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UNITED STATES
DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
Metal and Nonmetal Mine Safety and Health

REPORT OF INVESTIGATION

Surface Nonmetal Mine
(Lime Mill)

Fatal Other Accident
August 6, 2002

Buffington Plant
Carmeuse Lime, Inc.
Gary, Lake County, Indiana
I.D. No. 12-00426


Accident Investigators

Thomas J. Pavlat
Mine Safety and Health Specialist

George R. Kent
Mine Safety and Health Inspector

Michael A. Hockenberry
Fire Protection Engineer
Engineering Support Branch

Ronnie J. Deaton
Mine Safety & Health Specialist
Education Field Services


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


OVERVIEW

On August 6, 2002, Carlos Ponce, maintenance person, age 55, was fatally injured by heat and/or gases in the No. 2 compartment of the No. 3 bag house dust collection system. Ponce had been assigned to monitor conditions of the No. 3 bag house. The accident occurred because Ponce became trapped in the No. 2 compartment.

Ponce had a total of 28-1/2 years mining experience as a maintenance person. He had received training in accordance with 30 CFR, Part 46.

GENERAL INFORMATION

Buffington Plant, a milling operation, owned and operated by Carmeuse Lime, Inc., was located at Gary, Lake County, Indiana. The principal operating official was Ron L. Vessell, plant manager. The mine operated three, 8-hour shifts, seven days a week. A total of 55 persons was employed at the plant.

Lime was produced at the plant by five kilns; three were operating on the day of the accident. The kilns were direct fired using pulverized coal as the main fuel source. Limestone utilized in the process was received at the plant by boat. The finished products were used in the manufacture of steel and the construction industry.

A regular inspection of this operation had been started on August 5, 2002, a day before the accident. The inspection was completed following this investigation.

DESCRIPTION OF ACCIDENT

On August 5, 2002, Carlos Ponce (victim), reported for work at 2:48 p.m., his normal starting time while working second shift. Ponce was assigned by maintenance lead person Tim J. Vessell to conduct daily routine maintenance on the compressors located below No. 1, No. 2, and No. 3 bag houses. Ponce was also instructed by Vessell to monitor conditions at the No. 3 bag house. Normally a maintenance person was not assigned to the bag house area on the second shift but, due to the scheduled emission stack test that afternoon and high bag pressure readings of the No. 3 bag house, Ponce was assigned to monitor the area. High bag pressure on the dust collection bags could have caused the bags to break, raising the amount of emissions from the bag house.

At approximately 4:00 p.m., Terry Carron, assistant plant operator, received a telephone call from Ponce. Ponce stated the bag pressure for the No. 3 bag house was running high and he requested the exhaust fan for the No. 3 kiln be slowed so the bags in the No. 3 bag house could be cycled (emptied). Carron told Ponce that the No. 3 bag house could not be cycled at this time because the stack emission test was still being conducted. Cycling the bags could have caused the emission reading for the bag house to rise, affecting the emission test.

Some time between 5:30 p.m. and 6:00 p.m., equipment operator Antonio D. Suarez talked to Ponce at the shop area. Ponce, who normally took his break at the shop, was on a forklift and stated the No. 3 bag house had high bag pressure. Ponce then drove the forklift in the direction of the No. 3 bag house.

At approximately 6:00 p.m., Dave L. Sparacino, engineer, was at the No. 3 bag house material feed tower and observed a forklift parked between No. 1 and No. 2 bag house.

Bill Williams, plant operator, went back to the No. 3 bag house at approximately 6:30 p.m. The bag pressure was still high on the No. 3 bag house. The emission test for No. 3 bag house had been completed at approximately 5:30 p.m. and the compartments could be cycled. Williams utilized the controls on the ground floor of the bag house to cycle compartments No. 1, No. 6, No. 7, and No. 12 of the No. 3 bag house. The process only took a couple of minutes and the bag pressure was reduced. Williams did not see Ponce in the area of the No. 3 bag house at this time, but was only at the ground floor area of the bag house.

At approximately 2:00 a.m., August 6, 2002, Antonio D. Suarez and Oscar D. Suarez, electrician, were in the parking lot getting ready to leave the plant when they noticed Ponce's car. They called the kiln floor to see if anyone had seen Ponce. An examination of the shop area indicated Ponce's locker was still open.

Upon receiving the call concerning Ponce, Angel Bonilla, Jr., plant operator, and Jim O. Cayer, third shift supervisor, began searching the plant. At approximately 3:15 a.m., after searching the No. 1 and No. 2 bag house, Bonilla began searching the No. 3 bag house. At approximately 4:00 a.m., Bonilla discovered Ponce laying on the floor in the No. 2 compartment of No. 3 bag house. The door to the compartment had been closed and latched.

The Gary police department and local emergency personnel were notified and arrived a short time later. The victim was pronounced dead at the scene at approximately 6:40 a.m.

The coroner listed the cause of death as severe coronary atherosclerosis with extensive burns and charred body.

INVESTIGATION OF THE ACCIDENT

MSHA was notified at approximately 5:45 a.m. on August 6, 2002, when George R. Kent, MSHA safety and health Inspector, arrived at the plant to continue a regular inspection of the plant he had commenced the previous day. An accident investigation began the same day. An order was issued pursuant to Section 103(k) of the Mine Act to ensure the safety of miners.

MSHA's investigation team conducted a physical inspection of the accident site, interviewed a number of persons, conducted tests, and reviewed procedures performed by the crew and victim at the time of the accident. The investigation was conducted with the assistance of management and the miners.

DISCUSSION

The production of lime at the plant was made from five, 300-feet long by 10.5 feet inside diameter rotary kilns manufactured by Allis Chalmers. The kilns were numbered one through five and were direct fired using pulverized coal as the main fuel source. The feed rate of the coal was approximately six tons per hour. The coal was pulverized using a C.E. Raymond 533-bowl mill. The plant used natural gas as the fuel source during start-up.

The accident occurred in the No. 3 bag house, which was used to filter solid dust particles from the exhaust gasses exiting the No. 3 kiln.

Air was conveyed through the kiln by a Buffalo Forge induced draft (I.D.) fan located between the No. 3 bag house and the No. 3 kiln. The fan was rated at 140,000 cfm at 13 inches of water column and 600º Fahrenheit. The I.D. fan was powered by a 400 hp, 4160-volt AC, 1750-rpm motor.

The I.D. fan supplied each of the 12 compartments of the bag house with hot exhaust gas from the kiln. The gasses entered each compartment from the bottom and flowed upward through the filter bags before entering the atmosphere through one of six, 8.5-foot diameter stacks located on top of the bag house.

The No. 3 bag house contained three levels; the ground level, the first floor, and the second floor. The ground level provided access to the silos, screw conveyors, duct work, and cycling control panel for each of the 12 compartments. The pressure monitoring display, which measured the total static pressure drop across the entire bag house, was also located at ground level. It was in this area where the lime kiln dust was collected and conveyed away from the bag house to a separate storage silo.

The first and second floors were accessible only by a stairway on the outside of the bag house. The victim was found on the first floor inside No. 2 compartment of No. 3 bag house. The No. 3 bag house measured 60 feet by 30 feet. All 12 compartments in the bag house measured 10 feet wide by 15 feet deep. Six exhaust stacks were located on top of the bag house. Two adjoining compartments shared one of the six stacks. (See Appendix C) Each compartment contained six rows of 12 filter bags. A walkway, 26 inches wide by 15 feet long, was located in the center of the compartment. On each side of the walkway were three rows of 12 bags (See Appendix D). There were 72 bags per compartment and a total of 864 bags in the No. 3 bag house.

The access doors were located on the west side of the bag house for compartments one through six and on the east side for compartments seven through 12. Each compartment contained only one door, which was the only means of entry and egress. The access doors were constructed of metal and measured 24 inches by 79 inches. These doors opened to the outside and were equipped with a handle on the outside and a "latch" to hold the doors closed while the bag compartment was operating. The latch was a piece of 2 by 2-� inch angle iron 8 inches long. This angle iron was bolted to the outside of the door so that the it was able to rotate around its attached pivot point. There was a bracket welded to the doorframes that would act as the contact point to secure and lock the doors from the outside. The doors were latched closed during operation of the bag house to insure that lime dust did not escape from the bag house. (See Appendix E) If latched from the outside, the doors could not be opened by persons inside the bag house.

