DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
Report of Investigation
Surface Nonmetal Mine
(Sand and Gravel)
Fatal Powered Haulage
December 4, 2001
Cagi Portable Wash Plant
Columbia Ready-Mix, Inc.
Parker, Yakima County, Washington
ID No. 45-03388
Robert V. Montoya
Mine Safety and Health Inspector
Gerald A. Killion
Mine Safety and Health Inspector
John C. Kathmann
Mine Safety and Health Specialist
Mine Safety and Health Administration
2060 Peabody Road Suite 610
Vacaville, Ca. 95687
Lee D. Ratliff, District Manager
Juan Dominguez, laborer, age 52, was fatally injured on December 4, 2001 when he was engulfed by material in the wash plant primary feed hopper.
The accident occurred because hazards related to the task had not been properly evaluated. A means of access had not been provided to the top of the hopper. Mechanical devices or other effective means of handling materials were not installed on the hopper to aid in dislodging materials.
Dominguez had a total of 5 years experience all at this mine. He worked as the wash plant operator intermittently for 2 months. He had not received training in accordance with 30 CFR Part 46.
Cagi Portable Wash Plant, a surface sand and gravel operation, owned and operated by Columbia Ready-Mix, Incorporated, was located in Parker, Yakima County, Washington. The principal operating official was Leonard Sali, president. The plant was normally operated one 10-hour shift, 5 days per week. Total employment was 2 persons.
The material processed through the wash plant was Department of Transportation reject pit material hauled to the plant site and stock piled. The plant utilized a wet process operation to separate the oversized rock, clay and debris. Multiple screens sized and separated the aggregates. Two spiral washers removed the clay as it was being conveyed from the finished products. Washed sand and aggregates were recovered. The finished products were used in the batch concrete and asphalt plants and sold for use as construction aggregate.
The last regular inspection of the operation was conducted on September 6, 2001. Another inspection was conducted in conjunction with the fatal accident investigation.
On the day of the accident, Juan Dominguez reported for work at 7:00 a.m., his normal starting time. He was assigned to operate the wash plant which had not been operated for a few days prior to the accident.
Geraldo Maravilla, mechanic, started the wash plant and, once it was operable, he turned it over to Dominguez. Dominguez had been observed by employees pounding on the sides of the hopper with a bar and hammer and working from the elevated bucket of the front end loader attempting to free the flow of materials inside the primary feed hopper.
At approximately 3:30 p.m.. Gilbert Phillips, loader operator, noticed that there was no materials flowing from the product conveyor belts. He looked at the primary feed hopper and saw the parked front-end loader that Dominguez had been operating with the bucket elevated above the bin, but he did not see Dominguez. He drove his loader to the hopper and noticed the victim's feet sticking out of the bottom of the discharge chute. He shut the wash plant down and summoned help.
Several employees from the concrete batch plant and mechanic shop arrived at the accident scene and began digging the victim out. Paramedics arrived on the scene a short time later and the victim was extricated through the bottom discharge chute of the hopper. He was pronounced dead at the scene. Death was attributed to asphyxia.
MSHA was notified of the accident at 5:30 p.m., on December 4, 2001 by a telephone call from the Yakima County Sheriffs Department to Stephen Cain, field office supervisor. An investigation was started the next day. An order was issued pursuant to section 103k of the mine act to ensure the safety of miners. MSHA's investigation team traveled 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, his co-workers and training records. The miners did not request nor have representation during the investigation.
The accident occurred at the wash plant primary feed hopper. The plant had operated at this location for about two years. The primary materials process flow was re-configured about two months prior to the accident. An additional scalping screen had been installed in the process to remove oversized materials before it transferred to the elevated secondary screen and spiral washers, via an inclined conveyor belt. The primary feed hopper was relocated to a different position to allow for the screen.
The primary feed hopper was locally fabricated and was originally intended to be used for asphalt. It was rectangular in shape and measured approximately 13 feet in length, 9 feet in width, and was 8 feet in depth. It transitioned to a smaller rectangular opening at its bottom which measured approximately 6 feet in length and 18 inches in width. The height of the hopper measured about 9 feet on the ramp side and 13 feet on the ground level side.
There was an opening on the bottom discharge end of the bin that measured approximately 15 inches by 16 inches. A metal cover plate that measured approximately 9 inches by 15 inches was secured with 2 mounting bolts on the bottom of the hopper of the materials discharge side. The plate had been used previously to regulate the amount of materials that flowed out of the hopper onto the discharge conveyor belt. With the plate in place there was an opening of approximately 6 inches by 15 inches between the bottom of the hopper and conveyor belt. The plate was removed to extricate the victim during the rescue/recovery effort.
The bottom of the bin was also equipped with a metal bracket that held � inch wide by 6 inch rectangular rubber belting that measured approximately 6 feet in length. This served as an adjustable skirt board. The belting aided in the prevention of spillage between the bottom of the hopper and the discharge conveyor belt.
Four I-beams installed vertically at the corners to about mid-point of the bin supported the structure. A concrete footing existed below the structure to support its weight. Marks which indicated there had been pounding with a hammer and bar were observed on all four sides of the bin. This indicated that the wash plant operators had experienced problems with the feed materials adhering to the sides of the bin.
The feed discharge conveyor belt was located directly beneath the bin. The equipment was positioned in a parallel fashion. The conveyor belt measured approximately 12 feet in length and was approximately 27 inches wide. It appeared to be positioned fairly level. The conveyor belt drive motor was manufactured by Baldor and was rated at 7.5 horsepower. It was designed to turn at 1725 revolutions per minute. The drive motor was secured on a shaft mounted speed reducer. Two sets of speed/gear reduction sheaves existed between the drive motor and rubber lagged head pulley.
