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
April 25, 2001
Portable Crushing Plant No. 5
Southway Construction Co., Inc.
Maybell, Moffat County, Colorado
ID No. 05-04110
Steve I. Pilling
Mine Safety and Health Inspector
Dale D. Teeters
Mine Safety and Health Inspector
John R. Turner
Mine Safety and Health Specialist
Dennis L. Ferlich
Chief, Mine Equipment Branch
Mine Safety and Health Administration
Rocky Mountain District
P.O. Box 25367
Denver, Co 80225-0367
Irvin T. Hooker, District Manager
Nester R. Tafoya, front-end loader operator, age 39, was fatally injured on April 25, 2001, when a suspended conveyor fell on him.
The accident occurred because suitable rigging equipment had not been provided and all persons were not clear of the suspended load.
Tafoya had a total of one year and 11 months mining experience all at this mine. He had received training in accordance with 30 CFR, Part 46.
Portable Crushing Plant No. 5, a sand and gravel operation, owned and operated by Southway Construction Co., Inc., was located three miles east of Maybell, Moffat County, Colorado. Principal operating officials were Henry I. Southway, president; Rocky I. Southway, vice-president of operations; Roy C. Burtraw, mine superintendent; and Albert A. DeHerrera, crusher foreman. The mine was normally operated one, 12-hour shift a day, seven days a week, by two crews rotating every four days. Total employment was eight persons.
Sand and gravel was mined from the pit by a bulldozer and front-end loaders. Pit material was transported to the primary crushing plant where it was crushed, sized and stockpiled. The finished product was sold primarily for use as road construction aggregate. The last regular inspection was completed on November 20, 2000.
DESCRIPTION OF ACCIDENT
On the day of the accident, Nester R. Tafoya (victim) reported for work at 7:00 a.m., his regular starting time. About 8:00 a.m., the primary jaw crushing plant arrived on-site and was set up by the crew. After lunch, several loads of material were run through the plant to check for correct alignment and operation. The crusher was then shutdown to change screens and to make repairs. Tafoya was assigned to clean the material from under the 3/4-inch stacker conveyor with a front-end loader. While cleaning, the left tooth on the loader bucket caught a leg support on the stacking conveyor and tipped the conveyor over.
Tafoya parked his loader and asked Mark Gallegos, loader operator, who was operating another front-end loader, to assist him in repositioning the stacker conveyor.
Gallegos retrieved two chains and attached one on each corner of the bucket. Gallegos positioned the loader over the fallen stacker conveyor as Tafoya hooked the right chain to the stacker conveyor and looped it over the right tooth of the bucket. The other chain was not used. Tafoya instructed Gallegos to raise the conveyor. After the conveyor was raised about eight to ten feet off the ground, Gallegos noticed that the support legs were damaged and moved his loader forward so that the stacker conveyor was clear of the support legs. Tafoya then walked under the suspended conveyor when the chain slipped loose causing the conveyor to fall on him.
Gallegos immediately backed the loader, dropped the bucket and lifted the conveyor. Tafoya rolled out from under it and remained on the ground. Gallegos checked his condition, then summoned Albert DeHerrera, crusher foreman, and Zach Villagomez, laborer, who were changing screens. DeHerrera called 911 to summon emergency assistance.
Emergency medical personnel responded within 10 minutes and Tafoya was transported to a local hospital where he died later that day. Death was attributed to crushing injuries to the upper body.
INVESTIGATION OF THE ACCIDENT
MSHA was notified at 7:30 p.m., on the day of the accident by a telephone call from Kris Degolyer, office manager, to Irvin T. Hooker, district manager. An investigation was started that day. MSHA's accident investigation team conducted a physical inspection of the accident site, interviewed a number of persons, and reviewed training records and work procedures being performed at the time of the accident. The investigation was conducted with the assistance of mine management and mine employees. Employees did not request nor have miners' representation during the investigation.
The Portable Crushing Plant No. 5 consisted of five crushers, including one jaw crusher, one impact crusher, and three cone crushers. Material was first fed into the jaw crusher and then transported by conveyors to the other four crushers where the material was crushed and screened to various sizes. A series of portable conveyors transported the aggregates to various piles where they were then loaded out for sale or transported by loaders to their respective stockpiles.
