DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
ACCIDENT INVESTIGATION REPORT
(Underground Coal Mine)
Fatal Sliding of Rock
Bear Canyon #2 (42-02095)
C.W. Mining Co. (Co-op Mine)
Huntington, Emery County, Utah
December 23, 1996
Originating Office - Mine Safety and Health Administration
P. O. Office Box 25367, Denver Colorado 80225-0367
John A. Kuzar, District Manager
On Friday, December 20, 1996, a roof fall occurred on a development section in the East Bleeders panel while a remote controlled continuous mining machine (a.k.a. continuous miner) was making the final clean-up pass of a cut. This roof fall disabled the continuous miner. It was assumed that an overload relay switch, located on the right side near the back of the machine, had been damaged when the roof material fell on the continuous miner. The mine operator intended to install roof bolts to allow access for the mechanic to repair the continuous miner. Afterward, the continuous miner would be trammed outby so that clean-up of the roof fall could continue.
On Monday, December 23, 1996, at approximately 11:30 a.m., enough roof bolts had been installed to allow the mechanic to access the continuous miner. As the mechanic was standing in the vicinity of the overload relay switch to be repaired, a rock, measuring 9.5-feet long, by 2- to 4-feet wide, by 1- to 2-feet thick, slid off of the top of continuous miner, fatally crushing the mechanic between the rock and the roof bolting machine.
Bear Canyon #2 is an underground coal mine, located nine miles Northwest of Huntington, Utah, adjacent to State Highway 31. The mine opened in 1994, and is owned and operated by C.W. Mining Co. (Co-op Mine).
The mine has three drifts into the Tank coal seam, which has a variable thickness of 4 to 9 feet. The mine has two active working sections, both of which use remote-controlled Joy 14CM15 continuous mining machines, Joy shuttle cars, Lee Norse TD-142 single-boom roof bolting machines, and belt haulage. A Fletcher DDR-13-B-CW double-boom roof bolting machine is used to install supplemental supports.
The mine employs 40 underground miners and 24 surface workers, and has a daily production of approximately 2,500 tons of coal. The mine works two, 10-hour production shifts and one 10-hour overlapping maintenance shift each day, 5 days per week. The mine liberates negligible amounts of methane.
In the area of the accident, main entries were being developed. The immediate roof consisted of a 3-foot layer of sandstone with clay-filled joints overlain by a 1-inch layer of coal. The main roof consisted of a massive layer of sandstone. The average mining height was 8.5 feet and the average mining width was 19 feet.
The last regular safety and health inspection at this mine was completed by the Mine Safety and Health Administration (MSHA) on November 6, 1996.
The principal officials at the mine are:
Cyril Jackson..................................Safety Director
DESCRIPTION OF THE ACCIDENT
On Friday, December 20, 1996, at approximately 1:30 p.m., a Joy 14CM15 remote-controlled continuous mining machine (a.k.a. continuous miner) was being used to complete the final clean-up pass on the left side of the face. A 40-foot deep extended cut had just been completed in this face, which was located in the #1 entry, 113 feet inby the centerline of crosscut 7 in the East Bleeders panel. At that time, a roof fall occurred in the face with a length of 40 feet, a width ranging from 5 to 14 feet, and a thickness of approximately 3.5 feet. The material that fell completely covered the continuous miner and consisted primarily of massive blocks of sandstone with small fragments of claystone, sandstone, and coal. No injuries occurred and MSHA conducted an investigation that same day. After the investigation was completed, the continuous miner operator tried to tram the continuous miner out of the face, but the continuous miner was not operational. It was suspected that an overload relay switch in the electrical circuit for a pump motor had been damaged by the roof fall. This overload relay switch was located on the right side near the rear of the continuous miner.
The mine operator devised clean up and support procedures for the area of the roof fall. These procedures consisted of using a scoop to knock rocks off of the continuous miner and to scoop rocks off of the mine floor as much as practicable, provided that the scoop operator remained under supported roof at all times. Next, a roof bolting machine (a.k.a. roof bolter) would be used to install roof bolts up to the right rear side of the continuous miner so that a mechanic could access and repair the damaged overload relay switch while remaining under supported roof. After it was repaired, the continuous miner would, via remote control, be trammed outby to be underneath fully supported roof. Any rocks that had not fallen off of the continuous miner during the tramming process would then be removed from the top of the machine with pry bars. Finally, the scoop and roof bolter would be used alternatingly until the entire area was fully supported. All persons assigned to perform this rehabilitation work were verbally instructed in the clean up and support procedures. This plan was not in writing.
