In the context of mining, and English coal mining in particular, the term Deputy invariably means one thing: a man who deputises for a higher official of the miner. The precise details- whom he deputises for, and so on, vary according to date. Originally, he was a workman who deputised for the manager, but over time and as pits became larger and larger, the hierarchy grew, so that between Manager and the Deputy there might be an Under-manager, an Overman, an Under-overman, a Viewer, an Under-viewer, a Back-overman and so forth.
What you can be sure of is that the Deputy was a man with responsibilities. Typically he either did, or oversaw, the most dangerous work. He would be responsible for the safety of an area of the mine, known as his district. This is still true today, alothugh in small mines, it is possible that the Deputy's district is the whole mine.
Among the Deputies responsibilities are:
To ensure that dangerous gases do not accumulate. originally, men carried flame safety lamps (Davy lamps) for illumination. But once electric lights cem in, these were abandoned by the workforce. The Deputy however continued to use the lamp because it can demonstrate to presence of methane (fire damp), and carbon diaoxide (stythe) easily and cheaply. The flame safety lamp is still in use by Deputies in British Collieries today. Before the Davy lamp, the Deputy used to disperse methane by buring it off. He did this by wrapping himself in damp clothes and putting a buring torch to the roof of the mine wher the gas accumulated. The idea (not to be recommended) was that the methane would burn off before it reached explosive concentrations. For this reason, an early name for the Deputy was the Fireman.
To ensure the safety of the roof and sides. Each shift, every four hours or less, the Deputy must inspect the areas where his men work. Sometimes (usually at the face), the great wieght from above casues the roof or the walls of the workings to crack, and pieces may fall out. The Deputy must inspect the workings to make sure such events are kept to a minimum.
To ensure that safety procedures are adhered to. The Deputy inspects workings to ensure for example, that props have been set at the corect distance. In confined spaces, the timbers used to support the roof are very restrictive, and make coal extraction difficult. For this reason, miners may be tempted to take risks by leaving greater space between props than allowed by the Manager's rules. The Deputy prevents this.
Explosives. Special qualifications are required in order for a miner to "fire shots". The Deputy hold such a qualification and there are few miners today who are qualified to use explosives but who are not Deputies.
The term Deputy is recorded in the English mining glossaries: