Rocky Mountain District
Metal and Nonmetal Mine Safety and Health


Cyprus Sierrita Corporation (Mine)
I.D. No. 02-00144
Cyprus Sierrita Corporation
Green Valley, Pima County, Arizona

January 18, 1995


Clarence Ellis
Mine Safety and Health Inspector

Wayne D. Pilling
Mine Safety and Health Inspector

Originating Office
P.O. Box 25367 DFC
Denver, CO 80225-0367

Robert M. Friend
District Manager


Thomas Neff, truck driver, age 48, was fatally injured at approximately 10:15 p.m., on January 18, 1995 , when he backed the truck he was operating over a dump site berm. The truck overturned. The victim had a total of 13 years mining experience, the last 8 years at this mine.

Elton Hogg, safety manager, Cyprus Sierrita Corporation, notified Richard Laufenberg, MSHA supervisory mine safety and health inspector, of the accident on the evening of January 18, 1995 , at approximately 11:30 p.m. An investigation was started the following day.

Cyprus Sierrita Corporation, an open pit, multiple-bench copper and molybdenum mine, was owned and operated by Cyprus Sierrita Corporation. The property was located near Green Valley , Pima County , Arizona . The principal operating official was Steven Roesa, general manager. The mine operated two, 12-hour shifts a day, 7 days a week. A total of 750 persons was employed at the mine.

Electric shovels were used to load the blasted copper and molybdenum ore into haul trucks for transporting to various leaching pads, or to one of the two crushers. The mined product was processed into smelter concentrate and was also used to develop large leach pads to provide copper solution for the Solvent Extraction Electrowinning Plant (SXEW).

The last regular inspection was conducted on January 12, 1995 . An approved training plan was in effect that complied with the training requirements in 30 CFR Part 48.


The accident occurred during night-shift on January 18, 1995 , at the V1 dump. The V1 dump was the lower of three dumps, identified as: V3 (upper), V2 (middle) and V1 (lower). Fifty-foot high benches separated each dump.

The V1 dump had been a restricted dump area since 1992; however, it was reactivated for dumping use on day-shift, January 16, 1995 . Furthermore, on January 17, 1995 , it was used during day-shift and night-shift. The V1 dump edge was provided with a 40 to 55 inch high berm that was constructed of heavy broken rock which ran northwest and southeast along the dump crest for approximately 1,000 feet. At the location where the haul truck went over the edge of the V1 dump, the face (bank) distance averaged approximately 75 feet at an estimated slope of 38 degrees from the crest to the toe.

The haulage truck involved in the accident was a six-wheeled Caterpillar, Model 789, Serial No. 9ZC00158, Equipment No. 16002, rated for hauling loads up to 195 tons; maximum GVW of 700,000 pounds. The truck was equipped with four rearview mirrors, two on each side; an operator restraint system (seatbelts), and backup lights.


On the day of the accident, Thomas Neff, victim, reported to work at 7:00 p.m., his assigned starting time, and received instructions from Stephen Mahaffey, operations supervisor.

At approximately 9:00 p.m., Mahaffey instructed the No. 14533 shovel oiler to locate a portable light plant and move it to the lower V1 dump. Reportedly, Mahaffey inspected the lower V1 dump area for safe conditions. No problems were reported. Mahaffey then radioed the truck drivers and informed them that the new dump location was at the V1 dump. He then left the area.

At approximately 10:00 p.m., Neff received the first load of waste ore from Shovel No. 14533 and proceeded to the V1 dump area. The V1 dump site portable illumination unit had not yet been placed in service. Approximately 5-6 minutes later, Herb Matthews, truck driver, followed behind Neff with a second load of waste ore to the V1 dump. Upon arrival at the V1 dump, Matthews observed a wide opening in the dump edge berm and became concerned. Matthews parked his haul truck and walked to the dump edge, looked down the bank, and observed Neff's truck upside down.

