UNITED STATES
DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION

Rocky Mountain District
Metal and Nonmetal Mine Safety and Health

ACCIDENT INVESTIGATION REPORT
SURFACE METAL MINE

Fatal Fall of Highwall Accident

Open Cut-Lead
I.D. No. 39-01284 X52
Summit, Inc. (Contractor)
Homestake Mining Company of California (Owner)
Lead, Lawrence County, South Dakota

January 5, 1995

By

Gary Grimes
Mine Safety and Health Inspector

Roger Nowell
Mine Safety and Health Inspector

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

Robert M. Friend
District Manager

GENERAL INFORMATION

Tracy D. Millard, a 34 year old shovel operator, was fatally injured at approximately 1:50 a.m., on January 5, 1995. A massive fall of ground buried the shovel he was operating. The victim had a total of 13 years mining experience. He had worked twelve years at this operation, the last three years as a shovel operator. Michael Wagner, a 43 year old truck driver, was injured.

Tyrone Goodspeed, supervisory mine safety and health inspector, from the Rapid City, South Dakota Field Office, was notified of the accident by a telephone call from Steve Smith, health and safety manager with Homestake Mining Company of California, at 2:40 a.m., on January 5, 1995. An investigation was started the same day.

The Open Cut-Lead mine, a multiple bench, open pit gold mine, owned and operated by Homestake Mining Company of California, was located within the city limits of Lead, South Dakota. The principal operating official was Steve Orr, general manager. The mine normally operated 2, 10-hour shifts a day, 4 days a week.

The victim was employed by Summit, Inc., an independent contractor from Rapid City, South Dakota. The principal operating official was Owen H. Emme, president. A total of 93 persons was employed by the contractor at the Open Cut-Lead mine.

Gold ore was drilled, blasted, and transported to stock pads where crushing and milling occurred. A final refining process was used to extract the gold product.

Mining in the Open Cut-Lead area began in the late 1800's, primarily as an underground operation. In the early 1980's surface mining began in the north portion of the pit known as the "Test Pit". Homestake subsequently determined that open pit mining was economically feasible in the area and, in 1985, made the decision to pursue mining in the main portion of the pit. In 1991, the pit was expanded to the west and south to recover additional reserves.

In October 1994, Summit, Inc. began mining the area known as the "Mini Pit". The Mini Pit was located at the north end of the Open Cut-Lead mine; where the main haul road to the lower levels of the open pit mine existed. The mining plan for the Mini Pit included the extraction of ore from the 4900 level down to the 4840 level. This process subsequently eliminated the original haul road as mining progressed deeper. After mining was completed through the 4840 level, the objective was to backfill the Mini Pit to the 4900 level and establish a new haul road to the lower level of the open pit.

An MSHA-approved training plan was in effect at this operation. The victim received annual refresher training on October 31, 1994. The last regular inspection was conducted on December 15, 1994.

PHYSICAL FACTORS INVOLVED

The accident occurred on the 4840 level of the Mini Pit. The Open Cut-Lead mine was 4800-ft long north to south, 2400-ft wide east to west, and 900-ft deep.

The 4860 bench level was the last level to be mined in the Mini Pit area. As mining progressed, an 80-ft highwall consisting of phylite was created on the east side. On the west side, a 40-ft highwall of unconsolidated material was created which left a narrow working level approximately 150-ft wide for a length of 550-ft progressing to the north. At the time of the accident, the shovel was being operated on the 4840 level, removing ore from the 4860 level which was mixed with old mine timber from previous underground operations in this area.

The equipment involved in the accident was a 5130 Caterpillar hydraulic shovel, Serial No. 5Z10021 and a 777B Caterpillar, 85-ton off-highway truck, Serial No. 4YC1610.

DESCRIPTION OF THE ACCIDENT

Tracy D. Millard, victim, and Mike Wagner, injured, truck driver, reported for work at their normal starting time for night shift at 7:00 p.m., on January 4, 1995.

Loading and hauling operations proceeded on the west side of the 4840 bench until 8:00 p.m., when the west wall sloughed, partially burying a 777B CAT, 85-ton, haul truck. The truck could not pull away from the loading area under its own power. The night foreman, Delvin Price, was notified and the shovel was used to remove material from around the truck. A cable was used with a bulldozer to pull the truck from the loading area. Price notified Tom Lester, general superintendent, of the west wall sloughing incident, who then notified Charles Rounds, Jr., vice president. Rounds arrived at the mine site at approximately 10:30 p.m., and conferred with Price.

The shovel operator (Millard) was instructed to slope the west wall and begin excavation from the north face adjacent to the east pit wall. Loading and hauling of ore continued without incident until 12:30 a.m., at which time Wagner and Price broke for lunch. During lunch, Wagner voiced his concern to Price about working under the highwalls on the 4840 level.

After lunch, the shift proceeded without incident until approximately 1:45 a.m. At that time Wagner, next in line to be loaded and waiting at the south end of the 4840 level, observed a trickling of material falling off the east highwall. Wagner backed his truck to the loading position and Millard began loading him.

Witnesses to the accident said the top of the east highwall leaned out toward the middle of the 4840 level and suddenly crumbled under the weight of the rock. The fall engulfed the 5130 shovel and partially buried the 777B CAT haul truck.

Immediately after the highwall failed and the dust cleared, Bob Hepburn, truck operator, who was waiting to be loaded, located Price who had left the loading area prior to the accident. Price then radioed the maintenance shop for an ambulance and implemented emergency procedures. Eldon Huber, another truck driver, realized that he was not hurt but could not move his truck because rock from the fall had rolled under his tires. He climbed down from his truck and proceeded to Wagner's truck which was almost buried on the left side. Huber observed Wagner's legs pinned between the steering wheel and the shift console and went for help.

