DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
South Central District
Metal and Nonmetal Mine Safety and Health
Accident Investigation Report
Surface Nonmetal Mine
Fatal Machinery Accident
Lone Star Industries, Inc.
Mine-Maryneal Quarry and Mill
Sweetwater, Nolan County, Texas
I.D. No. 41-00283
September 8, 1997
Ronald M. Mesa
Mine Safety and Health Inspector
South Central District Office
1100 Commerce Street, Room 4C50
Dallas, Texas 75242-0499
Doyle D. Fink
Gary Don Davis, machinist, age 48, was fatally injured about 9:45 a.m. on September 9, 1997, when he fell between the hoist drum and the closing line drum of a P&H overhead trolley bridge crane. Davis had a total of 1 year, 22 weeks mining experience, all as a machinist at this operation. The victim was not trained in accordance with 30 CFR Part 48.
Robert C. Peterson, safety trainer/engineer, notified MSHA of the accident on September 9, 1997, at approximately 10:45 a.m. The accident investigation was started the same day.
Maryneal Quarry and Plant, a crushed limestone operation, was owned and operated by Lone Star Industries, Inc. The mine was located on County Road 608, 1 mile north west of Maryneal, Nolan County, Texas. Principal operating official was Charles Bledsoe, plant manager. The mine normally operated three 8-hour shifts per day, 7 days a week, and employed a total of 118 persons.
Limestone was drilled, blasted, and loaded into haul trucks by front-end loaders. It was then transported from the quarry to the primary crushing plant where it was crushed and stored in a material storage building before processing in the cement plant. The last regular inspection was conducted May 8, 1997. Another regular inspection was conducted at the conclusion of this accident investigation.
PHYSICAL FACTORS INVOLVED
The accident occurred on the trolley of the south Harnischfeger P&H bridge crane located in the clinker and raw material storage building. The crane, serial number C-21849-50, was installed in the storage building during March of 1993. The bridge crane had a lifting capacity of 9 tons and a lifting height of 82 feet. It operated from the south side of the building and an identical one operated from the north side. The crane buckets fill bins with materials to feed the kilns in the processing plant to produce cement.
The trolley had a "holding hoist" and "closing hoist" installed on a 12 foot square steel box that travels on top of a 75 foot long bridge. This square box also served as a work platform and had 37 inch handrails installed on its perimeter. The trolley set on 15 inch diameter wheels, spaced on a 11 foot span, and moved side to side (east to west) on 60 pound rail across the width of the storage building. The trolley platform was not visible from the operator's cab.
The "holding hoist" and "closing hoist" were both powered by 125 HP electric motors, which operate at 900 RPM and were equipped with 26 inch diameter drums, located six inches apart. The hoist drums had machined grooves depth hardened approximately 3/16 inch and 500 Brinell. The wire cable on both hoists was 1 inch by 188 feet, Type W, 6 X 25 EIP, Right Lang Lay, FS. Both hoists were equipped with a 19 inch electric holding brake and a P&H Magna torque control brake. The holding hoist lifts the bucket up and down and the closing hoist opens and closes the clam style bucket.
The 75 foot bridge spanned the width of the storage building and traveled from end to end (north to south) of the building on 21 inch diameter wheels on 80 pound rail. The bridge section of the crane had the capability of traveling 350 feet per minute and the trolley section could travel 250 feet per minute.
There were no mechanical or electrical problems found on the bridge or trolley sections of the crane.
The operator's cab was totally enclosed all-vision type of steel construction and equipped with an operator's seat, controls, alarms and window type air conditioner. The cab was mounted underneath the bridge and trolley sections of the crane and travels with the trolley section. Access to the operators cab was by a stairway from the bridge of the crane.
Reportedly, while performing any maintenance on the bridge or trolley sections of the crane, communication between the crane operator and the maintenance crew was done by hand held radios. The radios were portable Motorola HT 1000, type KDHA, model number H01KDC9AA1CNNX.
DESCRIPTION OF THE ACCIDENT
On the day of the accident, Gary Don Davis, (victim), reported to work at 7:00 a.m., his regular starting time. Davis was instructed by Mark Gentry, maintenance supervisor, to change out some blades on one of the raw material/cement separators. Davis and Jacinto L. Rosas, overhead crane operator, performed this task until around 8:30 a.m. It did not require the use of a crane. At the completion of this job they were assigned by Gene Kropp, maintenance supervisor to cut the closing cable on the south crane located in material storage building. Wear caused by the bucket sheave wheel required this activity to be conducted two to three times each week.
This repair job involves (1) cutting away worn cable on the bucket with a cutting torch, (2) reattaching the cable to the bucket, and then (3) repositioning and respooling the cable on the closing line hoist drum.
While Davis and Rosas proceeded to the material storage building, Mark Gentry called Jobita Diaz, overhead crane operator, to advise her that they were on the way to cut the cables on the south crane closing line. Gentry also called Wayland Wood, shift foreman, to advise him that Davis and Rosas would be locking out the number 1 rock bin so they could set the bucket on the material storage while they cut cables. Davis was carrying a radio and was assigned by Kropp to be lead man on this job.
Davis and Rosas arrived at the number 1 rock bin and locked it out. Davis called Diaz and told her there was not enough rock in the bin to set the bucket down on. Diaz filled the rock bin while Davis and Rosas waited. When it was full, she lowered the bucket and situated it where they could safely remove the worn cable. After cutting away the worn cable, Davis had Diaz lower some more cable so they could reattached it to the bucket. Once the cable was reattached, Davis had Diaz move the crane to the south landing to wait for them to come up to the landing.
They went to the south landing and climbed up on the trolley. There was no discussion between the three regarding communication commands to be given or the sequence of the work to take place. The crane was located under one of the wall supports, so Davis had Diaz move the crane just a little north. After moving the crane she waited for Davis' next command. Rosas positioned himself on the platform east of the closing line hoist drum. Davis climbed over the closing and holding drums and was standing with his right foot on the holding hoist drum and his left foot on top of the machinery guard on the gear box of the holding hoist.
Davis had the radio in his right hand and instructed Diaz to "let the bucket down". It is persumed that he intended to say "lower the closing line" and gave the wrong command. It is not known why he used the word "let" instead of "lowering". "Lowering the bucket" requires both hoist drums to rotate and "lowering the closing line" only causes the closing line hoist drum to rotate.
Rosas stated as both drums started to spin that Davis's right foot got pulled down in between the hoist drums. He thought one of the cable dead ends might have hit Davis' foot or that he lost his balance. Rosas hollered to Diaz to stop the crane and hearing the screaming immediately stopped the crane.
Rosas jumped from the trolley and began screaming to call 911. Diaz came up from the operators cab to see what had happened and saw Rosas screaming and running from the trolley. She then saw Davis between the drums and immediately called for help on the radio.
Johnny Santiago and Wayland Wood arrived at the scene and administered CPR and first aid to Davis. The Blackwell Texas EMS crew arrived at the scene at 10:15 a.m. The victim was pronounced dead at the scene by Will Lenior, marshall, City of Blackwell at 10:30 a.m.
The failure to ensure that persons were effectively protected from the hazardous motion of hoist drum movement, prior to performing maintenance, was the primary cause of the accident. Contributing causes were the failure to establish a formal written procedure; to have explicit written commands for hoist movement that are understood and used by all; inexperience of the victim; and inadequate training for employees in safe work procedures.
Order Number 4453738
Issued on September 8, 1997, at 10:45 a.m., under the provisions of Section 103(k) of the Mine Act:
Citation Number 4444399
Issued under the provision of Section 104(d)(1), for a violation of 30 CFR 56.14105:
The following recommendations could help avoid the recurrence of similar accidents:
develop written instructions, emphasizing safe work practices to follow for this and other similar hazardous tasks.
/s/Ronald M. Mesa
Approved By: Doyle D. Fink, District Manager
Related Fatal Alert Bulletin: