Here's a documentary about coal produced by the famous General Post Office film unit. It seems a bit off the beam for the people involved. NIGHT MAIL, another famous and excellent documentary makes more sense, seems closer to the GPO remit... or convincing people they were not wasting their money, drawn from the National store, on anything but the mail.
Yes, it does seem a bit odd for the Post Office to produce films telling the public what good jobs they are doing. It's even odder for them to produce films about the coal industry. Still, when you look at the storied talent involved here: W.H. Auden writing and narrating, Benjamin Britten composing, Alberto Cavalcanti directing, with John Grierson producing and Humphrey Jennings credited for 'additional photography', you start to realize the alignment of some very heavyweight talent. You under why, a few years later, the unit could produce some of the greatest propaganda films of all time.
This is no slouch either, with its Academician-influenced editing. It's pretty good, in fact.