The bag house was equipped with a self-cleaning stage that automatically cycled and shook the filter bags. During this cycle, a gate valve closed the inlet air off from the I.D. fan to one of the 12 compartments. When this occurred, another gate valve opened to the reversible air fan. This changed the bags in the compartment from positive to negative pressure, which cleaned any dust that had built up on the inside of the bag walls. After two minutes, the gate valves switched back to their original positions, placing the compartments back in positive pressure. The sequence ran for three minutes before the next compartment was cycled. This three minute time interval was known as the dwelling period. The program cycled through the 12 compartments in numerical order. The cycle began with the number one compartment and cycled through to the twelfth compartment. The reverse air fan and dwelling period was five minutes. Therefore, it would take one hour to cycle through all 12 compartments.

The normal practice at this plant was for personnel to enter these compartments during cycling periods to manually shake the bags to aid in their cleaning. During this manual shaking of the bags, the worker opened the man door to reduce the compartment temperature. After the room cooled, the worker would physically shake or "slap" the bags, to loosen any lime dust that had built up on the inside of the filter bags.

A worker would also enter these compartments while they were operating to check if a bag had ruptured. If a bag had ruptured, the lime dust would be expelled from the bag into the bag house compartments and exit the building through the stacks.

The air entering the bag house was approximately 400 to 450º Fahrenheit. At the time of the on-site investigation, temperature readings were taken in the No. 7 bag compartment of the No. 5 bag house while in full operation. The surface temperatures were taken with a Cole Parmer infrared thermometer. The highest initial temperature recorded was in the No. 7 bag compartment at approximately 295º Fahrenheit. This temperature was the same for the surface of the bags and the bag compartment floor. The door was opened completely and temperature readings were taken while the compartment was allowed to cool. Within 30 seconds after opening the door, the compartment floor temperature dropped to approximately 225º Fahrenheit.

The victim was found on the walkway of No. 2 compartment of No. 3 bag house. He was positioned approximately 8 feet from the compartment entrance, laying face down with his feet toward the door. The door was closed and latched. The switch which controlled the gate valves for the No. 2 compartment was found in the automatic position. This indicated that the room was running its normal shaking cycle.

The No. 3 compartment access door was propped open with a pipe. A utility light was found hanging on an adjacent hand rail opposite the access door that provided light for the No. 3 compartment.

During the on-site investigation, the man door to the No. 2 bag compartment of the No. 3 bag house was pushed shut in an attempt to simulate a possible scenario of the door closing and latching. When the door struck the doorframe, the latch fell into the locked position. If the door were to close while an employee was inside the compartment, the door could lock.

When the door was opened while the room was operating, the ambient outside air rushed into the opening and exited the stack. This created a stack effect due to the difference in temperatures inside the room compared to ambient outside air. This effect could cause the door to close behind an employee.

As part of the investigation, extensive air quality testing was conducted in compartment No. 2 of No. 3 bag house while it was operating on September 11, 2002. Low oxygen levels and high carbon dioxide levels were found. (See Appendix F)

The weather on the night of the accident was clear with the temperature approximately 70º Fahrenheit and wind gusts up to 23 miles per hour.

CONCLUSION

The cause of the accident was the inability of the victim to exit No. 2 compartment of No. 3 bag house after the door had closed and latched. An inside door latch was not provided. The root cause of the accident was the failure to establish a safe job procedure when performing maintenance checks in the operating bag houses.

ENFORCEMENT ACTIONS

Order No. 6142258 was issued on August 6, 2002, under the provision of Section 103(k) of the Mine Act:
A fatal accident occurred at this operation on August 6, 2002, when a maintenance man was found in the dust collector, No. 2 bag room, located on the second floor of the No. 3 bag house. This order is issued to assure the safety of all persons at this operation until affected areas of the plant can return 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 equipment and/or return affected areas of the mine to normal.
Order No 6142258 was terminated on August 29, 2002: The condition that contributed to the accident no longer exists.

