DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
Metal and Nonmetal Mine Safety and Health
Accident Investigation Report
Underground Nonmetal Mine
Fatal Fall of Roof Accident
Clinch Valley Mine
Savage Zinc, Incorporated
Thorn Hill, Grainger County, Tennessee
Mine I.D. No. 40-01627
February 3, 1997
James B. Daugherty
Supervisory Mine Inspector
Charles E. Morgan
Mine Safety and Health Inspector
Mine Safety and Health Administration
135 Gemini Circle, Suite 212
Birmingham, Alabama 35209
Ronnie M. Davis, miner, age 36, was fatally injured at about 1:15 p.m. on February 3, 1997, when he was struck by a massive roof fall while operating a jumbo drill. The victim had a total of 5 years and 3 months experience, all with this company. The victim had received all mandatory training in accordance with 30 CFR, Part 48.
Walter J. Toepfer, manager, Savage Zinc, Incorporated, notified the MSHA Knoxville, Tennessee field office of the accident at 2:05 p.m. on February 3, 1997. An investigation was started the same day.
The Clinch Valley Mine, an underground zinc mining operation, owned and operated by Savage Zinc, Incorporated, was located off Highway 131 north, 1.5 miles east of Thorn Hill, Grainger County, Tennessee. The senior operating official was Walter J. Toepfer, manager. The mine normally operated two, 12-hour shifts a day, 3 days a week. The mine employed 65 persons, with 39 assigned to work underground.
The mine was developed by a random room-and-pillar, open-stoped method of mining and was accessed from the surface by a decline adit and a 1460 foot vertical shaft. Development drifts, approximately 15 to 20 feet wide, and 15 to 18 feet high, were driven off the decline. Ore production principally came from open stopes which were developed off mine drifts. These stopes were initially mined 18 feet high and widened in stages until the lateral extent of the ore was mined. Stope dimensions were variable and ranged up to approximately 70 feet in width, 200 feet in length, and 100 feet in height. Roof support consisted of 5 foot long split set bolts installed on a 5 foot by 5 foot pattern. Ore was drilled, blasted, then transported by diesel haulage equipment to transfer raises where it was crushed and hoisted to the surface to storage bins for further processing.
The last regular inspection of this operation was conducted December 10-17, 1996.
The accident occurred in the 4817 stope which was recently mined to approximately 60 feet wide, 100 feet long, and 18 feet high.
The section of the roof that fell was approximately 30 feet wide, 70 feet long and 8 feet thick and was estimated to weigh 250-300 tons. The fall was not centered in the stope but favored the north and east riblines.
The drill involved in the accident was a rubber-tired, one-boom Secoma Pluton, Model 17 jumbo drill, Serial No. Z461. The drill was equipped with a Deutz, 6 cylinder, 82 h.p. diesel engine with a hydrostatic drive transmission, and a Lincoln 50 h.p. electric motor. The drill weighed 26,440 lbs. The operator's compartment was provided with factory installed FOPS.
DESCRIPTION OF ACCIDENT
Ronnie M. Davis, victim, reported for work on February 3, 1997, at 6:30 a.m. Dennis Bayse, mine superintendent and Davis proceeded underground and Bayse instructed Davis to get the drill and drill a brow in the 5127 stope, then to drill the 4817 stope.
Work continued without incidence until approximately 12:20 p.m. when Davis completed drilling the 5127 stope. Before going to the 4817 stope, he called the shop for parts to make minor repairs on the drill. Bayse heard the call and went to the shop and got the parts for Davis, then went to 4817 and met Davis going down the drift. Both Bayse and Davis looked at the back in 4817 and discovered there was a brow that was left from a previous shot. Bayse instructed Davis to drill two or three holes in this brow. Bayse showed Davis the direction to drill and after looking over the 4817 stope, was satisfied that everything was okay, except for straightening out the brow in the back. Bayse left the 4817 stope at around 12:40 p.m.
At approximately 1:20 p.m., Scottie Witt, lead miner, went to 4817 to check on Davis. Upon arriving Witt found the 405 jumbo drill covered with a massive rock fall. Witt got out of his truck and went as far as he thought was safe and called out to Davis. Witt got no response and immediately got back into his truck and backed up the drift until he was within radio range where he called Bayse and told him that he had an emergency and needed immediate help.
Witt went back to the accident site and was joined by Bayse and Johnny Beckler, miner. The rock that fell had broken into three pieces leaving a small opening between it and the drill canopy. Beckler crawled through the hole and found Davis pinned under the canopy. Beckler checked Davis for a pulse and found none.
Bayse went to the surface and called for emergency assistance then returned underground. He and several other employees tried to free the victim by using two 8-yard loaders to move the rock. When this did not work, a rock breaker was brought in but they were unable to break the rock. A jumbo drill was then brought in, holes were drilled in two of the rocks, and the rocks were blasted. A chain was used to lift the rock and canopy off the victim. At 6:35 p.m. employees were able to extract Davis' body from the drill, place him on a stretcher and take him to the surface where he was transported by the rescue squad vehicle to Grainger County Morgue where he was officially pronounced dead.
Recent mining activity, which increased the span of roof in combination with an undetected discontinuity above the anchorage level of the roof bolts, caused the roof to fall.
Order No. 4355551
Issued on February 3, 1997, under the provisions of Section 103(k):
/s/ James B. Daugherty
Supervisory Mine Inspector
/s/ Charles E. Morgan
Mine Safety and Health Inspector
Approved by: Martin Rosta, District Manager
Related Fatal Alert Bulletin: