Can you imagine working underground in a location where mine tubs travelled at fairly fast speeds, propelled by the force of gravity while travelling downhill.
This was the situation in many coal mines. The only method of halting or slowing down the tubs was by inserting a steel locker (their names varied from pit to pit) into the tub wheel, this locked the wheel and friction between the wheel and the tub track caused the tub and any others coupled to it, to come to a standstill.
This was a simple method of controlling the tubs.
Basic training in the use of lockers involved holding the locker in a way which minimized the risk of injury. The fingers and thumb were to be kept closed like a fist around the back end of the locker.
Some men became very adapt in the art of lockering up the tubs. With a locker in both hands they could place lockers in both wheels at once, pick up two more lockers and repeat the process with ease. Some were so good they could actually throw the lockers into the wheels.
However many miner's suffered from terrible hand injuries through forgetting the basic principles they had been taught. Occasionally tubs came towards the miner when they did not expect them so they quickly looked for a locker, picked it up and hurriedly inserted it into the wheel. Sometimes they left their finger (mostly the fore finger) or their thumb pointing forward towards the wheel which resulted in the finger/thumb becoming trapped and all to often amputated. Many miners lost fingers and this was just one of the ways fingers were lost.
As the years went by the design of the locker was improved and a cover was even placed all the way around the locker to prevent fingers from coming in to contact with the wheels.This type of hand injury occurred less frequently but they were not eliminated.
