DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
Metal and Nonmetal Mine Safety and Health
Accident Investigation Report
Underground Gold Mine
Fatal Hand Tool Accident
Tonto Drilling Services Inc.
Contractor ID IU3
ID No. 26-02246
Barrick Goldstrike Mines
Carlin, Elko County, Nevada
March 9, 1996
Michael J. Drussel
Mine Safety and Health Inspector
Mine Safety and Health Administration
3333 Vaca Valley Parkway, Suite 600
Vacaville, CA 95688
Fred M. Hansen
Donald Moore, diamond driller, age 42, was seriously injured at approximately 12:15 p.m., on March 9, 1996, when he was struck by a pipe wrench he was using to free core drill rods. He died of his injuries on April 14, 1996. Moore had five years of mining experience, all as a diamond driller with the same company. Moore had received training in accordance with 30 CFR Part 48.
MSHA was notified at 1:30 p.m. on the day of the accident by a telephone call from Charles Warner, loss control director for the mining company. At the time it did not appear that the injury was life threatening. An investigation was begun on March 18 after MSHA was informed that Moore's condition had worsened.
The Meikle Mine, an underground gold operation, owned and operated by Barrick Goldstrike Mines, was located 28 miles north of Carlin, Elko County, Nevada. The senior company official was Roderick Pye, manager. The mine was under development and was normally operated three 8-hour shifts a day, five days a week. A total of 95 persons was employed.
As a part of the mine development, a production shaft and a ventilation shaft had been sunk and about 3000 feet of drifts were completed on three levels.
Tonto Drilling Services, Inc., headquartered in Salt Lake City, Utah, was an independent core drilling contractor enlisted to perform exploratory drilling on the 1225 level. The firm specialized in this type work and had completed similar jobs at other operations. The senior official at this site was Daniel Mayberry, job superintendent. Exploratory drilling was normally performed two 8-hour shifts a day, five days a week. A total of 9 persons was assigned to this job.
The last regular inspection of this operation was completed on November 2, 1995. Another inspection was conducted in conjunction with this investigation.
PHYSICAL FACTORS INVOLVED
The drill being used at the time of the accident was a Hagby Model 1000. It was set up in the 1225(ramp) drill station at a 18-degree down hole. The hole was collared about 24 inches above the sill of the station. A 400 foot string of ten-foot NQ drill rods was stuck in the hole at the bit. NQ is a designation for rods having a 2.75 inch outside diameter.
Drill rods stuck in the hole was an occasional ocurrence. Stuck rods were usually the result of the drill bit becoming jammed between cracks or crevices, or the drill running dry. When this occurred, it was routine practice to first apply torque to the rods with the drill. If this failed to free the bit, pipe wrenches were used to rotate the rods by hand. The alternative was to reverse the rotation of the string of rods, causing it to separate at one of the joints. Remaining rods and the bit would then be abandoned.
The two Rigid (brand name)24-inch pipe wrenches involved were of cast steel construction. The movable and stationary jaws on both wrenches were in good condition with little wear. A six-foot extension pipe commonly known as a "cheater" was placed over the handle of one of the wrenches to increase leverage. The use of a cheater pipe is not recommended by the manufacturer in that the extra leverage can distort the wrench and cause torque to be exerted in excess of the wrench's design capacity. The pipe can also slip off the handle causing the wrench to spring back forcefully.
DESCRIPTION OF ACCIDENT
On the day of the accident, Donald Moore (victim) began work at 8:00 a.m., his regular starting time. Just before noon the drill he was operating stopped rotating because the drill bit had become wedged in the hole. Moore and Ronald Cunningham, driller's helper, attempted to free the bit by rotating and pulling the string of approximately 40 rods with the drill. Unsuccessful at this, and with the assistance of job superintendent Daniel Mayberry, they attempted to free the bit by using the pipe wrenches. Cunningham and Mayberry used one wrench with a six-foot cheater pipe to twist the rods while Moore braced the handle of the other wrench against the drill frame to maintain the incremental torque gained.
At about 12:15 p.m., after twisting the string of rods one-half to one revolution without freeing the bit, the three men decided to discontinue the effort. When the cheater pipe was removed, the back-up wrench slipped and built-up torque was released. The other wrench rotated around the rod striking Moore on the arm and head.
Emergency Medical Technicians were immediately summoned to assist Moore. He was transported by ambulance to a hospital in Elko, Nevada and then transferred to a medicial facility in Salt Lake City, Utah. He died on April 14, 1996 in a convalescent home near his residence in Upton, Wyoming.
The cause of the accident was the improper use of the pipe wrench. By placing the cheater pipe extension on the handle, the wrench was used beyond its design capacity.
Citation No. 4141245, 104(a), Part 57.14205
Issued March 18, 1996.
/s/ Michael J. Drussel
Mine Safety and Health Inspector
Fred M. Hansen, Manager,
Related Fatal Alert Bulletin: