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DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
Metal and Nonmetal Mine Safety and Health
REPORT OF INVESTIGATION
Surface Nonmetal Mine
Fatal Handling Material Accident
October 1, 2007
Twin State Sand & Gravel Co., Inc.
Twin State Sand & Gravel Company, Inc.
West Lebanon, Grafton County, New Hampshire
Mine I.D. No. 27-00070
Anthony M. Fortino
Mine Safety and Health Inspector
James R. Logan
Mine Safety and Health Inspector
Robert S. Setren
Mine Safety and Health Administration
Thorn Hill Industrial Park
547 Keystone Drive, Suite 400
Warrendale, Pennsylvania 15086-7573
James R. Petrie, District Manager
Charles P. Hughes, front-end loader operator, age 57, was critically injured on October 1, 2007, when a return roller that was being installed on an overhead conveyor fell and struck him. Hughes was hospitalized and died on October 4, 2007.
The accident occurred because procedures were not established to conduct a risk assessment of the maintenance task being performed. All hazards associated with the task were not identified and appropriate controls were not in place to ensure that persons working in the area were protected from the hazards of falling objects. The travel way underneath the overhead conveyor structure was not barricaded or posted with warning signs to prevent persons from traveling through the area.
Twin State Sand & Gravel Co., Inc., an independent crushing and screening mill, owned and operated by Twin State Sand & Gravel Company, Inc., was located in West Lebanon, Grafton County, New Hampshire. The principal operating official was Warren B. Ames, owner. The plant operated one 9-hour shift per day, 5 � days per week. Total employment was 12 employees.
Limestone was extracted from a quarry located several miles away and transported by truck to the plant. A front-end loader was used to feed the raw material into the crushing plant where it was broken and screened into various sizes. Finished products were sold for use as construction aggregate.
The last regular inspection was completed on September 6, 2007.
DESCRIPTION OF ACCIDENT
On the day of the accident, Charles P. Hughes (victim) reported for work at 6:30 a.m., his normal starting time. Mark Martin, plant foreman, directed Hughes; Craig Richardson, truck driver/ laborer; William Becker, crusher operator; and Dale Balleau, truck driver/laborer, to change out a screen before starting the plant. When the task was completed, the plant was started and Martin noticed the snub roller assembly on the 30-inch wash plant feed belt conveyor was broken.
Hughes, Becker, and Balleau started to disassemble the snub roller assembly. At the same time, Martin and Richardson installed a return roller about 12 feet away from the snub roller and about 40 feet above ground.
At about 7:40 a.m., Hughes went to the crusher to get a pry bar to remove the snub roller. Martin and Richardson were attempting to install one end of the return roller in a bracket and just as Hughes walked under the conveyor, the return roller slipped out of their hands and fell striking him.
Martin and Richardson saw the return roller strike Hughes and immediately called James Benjamin, mine superintendent, to report the accident. Benjamin called for emergency medical assistance and traveled to the scene. Emergency medical service (EMS) personnel arrived and transported Hughes to a local hospital where he died on October 4, 2007. The cause of death was attributed to blunt force trauma.
INVESTIGATION OF THE ACCIDENT
The Mine Safety and Health Administration (MSHA) was notified of the accident at 7:47 a.m. on October 1, 2007, by a telephone call from Duane Moody, safety director, to the National Call Center. Donald J. Foster, assistant district manager, was contacted and an investigation was started the same day. An order was issued under the provisions of Section 103(k) of the Mine Act to ensure the safety of miners.
MSHA's accident investigation team traveled to the mine, made a physical inspection of the accident scene, interviewed employees and reviewed documents and work procedures relevant to the accident. MSHA conducted the investigation with the assistance of mine management and employees.
Location of Accident
The accident occurred at ground level in the area beneath the 30-inch wash plant feed belt conveyor which fed the wash plant. On the day of the accident, the weather was cloudy with an average temperature of 64 degrees Fahrenheit and no precipitation. Weather was not considered to be a factor in the accident.
