DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
District 4
ACCIDENT INVESTIGATION REPORT
Underground Coal Mine
FATAL ROOF-FALL ACCIDENT
Big Branch Mine (ID No. 46-05978)
Eastern Mingo Coal Company
Naugatuck, Mingo County, West Virginia
November 8, 1995
by
Curtiss Vance, Jr.
Coal Mine Safety and Health Inspector
Joseph A. Cybulski
Supervisory Mining Engineer, Roof Control Division
William J. Gray
Mining Engineer, Roof Control Division
Originating Office - Mine Safety and Health Administration
100 Bluestone Road, Mount Hope, West Virginia 25880
Earnest C. Teaster, Jr., District Manager
OVERVIEW
Abstract
On Wednesday, November 8, 1995, about 11:20 p.m., a fatal roof- fall accident occurred in the last open crosscut between the No. 5 and No. 6 entries on the No. 4 working section at the Big Branch Mine, Eastern Mingo Coal Company. Milton Bryant, roof- bolting-machine operator and mobile roof-support operator, was fatally injured during the mining cycle of the second lift, off the lower outby portion of the No. 15 pillar block. The victim, along with two other miners, was positioned on the off side of the continuous-mining machine observing the hydraulic pressure readings on the gauges of the No. 1 and No. 2 mobile roof-support units that were set up in the No. 6 entry on the inby side of the intersection.
As the mine roof began to fall in the pillared-out area behind and directly over the pillar being mined, the fall rode over both sets of the mobile roof supports, the continuous- mining machine, and the off-standard shuttle car, fatally injuring the victim. The continuous-mining-machine operator and the second mobile roof-support operator received minor injuries. The shuttle-car operator and continuous-mining-machine helper escaped without any injuries.
Background
The Big Branch Mine is located near Naugatuck, Mingo County, West Virginia. The mine is extracting the Coalburg coalbed which is about 72 inches in thickness. The immediate roof in the mine varies from shale, up to 25 feet thick, to sandstone. The immediate roof in the No. 4 section, the area of the accident, was sandstone. The sandstone unit above the Coalburg seam has a published Coal Mine Roof Rating (CMRR) of 96, indicating a very competent immediate roof.
The mine floor consists of shale. Depth of cover ranges from the outcrop up to 675 feet and averages about 400 feet. Cover at the accident site was estimated at 150 feet. Primary roof support installed in the No. 4 section consisted of 30-inch-long mechanical bolts. Bolts are installed four per row with 4-foot spacing between rows and 4- to 5-foot spacing within rows.
The No. 4 section was full pillaring a nine-entry panel which had been developed in an easterly direction to within 150 feet of the outcrop. Entries and crosscuts were driven 20 feet wide on 60- foot centers, leaving pillars approximately 40 feet by 40 feet. Crosscuts were turned on a 90-degree angle. The panel had been developed as a super-section with two continuous-mining machines.
At the time of the accident, one continuous-mining machine was being used for pillaring operations, while the second continuous- mining machine was located several crosscuts outby driving rooms to the right toward previous workings. A set of four Fletcher mobile roof supports was being used in conjunction with a radio- remote-controlled continuous-mining machine during the pillaring operation. The Christmas-tree method of pillar extraction was being used in the No. 4 section.
An analysis of Retreat Mining Pillar Stability (ARMPS) evaluation was performed by the Pittsburgh Safety and Health Technology Center to estimate stability factors for the pillars on the No. 4 section. A conservative evaluation was performed utilizing the following input parameters: mining height - 7 feet; overburden - 400 feet; No. of entries - 9; in situ coal strength - 900 psi; pillar size - 40 x 40 feet; entry/crosscut width - 20 feet; abutment loading - active gob only; abutment angle - 90 degrees (first fall condition); extent of active gob - 140 feet. This ARMPS evaluation indicated a stability factor of 1.56 for the pillars in the No. 4 section. A stability factor of 1.5 or higher usually indicates that the current pillar design will produce satisfactory ground conditions. The observed condition of the pillars during the investigation supports the ARMPS evaluation.
The principal officers of Eastern Mingo Coal Company are David Michael Young, president; Donald Arrowsmith, vice president; Kevin L. Yocum, secretary; and Sharad M. Desai, treasurer.
The Big Branch Mine provides employment for 265 persons underground and 30 persons on the surface, working out of three different portal locations, each under separate management. There are 110 persons employed at the Marrowbone Creek portals working three production shifts per day, 70 persons are employed at the Spruce Creek portals working two production and one maintenance shifts per day, and 85 persons at the Big Branch portals working three production shifts per day.
The mine produces an average of 20,650 raw tons of coal daily from four continuous-mining-machine sections. Coal is transported from the sections to the surface via belt conveyors. The miners are transported to their assigned work areas by a battery-powered man bus.
The operator's approved roof control plan requires that a test hole be drilled in every intersection immediately prior to mining the inby blocks by the shift that will mine the block, to a point at least 1 foot above the anchor point of the bolts used to pin the intersection on advance.
Supplemental supports provided during pillar recovery are comprised of four mobile roof-support (MRS) units operated in pairs in entries and crosscuts adjacent to the gob line. These MRS units are operated by remote control and moved in a staggered configuration as the coal pillars are extracted.
After extraction of a pillar has been completed and the No. 1 and No. 2 MRS units have been moved out of the pillared area, and the No. 3 and No. 4 MRS units have been set up in the intersection, breaker posts are to be installed in the outby entry. Mining was being conducted in the second lift off the outby wing of the No. 15 pillar block. The roof control plan on page 22 shows the pillar recovery plan sequence of lifts to be mined, indicating the lift being mined at the time of accident as the No. 8 lift. The roof control plan stipulates on page 21 that during the pushout, the MRS units are moved to maintain a 16-foot roadway.
Ventilation is induced into the Marrowbone Creek portals with two 6-foot blowing fans which produce about 230,000 cubic feet of air per minute. There has been no significant liberation of methane detected in the mine atmosphere.
The last regular (AAA) inspection by the Mine Safety and Health Administration was completed September 26, 1995. Another AAA inspection was ongoing at the time of the accident.
STORY OF EVENT
The afternoon production crew for the Big Branch 032-0 MMU working section entered the mine at 4:00 p.m. on Wednesday, November 8, 1995. The production crew was supervised by Carlos Hess, section foreman. Carl Thompson operated the Joy 14CM15 continuous-mining machine, and Donald Farris was the continuous- mining-machine helper. Milton Bryant (victim) and Kathy Ball operated the four Fletcher Model 13 mobile roof-support (MRS) units. The Joy 10S/C32B shuttle cars were operated by Calvin Tomblin, Ron Wood and Julias Lucas. The 488 S&S scoop was operated by Stan Ball. The timberman was David Hundley and the section electrician was David Mcloud. The Lee-Norse TD-32 roof- bolting-machine operators were Mike Walker and Robert York.
The production crew arrived on the No. 4 section of the Big Branch Mine about 4:30 p.m. Hess talked briefly with the crew and then proceeded to examine the faces across the pillar line. Hess tested the working places for gasses and measured the velocity of the air current in the last open crosscut outby the pillar line between the No. 2 and No. 3 entries.
Hess then notified crew members of the location of the section equipment and that not all the shuttle cars would reach the right side of the pillar line due to the power box being moved back by the day shift. Hess had the No. 9 continuous-mining machine taken to the pillar to start mining. Hess assigned the electrician and two other crew members to check and make repairs to cables and equipment not being used. Once the cables were straightened out from the power move, the No. 29 continuous-mining machine was set up to start mining the rooms off the No. 9 entry outby the pillar line on the right side of the section.
Mining of the pillar blocks was conducted from right to left, removing the No. 13 and No. 14 pillar blocks entirely and part of the No. 15 and No. 16 pillar blocks. Once the inby mining of the No. 15 and No. 16 pillar blocks was completed, Ball moved the No. 1 and No. 2 MRS units and set them up to mine the lower outby portion of the No. 15 pillar block. Thompson stated that one lift had been mined out of the lower outby portion and that Bryant had moved the No. 3 and No. 4 MRS units in tight on the right side of the continuous-mining machine. Bryant, Ball and Farris were positioned on the left side of the continuous-mining machine.
Ball stated she observed the hydraulic pressure on gauges mounted on the No. 1 and No. 2 MRS units slowly rise a couple hundred pounds during the mining cycle of the first lift off the outby end of the No. 15 pillar block. Ball stated she was leaning on the MRS units watching the gauges and breaker timbers back behind the pillar line taking weight. She stated that the hydraulic gauges took a sudden rise in pressure of a couple hundred pounds, alerting her that something was happening. When she turned to warn Bryant and Farris, the mine roof began to fall and she exited through the crosscut over into the No. 5 entry.
Tomblin stated that while he was operating the off- standard shuttle car being loaded by the continuous-mining machine, he observed the MRS operators start to run, and before he could reverse the shuttle car to exit the intersection, he heard the mine roof crack and fall, catching the shuttle car.
Tomblin stated that once the mine roof stopped falling and dust that was raised from the falling rock settled so he could see, he climbed out through the back of the shuttle car deck from under the operator's canopy to clear the roof fall. Tomblin stated he saw Thompson get hit with the falling roof, and once out of the shuttle car, he began to call out and search for him. Thompson had crawled outby Tomblin into the outby intersection where Tomblin found him sitting.
