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
(Sand and Gravel)


Fatal Powered Haulage Accident


Portable Wash Plant #1 (I.D. No. 13-02149)
Rohlin Construction Company, Incorporated
Milford, Dickinson County, Iowa


May 16, 1996


By


Arthur J. Toscano
Mine Safety and Health Inspector


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


James M. Salois
District Manager

GENERAL INFORMATION

Eric J. Gibson, front-end loader operator, age 41, was fatally injured at about 3:50 p.m. on May 16, 1996, when he was crushed between a conveyor drive brace and the conveyor belt. He had been standing on the conveyor shoveling spillage when the conveyor was started. Gibson had worked for this operation for about four years and ten months and had operated a front-end loader for about three years. He had received training in accordance with 30 CFR Part 48. Annual refresher training had been completed on March 15, 1996.

MSHA was notified at 5:40 p.m. the day of the accident by a telephone call from Randall Zeigler, safety director. An investigation was started the following day.

Portable Wash Plant #1, owned and operated by Rohlin Construction Co., Inc., was located near Milford, Dickinson County, Iowa. The principal operating official was James Zeigler, president. The plant was normally operated one, 10 to 11-hour shift a day, five days a week. A total of four persons was employed.

Pit material was loaded into a conveyor hopper with a front-end loader then was conveyed to the wash plant where it was washed, sized into various products, and stockpiled for sale to local customers.

The last regular inspection of this operation was completed on October 19, 1995. Another regular inspection was initiated on May 29, 1996.

PHYSICAL FACTORS INVOLVED

The accident occurred at the No. 3 conveyor belt to the plant from the pit. The belt was one of four in series that conveyed material from the North Pit to the wash plant, a distance of about one-quarter mile. The No. 3 conveyor was 220 feet long, 30 inches wide, and was driven by a 20-HP electric motor through a 1.52- to-1 ratio, gear-type speed reducer. The conveyor was 150 feet long when originally installed, however, it had been extended to approximately 220 feet and the motor size was increased from 10-HP to 20-HP by mine personnel. The drive motor assembly mounted above the head pulley was stabilized by cross-braces constructed of angle iron that extended to each side of the conveyor frame. Clearance between the conveyor belt and cross-braces was 12 inches at the center and 6 inches at the sides. The conveyor traveled at about 320 feet per minute and was about 54 inches above the ground at the tail pulley, rising to about 9-1/2 feet at the head pulley.

The conveyors were numbered 1 through 4, with No. 4 conveyor receiving material at the pit.

An emergency stop switch to de-energize the No. 3 conveyor was mounted on the east side of the No. 4 conveyor near the head pulley. It was located about 12 feet north of the No. 3 conveyor tail pulley where the accident occurred. The coworker, who was shoveling spillage with the victim, had been recently hired and was not aware of the location of the stop switch. The switch was tested during this investigation and found to be functional.

An elevated roadway crossed over the No. 2 conveyor and blocked visibility of the No. 3 and No. 4 conveyors from the start/stop control panel at the generator unit, about 500 feet away. An audible pre-startup signal had not been installed and a visual warning system had not been formally established at the time of the accident.

A diesel-powered generator provided power to the mine electrical equipment. It was located about 500 feet south of the accident site. Reportedly, the generator was shut down and the access door locked by the foreman or an authorized person to protect against inadvertent starting of equipment during repairs or maintenance work.

DESCRIPTION OF ACCIDENT

On the day of the accident, Eric Gibson (victim), reported for work at 7:00 a.m., his normal starting time. Work activities progressed routinely until about 3:30 p.m. when the No. 3 conveyor stalled. The No. 4 conveyor continued to operate, causing a spill at the No. 3 conveyor tail pulley. Donald Sidles, foreman, drove to the generator and turned off the power, then returned to the No. 3 conveyor drive motor to investigate the problem. Mark Higgins, truck driver, noticed the stoppage of finished stone at the wash plant and walked to the No. 3 conveyor where Sidles was working. Higgins helped Sidles remove the cover plate for the drive motor for the v-belt guard. Sidles commented that the motor was quite hot but the gear box and motor were turning freely. He told Higgins that the spillage would have to be shoveled from underneath the tail pulley before restarting the conveyor. As Higgins walked away, Gibson arrived with his loader. Higgins heard Gibson and Sidles talking but could not distinguish the words. Higgins walked to the tail pulley where he was joined by Gibson. Higgins began to shovel on the west side of the conveyor tail pulley while Gibson shoveled on the east side.

Sidles stated he told Gibson that after he finished installing the guard cover plate he was going to the generator to check the fuses and he would try to start the conveyor so they should stay away from the conveyor. Sidles also stated he visually observed both men standing safely away from the conveyor when he left to start the generator.

Higgins and Gibson continued to shovel spillage from underneath the tail section. After a few minutes, Gibson told Higgins that it looked good underneath but there appeared to be a hang-up in the No. 4 discharge chute. Gibson then climbed onto the No. 3 conveyor and began to clear the spillage at the No. 4 chute. Suddenly, the No. 3 conveyor started and Gibson fell on the conveyor, which rapidly carried him towards the head pulley. Gibson yelled for Higgins to help him get off the conveyor. Higgins ran alongside the conveyor trying to catch up to him. When Gibson reached the head pulley he braced his feet against the motor mount cross-braces, trying to avoid becoming wedged between them and the conveyor.

Unaware of the emergency stop switch, Higgins could not shut off the conveyor. He then ran toward the generator yelling for Sidles to shut off the power. Sidles heard Higgins yelling and shut the power off. They returned to assist Gibson and, seeing that he was seriously injured, summoned emergency help.

Employees from the mine and the adjacent asphalt plant removed the guard from the drive pulleys and manually rotated them in reverse to remove Gibson from between the conveyor belt and the braces. First aid was administered until emergency personnel arrived a short time later. Gibson was transported by ambulance to a local hospital where he was pronounced dead.

CONCLUSIONS

This accident was caused by failure to ensure that persons were clear of the conveyor before it was started. Failure to indoctrinate new employees in the location and function of emergency stop controls contributed to the severity of the accident.

VIOLATIONS

Citation No. 4419634

Issued on May 22, 1996, under the provisions of Section 104(a) of the Mine Act for violation of 30 CFR Part 56.14105:

A miner was fatally injured when the No. 3 conveyor on which he was positioned was started. The victim was carried along the belt into the head pulley assembly where he received fatal injuries at about 1550 hours on May 16, 1996. After an excessive spillage of material was removed from the No. 3 conveyor tail pulley area, defective fuses in the electrical system were discovered and replaced. Although the diesel-driven generator which provided power had been shut off, no steps were taken to prevent equipment motion or activation of the conveyor while two persons were still working to remove the spillage.

Citation No. 4419635

Issued on May 22, 1996, under the provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR Part 56.14201b:

An employee was fatally injured on May 16, 1996 when he was crushed between the drive motor support braces and the belt on the No. 3 conveyor. Donald Sidles, foreman, stated he had observed two employees working near the tail pulley of the conveyor. Even though Sidles could not see these two employees from the start-up switch, he started the conveyor. Failure to provide an audible start-up alarm or to establish a visible signal to warn employees that the conveyor will be started show aggravated conduct. This violation is an unwarrantable failure.

[FAB96M21]