It's things like this that bring history to life. A name and a date on the wall have a certain value, but to be able to tie it into a bit of social history (like child labour) adds an extra dimension to a feature. We have (had) some 1911 graffiti and names and dates in pencil on a wall, but without a newspaper account from the time of the surprise discovery of the ancient mines following a flood which washed the entrance open, it is (was) just a set of names, initials and dates. The devastation caused underground by the flood is there to be seen by anyone who opens their eyes.