It was about a mining strike, based on a true story of the Empire Zinc strike in 1950. The movie, directed by Herbert Biberman, deals with issues of labor, mining safety, discrimination against Hispanics and feminism (the real heroes of the film are the wives of the miners.)
But just a few moments ago, the New Mexico state Senate passed a memorial by Sen. Howie Morales, D-Silver City, honoring the anniversary of the film. It passed unanimously with all Democrats and Republicans voting in favor.
That's a little different than the initial reception in New Mexico. From the American Film Institute:
On 2 Mar 1953, the film's cast and crew were met by a citizen's committee in Central, NM, and ordered to leave town. The following day, in Silver City, NM, the company was warned to "get out of town...or go out in black boxes." (Actor Clinton) Jencks was beaten and shots were fired at his car while it was parked outside his home. When the company did not capitulate to the demands, there was a "citizens' parade" led by a sound car blaring, "We don't want Communism; respect the law; no violence, but let's show them we don't like it."
Happy anniversary Salt of the Earth.