DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
Report of Investigation
August 28, 2000
(Underground Coal Mine)
Fatal Hoisting Accident
Mine No. 2 (I.d. No. 15-09571)
Excel Mining LLC
Pilgrim, Martin County, Kentucky
Hei-tech (I.d. No. Twn)
Robert M. Bates
Mark V. Bartley
Originating Office - Mine Safety and Health Administration
4159 North Mayo Trail, Pikeville, Kentucky 41501
Carl E. Boone, Ii, District Manager
Release Date: November 6, 2000
At approximately 12:30 p.m., two employees of Heitech Corporation boarded the mantrip and prepared to enter the mine. Another independent contractor employee, hired to perform various outside duties, was operating the hoist controls at the time. When the hoist was activated, the cars traveled a few feet down the track and stopped just outside of the portal. This created slack in the hoist rope and activated the slack rope switch, which stopped the hoist drum. Using a small loader, the hoist operator pushed the stalled cars forward in order to take up the slack in the rope. At some point during this process, the slack rope protection system on the hoist failed and several hundred feet of slack rope accumulated in the hoist machinery room. When the cars started moving again, they traveled down the slope at a high speed until the slack in the rope was taken up. At this point the hoist rope broke and the cars continued downward, eventually derailing and striking a solid concrete wall near the bottom of the slope. The two occupants of the passenger car were fatally injured in the accident.
Excel Mining, LLC., Mine No. 2, is located off Kentucky Route 1439, approximately six miles from the unincorporated town of Pilgrim in Martin County, Kentucky. Excel Mining, LLC. is a wholly owned subsidiary of Alliance Coal LLC, located in Tulsa, Oklahoma. The mine was last placed into active status on November 1, 1999, but was originally developed in 1977 by Pontiki Coal Company, a division of Mapco Coals, Inc. The victims were employed by Heitech Corporation of Cedar Bluff, Virginia. Heitech Corporation specializes in injection-bolting, ventilation seals, roof-strata consolidation and drilling applications for the mining industry.
Coal is produced on two active mechanized mining units (MMU's) utilizing continuous mining machines with shuttle car haulage. Coal is transported via belt conveyor to the surface and onto the preparation plant for processing. The mine operates seven days a week, with production occurring five to six days per week. Maintenance is normally performed on third shift and weekends. The mine produces an average of 5,000 tons of coal daily. An organizational chart is provided in the appendix to illustrate the structure of mine management.
The last complete regular safety and health inspection of the mine was completed on June 29, 2000. Another regular safety and health inspection of the mine was started on July 7, 2000, and was ongoing at the time of the accident.
DESCRIPTION OF ACCIDENT
On Sunday, August 27, 2000, the third shift crew arrived at the mine site at approximately 11:30 p.m. Sixteen Excel Mining employees, eight contract employees, Hobert Webb (MSHA mine inspector) and Eugene Vanhoose (mine inspector trainee) boarded the mantrip and prepared to enter the mine in the 16 degree slope. The mantrip conveyance consisted of a brake car coupled to a passenger car. A wire hoist rope was attached to the rear of the passenger car.
The hoist at the mine was constructed to be operated from three locations: the hoist machinery room, the hoist house, and a remote station located approximately 54 feet from the mine portal. The machinery room contains the operating mechanisms of the hoist which includes the following equipment: the hoist drive motor, the hoist drum and rope, electrical control panels, safety switches, braking mechanisms, and speed control devices.
David West, who was not a qualified hoisting engineer, was assigned the task of operating the hoist controls for the third shift. At approximately 11:35 p.m. West activated the down button and the cars moved approximately ten feet down the track before stopping due to the angle of the track and the build-up of debris around the rails. The stalling of the cars caused slack to develop in the hoist rope which automatically stopped the hoist by activating the slack-rope switch. When this occurred, West requested the assistance of Wayne Adkins, belt mechanic, who was working in the shop area of the warehouse. West instructed Adkins, who was unfamiliar with the operation of the hoist controls, on the procedure used to remove slack from the hoist rope. Adkins positioned himself at the hoist controls located near the top of the slope while West traveled to the hoist machinery room located approximately 300 feet from the mine portal.
When West arrived in the machinery room, he disconnected the slack rope trip cable and began taking up the slack in the hoist rope using the hoist controls at that location. When tension was restored to the hoist rope, West reconnected the slack rope trip cable and told Adkins (using a two-way radio) to push the down button on the hoist controls located near the top of the slope. Adkins activated the down button and the cars descended the slope without incident. Adkins went back to work in the shop and West returned to the top of the slope to operate the hoist controls. After the cars reached the bottom of the slope the passengers disembarked and West activated the up button to return the cars to the surface. When the cars reached the surface, West positioned the brake car at the charging station located approximately 54 feet from the portal.
While the cars were ascending the slope, David and Robert Helbert, Heitech Corporation employees, arrived at the mine site. The contractors had been working at the mine for approximately two weeks performing rehabilitation work on a portion of the mine roof located approximately 600 feet down the slope. The procedure being used involved drilling holes and injecting a resin compound in an effort to stabilize the roof. West informed the contractors that before the cars could be lowered again, the batteries needed to be charged for 20 to 25 minutes. (The batteries on the brake car provide power for the lights and the magnetic braking system. The magnetic braking system is designed to stop the car in the event of a hoist rope failure and engages automatically at a predetermined speed. The braking system can also be activated manually by a button located near the front seat of the brake car.)
While the batteries were charging, West talked to the Heitech employees concerning the location of their work and the procedure for transporting them to the surface at the end of the shift. For the previous week, West had been lowering the two men to the correct location using the controls and the depth indicator located in the hoist house located approximately 60 feet from the charging station.
After the batteries had charged for approximately 40 minutes, the two Heitech employees boarded the mantrip, positioning themselves in the front seat of the passenger car. (Seated in this location, the men were unable to reach the button that manually engages the magnetic braking system) West activated the down button and the cars rolled approximately 10 feet down the track and stopped near the same point as on the previous trip. Once again, this situation caused slack to develop in the hoist rope.
On this occasion, however, West did not go to the machinery room to check the slack rope switch and take up the slack. Instead, he proceeded to the control panel located near the top of the slope and used a roof drill bit and black electrical tape to bind the down button in the activated position. West walked over to the shop area of the warehouse where a Case, Model 1840 endloader (skid-steer type) was located.West started the endloader and trammed it over to the track where the brake and passenger cars were located. West used the bucket of the loader to push the cars in order to get them started again.
At some point during this process, the slack rope protection system failed and the hoist drum started turning. By the time the cars started moving again, the hoist drum had been unwinding the hoist rope for approximately two minutes and 55 seconds, allowing approximately 762 feet of slack cable to accumulate in the hoist machinery room (A determination of this time period is explained in the Discussion section of this report). West parked the loader and dropped the bucket. He exited the loader, walked over to the control panel located near the top of the slope, and removed the electrical tape from the down button.
Once in motion, the cars moved very slowly until they reached the knuckle of the slope (the point at which the slope increases to a 16 degree pitch). After reaching this point the cars accelerated rapidly down the slope. West, realizing that something had gone wrong, ran to the hoist house and hit the emergency stop button. The brake and passenger cars traveled approximately 762 feet down the slope until the slack in the wire rope had been consumed. At that point, the weight of the rope and speed of the descending cars resulted in a complete failure of the hoist rope. After the hoist rope failed, the cars traveled another 662 feet down the slope before derailing at a curve in the track located approximately 1,424 feet from the portal and approximately 109 feet from the bottom of the slope. Measurements taken during the investigation indicate that the hoist rope broke at a point between the hoist machinery room and the directional sheave structure located on the surface of the mine. The investigation revealed that the magnetic braking system on the brake car failed to operate at any time during this sequence of events.
The sound of the descending cars and the sparks produced by the severed cable attracted the attention of Wayne Adkins, who was working in the shop at the time. He ran to the top of the slope where West informed him that cars had descended the slope at an abnormally high speed. West and Adkins traveled to the portal and looked down the slope. The two men saw no movement at the bottom of the slope. It was apparent while the men were standing at the mine portal that the hoist rope was no longer intact and laying its normal position between the hoist rails.
West ran back to the hoist control room to call Johnny Meade and Lowell Spaulding, who West thought were the closest to the bottom of the slope. John Greene, electrician, who was near the bottom of the slope at the company designated belt conveyor F-drive, heard the conversation and proceeded to the accident scene. West contacted Larry Howell, third shift foreman, who was at the 007 section with MSHA personnel, Hobert Webb and Eugene Vanhoose. Howell, Webb, and Vanhoose immediately proceeded to the accident scene. West notified Net-Care Ambulance Service and requested two ambulances. He then contacted John Small, general manager; Dave Jude, superintendent; and Sharon Smith, safety director, at their residences and notified them of the occurrence.
When John Greene arrived at the scene of the accident he checked the victims and found no signs of life. Larry Howell, Hobert Webb and Eugene Vanhoose arrived shortly after Greene and also checked the victims for signs of life. Miners on the two working sections were called and instructed to evacuate the mine. The victims were carried by Excel Mining personnel and contract miners up the slope to the surface of the mine, where Martin County Coroner, Mike Crum and Deputy Coroner Maurice Mills, pronounced them dead.
INVESTIGATION OF THE ACCIDENT
David West called Larry Little, acting field office supervisor of the Martin, Kentucky MSHA field office and reported the accident at approximately 12:55 a.m. Little called Carl E. Boone II, district manager, who in turn notified John South, supervisory special investigator. South contacted Mark Bartley, accident investigator and instructed Bartley to contact Robert Bates, electrical engineer/accident investigator, to help. Bartley and Bates proceeded to the mine site, arriving at approximately 3:45 a.m. MSHA inspectors' Webb and Vanhoose, who were underground at the mine at the time of the accident were present at the scene. Larry Little was also on the scene when Bartley and Bates arrived. Representatives of the Kentucky Department of Mines and Minerals (KDMM) and Excel Mining LLC were also present at the accident scene. Excel Mining LLC management personnel who had been offsite at the time of the accident responded to the scene to assist with recovery operations.
Bartley and Bates proceeded down the slope to the accident scene where recovery of the two victims was taking place. The two victims were recovered and taken to the surface of the mine. Bartley and Bates proceeded to overview the scene. Bartley, Bates, and KDMM personnel sketched the scene, took measurements, took photographs, made an examination of the slope track, and made a preliminary examination of the brake car and personnel car. A 103 (K) withdrawal order was issued by MSHA to protect persons against possible hazards until the investigation could be completed.
After the onsite examination of the scene at the bottom of the slope, Bartley and Bates traveled to the surface, and made a preliminary examination of the hoist house, hoist machine and surface installation. MSHA personnel contacted the Pikeville District office to relay preliminary information and to request additional assistance from MSHA Technical Support.
An interview was set up with David West, eyewitness, to help determine the cause of the accident and to assist investigators in determining the most direct course for the investigation. The initial phase of the interview was conducted on August 28, 2000. Sixteen subsequent interviews were conducted with West and other mining personnel on August 29 and 30, 2000. The onsite portion of the investigation continued each day until September 8, 2000. Dean Skorski, a supervisory electrical engineer from MSHA Technical Support, and Robert Phillips, coal mine safety and health specialist from MSHA Safety Division, assisted District 6 investigators in the examination of the hoist system and brake car. Lynn Hooley, field technician from ABB Automation Services was present to assist in the testing procedure. A re-creation of the events relative to testimony and physical evidence found was done by MSHA personnel to assist in determining the cause of the accident.
The 103 (K) withdrawal order was terminated on September 8, 2000, after all equipment involved in the accident had been examined and hoist training had been conducted for employees of all three shifts at the mine. The brake car and personnel cars were replaced with reconditioned units, the hoist rope was replaced, and the entire system was examined and functionally tested prior to returning the man-hoist into operation.
The investigation revealed the following factors relevant to the occurrence of the accident:
1. David West was the only known eyewitness to the accident.
2. The coroner's report listed "massive head trauma" and "chest trauma" as the immediate causes of death for David Helbert and Robert Helbert respectively.
3. The slope on which the brake and passenger cars were operating was inclined 16 degrees and was approximately 1400 feet in length.
4. The slope entry is divided horizontally into two compartments by a steel partition. The conveyor belt is routed through the upper compartment, while the track is contained in the lower.
5. The mine is not provided with a personnel elevator. All mantrips and supply trips use the slope entry to travel in and out of the mine.
6. The Selsyn (depth) indicator in the machinery room indicated that the mantrip had descended approximately 766 feet from the normal stopping position at the top of the slope when the hoist rope failed.
7. The mantrip conveyance involved in the accident consisted of a Sanford-Day Brakeman� Safety Car (brake car) attached to a passenger car. The passenger car was attached to the rear of the brake car.
8. The approximate weight of the brake car was 13,500 pounds. The manufacturer recommends this car for use on slopes with grades up to 18 degrees.
9. The brake car is an eight-wheel unit equipped with six magnetic track brakes designed to prevent runaway trips due to rope breakage or hoist failure. The braking system can be activated manually by pressing an emergency stop button or automatically when the car exceeds a certain speed (typically 115% of normal operating speed). Two belt-driven centrifugal switches are provided to monitor the speed of the car and set the brakes when an overspeed conditions occurs.
10. The emergency stop button, used to activate the magnetic braking system on the brake car was located in the front seating compartment of the brake car. There was no emergency stop button located in the passenger car. The victims were seated in the front seat of the passenger car at the time of the accident and therefore could not have activated the emergency stop button.
11. The brake car was provided with roll-back protection designed to set the brakes if the car rolls backward while coming out of the mine.
12. Power for the magnetic braking system and the lights was provided by a 48-volt set of automotive type batteries. Most of the battery cells were significantly damaged in the accident and could not be tested. However, specific gravity readings taken on the intact cells after the accident indicated that the charge was within manufacturers guidelines.
13. The centrifugal overspeed switches (Hubbell Model # 2200-PR-026-XX) on the brake car involved in the accident were initially tested at the scene and found to be inoperative. When the flyweights were fully extended, the switch contacts would not close. As found, neither switch would have actuated the braking mechanism on the brake car. The switches were later taken into custody by MSHA's Technical Support for further testing after being taken into custody.
14. Testing of the switches was conducted in a laboratory at the Pittsburgh Safety and Health Technology Center on October 3, 2000. Each switch failed to actuate at any speed. The switches were tested at speeds up to approximately 4,000 feet per minute. Both switches appeared to be adjusted to the same degree and did not suffer a change in their adjustment due to the accident. However, the right-side speed switch had a slightly bent shaft near the pulley. This may have been caused by the accident.
15. The hoist system involved in the accident consisted of a Nordberg single-drum hoist equipped with controls designed by P&H Electronics.
16. The hoist was designed to operate at either 300 or 600 feet per minute.
17. A test of the hoist mechanism and controls after the accident indicated that the hoist machine, with the exception of three unrelated deficiencies, was functioning correctly at the time of the accident.
18. The hoist was provided with a slack rope protection system consisting of a 1/8" diameter steel cable (trip wire) and a Westinghouse type HDH23 limit switch. The steel cable was suspended across the opening through which the hoist rope entered the machinery room. The system is designed such that when a slack rope condition occurs, the weight of the hoist rope falling on the trip wire causes the limit switch to operate and stop the hoist drum from turning.
19. The slack rope trip wire was severed at some point either shortly before or during the accident. The two ends of the 1/8" trip wire were analyzed by MSHA's Approval and Certification Center on September 28, 2000 to determine the mode of failure. Visual examination, aided by the use of a stereo microscope, of the slack rope trip wire indicated that it failed primarily due to abrasion. All of the surfaces of the fractured strands and individual wires examined appeared clean and rust-free. There were also isolated areas of long-term abrasion identified on this wire rope.
20. The 1.25 inch hoist rope (6x30 construction) was of right lang lay configuration with a rated breaking strength of 167,000 pounds. The rope was installed on February 26, 2000.
21. Prior to the accident, the hoist rope was installed in a single layer on the hoist drum with approximately seven wraps of hoist rope remaining on the drum with the brake car at the bottom of the slope.
22. Measurements taken after the accident indicate that the hoist rope broke at a point on the surface between the machinery room and the directional sheaves.
23. The hoist rope was supported by a gantry structure with rollers between the machinery room and the directional sheaves. Several rollers on the gantry structure were completely inoperative and exhibited damage (grooves) caused by the abrasion of the hoist rope.
24. The two ends of the 1.25" hoist rope were analyzed by MSHA's Approval and Certification Center on September 28, 2000 to determine the mode of failure. These findings were:
A. The exterior of the hoist rope was dry and not lubricated. However, the internal portions of the rope appeared to have adequate lubrication. There was no indication of corrosion on the individual wires.25. MSHA investigators simulated the events of the accident as described during testimony. Investigators physically recreated the accident scene (location of machinery and personnel) and proceeded to time the sequence of events as described in testimony and found from physical evidence. The speed of the hoist drum was found set to operate at 65 feet-per-minute during the startup cycle of the hoist. During the normal operating cycle of the hoist, the hoist was found set to operate at 300 feet-per-minute. These operating speeds were verified during the investigation. Utilizing the time sequence determined during the recreation of events and the documented operating speeds of the hoist, a period of 2 minutes and 55 seconds was established in which the hoist rope unwound on the reel. This time sequence later corresponded to the amount of rope which was found to be unwound (both sections of rope were measured).
B. A significant amount of wear was noted on a portion of the rope away from the fracture. This wear is believed to have been present prior to the accident. The outer wires in this area exhibited a loss of 0.010" (approximately 11%) due to wear. This loss would equate to a loss of strength in those wires of approximately 15% and an overall loss in rope strength of approximately 8%.
C. At the fracture, a significant amount of damage was noted to individual wires. The damaged wires in this area were oval with an average minor diameter of 0.060" and an average major diameter of 0.106". This indicates that this damage is due to "peening" and is believed to have been caused during the accident.
D. The damage to the rope is consistent with a rapidly applied load ("shock load") where the rope has either bent over a "sharp" (small diameter) object, or been looped or knotted about itself. The overall appearance of the rope, the peening, heating of individual wires, and the fracture appearance of the wires all are indicative of this mode of failure.
The fatal hoisting accident occurred due to the following reasons:
A. The hoist operator failed to operate the hoist controls in a manner consistent with recognized and established guidelines. The hoist operator did not use a safe procedure to address the initial slack rope condition. This unacceptable procedure contributed to the massive accumulation of slack rope behind the mantrip. Mine management placed the hoist operator in a job that he was not properly trained and qualified to perform.
B. The slack rope protection system failed to operate, allowing 762 feet of wire rope to accumulate in the hoist machinery room. It is likely that either the slack rope switch trip cable was broken or the hoist rope bent into a position that prevented contact with the slack rope switch trip cable.
C. The safety system provided on the brake car failed to operate when the rope broke and the car went into an overspeed condition. The safety system was designed to stop the car in the event of an overspeed condition.
1. A 103 (k) order was issued to protect persons from possible hazards until the investigation could be conducted.
2. A 104(d)(1) citation was issued to Excel Mining, LLC because the brake car used to transport men in and out of the mine was not provided with funtional safety catches or other no less effective devices. This was a violation of 30 CFR, Section 75.1400 (c).
3. A 104 (d)(1) order was issued to Excel Mining, LLC because the hoist used to transport persons in and out of the mine was being operated by a person who was not a qualified hoisting engineer. The operator failed to ensure that a qualified hoisting engineer was on duty for the third shift. This was a violation of 30 CFR, Section 75.1400(e).
4. A 104(d)(1) order was issued to Excel Mining, LLC because an examination of the hoist used to transport persons in and out of the mine was not performed on 08/27/00. This was a violation of 30 CFR, Section 75.1400(d).
5. A 104 (d)(1) order was issued to Excel Mining, LLC because the operator failed to conduct the required bimonthly tests of the centrifugal overspeed switches for the Sanford-Day brake car. This was a violation of 30 CFR, Section 75.1400(c).
6. A 104(a) citation was issued to Excel Mining, LLC because the hoist used to transport persons in and out of the mine was not maintained in safe operating condition. The hoist's slack rope system did not detect and prevent a severe slack rope condition from occurring. This is a violation of 30 CFR, Section 75.1725(a).
7. A notice to provide safeguard was issued to Excel Mining, LLC because the angle of the rails and the build-up of debris around the track at a location approximately 50 feet outby the portal was preventing the brake car from initiating the descent down the slope. The safeguard requires that the track be maintained in a manner that will prevent conveyances from stalling outby the knuckle of the slope. This was issued relative to 30 CFR, Section 75.1403.
8. A notice to provide safeguard was issued to Excel Mining, LLC because the hoist used to transport persons in and out of the mine was not maintained in safe operating condition. On 08/28/00, the hoist's slack rope system did not detect and prevent slack a rope condition from occurring. This condition resulted in the failure of the 1.25" hoist rope and the death of two persons being transported in the hoistway. The safeguard requires that two independent slack rope switches be installed and maintained to prevent a slack rope condition from going undetected in the future. This was issued relative to 30 CFR, Section 75.1403.
9. A notice to provide safeguard was issued to Excel Mining, LLC because on 8/28/00 a rope failure occurred while two independent contractors were being lowered down the slope in a passenger (slave) car attached to a Sanford Day brake car. The overspeed devices on the car failed to operate and the car ran down the slope, resulting in two fatalities. Neither of the victims were positioned such that they could activate the emergency stop button located at the front of the brake car. This is a notice to provide safeguard requiring that a person be located in the front seat of the brake car within reach of the emergency stop button whenever men are transported using the hoist.
Related Fatal Alert Bulletin:
FAB00C23 - 24
List of Persons Participating in the Investigation1. Excel Mining, LLC Officials
John D. Small ............... General Manager2. Excel Employees
David D. Jude ............... Mine Superintendent
Willie E. Williams ............... Mine Foreman
Sharon Smith ............... Safety Director
Frosty Sammons ............... Safety Coordinator
Rick Wyman Akers ............... General Maintenance Superintendent
Lloyd E. McCoy ............... Chief Electrician
Larry Eugene Howell ............... Third Shift Foreman
William R. Mann ............... Section Foreman
Bill Turner ............... Warehouse Supervisor
Joseph Lee Kitts ............... Electrician3. Island Fork Construction LTD, Employees
John David Greene ............... Electrician
Wayne Authur Adkins ............... Belt Mechanic
Charles B. Mullins ............... Outside Supply Man
Ronald W. Johnson ............... Repairman
Dale Clayton Howell ............... Repairman
David William West ............... General Laborer4. Heitech
Rodney A. Howery ............... General Manager5. Martin County, Kentucky Officials
Mike Crum ............... Martin County Coroner6. Kentucky Department of Mines and Minerals
Tracy Stumbo ............... Chief Accident Investigator7. Mine Safety and Health Administration
Bobby Sexton ............... Accident Investigator
David Johnson ............... Chief Electrical Inspector
Wes Gearheart ............... Deputy Chief Electrical Inspector
Freddie Moore ............... Coal Mine Inspector
Robert Bates ............... Electrical EngineerList of Persons Interviewed
Mark V. Bartley ............... Electrical Engineer
Dean Skorski ............... Supervisory Electrical Engineer
John South ............... Supervisory Special Investigator
Rick Dunst ............... Metallurgical Engineer
Gerald W. McMasters ............... Conference Litigation Representative
Harold Thornsbury ............... Training Specialist
Robert Phillips ............... Senior Mine Safety and Health Specialist
Mary Beth Bernui ............... Attorney
1. Joseph Lee Kitts, Repairman, Excel Mining LLC
2. David William West, Warehouse Person, Island Fork Construction
3. Larry Eugene Howell, Third Shift Foreman, Excel Mining LLC
4. John David Greene, Electrician, Excel Mining LLC
5. William R. Mann, Section Foreman, Excel Mining LLC
6. Wayne Authur Adkins, Belt Mechanic, Excel Mining LLC
7. Lloyd E. McCoy, Chief Electrician, Excel Mining LLC
8. Ricky Wyman Akers, Maintenance Superintendent, Excel Mining LLC
9. Rodney A. Howery, General Manager, Heitech
10. Charles B. Mullins, Outside Supply Man, Excel Mining LLC
11. Bill Turner, Warehouse Supervisor, Excel Mining LLC
12. Ronald W. Johnson, Repairman, Excel Mining LLC
13. Dale Clayton Howell, Repairman, Excel Mining LLC
14. Willie E. Williams, Mine Foreman, Excel Mining LLC
15. John D. Small, General Manager, Excel Mining LLC
16. David D. Jude, Mine Superintendent, Excel Mining LLC