DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
ROCKY MOUNTAIN DISTRICT
Metal and Nonmetal Mine Safety and Health
Underground Nonmetal Mine
Fatal Fall of Rib/Pillar Accident
Kansas City, Wyandotte, Kansas
ID No. 14-00159
October 26, 1999
Richard R. Laufenberg
Supervisory Mine Safety and Health Inspector
Dale D. Teeters
Mine Safety and Health Inspector
Paul L. Tyrna
William J. Gray
Mine Safety and Health Administration
Rocky Mountain District
P.O. Box 25367, DFC
Denver, CO 80225-0367
Claude N. Narramore, District Manager
Michael L. Scott, scaler, age 46, was fatally injured at about 9:30 a.m., on October 26, 1999, when he was struck by a fall of ground while hand scaling a pillar. The rock that struck Scott weighed about 500 pounds. The accident occurred because scaling was performed from a location which exposed him to falling material. Scott had a total of 13 years mining experience, 8 years as a scaler, all at this mine. He had received training in accordance with 30 CFR Part 48.
Inland Quarries, an underground limestone mine, owned and operated by AmeriCold Corporation, was located at Kansas City, Wyandotte County, Kansas. The principal operating official was Bohn A. Frazer, division manager. The mine was normally operated one, 10-hour shift a day, five days a week. Total employment was 32 persons.
Limestone was extracted by the room and pillar mining method. Broken material was transported by truck to a processing plant on the surface where it was crushed, screened and stockpiled. The finished products were sold primarily for use as construction aggregate.
The last regular inspection of this operation was completed on August 10, 1999. Another inspection was conducted following this investigation.
DESCRIPTION OF ACCIDENT
On the day of the accident, Michael Scott (victim) reported for work at 5:45 a.m., his normal starting time. Scott conversed briefly with Earl Huffman, mine superintendent, then helped the powderman load bags of ammonium nitrate fuel oil on the powder truck.
Scott's daily work assignment was to scale rooms blasted on the previous shift and, to his discretion, scale pillars near the working faces.
At about 8:00 a.m., Doyle Todd, driller, saw Scott as he drove past in the scaling truck. A short time later he saw Scott pass by on foot. At about 9:30 a.m., Todd walked out of the room where he had been drilling and noticed a cap lamp on the ground. Todd went over to the light and found Scott lying motionless on the ground. Todd immediately drove his truck to the shop to get help. James Billetter and Gary Novick, mine mechanics, and Huffman, were in the shop.
Huffman grabbed the first aid kit and instructed Billetter to come with him. Novick called Charles Scott, mine manager, to report the accident. Huffman and Billetter went to assist Scott. Huffman started CPR and continued until emergency medical technicians relieved him a short time later. Scott was taken out of the mine by ambulance to a waiting helicopter and transported to a local hospital where he was pronounced dead. Death was attributed to crushing chest injuries.
INVESTIGATION OF THE ACCIDENT
MSHA was notified at 10:15 a.m., on the day of the accident by a telephone call from Bohn Frazer, division manager, to Jake DeHerrera, assistant district manager. An investigation was started the same day. MSHA's accident investigation team traveled to the mine and made a physical inspection of the accident site, interviewed a number of persons and reviewed documents relative to the job being performed by the victim and his training records. An order was issued pursuant to Section 103(k) of the Mine Act to ensure the safety of miners. The miners' representative was present during the accident investigation.
Inland Quarries extracted the lower 15 feet of the 25-foot-thick Bethany Falls limestone formation. Rooms were mined 40 feet wide on 65-foot centers, leaving 25-foot-square pillars for ground support. Mining height was generally 15 feet except where erosional channels in the upper surface of the formation necessitated a 13-1/2-foot height. Overburden ranged from 70 to 250 feet. Mine access was via an adit. The entire mine was at adit level.
The limestone being extracted was fine grained, crystalline, light to medium gray, thin to thickly bedded, and fossiliferous with coarse grained calcite in fossil traces. Prominent, thin (< 0.25- inch), wavy, laterally continuous shale partings occurred roughly 6, 7-1/2, and 9 feet above the basal contact (mine floor).