The Baldor drive motor was powered by a Reliance Electric 460 volts three phase variable frequency drive, model number SP500. The drive unit was mounted in an electrical enclosure that was secured to the structural steel support for the second inclined conveyor. The enclosure was equipped with a panel mounted safety disconnect switch which actuated a three knife blade assembly. This mechanically interrupted the line power from the top of the primary in-line fusing, when actuated. The safety disconnect switch was positioned about 40 feet from the drive motor. The variable frequency drive had the capability of being locked out at the panel actuating handle. There were no obstructions between the drive motor and its source of power. The main service disconnect switch that powered the entire wash plant had been locked out and tagged prior to the accident investigation by the mine operator.
The variable frequency drive gave the wash plant operator the ability to adjust the revolutions per minute of the feed conveyor belt. This in turn set the rate of primary feed materials that went through the wash plant. The feed conveyor belt was energized and tested during the accident investigation. The conveyor belt was set to turn at approximately 11 revolutions per minute.
The wash plant primary feed hopper was fed with a John Deere 644E front-end wheel loader. An elevated ramp equipped with berms was positioned adjacent to the bin. This aided the loaders capability of the bucket to be well extended above the hopper as it was being filled.
The materials that were being run through the wash plant at the time of the accident had been stockpiled next to the ramp. The mine operator classified it as department of transportation rejects. It had been hauled to this location from another pit. The materials appeared to be mostly fine sand, clay, and various sizes of aggregate. Vegetation roots were also observed in the stockpile. Roots and oversized materials were present at the first scalping screens reject pile. The straight-hoe scraping tool the victim had been using was found in this area. It had gone through the feed hopper, up the first inclined conveyor belt, and was found at the base of the first screen. The primary materials contained moisture; that made it difficult to flow through the bin without adhering to the sides.
The victim had used the elevated loader bucket and tire to access the top of the hopper. It could not be determined during the accident investigation if the miner purposely entered the bin, or fell in while attempting to dislodge the materials.
The feed conveyor belt beneath the hopper had not been de-energized or locked out, which hindered his escape once he entered the bin.
The following root causes were identified:
Failure to establish procedures that required the discharge conveyor belt to be locked out, prior to persons manually removing materials inside the plant hopper.
Failure to equip the hopper with mechanical devices or other effective means of handling materials adhering to the sides of the hopper.
Failure to provide ladders, platforms, or staging at the plant hopper, for inspection or maintenance purposes.
Order No. 7999361 was issued on December 5, 2001 under the provisions of section 103k of the Mine Act:
A fatal accident occurred at this operation on December 4, 2001, an employee was in a hopper when materials engulfed him. This order is issued to ensure the safety of persons at this operation and prohibits any work in the affected area until MSHA determines that it is safe to resume normal operations as determined by an authorized representative of the secretary of labor. The mine operator shall obtain approval from an authorized representative for all actions to recover and/or restore operations in the affected area.
This order was terminated on December, 07, 2001. Conditions that contributed to the accident have been corrected and normal mining operations can resume.
Citation No. 6335060 was issued on December 4, 2001 under the provisions of 104d1 of the Mine Act: Part/Section of Title 30 CFR 56.16002.
A miner was fatally injured on December 4, 2001 when he was engulfed with materials that he was attempting to dislodge in the wash plant primary feed hopper. Walkways, platforms, staging, or ladders had not been provided. Mechanical devices or other effective means of handling materials were not installed.
Failure to provide a means of access to the top of the hopper, or mechanical devices or other effective means of handling materials, demonstrated a serious lack of reasonable care constituting more than ordinary negligence. This is an unwarrantable failure to comply with a mandatory standard.
This citation was terminated on February 08, 2002. The company established written procedures when working in and around bins and hoppers. Training of employees in safe work procedures was conducted, to include lock out/tag out, safe access and usage of safety belts and tag lines with a second person to tend the lifeline.
Related Fatal Alert Bulletin:
Persons Participating in the Investigation
Columbia Ready-Mix, Incorporated
Leonard Sali ............... presidentMine Safety and Health Administration
Robert V. Montoya ............... mine safety and health inspector
Gerald A. Killion ............... mine safety and health inspector
John C. Kathmann ............... mine safety and health specialist
Columbia Ready-Mix, Incorporated
Steve Sali ............... vice-president, columbia ready-mix and asphaltAmerican Medical Response
Gilbert Phillips ............... asphalt plant operator, loader operator
Nancy Orris ............... shop clerk, payroll
Deleta D. Sali ............... payroll, office manager
Geraldo Maravilla (Rico) ............... fabricator and mechanic
Leonard Sali ............... president Columbia ready-mix, inc.
Barbara Laurvick ............... truck dispatcher and payroll
Jens E. Quick ............... portable crusher operator
Judah Sali ............... dispatcher, network administrator, training
Chad Carlson ............... salesman and dispatcher
Jesse Sifuentes ............... mechanic
Bill Lynch ............... truck driver
Chad Rowland ............... truck driver
Larry Gilkey ............... truck driver
Everett Mullams ............... truck driver
Kevin Odman ............... truck driver
Larry Wise ............... truck driver
Manuel Gonzales ............... laborer
Matt Hareth ............... paramedicFormer employees of Columbia ready-Mix, Inc.
Travis Jacob ............... paramedic
Fred Fischer ............... former crusher operator