Citation No. 6142261 was issued on November 4, 2002, under the provision of Section 104(a) of the Mine Act for violation of CFR 56.11001:
A fatal accident occurred at this operation on August 6, 2002, when a maintenance person was trapped in the No. 2 room of the No. 3 bag house. A safe means of access was not provided and maintained to the No. 2 room of the No. 3 bag house. The access door had closed behind the victim, trapping him and thereby exposing him to an elevated heat and toxic environment. The access door to this room of the bag house had been altered during modifications to the dust collecting system and the company had failed to provide an interior latch per the manufacturer's original design. This prevented the victim from exiting the bag house.
Citation No. 6142261 was terminated on November 8, 2002. The exterior door latches have been removed on all kiln exhaust bag house room doors, eliminating the possibility of doors becoming latched/locked. To insure a safe means of access upon entering the bag house rooms, the operator has implemented new procedures. The kiln exhaust to the rooms is directed elsewhere and the rooms are ventilated prior to entering the room. The room's atmosphere is tested for six toxic gases by a digital multiple gas detector, including low oxygen level testing. Workers are also provided with communication devices prior to entering the rooms.

Related Fatal Alert Bulletin:
Fatal Alert Bulletin Icon FAB02M22




APPENDIX A


Persons Participating in the Investigation


Carmeuse Lime, Inc.
Thomas A. Buck ......... executive vice-president, chief operating officer
Lisa A. Potts ......... director environmental and safety compliance
Bob W. Courson II ......... vice-president, human resources
Jim P. Brennan ......... vice-president, general manager
Ron L. Vessell ......... plant manager
Donald E. Patterson ......... technical coordinator
Dave L. Sparacino ......... engineer
Kent M. Purcell ......... environment, health & safety manager
Pat F. Babusch ......... shift foreman (second shift)
Jim O. Cayer ......... shift foreman (third shift)
Dave R. Tallent ......... maintenance leader
Tim J. Vessell ......... maintenance leader
Mike W. Williams ......... equipment operator, miner's representative
Kevin L. Metcalf ......... conveyor person
Gwendolyn M. Mason ......... conveyor person
Steward E. Mckee ......... maintenance person
Gary Calloni ......... maintenance person
Angel Bonilla, Jr. ......... plant operator (third shift)
Bill W. Williams ......... plant operator (second shift)
Rene F. Couture ......... assistant plant operator (third shift)
Terry Carron ......... assistant plant operator (second shift)
Oscar D. Suarez ......... electrician (second shift)
Antonio D. Suarez ......... equipment operator
Suzanne Ritzler ......... attorney
Sesco (Emission Testers)
Andrew Young ......... emission technician
Carlos Brown ......... emission technician
Gary City Police Department
Lanita Titus ......... detective
Lake County Coroner's Office
Ray RaDoja ......... deputy coroner
Mine Safety and Health Administration
Thomas J. Pavlat ......... mine safety and health specialist
George R. Kent ......... mine safety and health inspector
Michael A Hockenberry ......... mine safety and health fire protection engineer
Michael P. Valoski ......... acting chief, toxic agent branch, physical and toxic agents division
Charles D. Campbell, P.E. ......... senior mining engineer
Christopher Findlay ......... industrial hygienist
Ronnie J. Deaton ......... mine safety and health specialist

APPENDIX B

Persons Interviewed

Carmeuse Lime, Inc.
Ron L. Vessell ......... plant manager
Dave L. Sparacino ......... engineer
Pat F. Babusch ......... shift foreman (second shift)
Jim O. Cayer ......... shift foreman (third shift)
Dave R. Tallent ......... maintenance leader
Tim J. Vessell ......... maintenance leader
Mike W. Williams ......... equipment operator, miner's representative
Kevin L. Metcalf ......... conveyor person
Gwendolyn M. Mason ......... conveyor person
Steward E. Mckee ......... maintenance person
Gary Calloni ......... maintenance person
Angel Bonilla, Jr. ......... plant operator (third shift)
Bill W. Williams ......... plant operator (second shift)
Rene F. Couture ......... assistant plant operator (third shift)
Terry Carron ......... assistant plant operator (second shift)
Oscar D. Suarez ......... electrician (second shift)
Antonio D. Suarez ......... equipment operator
Sesco (Emission Testers)
Andrew Young ......... emission technician
Carlos Brown ......... emission technician