At approximately 10:15 p.m., Matthews radioed the dispatcher from his truck and reported that Neff had gone over the V1 dump edge. He then walked down the dump bank to check on Neff and observed that Neff was not wearing the seatbelt. Upon hearing Matthew's radio message to the dispatcher, Mahaffey immediately radioed the dispatcher and instructed him to activate the emergency response alarm. At 10:16 p.m., the alarm was activated, and shortly thereafter, first responders started arriving at the accident site and checked for a pulse on Neff.

When unable to detect a pulse, the first responders removed Neff from the cab and administered cardiopulmonary resuscitation (CPR).

At 10:42 p.m., E.M.T.'s with the Rural Metro Emergency Services arrived at the scene of the accident and their subsequent efforts to revive Neff were unsuccessful. An autopsy later revealed that Neff died as a result of multiple blunt trauma injuries to the upper half of his body.


The direct cause of the accident was that the truck driver did not maintain control of the loaded haul truck when he backed it over the V1 dump site berm. This caused the truck to overtravel the edge of the site and overturn as it traveled down the dump bank. A contributing factor to the accident was the lack of dump site area illumination.

It could not be determined if the victim was wearing the seatbelt when the truck went over the dump bank. The investigation revealed it was possible he was wearing the seatbelt and unfastened it before expiring.


The following order was issued during the investigation:

Order No. 4360294, 103 (k)

Issued 1/19/95 , at 0700 hours.

The order is being issued as a result of a fatal accident that occurred at about 2200 hours on 1/18/95 . The order covers the V waste dump where the accident occurred.

The purpose of this control order is to ensure the safety of any personnel allowed in the area until the order is terminated.

No production of any kind is allowed on the V dump.

This order was initially issued at about 0700 hours over the telephone by MSHA supervisor Larry Aubuchon.

Terminated 1/20/95 , at 1102 hours.

This 103 (k) order is now being terminated. Haul truck #2 which was involved in the accident is now released for recovery.

This action also releases the entire lower V dump that was affected by the original order.

The following citations were issued during the investigation:

Citation No. 4406510, 104 (a)

Issued 1/20/95 , at 1800 hours for a violation of 56.17001.

A fatality occurred at the lower V dump area of the Cyprus Sierrita Corporation's open pit operation. A Caterpillar haul truck, Model 789, Equipment No. 16002, backed over a berm, and turned over fatally injuring the driver. The bank was approximately 15.24 meters (50 ft) high. There was no portable illumination provided at the dump area. The haul truck was equipped with two back-up lights that were quite dirty. It was not believed or known if the back-up lights were adequate.

Portable lighting plants should be provided at all dumping areas to provide sufficient illumination for safe dumping operations.

Citation No. 4406512, 104 (a)

Issued 1/31/95 , at 1600 hours for a violation 56.9101.

A fatality occurred at the lower V dump area of the Cyprus Sierrita Corporation's open pit operation at approximately 2200 hours, on January 18, 1995 . A Caterpillar haul truck, Model No. 789, Equipment No. 16002, backed over a berm, and turned over fatally injuring the driver. An investigation of the truck's brakes, governor, accelerator, and fuel system was made by Caterpillar and Cyprus personnel. The investigation revealed that no defects existed in the components to cause the truck to be out of control at the time of the accident. The autopsy report ruled out the possibility that the victim had a heart attack. Based on the above information and from evidence examined at the accident site, it was apparent that the victim failed to maintain control of the truck. It was believed that the victim backed the haul truck against the berm with an excessive force causing the berm to collapse, allowing the truck to back over the berm and overturn. There were no witnesses to the accident.


Respectively submitted:

/s/ Clarence Ellis

Clarence Ellis
Mine Safety and Health Inspector

/s/ Wayne D. Pilling

Wayne D. Pilling
Mine Safety and Health Inspector

Approved by,

Robert M. Friend
District Manager
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