Thompson had lacerations to his face and the top of his head. Tomblin called out for help just as some of the other crew members working outby the pillar line began to arrive at the accident site. Tomblin asked other crew members to care for Thompson as he traveled over into the No. 5 entry where Ball was found lying on the mine floor.
Tomblin stated he assessed Ball for injuries because she appeared to be going into shock. Tomblin asked Ron Wood to take Ball to the power center and treat her for shock, and no other injuries were observed. Tomblin traveled on into the last open crosscut from No. 5 entry toward No. 6 entry to the edge of the roof fall where he found Bryant (victim) caught 3 to 4 feet back under the edge of the roof fall.
Hess, an EMT, assessed and treated Ball and Thompson and told Mike Walker and Ronald Wood to take them to the surface where emergency assistance was waiting. Tomblin had told the scoop operator to bring the scoop and timbers over to the accident site to timber around the edge of the roof fall. The crew was setting timbers at the edge of the roof fall to recover the victim when Hess arrived from the No. 5 entry after sending Ball and Thompson outside. Hess instructed one crew member to get a lifting jack, slate bar, and sledge hammer from the power center to lift and break rock off the victim to recover him.
Once the victim was removed from under the roof fall, Hess began to assess the Victim's vital signs; none could be found, and CPR treatment was started. The victim was loaded onto a stretcher, taken to the end of the track, loaded onto a man bus, and transported to the surface.
The Mingo County Ambulance Service was waiting on the surface to give emergency assistance to the victim once he arrived at the mine surface. Hess assisted the ambulance personnel in performing CPR during the initial evaluation by the ambulance service. The victim was transported to the Williamson Memorial Hospital where he was pronounced dead on arrival at 2:00 a.m.
INVESTIGATION OF THE ACCIDENT
The Mine Safety and Health Administration was notified at 12:05 a.m. on November 9, 1995, that a fatal roof-fall accident had occurred. Mine Safety and Health Administration personnel began to arrive at the mine at 1:10 a.m. A 103(k) Order was issued to ensure the safety of the miners until the accident investigation could be completed.
The Mine Safety and Health Administration and the West Virginia Office of Miners' Health, Safety and Training jointly conducted an investigation with mine management personnel, the miners, and representatives from the United Mine Workers of America.
All parties were briefed by mine management personnel as to the circumstances surrounding the accident. A discussion was held with all the miners working in the Big Branch Mine on the No. 4 section at the time of the accident. Representatives from all parties traveled to the accident scene where an examination was conducted. Video recordings and sketches were made and photographs and relevant measurements were taken at the accident site on November 9 and 10, 1995.
Interviews of individuals known to have direct knowledge of the facts surrounding the accident were conducted at the Mine Safety and Health Administration field office conference room at Mount Gay, West Virginia, on November 13, 1995.
The physical portion of the investigation was completed December 11, 1995.
DISCUSSION
Training
Records indicated that training had been conducted in accordance with Part 48, 30 CFR.
An examination of Bryant's training records revealed that he had received all required training.
Examinations
Records and the examiners' date, time, and initials indicated that the required examinations were being conducted in the Big Branch Mine 032-0 MMU working section.
Physical Factors
- The fall was comprised of sandstone roof measuring 80 to 120
feet wide, 320 to 340 feet long, and 8 inches to 15 feet
thick.
- The roof did not indicate any problems until the fall
occurred.
- There were no indications of excessive pressure on the
pillars in the immediate area surrounding the roof fall.
- There was approximately 150 feet of cover over the pillars
in the fall areas.
- Pillars were being extracted approximately 150 feet from the
coal outcrop.
- The mine roof was bolted with 30-inch conventional-type roof
bolts.
- The mine floor was damp in the crosscut at the site of the
accident.
- No additional roof supports were installed, other than the
minimum requirements stipulated in the approved roof control
plan.
- The pressure gauges mounted on the frames of the MRS units were located in positions requiring some machine operators to stand close to the MRS units to observe pressure readings on the gauges.
CONCLUSION
The resultant fatality occurred when the mine roof suddenly collapsed while the victim and other miners were mining the second lift from the lower portion of the No. 15 pillar block. The victim was caught by the collapsing mine roof, while those miners working nearby escaped with only minor injuries. The hydraulic gauges were mounted on the machine in positions that forced some of the MRS operators to stand in close proximity to the machine to observe pressure readings on the gauges.
CONTRIBUTING VIOLATION
There were no contributing violations of 30 CFR cited during the investigation of the fatal roof-fall accident.
Submitted by:
Curtiss Vance, Jr.
Coal Mine Safety and Health Inspector
Joseph A. Cybulski
Supervisory Mining Engineer
William J. Gray
Mining Engineer
Approved by:
Richard J. Kline
Assistant District Manager
Earnest C. Teaster, Jr.
District Manager
Related Fatal Alert Bulletin:
FAB95C39