Black Diamonds is a 1940 American drama film directed by Christy Cabanne and starring Richard Arlen, Andy Devine, and Kathryn Adams.

Norton and his friend, Barney Tolliver, lure Mathews into the mine, where they threaten to bury him in an explosion unless he comes clean and admits to the bribery and the unsafe conditions.

Mathews, upset at the betrayal of Johnson, publicly confesses of the bribery of Redman and of the mine's unsafe working conditions.

Redman is arrested and control of mine is taken over by local authorities, who immediately implement better safety measures, while Norton and Linda resume their childhood romance.

[3] It was announced that Arlen and Devine had wrapped production on Hot Steel, and would be immediately beginning on their next picture, Black Diamonds.

[11] The National Legion of Decency gave the film a class A-1 rating, meaning it was unobjectionable for general audiences.