On Saturday, December 21, 1996, a Fletcher DDR-13-B-CW double-boom roof bolter was used to install 6-foot fully-grouted resin bolts in the area of the roof fall. With the continuous miner blocking more than half the width of the entry, the Fletcher roof bolter was too wide and, consequently, could not be used to install roof bolts all the way up to where the damaged overload relay switch was located on the continuous miner. Management decided that on Monday, a Lee Norse TD-142 single-boom roof bolter would be used to install the remaining roof bolts, because it was narrow enough to work adjacent to the continuous miner. This roof bolter was normally used to install supplemental support in the working section.
No clean up work was performed in the area of the roof fall on Sunday, December 22, 1996.
On Monday, December 23, 1996, at approximately 6:15 a.m., nine miners and Shain Stoddard, section foreman, entered the working section in the East Bleeders panel. While three of the miners built stoppings, the others began to clean up and support the area of the roof fall. The Fletcher roof bolter was removed from the area of the roof fall. Then, a Wagner ST5-DS diesel-powered scoop, operated by Harvey A. Randall, mechanic/electrician, (victim), was used to knock rocks off of the top of the continuous miner. One rock, which was 9.5-feet long, by 2- to 4-feet wide, by 1- to 2-feet thick, was located on top of the right rear side of the continuous miner. When Randall tried to knock this rock off of the continuous miner, he inadvertently pushed it further inby so that the scoop could no longer reach it.
At approximately 10:30 a.m., a Lee Norse TD-142 single-boom roof bolter was trammed into the #1 entry by Rigo Rodriguez, roof bolter operator, with the assistance of Natividad Flores, shuttle car operator. Before he trammed the roof bolter adjacent to the right side of the continuous miner to begin bolting, Rodriguez, along with Flores, Stoddard, Randall, and Fransisco Leon, mechanic's assistant, examined the rock which Randall had tried to knock off of the continuous miner with the scoop. Rodriguez tried to push the rock with his hands. Since the rock did not budge, everyone assumed that the rock was stable.
While the others ate lunch, Rodriguez and Flores, under the direct supervision of Stoddard, began installing roof bolts adjacent to the right side of the continuous miner. After the roof bolter had advanced far enough to allow safe access, Stoddard removed the first of two side-cover plates from the right side near the back of the continuous miner. Two side-cover plates on the right side near the back of the continuous miner had to be removed to provide access to the damaged overload relay switch. At approximately 11:00 a.m., while advancing to the next bolting position, the roof bolter lightly bumped the continuous miner.
Stoddard left the roof fall area and traveled outby to check the progress of the stopping construction work. At approximately 11:15 a.m., Stoddard, Randall, and Leon returned to the roof fall area. After watching the roof bolting procedure for a few minutes, Randall and Stoddard decided to remove the second side- cover plate from the continuous miner. After the bolts were removed, Randall used a pry bar to remove the side-cover plate. When the side-cover plate was removed, the top- (horizontal) cover plate, that was above the side-cover plate location, sagged approximately 1.5 inches. The heaviest end of the rock that Randall had tried to move earlier was located on top of this top-cover plate.
At 11:30 a.m., approximately 3 to 4 minutes after the second side-cover plate had been removed, Stoddard and Randall were standing near the front of the roof bolter and Leon and Flores were standing behind the continuous miner. All of them were watching Rodriguez drill a hole with the roof bolter. At that time, the rock that Randall had tried to move earlier with the scoop began to slide off of the continuous miner toward the roof bolter. Leon and Flores saw this, and shouted, in Spanish, "Watch it! Rock!" Stoddard heard the warning and, thinking that a rock was falling from the roof, began to crouch down. When he did, he could see the rock sliding off of the continuous miner. As Stoddard jumped out of the way, the rock brushed the back of his hard hat. Stoddard noticed that Rodriguez had begun to crouch under the Automated Temporary Roof Support canopy of the roof bolter, as if he also expected a rock to fall from the roof. Realizing that Rodriguez was going to be struck by the sliding rock, Stoddard grabbed him and pulled him toward the front of the roof bolter. Neither of them sustained serious injuries.
When the rock began to slide off of the continuous miner, Randall was positioned between the continuous miner and the roof bolter. As the rock slid off of the continuous miner, it hit Randall in the back and pushed him toward the roof bolter. Randall's upper body was crushed between the rock and the panic bar that is near the front valve control levers of the roof bolter. As the rock continued to fall, Randall's body was freed from this position and he fell to the ground and landed under the valve control levers of the roof bolter. The rock landed beside, but not on top of him.
Stoddard saw Randall on the ground and immediately went to him. Randall did not respond to Stoddard's voice or touch. Stoddard ordered Leon and Flores to call for an ambulance. Seconds later, Randall stopped breathing. Stoddard could not feel Randall's heart beat either, so he began CPR. This continued for several minutes until Cyril Jackson, an Emergency Medical Technician, arrived. Jackson examined Randall and determined that he was dead. Nevertheless, CPR continued and Randall was promptly removed from the mine. An ambulance was waiting outside the mine. The ambulance attendants thoroughly examined Randall and pronounced him dead at 1:09 p.m.
PHYSICAL FACTORS INVOLVED IN THE ACCIDENT
- Shain Stoddard, section foreman and on-shift examiner,
stated that, after the second side-cover plate was removed
from the continuous miner, and the top-cover plate above it
sagged approximately 1.5 inches, no signs of instability of
the rock were observed.
- Examination of the second side-cover plate that had been
removed from the continuous miner revealed that the plate
had bowed approximately one inch. The plate was
approximately 3-feet wide by 2-feet high by 1/2-inch thick.
- The continuous miner had not been moved since the roof fall
- The small fragments of claystone that were on top of the
continuous miner, and under the rock before it fell, were
weak and could be crushed by hand.
- Testimony and physical evidence indicated that the rock
rotated 90 degrees as it fell off of the continuous miner.
- Shain Stoddard, the section foreman who was designated by
the mine operator to supervise the rehabilitation work, had
experience with doing rehabilitation work.
- Eight miners saw the rock on top of the continuous miner
before it fell. None of them considered it to be unstable
- The victim, Harvey A. Randall, could speak and comprehend
very few Spanish words. It is unknown whether he was able
to comprehend the warning of "Watch it! Rock!" which was
given in Spanish.
- There was no written policy addressing roof fall clean up at
- Due to the dip of the floor in the area of the roof fall,
the left side of the continuous miner was slightly higher
than the right side. The angle for this was approximately 3
degrees from the horizontal.
- The loose rocks on top of the continuous miner and under the
large rock before it fell were at an approximate angle of 25
degrees from the horizontal. The flat, bottom surface of
the large rock that was in contact with these loose rocks
had an angle of approximately 10 degrees. Therefore, the
top (visible) surface of the rock before it fell would have
appeared to be tilted approximately 15 degrees toward the
right side of the continuous miner.
- The rock that slid off of the continuous miner was sandstone
and measured 9.5-feet long, by 2- to 4-feet wide, by 1- to
2-feet thick. The weight of the rock was approximately 3
- The clean up and support procedures established by the
operator required that the roof over the right rear side of
the continuous miner had to be supported before repairs
could begin. The procedures did not specify that the roof
bolter had to be removed from the area before repairs could
- Six foot fully-grouted resin bolts were used to support the area after the roof fall. At the time of the accident, the roof was adequately supported over the right rear side of the continuous miner and over the miners that were standing nearby.
The 3-ton rock on the continuous miner was in an extremely unstable condition due to the soft, easily deteriorated claystone under the rock, the re-positioning of the rock by the scoop, the vibration of the rock when the continuous miner was bumped by the roof bolter, and the slope of the loose material under the rock. The subsequent sagging of the top-cover plate after the side-cover plate was removed augmented this unstable condition and ultimately caused the rock to slide off of the continuous miner.
A contributing factor to the accident was that the roof bolter was not removed from the area before repairs began. This created a confined space between the continuous miner and the roof bolter. The victim and section foreman placed themselves in this confined space while removing the side cover plates from the continuous miner and while watching the roof bolter. Since the roof bolter contributed to the crushing injuries of the victim, and since the rock did not land on the victim, it is possible that if the roof bolter had not been in the area, the accident may not have resulted in a fatality.
A section 103(k) order, number 4076554, was issued following the accident to ensure the safety of the miners.
There were no violations of Title 30 of the Code of Federal Regulations that contributed to the accident.
Citation number 3560130 was issued under a separate event number for a violation of 30 CFR 48.8(a) because the victim had not received annual refresher training. However, this training would not have prevented the accident.
Respectfully submitted by:
David W. Elkins
Archie D. Vigil
Assistant District Manager for Inspections
John A. Kuzar
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