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 Powered Haulage Accident
July 27, 1999
Crusher No. 1
Huachuca Concrete, Incorporated
Huachuca City, Cochise County, Arizona
ID No. 02-02451
Supervisory Mine Safety and Health Inspector
David D. Estrada
Mine Safety and Health Inspector
Dennis L. Ferlich
Mine Safety and Health Administration
Rocky Mountain District
P.O. Box 25367, DFC, Denver, CO 80225-0367
Claude N. Narramore, District Manager
Frank A. Mejia, wash plant operator, age 36, was fatally injured at about 3:15 p.m., on July 27, 1999, while he was attempting to dislodge a hang-up in a feed hopper and was engulfed by material. The feeder belt was running and no safeguards were in place to prevent dumping material into the hopper while he was inside.
Mejia had a total of nine years mining experience, one week and two days as a wash plant operator at this operation. He had not received training in accordance with 30 CFR, Part 48.
Crusher No. 1, a sand and gravel mine, owned and operated by Huachuca Concrete, Incorporated, was located at Huachuca City, Cochise County, Arizona. The principal operating official was Michael Berry, general manager. The mine was normally operated one, 8-hour shift a day, five days a week. Total employment was eight persons.
Sand and gravel was extracted from a single bench in the pit using front-end loaders to excavate and transport the material to the plant where it was crushed, sized and stockpiled. The finished product was sold primarily for use as concrete aggregate.
The last regular inspection of this operation was completed on April 15, 1999. Another inspection was conducted at the conclusion of this investigation.
DESCRIPTION OF ACCIDENT
On the day of the accident, Frank Mejia (victim) reported for work at 5:30 a.m., his normal starting time. He performed clean-up work throughout the day without unusual incident. At about 2:45 p.m., Mejia attempted to dislodge material hung-up inside the feed hopper at the wash plant. Apparently, he climbed inside the hopper in order to free the hang-up using a piece of metal conduit and a bucket-load of material was dropped into the hopper on top of him.
Brian Champagne, loader operator, noticed the conduit protruding from the hopper and could see Mejia's legs and feet. Michael Berry, general manager, arrived at this time and Champagne informed him that Mejia was trapped inside the hopper.
Local authorities and emergency medical personnel were summoned and arrived at the mine a short time later. Mejia was pronounced dead at the scene. Death was attributed to asphyxiation.
INVESTIGATION OF THE ACCIDENT
MSHA was notified at 5:07 p.m., on the day of the accident by a telephone call from Kevin Thompson, operations manager for the mining company, to the MSHA headquarters' code-a-phone message line. An investigation was started the next day. MSHA's accident investigation team went to the mine and made a physical inspection of the accident site, interviewed a number of persons, and reviewed documents relative to the job being performed by the victim and his training records. An order was issued pursuant to Section 103(k) of the Mine Act to ensure the safety of miners. The miners did not request, nor have, representative during the investigation.
The accident occurred at the wash plant. Equipment operating at the time consisted of a hopper and feeder, a conveyor belt leading from the feeder to the vibrating screen section, a vibrating section with a triple-deck screen, and four conveyor belts that carried the separate material to stockpiles.
Material flowed from the hopper onto a 36-inch-wide belt that carried it onto a 30-inch-wide belt feeding the vibrator section. The material passed through the course material washer then into the triple-deck vibrating screen where it was separated into reject material, concrete rock, chips, and sand. The materials were then transported to their respective stockpiles by conveyor belts.
The hopper consisted of a belly-dump section from a truck, mounted on four, 8-inch-diameter posts. It had been installed at this operation approximately three years ago. Diagonal bracing made of 2-inch by 2-inch by 3/16-inch angle iron was placed between the posts for additional support. The chute had been modified by adding plates to size the chute outlet to the feeder. Two plates were welded on each end of the top sections of the hopper to reduce material spillage while being filled by the front-end loader. The top opening of the hopper was rectangular, approximately 10 feet long and 7 feet wide. The hopper was 7 feet deep as measured from top edge to the feeder belt. There were no ladders or walkways for access to or around the hopper.
The feeder conveyor consisted of a motor-driven belt approximately 36 inches wide and 10 feet long. Metal guarding was installed around the edges of the feeder belt, roller, and motor assembly. Material was conveyed from the feeder conveyor to the vibrator section by a motor-driven belt approximately 30 inches wide and 100 feet long. Metal guarding had been installed around the edges of the belt and rollers.
