DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
Northeastern District
ACCIDENT INVESTIGATION REPORT
SURFACE METAL/NONMETAL MINE
FATAL FALL OF PERSON ACCIDENT
Certified Welding, Inc. ID No. 18-00326-WHX
at
Perryville Plant
York Building Products Co. Inc.
Perryville, Cecil County, Maryland
October 4, 1995
By
Dale R. St. Laurent
Supervisory Mining Engineer
Ricky J. Horn
Mine Safety and Health Inspector
Northeastern District
Mine Safety and Health Administration
230 Executive Drive, Suite 2
Cranberry Township, Pennsylvania 16066-6415
James R. Petrie
District Manager
GENERAL INFORMATION
Alvin Davis, job superintendent, age 52, was fatally injured on October 4, 1995, at approximately 2:45 p.m., when he fell from a concrete block that was being raised by a crane. He had 26 years experience with the contractor, Certified Welding, Inc. He had supervised this contract job at the mine for approximately 6 months.
York Building Products Co., Inc. was rebuilding the Perryville Plant, located near Perryville, Cecil County, Maryland. The mine was designed to produce sand and gravel from a surface pit. The principal operating official was Phillip Reichard, manager. Certified Welding, Inc. of Peach Bottom, Pennsylvania, had been contracted to erect the entire plant structure. The principal operating official for the contractor was Clarence Blevins, owner. Construction activity was scheduled for one 8- to 10-hour shift per day, 5 days per week. There was a total of 12 persons on mine property at the time of the accident; 6 were employed by York Building Products; 4 by Certified Welding; and 2 were contract electricians.
The last regular inspection was done in 1972 when the Perryville Plant was permanently abandoned.
At approximately 10:15 a.m. on October 5, 1995, James R. Petrie,
Northeastern district manager, received a call from Maryland
Occupational Safety and Health informing him that a fatality had
occurred at the mine. It was determined that the accident was
under MSHA jurisdiction and an investigation was started
immediately. Stephen J. Moyer, Jr., mine safety and health
inspector, arrived at the scene about 2:35 p.m. that day. Dale
R. St. Laurent, supervisory mining engineer, and Ricky J. Horn,
mine safety and health inspector, arrived at the property at 5:45
p.m. that afternoon.
PHYSICAL FACTORS INVOLVED
The concrete block was cast by York Septic Tank and Precast Concrete Company (a York Building Products subsidiary) on September 25, 1995. The block was designed to be a counterweight for a conveyor belt take-up pulley assembly. It was 45 inches long, 33 inches wide, 36 inches high, and weighed 3,770 pounds.
Each corner of the block was provided with a thermoplastic insert that was flush with the top surface of the block. Each insert was located approximately 3 1/2 to 5 inches from the corner of the block. The inserts were manufactured by Pennsylvania Insert Corp. (a York Building Products subsidiary). They were 3 1/4 inches long and tapered from 1 inch in diameter at the top to 1 1/2 inches in diameter at the base. The insert contained No. 10 N.C. (not common) threads for the 3/4-inch diameter steel anchor bolt. Each insert was rated for a working load of 3,020 pounds. The anchor bolts were 2 inches long with an eye on the end. The anchors were screwed into the thermoplastic inserts. The 2-inch shaft of each anchor, however, only engaged about half of each insert's threads. Additionally, the shaft of one anchor was bent and appeared to have not been completely screwed into the insert.
A clevis was inserted into each of the four anchor bolts. One clevis was 1 3/8 inches with a working load of 13 1/2 tons; two were 1 1/8-inch rated at 9 1/2 tons; and one was 1 1/8-inch rated at 8 1/2 tons.
A 3/8-inch link chain, 10 feet long with a 10-ton rating, was looped through the two corner clevises on the long side of the block. A second identical chain was looped through the two clevises on the other side of the block. Each chain was in turn looped through the eyelet of a nylon sling. The chains were fastened by placing the chain hook on the chain link. The top end of each nylon sling was then connected to another nylon sling by a 1 1/8-inch clevis. These two-set slings ran vertically from the chains on the block and passed on each side of the conveyor belt located above the block. The top ends of both two-sling sets were connected together with one clevis, which was fastened to the hook of the crane line. Each nylon sling was 4 inches wide and 16 feet long. The vertical lift rating of each of the slings was 19,800 pounds. Figure 2 in Appendix B depicts the rigging of the nylon slings.
The crane line on the Grove, Model TMS-300, hydraulic crane, was rated at 35 tons. At the time of the accident, 81 feet of the boom was extended with a boom angle of 72 to 74 degrees. The distance from load line to centerline of the swing gear was about 20 feet. At this boom length and angle, the rated lift capacity was 28,700 pounds. The crane was equipped with an anti-two-block warning switch.
The top of the concrete block had been raised to within inches of the take-up pulley connecting pin. The block was approximately 40 feet above the ground at the time of the accident.
Reportedly, the insert and anchor located on the far left corner
of the concrete block, as viewed from the crane, was the first to
fail. The insert broke at the bottom of the anchor shaft. The
top part of the insert, with the anchor still threaded onto it,
pulled out of the concrete block. The corner of the block broke
off around the break. The flared base of the insert remained
embedded in the concrete. The other three inserts failed
immediately thereafter. Two of these exhibited the same failure
mode and results, whereas the fourth insert was in one piece when
it broke free from the block.
DESCRIPTION OF THE ACCIDENT
On the day of the accident, Alvin Davis arrived at the mine about 7:00 a.m., his normal starting time, and carried out his duties as job superintendent. He and Charles Fryberger, welder, had installed three similar concrete take-up pulley counterweight blocks that day. At approximately 2:00 p.m., the crew consisting of Glenn Spangler, York Building Products crane operator; Christopher Bowman, York Building Products front-end loader operator; Davis, and Fryberger began to install the final counterweight block on the No. 6 conveyor.
Davis rigged the block, and directed the crane operator to lift it by the steel mounting brackets and place it on the flat back-side of the Caterpillar 988 loader bucket. Davis then rigged the two nylon sling sets to the crane and had it lifted above the conveyor belt, directly over the take-up bend pulley. Fryberger was on the catwalk of the conveyor and positioned the loose ends of the sling around each side of the conveyor so they hung down near the block. Davis then climbed up on the loader bucket and directed Bowman to raise the bucket up to the hanging slings. Davis rigged the block connecting the two chains through the clevises on the block and the eyelets on the two nylon slings. He then directed Spangler to raise the block. As the block was being raised, Davis climbed up on it and in a kneeling position rode on the block as it was being lifted. When the block was only about an inch from the position needed to push in the retaining pin, he signaled the crane to stop.
Spangler stopped the block as directed by Davis and saw Davis attempting to position the block by hand. The pin was still in place in the take-up pulley frame. He saw the block list suddenly to the side and saw pieces of block fall. Then Davis fell toward the far side of the block and was obscured by the front-end loader bucket. Spangler heard the heavy thump of the block falling on the loader bucket a moment later.
Fryberger also witnessed the accident. He was looking down on the block from the conveyor catwalk. He heard a popping noise and saw one anchor come out of the block. As one corner dropped, it pitched Davis off balance. He tried to grab the rigging but missed and fell.
Bowman had also observed Davis riding up on the block but lost sight of him as he rose. Bowman decided to get out of the loader cab to get a better view and had just begun climbing down the ladder when he heard a pop and saw Davis falling. Seconds later there was a loud crash and the loader lurched violently when the block hit the bucket.
Steven Ahler, York Building Products maintenance man, was filling a counterweight with ballast at a conveyor about 80 feet away. Two Certified Welding employees and a York employee were helping him. He heard a crash and looked up to see the block lying upside down on the loader bucket. He ran to the site and saw Davis lying on the ground. He shouted to Davis but received no response. He checked for a pulse and breathing but none could be detected. Ahler started CPR and noted the injuries.
Dallas Kline, superintendent, was inside the maintenance building several hundred feet away. He heard something fall and ran outside. He saw Bowman coming down off the loader. Someone asked him to call 911. Kline went to his pickup truck and placed a call on his radio.
Spangler, Fryberger, and Bowman all ran to the site and assisted
in CPR. The ambulance and EMT unit arrived about 3:00 p.m. and
took over treatment. Davis did not respond. A medical examiner
was called and pronounced him dead at the scene.
CONCLUSION
The accident occurred primarily because the victim exposed
himself to danger by riding the load being lifted by the crane.
Contributing to the accident was the improper rigging of the
concrete block. A forensic analysis of the materials involved in
this failure was conducted by the MSHA Health & Safety Technology
Center (Appendix B). Their report concluded that the concrete
block broke in the vicinity of all four connection points
primarily because the rigging employed subjected the
thermoplastic inserts, anchors, and concrete to stress levels in
excess of their respective strengths. The embedded thermoplastic
inserts were loaded in such a fashion to which they were neither
designed nor intended to be loaded. Three less significant
contributing factors were the reduced strength of the "green"
concrete; locating the inserts too close to the corners of the
concrete block; and, the shaft of the anchors being too short to
fully engage the threads of the inserts.
VIOLATIONS
The following order and citations were issued to York Building Products Co. Inc.:
Order No. 4296124 was issued under the provisions of Section 103(k) of the Mine Act on 10/5/95, to secure the safety of persons in the area. This order was abated on 10/7/95, after MSHA had completed the investigation.
Citation No. 4430143 was issued under the provisions of Section 104(a) on 10/16/95, for violation of 30 CFR 50.10:
The operator failed to immediately notify MSHA of an accident that occurred at approximately 14:45 hours on 10/4/95. An employee was fatally injured when he fell approximately 40 feet to the ground. The operator notified Maryland OSHA but did not notify MSHA.
This citation was abated on 10/16/95, after the operator was made aware of 30 CFR Part 50 requirements.
Citation No. 4430163 was issued under the provisions of Section 104(a) on 10/24/95, for violation of 30 CFR 56.16011:
The supervisor for a contractor was fatally injured on 10/4/95, at approximately 1445 hours when he was riding on top of a concrete block for the take-up pulley counterweight of #6 conveyor belt. He had been hoisted approximately 40 feet by a Grove mobile crane (Model TMS-300) when one of the lifting anchors broke out of the block. The supervisor lost his balance and fell to the ground.
The crane operator, who was an employee of York Building Products Co. Inc., should not have lifted the block with the supervisor riding on it.
This citation was abated on 10/24/95, after 30 CFR 56.16011 regulation was thoroughly reviewed with the crane operator and management. This work practice shall not be permitted or continue.
Citation No. 4430166 was issued under the provisions of Section 104(a) on 10/24/95, for violation of 30 CFR 56.16007(b):
The supervisor for the contractor hired to erect the plant was fatally injured on 10/4/95, at approximately 1445 hours when he fell from a concrete block he was riding that was being hoisted by a York Building Products operated Grove mobile crane (Model TMS-300). The block was a counterweight for the #6 conveyor take-up pulley. The supervisor had been hoisted about 40 feet when a lifting anchor broke out of the block, tipping him off.
A York subsidiary cast the block on 9/25/95, and provided the thermoplastic inserts that anchored the lifting assembly. York also provided the hitch and sling equipment that was used to hoist the block. Reportedly, the block was designed for vertical lifting only. The hitch method used by the contractor created lateral forces on the lifting anchor that apparently contributed to the failure of the block.
The contractor selected the rigging material and made the hitches, but York personnel were involved in discussions of how to lift the block. York personnel were witness to the hitching method used and were responsible for ensuring the proper lifting techniques were used, but permitted it to be done incorrectly by the contractor.
This citation was abated on 10/24/95, after requirements for 30 CFR 56.16007(b) were discussed with management and employees to emphasize the mine operator responsibility for contractor safety. This rigging method will not be used again.
The following citation and order were issued to Certified Welding Inc.
Citation No. 4430164 was issued under the provisions of Section 104(d)(1) on 10/24/95, for violation of 30 CFR 56.16011:
The supervisor for this contractor was fatally injured on 10/4/95, at approximately 1445 hours when he was riding on top of a concrete block for the take-up pulley counterweight of #6 conveyor belt. He had been hoisted approximately 40 ft. by a Grove mobile crane (Model TMS-300) when one of the lifting anchors broke out of the block. The supervisor lost his balance and fell to the ground. This is an unwarrantable failure.
This citation was abated on 10/24/95, after 30 CFR 56.16011 regulation was thoroughly reviewed with Mr. Blevins and he shall re-emphasize this standard to all employees. This work practice shall not be permitted or continue.
Order No. 4430165 as issued under the provisions of Section 104(d)(1) on 10/24/95, for violation of 30 CFR 56.16007(b):
The supervisor for this contractor was fatally injured on 10/4/95, at approximately 1445 hours when he fell from a concrete block he was riding that was being hoisted by a Grove mobile crane (Model TMS-300). The block was a counterweight for the #6 conveyor take-up pulley. He had been hoisted about 40 feet when a lifting anchor broke out of the block, tipping him off.
The supervisor used a hitch to hoist the block that was not suitable. He passed the link chains directly through the anchor clevises so that the chains bent around the "U" of the clevis and back to itself.
The clevis pin diameters were not in close tolerance to the anchor eye opening diameter. This condition, coupled to the chain being bent around the clevis, would allow load shifts and/or sudden impact loads on the rigging or lifting anchors. The thermoplastic inserts embedded in the concrete block were reportedly designed for only vertical lifting forces. The hitch method used by the supervisor created lateral forces on the lifting anchors that apparently contributed to the failure of the block. This is an unwarrantable failure.
This order was abated on 10/24/95, after the rigging method was discussed with Mr. Blevins. This method shall not be used again and employees will be re-instructed to use suitable hitches and slings.
Respectfully submitted by:
/s/ Dale St. Laurent
Supervisory Mining Engineer
/s/ Ricky J. Horn
Mine Safety and Health Inspector
Approved by:
James R. Petrie
District Manager
Related Fatal Alert Bulletin:
[FAB95M36]