DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
Metal Nonmetal Mine Safety and Health
ACCIDENT INVESTIGATION REPORT
[MILL] FATAL MACHINERY ACCIDENT
Lathrop Mill, ID No. 26-00639
American Borate Company
Amargosa Valley, Nye County, Nevada
December 27, 1995
David A. Kerber
Mine Safety and Health Inspector
Mine Safety and Health Inspector
Western District Office
3333 Vaca Valley Parkway, Suite 600
Vacaville, California 95688
Fred M. Hansen
Heriberto D. Pinon, a 44 year old maintenance man, was fatally injured and Keith L. Turrill, a 39 year old laborer, was seriously injured when a cable snapped and the man basket they were riding in fell. The men were then struck by the main block as it fell. Pinon had one year and 38 weeks experience at this site and job. Turrill had 23 weeks and four days of experience at this site and job.
Vaughn D. Cowley, MSHA mine inspector at the Boulder City, Nevada Field Office, was notified of the accident by Lupe Regalado, American Borate safety director, at 3:45 p.m., the day of the accident. An investigation was begun the same day.
The accident occurred at Lathrop Mill, a borate processing facility owned and operated by American Borate Company in partnership with Roscorp, Inc. of Texas and American Borate Co. L.L.C. Located six miles south of Lathrop Wells, Nevada, the mill processed colmanite minerals into borates. The facility had 29 employees and operated three shifts, seven days a week.
Principal officials for this operation were:
James Sparks, President
American Borate Company trained according to a plan approved by MSHA March 1, 1984.
The last regular inspection at Lathrop mill was completed
June 29, 1995.
PHYSICAL FACTORS INVOLVED
The accident involved a 1972, self propelled, rubber tire, 15 ton Bantam crane, model No. S-628, serial No. 1196, manufactured by Koehring Co., Waverly, Iowa. The crane's boom, which could be extended 60 feet, was raised, lowered, extended, and retracted with hydraulic cylinders. Loads were lifted with a inch diameter wire rope, with a four part hookup between the stationary and main sheave blocks. The main block weighed 400 pounds. The crane was being used to hoist men into position to change a 1 HP electric motor on the mill cyclone.
The diesel-over-hydraulic crane, used mainly for equipment hoisting, was located about nine feet from the mill's Motor Control Center (MCC#10). The crane's condition, as noted by the investigators, included the following defects; the electrical system for the fuel pump and outriggers had been bypassed, one outrigger lacked a foot plate, the hoist rope was kinked and abraded, there was no grease in the boom's bushings and moving parts, oil covered the engine because the oil cap was not in place, the hoist cable was too long and had become jammed against the retaining bar, only the hand throttle could be used for tramming as the foot pedal linkage had been disconnected, and the spooled cable was wound unevenly and was overlapping itself.
The crane's boom was extended over the MCC#10 into an area congested by cables, walkways, pipelines, and mill structures. The man basket was five foot square and approximately 48 inches tall. It was built with angle iron and had toe, middle, and top rails. The basket was lifted by four cables, one from each corner, that were joined and then connected to the crane cable at a center point. Safety belts and lanyards were not included with the basket.
On the day of the accident, the weather was dry with no wind.
Temperatures were in the mid-fifties and visibility was good.
DESCRIPTION OF THE ACCIDENT
Pinon and Turrill reported to work at 7:30 a.m., their regular starting time. They worked throughout the morning without incident. At approximately 1:30 p.m., they brought the crane and man basket to an area near the MCC#10 room. The crane was to be used to lift the two men to a point where they could change out an electric motor located on the mill cyclone. Darrell Cypert, Vice President Western Operations, was asked to operate the crane because the person who would normally operate it was on vacation. Cypert trammed the crane about 60 feet to the point where he could level and secure the machine and begin the job. While the man basket was being raised it was discovered that the wire rope was not in the proper sheaves. The basket was lowered to the top of the MCC#10 building where it was disconnected and the rope realigned. The basket cables were then reattached and the two employees entered the basket.
Because of congestion in the area, the basket had to be lifted over a pipe and then lowered. The boom was then extended under another pipe. When the boom was extended and lowered the slack in the main hoist line was reduced until "two-blocking" (the main sheave block came into contact with the stationary sheave block) occurred. The wire rope broke and the basket fell to the ground, about 12 feet. The main block fell on the two men in the basket.
John E. King, Mill Foreman, was assisting Pinon and Turrill from the second deck of the calciner when the accident occurred. He ran down the stairs, checked the condition of the men and then called for an ambulance.
Two EMT's from the Amargosa Valley Volunteer Ambulance Service
arrived at the site in approximately three minutes. The Nevada
State Mine Inspector arrived within seven minutes of the
accident. Sheriff's deputies, and an ambulance, arrived a short
time later. The deputies, qualified as deputy coroners,
pronounced Pinon dead at 3:10 p.m. The ambulance crew stabilized
Turrill and he was transported by helicopter to a Las Vegas,
Nevada hospital. Turrill was listed in critical condition.
The accident occurred because the crane operator exceeded the
machine's intended limits. The operator did not feed-out the
hoist rope as he lowered and extended the boom, resulting in "two
blocking" of the sheaves. The cable stretched and broke and the
basket fell. Contributing to the occurrence was the condition
of the wire rope and the lack of an over-travel switch.
Order No. 4358320, 103(k)
This order prohibited anyone from removing evidence or moving equipment pending an investigation of a fatal accident.
Citation No. 3933964, 104(a), Section 115(c)
A copy of a task training certificate indicating that Darrell Cypert had been trained to operate the Bantam crane was not made available to the MSHA inspector.
Citation No. 3933965, 104(a), Section 56.14100(b)
Defects affecting safety on the Bantam Crane were not corrected in a timely manner. The wire rope was kinked and abraded and the right front outrigger was missing the foot plate.
Citation No. 3933966, 104(d)(1), Section 56.14100(c)
The company failed to take the crane out of service until known defects could be corrected.
Citation No. 3933968, 104(a), Section 56.14100(d)
Crane defects not immediately corrected were not recorded by the mine operator.
Citation No. 4143563, 104(d)(1), Section 56.14205
The crane involved in the accident was being used beyond the design intended by the manufacturer.
Citation No. 4143564, 104(d)(1), Section 56.15005
Employees being hoisted in a man basket were not tied off to prevent them from falling to the ground should the basket tip.
Citation No. 4143565, 104(d)(1), Section 56.11001
There was no safe access to the roof of the MCC electrical building, where the basket was located. Employees had to climb over the mill stairway handrails, walk across the cable run, and then step onto the roof.
Citation No. 4143566, 104(d)(1), Section 56.14132(a)
The back-up alarm on the crane was not maintained in a functional condition, creating a potential hazard to empoyees walking behind it.
Respectfully submitted by: