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Metal and Nonmetal Mine Safety and Health


Underground Nonmetal Mine
(Industrial Sand)

Fatal Machinery Accident
August 30, 2000

Maiden Rock
Wisconsin Industrial Sand Company
Maiden Rock, Pierce County, Wisconsin
I.D. 47-03110

Accident Investigators

Ralph D. Christensen
Supervisor Mine Safety and Health Inspector

Kenneth W. Diez
Mine Safety and Health Inspector

Wayne Colley
Mechanical Engineer

Michael Getto
Physical Scientist

David Weaver
Mine Safety and Health Specialist

Originating Office
Mine Safety and Health Administration
North Central District
515 West First Street, Room 333
Duluth, MN 55802-1302
Felix A. Quintana, District Manager


On August 30, 2000, James Hoffman, drill operator, age 47, was fatally injured when he was crossing over a rotating drill auger. A rotating protruded pin on the drill auger coupling caught the bottom of his left shoelace, pants, or coverall leg and wrapped the material around the auger, causing fatal injuries.

The accident occurred because management failed to ensure safe work procedures were followed while drilling.

Hoffman had a total of seven years mining experience, all with this company. He had received training in accordance with 30 CFR Part 48.


The Maiden Rock mine was an underground industrial sand operation, owned and operated by Wisconsin Industrial Sand Company, Maiden Rock, Pierce County, Wisconsin. It was a subsidiary of Fairmont Minerals, Ltd., 11833 Ravenna Road, Chardon, Ohio 44024. The mine was located 1/3 mile south of Maiden Rock, Wisconsin, on Highway 35. The principle operating official was M. Casey Koenig, plant manager. The mine normally operated one, 12-hour shift and one, 11-hour shift, five days per week. Total employment was 16 persons.

Industrial sand was mined underground by room-and-pillar method. Approximately 12 active drift faces were drilled and blasted. The sand was mucked out with a front-end loader and dumped through a grizzly and scalping screen located underground. After the oversized material was removed from the sand, it went through the underground wash plant, which removed clay, silt, and fine sand. A cyclone located underground removed water from the sand and the sand was stockpiled on a concrete slab to drain further. A front-end loader was used to load the drained sand onto a haul truck for transport to surface where it was dried and graded. The finished product was sold to the oil and gas industry.

The last regular inspection at this operation was completed on July 27, 2000. Another inspection was conducted following this investigation.


On the day of the accident, James Hoffman (victim) reported for work at approximately 6:00 a.m., his normal starting time. Work progressed without incident throughout the day. Sometime between 4:30 and 5:00 p.m., Hoffman requested Travis Ford, front-end loader operator, to clean out a face for him with the loader. He backed the drill up to provide enough room for the loader operator to work. After cleaning up, Ford talked to Hoffman for a few minutes. Hoffman told Ford that he would not work late that day. Occasionally, Hoffman would work later than his normal 6:00 p.m. quitting time if he had to finish a face or if he fell behind for some reason, such as a breakdown.

At approximately 9:30 p.m., Howard Enevold, a loader operator who had been moving material at the wash plant area inside the mine, went outside to fuel his loader. He then parked his loader and went to the lunchroom to punch out his time card. He mentioned to David Thompson, dryer operator, that Hoffman's car was still parked in the parking lot. Thompson checked Hoffman's time card and saw that he had punched in before 6:00 a.m. He shut the dryer down and asked Thomas Ohms, truck driver, to go with him into the mine to check on Hoffman.

Thompson and Ohms proceeded into the mine and followed the drill's trailing cable from the wash plant area. As Thompson and Ohms approached the drill, they saw Hoffman at the right front drill auger sash area, with his clothing wrapped around the auger tightly. The drill was stalled at the time. Thompson immediately went up to the driller's cab area and shut off the electrical switches, shutting the drill functions down, except for the lights. He ran back over to Hoffman and checked for vital signs. Finding none, Thompson and Ohms proceeded to the wash plant area of the mine where there was a telephone. Thompson called 911 and made a call to the mine production supervisor. He sent Ohms to the mine entrance gate to direct the emergency personnel.

The county sheriff's department and emergency medical services personnel arrived at approximately 10:27 p.m. The victim was transported to the coroner's office in Ellsworth, Wisconsin where he was pronounced dead at 11:40 p.m.

Death was attributed to probable asphyxia due to external thoracic compression.


MSHA was notified of the accident at 12:30 a.m. on August 31, 2000, by a telephone call from M. Casey Koenig, plant manager, to Felix A. Quintana, district manager, North Central District, Duluth, MN. An investigation was started the same day. An order was issued pursuant to Section 103(k) of the Mine Act to ensure the safety of miners. MSHA's accident investigation team conducted a physical inspection of the accident scene, interviewed employees, and reviewed training records and work procedures being performed at the time of the accident. The miners did not request, nor have, representation during the investigation.

  • The accident occurred in an underground mine drift face area described as "tunnel J". The mine back (roof) was an average of 25 feet high, with the drifts designed to be 35 feet wide.
  • The drill involved in the accident was a two-boom Gardner-Denver jumbo drill, model No. MEDI-BORE, serial No. JB-717, manufactured in 1976. The specified gross weight (GVW) (as originally built by Gardner-Denver) was approximately 16,680 pounds. The body of the drill was approximately 17.5 feet long, 7.5 feet wide, and 15 feet high. The length of the auger feed positioner (sash) was approximately 15 feet. Each positioner (sash) held a 12-foot long drilling auger. The drill was positioned 16 feet from the drilling face in the drift heading, with the outriggers planted firmly on the mine floor. The drill auger travel was measured and it was determined that the auger was drilled approximately 3 to 4 feet into the face.
  • The drill had a Duetz 4-cylinder, F4L-912W, 44 horsepower at 2200 rpm, diesel engine which powered the tramming of the drill and an air compressor which supplied compressed air to the brake system and the manual transmission clutch. It was also equipped with 480-volt power, via a trailing cable, that was used for lighting and the operation of electric motors that drove an additional air compressor for blowing out drill holes and operation of hydraulic pumps for operation of the boom and the augers.
  • The drill was originally purchased from Gardner-Denver by another company and sold as a pre-owned drill to the previous owner of the Maiden Rock mine. Reportedly the drill was extensively reconditioned and modified by the previous mine owner. The drill had been originally manufactured with a percussion drilling system that incorporated a male-threaded shank at the end of the drill steel rotation motor shaft, with the drill steel having female threads which threaded directly onto the shank.
  • The coupling assembly between the drill steel rotation motor shaft and the drill steel had been redesigned from the manufacturer's original threaded design in order to accommodate an auger. The redesigned motor shaft auger coupling was composed of a 6-inch long by 2-inch steel pipe welded onto the motor shaft. A hole was then drilled perpendicular through the pipe wall and through the end of the auger shaft. In order to couple the auger to the motor shaft, the end of the auger was placed into the pipe, with the hole in the pipe and on the auger shaft aligned to accommodate a 5/16-inch by 2-inch roll pin. The pin ends would be flush with the outside of the coupling when inserted. The pin would also serve as a shear pin so the coupling welds would not break if the auger got stuck in the drill hole.
  • Inspection of the coupling between the motor shaft and drill auger showed that the 5/16-inch diameter roll pin securing the auger into the pipe, protruded approximately � inch out from one side of the pipe coupling. The roll pin was measured and found the largest diameter to be 0.3155 inches. Inspection of the auger centralizer on the auger positioner (sash) showed that the inside black plastic lining was deeply scored with a helical spiral groove. Observation of the area showed that there were shreds of the black plastic lining material on the ground in the area of the previously drilled lower hole indicating that the pin was protruding on the prior hole. Duct tape was found wrapped, and worn out, around the pipe coupling and auger at the pin location, reportedly used to stop air from leaking and to keep the roll pin flush with the pipe coupling.
  • Only one boom of the two-boom jumbo drill was used at any one time during drilling. The right boom had been in operation, drilling a bottom hole, during the time the accident occurred. The hydraulic levers for the drill auger rotation and feed were located on the console of the operator's compartment. The console was approximately 8 feet above the mine floor and 12 feet back from the location of the auger coupling. Both sets of control levers, which were self-centering levers, for the right and left auger, were grouped in a single row of four levers. The right auger feed lever was located to the far right and the right side auger rotation lever was adjacent to it. Moving the feed control lever up fed the auger into the face, and pushing the feed lever control down extracted the auger. Moving the rotation control lever up resulted in counter-clockwise rotation of the auger and pushing the rotation lever down resulted in clockwise rotation of the auger. The rotation control lever was observed locked in the down position with a bungee cord. Reportedly, the victim also had a practice of using a pipe wrench against the auger feed control lever to hold the lever up to keep the auger feeding at a certain speed. It could not be determined if the pipe wrench was holding the feed lever up at the time of the accident.
  • The victim had exited the driller's compartment, retrieved a shovel, and stepped across the rotating auger, presumably to go to the face. As he stepped across the rotating auger, the pin protruding � inch on the auger coupling caught the victim's clothing. The auger rolled the material up to the victim's mid-section.

    The root cause of the accident was the practice of blocking the self-centering rotation control lever in the operating position with a bungee cord while the driller exited the driller's compartment. A contributing cause of the accident was the employee stepping over a drill auger while it was rotating. Contributing to the severity of the injury was the spring pin that had worked out � inch on the right side auger coupling, which caught the victim's clothing.


    Order No. 7831247 was issued on August 31, 2000, under the provisions of Section 103(k) of the Mine Act:
    A fatal accident occurred at this operation on August 30, 2000 when a drill operator's clothes became entangled on the drill steel. This order is issued to assure the safety of persons at this operation until the affected area can be returned to normal operations as determined by an authorized representative of the Secretary. The mine operator shall obtain approval from an authorized representative for all actions to recover persons, equipment, and/or return the affected area of the mine to normal.
    This order was terminated on September 6, 2000, when it was determined that the conditions that contributed to the accident on the Gardner-Denver twin boom jumbo drill (serial #JB-717) no longer exist.

    Citation No. 7817893 was issued on September 14, 2000, under the provisions of Section 104(a) of the Mine Act for violation of 30 CFR 57.14100(b):
    A drill operator was fatally injured at this operation on August 30, 2000, when his clothing became caught on a rotating drill auger coupling. The auger coupling had a spring pin holding the auger in the coupling, which had worked its way out approximately � inch. When the victim stepped over the auger, his left bottom pants and coverall leg were caught on the protruding pin.
    This citation was terminated on September 14, 2000. The operator repaired the protruding pin and removed the drill out of service for further repairs.

    Citation No. 7817894 was issued on September 14, 2000, under the provisions of Section 104(a) of the Mine Act for violation of 30 CFR 57.7052(a):
    A drill operator was fatally injured at this operation on August 30, 2000, when his clothing became caught on a rotating drill auger coupling. The auger coupling had a spring pin holding the auger in the coupling, which had worked its way out approximately � inch. When the victim left the operator's compartment and stepped over the auger in the front of the drill, the protruding pin caught the bottom of his left coverall leg. The drill operator did not have access to the control levers when he was in this position. The controls were being held in the drilling position with a bungee cord and pipe wrench.
    This citation was terminated on September 14, 2000. The mine operator established a policy and conducted training for all employees to use the drill control levers as designed by the manufacturer. This requires the driller to remain at the drill operator's compartment while drilling.

    Related Fatal Alert Bulletin:
    Fatal Alert Bulletin Icon FAB2000M36


    A. Persons Participating in the Investigation
    B. List of Persons Interviewed During the Investigation


    Persons Participating in the Investigation:

    Wisconsin Industrial Sand Company
    M. Casey Koenig . . . . .  . . . . . . . . . . . . . . . . plant manager
    Joseph Fodd . . . . .  . . . . . . . . . . . . . . . . . . . .vice president of operations, industrial sand
    Jeffery M. Fallon . . . . .  . . . . . . . . . . . . . . . . vice president-general manager-industrial sand group
    Jeffery Baum . . . . .  . . . . . . . . . . . . . . . . . . . production supervisor
    Mine safety and Health Administration
    Ralph D. Christensen . . . . .  . . . . . . . . . . . . . supervisory mine safety and health inspector
    Kenneth W. Diez . . . . .  . . . . . . . . . . . . . . . . mine safety and health inspector
    Wayne Colley . . . . .  . . . . . . . . . . . . . . . . . . .mechanical engineer
    Michael Getto . . . . .  . . . . . . . . . . . . . . . . . . .physical scientist

    List of Persons Interviewed During the Investigation:

    Wisconsin Industrial Sand Company
    M. Casey Koenig . . . . .  . . . . . . . . . . . . . . . . plant manager
    Jeffrey Baum . . . . .  . . . . . . . . . . . . . . . . . . . .production supervisor
    Thomas Ohms . . . . .  . . . . . . . . . . . . . . . . . . .haul truck operator
    David Thompson . . . . .  . . . . . . . . . . . . . . . . .dryer operator
    Travis Ford . . . . .  . . . . . . . . . . . . . . . . . . . . .front-end loader operator
    Norman Anderson . . . . .  . . . . . . . . . . . . . . . .front-end loader operator
    Paul Cordes . . . . .  . . . . . . . . . . . . . . . . . . . . previous drill operator
    Pierce County Sheriff's Department
    Phillip Meixner . . . . .  . . . . . . . . . . . . . . . . . .deputy sheriff