Outstanding and historically important film from1954 about a zinc miners' strike in New Mexico, USA. Made by a blacklisted director with blacklisted actors and also a lot of non-professional actors, including people who participated in the strike. Black and white, atmospheric and well-acted. In addition to the straight labour history, there is an added component - the film shows the conflict between the men, who have a traditional view of their role, and the women, who gradually want to get involved againsts the wishes of the men. It seems way ahead of its time. It also deals with divisions between the workers of Mexican origin and white workers also employed at the mines. I can't recommend this film highly enough if you are interested in this kind of subject matter.
See https://www.theguardian.com/film/2014/mar/10/salt-of-the-earth-labour-workers-blacklisted-filmmakers