Overconfidence and lack of training can sometimes lead to death on the job, as the death of a Tennessee maintenance worker has shown.
MSHA inspectors found that the fatal accident was partly caused by the fact that a group of miners thought they were doing maintenance on a jaw crusher in a safe way when, in fact, the situation was much worse than they thought.
One of the miners died when the swing jaw of the crusher moved and pinned him between the back of the jaw and a toggle block frame. All the workers in the group that were doing maintenance thought that the crusher couldn’t move because they didn’t understand what a danger sign meant.
The Sevierville Quarry is an open-pit mine for limestone that used a hopper and a jaw crusher to break the rock into smaller pieces. John Ogle was part of a four-man crew who were told to replace worn parts on the crusher, on the day of the incident.
The day before, the team used a chain hoist that was attached to the bottom of the moving jaw and the frame of the crusher to pull the moving jaw toward the stationary jaw and stop it from moving dangerously. They didn’t notice, however, that the left side cheek plate was preventing the swing jaw from moving freely and that the toggle bearing was stuck in the swing jaw’s bottom. Because of these two things, the swing jaw wasn’t stopped from moving dangerously.
On the day of the accident, the crew kept working on the crusher. Ogle and another miner went behind the swing jaw to take out a toggle gear. The crew put a chain hoist between a lifting loop that Ogle had welded to the bearing and the crusher frame behind the swing jaw.
As Ogle turned the chain hoist twice, the swing jaw away from the cheek plate so it could move freely. The swing jaw moved toward Ogle and pinned him between the back of the jaw and the toggle block.
Even though one member of the crew called 9-1-1 immediately, and rescue workers used special tools to get Ogle out of the grinder. He succumbed to his injuries a few hours later at a nearby hospital and passed away.
The MSHA review showed that the jaw should have been taken off before the toggle bearing and the toggle assembly. But because the crew took off three of the jaw’s four extension bolts too soon, the swing jaw was only loosely held in place. Additionally, there is a warning sign that says, “Crusher flywheel can move, causing serious injury or death.” This sign shows when the crusher chamber is safe or not safe for work that is not maintenance. Before you can work on the crusher, the black part of the flywheel must be on the bottom. “Check out the instructions.”
Before fixing the crusher, Ogle and his team didn’t read the directions on how to use it. They didn’t realize that when the toggle piece is taken off, the lower end of the swing jaw is no longer held in place.
Although Ogle and another worker did a pre-shift safety check of the area before work continued on the crusher, neither had been trained to do this job.
Since the incident, the miner operator created a written procedure for blocking machinery, and they have revised their training plan to include more thorough safety procedures for maintenance work.