Mining was conducted in three active sections, with multiple room development on each section. Up to seven faces per day (five days per week) were shot at the end of the shift. Scaling and loading was done the following day. The victim generally hand-scaled from the muck pile on all three sections. A truck with an elevated work platform was available for scaling, but was not being used at the time of the accident. Mechanical scaling was not done at the mine.
Mine-wide systematic rock support was not installed. Spot bolting was done where deemed necessary by mine management and was contracted out. Many of these spot-bolted areas were travelways and compressor stations, supported in a 5-foot by 5-foot pattern. Sixteen-foot-long, grade 60, No. 7, two-piece tensioned rebar with 6-inch by 6-inch by 1/2-inch bearing plates were used.
The accident occurred at the north side of pillar 103/2Q, roughly 70 feet from the face in the southeast corner of the mine. Dimensions of the entry in which the accident occurred were 38-40 feet wide and 14-15 feet high. The rock mass in the accident area was generally competent with joints widely spaced, tight, and nearly vertical with a N40-50 degree orientation. The roof was generally flat, following a prominent bedding plane, with a few small rough areas where shot breakage was not clean. The area on the north pillar face from where the block that struck the victim fell was approximately 12-13 feet above the mine floor and was not intersected by joints, slips or prominent bedding. The position of the block on the mine floor was roughly 5 feet north of its apparent in situ position on the rib.
The block that struck the victim was angular in shape, roughly 17 inches by 17 inches by 48 inches with sharp edges and was estimated to weigh 500 pounds. The victim was found lying face up, with his feet approximately 2-1/2 feet from the pillar edge. Initially, it was not apparent how the victim was killed, as there was no rock debris on his body. The block that struck him was identified by small fragments of his clothing and hardhat on one edge of the block.
A 7-foot-long scaling bar was found on the mine floor between the victim and the pillar rib. The position of the scaling bar was roughly parallel to the rib line.
Other rock debris in the vicinity included a 6-foot by 6-foot pile of smaller fragments adjacent to the northwest corner of the pillar, assumed to be scaled material. A few larger blocks, in the 30-50 pound range, were scattered about. One large block, weighing approximately 500 pounds, was resting on the scaling bar and was positioned next to the block that struck the victim.
The direct cause of the accident was failure to scale loose ground from a safe location.
Order No. 4661689 was issued on October 26, 1999, under the provisions of Section 103(k) of the Mine Act:
A fatal accident occurred at this operation on October 26, 1999, when a rock weighing approximately 500 pounds fell on a miner while he was scaling a pillar. This order is issued to ensure the safety of persons at this operation until the mine or affected areas 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 areas of the mine to normal.This order was terminated on October 28, 1999. Conditions that contributed to the accident have been corrected and normal mining operations can resume.
Citation No. 7923664 was issued on November 23, 1999, under the provisions of Section 104(a) of the Mine Act for violation of 30 CFR 57.3201:
A fatal accident occurred at this operation on October 26, 1999, when a rock weighing approximately 500 pounds fell on a miner while he was hand scaling a pillar. Scaling was performed from a location which exposed the miner to the hazard of falling material.This citation was terminated on December 6, 1999. Miners performing scaling were trained on testing and examining for loose ground and on scaling loose material from a safe location.
Related Fatal Alert Bulletin:
Persons Participating in the Investigation
Charles A. Scott, general managerMine Safety & Health Administration
Earl D. Huffman, mine superintendent
Scott Gow, miners representative
Jeff Bogle, regulatory compliance manager
Richard R. Laufenberg, supervisory mine safety and health inspectorAPPENDIX B
Dale D. Teeters, mine safety & health inspector
William J. Gray, mining engineer
Paul L. Tyrna, mining engineer
Earl D. Huffman, mine superintendent
Doyle L. Todd, driller
James D. Billetter, mechanic
Gary Novick, mechanic