 6-8, 1997.


The front-end loader involved in the accident was a diesel- powered, 1995 Caterpillar 990 Series II wheel loader, equipped with a 12 yard bucket. The hydraulic systems consisted of two separate circuits: one for the tilt, lift and brakes; the other for steering and the engine cooling fan. The systems functioned independently.

The bucket lifting mechanism consisted of two hydraulic cylinders and two lifting arms. The lifting arms were approximately four feet apart and connected with a cross brace. The bucket tilt mechanism consisted of a hydraulic cylinder and a Z-bar linkage. The valve assembly for the bucket tilt and lifting arms was located on the center front of the loader, below the lifting arm pivots. The lifting arms needed to be raised to gain access to the valve assembly from ground level.


Scott E. Mayer, victim, reported to the Benton County Quarry on May 21, 1997, at approximately 9:00 a.m., after receiving a call that the 990 front-end loader had trouble with the hydraulic system. Mike Conrad, front-end loader operator, told Mayer that the bucket tilt and the bucket lift were sluggish. After Mayer took hydraulic pressure readings Conrad turned the loader off and got out of the machine. Mayer then got into the loader and positioned the loader bucket so that the teeth extended into the ground. The bucket and lifting arms were held in place by constant hydraulic pressure.

After positioning the loader, Mayer went under the equipment and positioned himself between the lift arms and the machine frame. He removed the access door covering the main valve unit and then went to get a ladder.

Returning to the machine, Mayer resumed his previous position between the frame and the lift arms, and used the ladder to gain access to the main valve assembly. He partially pulled the tilt cylinder valve spool, which released the hydraulic pressure to the bucket. Mayer then pulled the lift cylinder valve spool which released the hydraulic pressure to the lifting assembly, causing the bucket to tilt toward the machine and the lifting arms to fall. The cross brace on the lifting arms crushed Mayer between the lifting assembly and the loader.

Conrad was standing on the right hand side with his back to the loader when he heard the lifting assembly fall. He yelled for help and ran to the left side of the loader where he found Mayer pinned under the bucket arm cross brace.

Several employees rushed to the scene of the accident and a call was placed for emergency assistance. Paramedics and the coroner arrived at the site and company employees used a crane to lift the bucket assembly. After blocking the bucket, Mayer was extricated and pronounced dead at the scene. He died as a result of crushing injuries.


The direct cause of the accident was the failure to block the bucket assembly against hazardous movement.


Vulcan Materials Company

Order No. 4521612
Issued on April 21, 1997, under the provisions of Section 103(k) of the mine act:

On April 21, 1997, a contractor mechanic was fatally injured at this operation when the boom and pivot bearing of a 990 loader bucket fell on him. This order prohibits the use of this loader pending an investigation by MSHA.

On April 22, 1997, this order was terminated. MSHA has concluded its investigation.

Thompson Machinery Commerce Corporation

Citation No. 4076527
Issued on May 2, 1997, under the provisions of Section 104(a) of the Mine Act for violation of Standard 56.14105:

A fatal accident occurred at this operation on April 21, 1997, at approximately 10:40 a.m. when a mechanic was crushed between the bucket assembly and the frame of the loader. The Caterpillar 990 front-end loader, SN 7HK00143 bucket assembly was not blocked from accidental movement when working on the hydraulic system.

This citation was terminated on May 2, 1997. A post accident safety training plan was made and training was given to personnel.

/s/ W. L. Wilkie
Supervisory Mine Inspector

/s/ T. G. Lingenfelter
Mine Safety and Health Inspector(Electrical)

Approved by: Martin Rosta, District Manager

Related Fatal Alert Bulletin:
Fatal Alert Bulletin Icon [FAB97M23]