A VIBCO, Model BVS 570, vibrator had been installed on the outside of the hopper chute. It was tested and found to be functional. A review of the specifications showed that the Model BVS 570 was the proper vibrator selection for this application; however, it was not effective when material was wet or sticky. The vibrator was a pneumatic turbine vibrator supplied by a 1-inch diameter inlet air line. The air outlet, also 1-inch diameter, was open directly to the atmosphere. Marks on the outside of the hopper feeder indicated that the chute had been hit repeatedly with a pipe to dislodge wet or sticky material.
Crushed material was normally transported from the crusher to the wash plant hopper, an estimated distance of 250 yards, using a Case, Model 821, loader with a 3-cubic-yard bucket. The hopper volume was 9 to 10 cubic yards. The feeder was set to empty a hopper-full of material in 8 to 10 minutes, which required continuous feeding of the hopper. The average loader cycle time between the crusher and the wash plant was approximately three minutes.
No safety belt or lines were found, nor was there a second person in the area to attend a lifeline. Reportedly, all the wash plant equipment, except the feeder belt were operating when the victim was found. The circuit breaker for the feeder belt motor had reportedly opened and stopped the belt when the victim's body became lodged in the hopper/feeder outlet.
The victim was found lying on his back at the bottom of the hopper chute, covered with an estimated 3 tons of material. This was equivalent to approximately one bucket-load from the front-end loader being used on the day of the accident.
The cause of the accident was failure to lock-out the feed belt before entering the hopper and failure to use a safety belt and line with another person in attendance. Failure to provide safeguards to prevent dumping material into the hopper while the victim was inside was a contributing factor.
Order No. 7934213 was issued on July 27, 1999, under the provisions of Section 103(k) of the Mine Act:
A fatal accident occurred at this operation on July 27, 1999, when a miner was engulfed by loose material while attempting to free a hang-up inside the wash plant feed hopper. This order is issued to assure the safety of persons at this operation until the mine or affected areas can be returned to normal operations as determined by an authorized representative of the Secretary. The mine operator shall obtain approval from an authorized representative of the Secretary for all actions to recover persons, equipment, and/or return affected areas of the mine to normal operations.This order was terminated on July 30, 1999. Conditions that contributed to the accident have been corrected and normal mining operations can resume.
Citation No. 7917291 was issued on August 18, 1999, under the provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR 56.16002(c):
A fatal accident occurred at this mine on July 27, 1999, when a plant operator entered the wash plant feed hopper to dislodge a hang-up and was engulfed by material. The supply and discharge of material had not ceased. Equipment was not locked out; ladders or staging were not provided; a safety belt and lifeline were not being used; and a second person was not in attendance. Failure to provide these safeguards and to assure that all employees utilized them is a serious lack of reasonable care which constitutes more than ordinary negligence and is an unwarrantable failure to comply with a mandatory safety standard.This citation was terminated on August 18, 1999, after all employees had received training on the hazards associated with entering hoppers. The equipment will be locked out, safety belts and lines will be used and a second person will be in attendance. The mine operator has committed to strict enforcement of these procedures.
Order No. 7917292 was issued August 18, 1999, under the provisions of Section 104(d)(1) of the Mine Act for violation of 30 CFR 56.11001:
A fatal accident occurred at this mine on July 27, 1999, when a plant operator entered the plant feed hopper to dislodge a hang-up and was engulfed by material. A safe means of access was not provided for persons to free hang-ups in the hopper. Failure to provide safe access is a serious lack of reasonable care which constitutes more than ordinary negligence and is an unwarrantable failure to comply with a mandatory safety standard.This order was terminated on August 18, 1999, after the mine operator installed a work platform and ladder for access to the hopper.
Related Fatal Alert Bulletin:
Persons Participating in the Investigation
Huachuca Concrete, Incorporated
Michael Berry, general managerMine Safety and Health Inspector
Kevin A. Thompson, operations manager
Tyrone Goodspeed, supervisory mine safety and health inspectorAPPENDIX B
David D. Estrada, mine safety and health inspector
Dennis L. Ferlich, mechanical engineer
Huachuca Concrete, Incorporated
Michael Berry, general manager
Kevin A. Thompson, operations manager
Brian K. Champagne, loader operator