While Huber was away, Wagner freed his legs and with the help of another truck driver, climbed off the truck. Wagner was transported to the hospital where he was treated for a head wound and numerous contusions.

Rescue efforts for the shovel operator were hampered due to the unstable highwall and large rocks perched above the rescue site. Two backhoes were used to drag loose rock down from above the rescue site while a front-end loader and other backhoes were used to remove rocks from around the lower part of the shovel and accident area. Rescue workers were unsuccessful in making voice contact with Millard.

At approximately 11:30 a.m., January 5, 1995, Millard was located and the coroner, who was at the accident scene, pronounced him dead.

CONCLUSION

The direct cause of the accident was the failure to use mining designs and methods that would maintain wall, bank, and slope stability as mining progressed deeper.

Contributing to the accident was the failure to conduct adequate examinations of the east highwall. The examinations may have revealed highwall problems that are common after blasting and changing weather conditions. Employee concerns about the highwall should have also been addressed.

VIOLATIONS

The following order was issued to Summit, Inc. during the investigation:

Order No. 4423064, 103 (k)

Issued 1/5/95, at 0400 hours.

This order is to ensure that the slide area on the 4840 foot level has been stabilized, loose rock which may endanger persons assisting in the rescue effort are taken down and the area and affected shovel and truck are secured until the accident investigation is completed.

A fatality occurred on 1/5/95, at approximately 0150 hours when the east side highwall sloughed off engulfing the CAT 5130 shovel and partially engulfing a 85-ton CAT haul truck.

Terminated 1/6/95, at 1125 hours.

Backhoes and a front-end loader were used to removed and scale down loose ground to ensure the safety of persons involved in the rescue work and recovery.

Investigation of the accident scene and equipment has been concluded.

Work to recover the shovel may require further dressing down of the east highwall to prevent other falls of material.

The following citation was issued to Summit, Inc. during the investigation:

Citation No. 4422929, 104 (d) (1)

Issued at 1/9/95, at 1105 hours for a violation of 56.3200.

The night shift supervisor was made aware of possible hazardous conditions at the east highwall Mini Pit during the lunch break from 12:30 a.m. to 1:00 p.m. on 1/5/95. An employee reported to the supervisor of his concern working under the 80 foot east highwall. No corrective action was taken by the night supervisor and the employees were allowed to continue to work in the Mini Pit area. A miner was fatally injured at approximately 1:50 a.m., on 1/5/95, when the east wall failed and fell on the shovel operator. This violation is an unwarrantable failure.

The following orders were issued to Summit, Inc. during the investigation:

Order No. 4422930, 104 (d) (1)

Issued 1/9/95, at 1135 hours for a violation of 56.3130.

The east highwall located in the Mini Pit approximately 80 feet high failed, burying the Caterpillar 5130 hydraulic shovel and partially burying a Caterpillar 777B, 85-ton, off-highway truck on the 4840 bench. Mining methods being utilized did not maintain the wall, bank and slope stability at the east highwall, Mini Pit area. An 80 foot east highwall was formed as the Mini Pit mining progressed deeper and the wall failed at approximately 1:50 a.m., on 1/5/95, engulfing the shovel, fatally injuring the operator and injuring a truck driver being loaded. This violation is an unwarrantable failure.

Order No. 4422931, 104 (d) (1)

Issued 1/9/95, at 1140 hours for a violation of 56.3401.

Miners were allowed to work on the 4840 bench on 1/5/95, even though management failed to adequately examine ground conditions at the east highwall prior to work commencing after weather conditions, prior blasting and other conditions warranted. This violation is part of a failure to conduct adequate examinations that contributed to the failure of the east highwall on 1/5/95, which resulted in the death of a miner. An adequate examination of the east highwall would have determined that possible evidence was visible and that the east highwall was progressively deteriorating, endangering the miners performing their assigned duties on the 4840 bench.

Adequate ground examinations of the east highwall were warranted to protect the miners regularly required to work in the area. Management engaged in aggravated conduct constituting more than ordinary negligence. This violation is an unwarrantable failure.

The following citation was issued to Homestake Mining Company of California during the investigation:

Citation No. 4422932, 104 (d) (1)

Issued 1/9/95, at 1135 hours for a violation of 56.3130.

The east highwall, approximately 80 feet high located in the Mini Pit failed, burying the Caterpillar 5130 hydraulic shovel and partially burying a Caterpillar 777B, 85-ton, off highway truck, on the night shift of 1/5/95, on the 4840 bench. Mining design and methods did not maintain the wall, bench and slope stability at the east highwall, Mini Pit area. The 80 foot high east highwall was formed as the Mini Pit mining progressed deeper and the wall failed at approximately 1:50 a.m., 1/5/95, engulfing the shovel, fatally injuring the shovel operator and injuring a truck driver being loaded. Mining design and methods were not being utilized to ensure the safety of the persons traveling or performing their assigned duties. When benching is necessary, to ensure the safety of persons working, the height and width shall be based on the type of equipment used for cleaning of benches or for scaling of walls, banks, and slopes. Management engaged in aggravated conduct constituting more than ordinary negligence.

This violation is an unwarrantable failure.

Respectively submitted by:

/s/ Gary Grimes

Gary Grimes
Mine Safety and Health Inspector

/s/ Roger Nowell

Roger Nowell
Mine Safety and Health Inspector

Approved by,

Robert M. Friend
District Manager
Related Fatal Alert Bulletin:
[FAB95M01]