The conveyor involved in the accident was identified by the No. 29-9504. The manufacturer of the conveyor was unknown. The conveyor was approximately 57 feet, 8 inches long by 51 inches wide by 23 inches deep. The structure was supported by two legs approximately 100 inches long fabricated from 3 inch square steel. Each leg was stabilized by a 2-inch angle iron diagonal brace attached near the middle of the leg that ran upward to the conveyor frame. In addition, a 3-inch angle iron brace was bolted horizontal between the legs at this point. A 6-inch wide steel channel about 1-foot long was welded to the bottom of each leg. A 10 foot long 3-inch angle iron that extended approximately 2 feet beyond the width of the legs was tack welded to these two channels.
Examination of the conveyor and leg support structure showed the leg support structure had collapsed. Braces were bent, welds were broken, bolts were bent and angle iron was detached from the support legs.
The chain involved in the accident was approximately 18 feet long. It had 3/8-inch diameter links and a 3/8-inch clevis grab hook at each end. The links were stamped with "L7", identifying the chain as Grade 70 chain. The lifting chain had been fastened to each side of the conveyor frame in choker hitch fashion about 22 feet from the head pulley. The middle of the chain had been looped over the extreme right bucket tooth of the front-end loader. The lifting chain was inadequately fastened. The link connector pins and several of the chain links were nicked, worn, stretched, bent, and distorted, but the chain had not failed structurally.
Recognized industry standards recommend the use of Grade 80 chains for overhead lifting. These standards also list wear, nicks, cracks, breaks, gouges, stretch, and bends as causes for removal of overhead lifting chains from service.
A Caterpillar Model 988B front-end loader, s/n 50W04780, had been used to lift the conveyor. The loader was examined and no defects contributing to the accident were found. The loader bucket did not have an attachment point where the lifting chain could be securely fastened in a manner to prevent the possibility of it slipping loose.
Rigging and overhead lifting equipment, designed in accordance with recognized industry standards, was not available on the mine site at the time of the accident.
The root cause of the accident was the failure to provided suitable rigging equipment and to properly attach it to the load being hoisted.
Failure to ensure that persons stay clear of suspended loads also contributed to the accident.
Order No. 7943801 was issued on April 25, 2001, under the provisions of Section 103(k) of the Mine Act:
A fatal accident occurred at this operation on April 25, 2001, when a stacker conveyor frame being lifted with a front-end loader and chains fell about 8 to 10 feet striking a person on the ground, causing fatal injuries. This order is issued to ensure 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 for all actions to recover persons, equipment, and/or return affected areas of the mine to normal operations.This order was terminated on April 27, 2001. Conditions that contributed to the accident have been corrected and normal mining operations can resume.
Citation No. 7912571 was issued on May 1, 2001, under the provisions of Section 104(a) of the Mine Act for violation of 30 CFR 56.16009:
A fatal accident occurred at this operation on April 25, 2001, when an employee was struck by a suspended conveyor that fell. The employee was positioned under the suspended load when the rigging failed.This citation was terminated on May 1, 2001. The company established procedures requiring all persons to stay clear of suspended loads. All employees were trained in these proper procedures.
Citation No. 7912573 was issued on May 1, 2001, under the provisions of Section 104(a) of the Mine Act for violation of 30 CFR 56.16007(b):
A fatal accident occurred at this operation on April 25, 2001, when a suspended conveyor structure fell and struck an employee. The suspended conveyor was attached with rigging that was not suitable in that the 3/8-inch sling was undersize and improperly attached.This citation was terminated on June 11, 2001. The company established procedures requiring use of hitches and slings suitable for the material being hoisted. All employees were trained in these procedures.
. Related Fatal Alert Bulletin:
Persons Participating in the Investigation
Southway Construction Co., Inc.
Rocky I. Southway .......... Vice-President of OperationsState of Colorado, Division of Minerals and Geology
John C. Barton .......... Mine Inspector/TrainerMine Safety and Health Administration
Steve I. Pilling .......... Mine Safety and Health Inspector
Dale D. Teeters .......... Mine Safety and Health Inspector
John R. Turner .......... Mine Safety and Health Specialist
Dennis L. Ferlich .......... Chief, Mine Equipment Branch
APPENDIX BPersons Interviewed
Southway Construction Co., Inc.
Rocky I. Southway .......... Vice President of Operations
Roy C. Burtraw .......... Mine Superintendent
Albert A. DeHerrera .......... Crusher Foreman
Mark Gallegos .......... Front-End Loader Operator
Zach Villagomez .......... Laborer