The 30-inch wash plant feed conveyor involved in the accident transferred material from the secondary crusher to the top of the wash tower. The conveyor frame consisted of steel lattice construction with a 30-inch wide conveyor belt. A 24- inch wide walkway constructed of metal grating was installed along one side the entire length of the conveyor. Toe boards were installed on both sides of the walkway and a 42-inch high handrail with a mid rail was installed on the outboard side. The area where the miners were installing the return roller measured 5.5 inches from the top of the toe board on the walkway to the bottom of the conveyor. The return roller being installed was located on the underside of the conveyor structure about 12 feet from the head pulley. The snub pulley assembly was located behind the head pulley and was used to maintain tension on the conveyor belt.
The return roller was a "C" class return roller manufactured by Superior Industries. It was 5 inches in diameter, 33 inches long, and weighed 25.5 pounds.
The method being used to install the return roller required a person to lay on the cat-walk parallel to the conveyor belt, guide the roller under the belt, and lift the roller and belt while attempting to insert the roller ends into the slotted brackets. Clearance to complete this installation was limited to approximately 5 inches between the bracket slot and a support angle (Appendix C). The travel way underneath the long belt was not barricaded or posted with warning signs during the repair. The victim was wearing a hardhat.
ROOT CAUSE ANALYSIS
A root cause analysis was conducted and the following root cause was identified:
Root Cause: Management failed to perform a risk assessment of the maintenance task being performed. All hazards associated with the task of changing rollers were not removed to ensure that persons could safely perform the task. Management failed to barricade or post warning signs in the work area to prevent persons from walking or traveling under the belt conveyor.
Corrective Action: Maintenance policies and procedures should be established to include conducting a risk assessment before performing work. Hazards should be identified and safe work procedures implemented to protect persons. The procedures should be discussed with all persons assigned to maintenance tasks.
The accident occurred because mine management failed to perform a risk assessment of the maintenance task being performed. All hazards associated with the task were not identified and controls were not put in place to protect persons working in the area from the hazards of falling objects. The travel way underneath the overhead conveyor structure was not barricaded or posted with warning signs to prevent persons from traveling through the area.
Order No. 6049470 was issued on October 1, 2007, under the provisions of Section 103(k) of the Mine Act:
A serious accident occurred at this location on October 1, 2007, when one miner was struck by a falling return roller while walking under the wash deck transfer belt. The order is issued to assure the safety of all persons at this operation. It prohibits all activity at the primary crusher, secondary crusher, wash plant, load out bins and all associated walkways and conveyor belts. The mine operator shall obtain prior approval from an authorized representative for all actions to recover and/or restore operations to the affected area.This order was terminated on October 3, 2007, after conditions that contributed to the accident had been corrected.
Citation No. 6046000 was issued on October 22, 2007, under the provisions of Section 104(a) of the Mine Act for violation of 30 CFR 56.20011:
On October 4, 2007, a front-end loader operator died as a result of injuries he received at this operation on October 1, 2007. The victim was walking under the belt conveyor that was in the process of being repaired when he was struck in the head by a return roller which fell approximately 40 feet. Neither barricades nor warning signs were utilized at ground level to restrict access and warn persons of the fall of material hazards from the elevated work location.The citation was terminated on October 22, 2007. The mine operator developed and implemented new safety procedures to address barricading and posting work areas to protect persons working in areas where hazards may exist that are not immediately obvious. A safety meeting was held with all mine employees to review the new procedures.
Persons Participating in the Investigation
Twin State Sand & Gravel Co., Inc.
Warren B. Ames ............... ownerMine Safety and Health Administration
Stuart Close ............... vice-president
Duane E. Moody ............... safety director
James A. Benjamin ............... superintendent
Mark A. Martin ............... plant foreman
Craig L. Richardson ............... truck driver/laborer
William Becker ............... crusher operator
Dale Balleau ............... truck driver/laborer
Anthony M. Fortino ............... mine safety and health inspector
James R. Logan ............... mine safety and health inspector
Robert S. Setren ............... mechanical engineer