Superman and the Mole Men

Bespectacled newsman Clark Kent arrives in a small Midwestern town to do a story on an unusually deep oil well. Soon he discovers that the hole leads to a subterranean realm inhabited by a race of radioactive misfits. Though these creatures pose their own threat, Clark -- and his caped alter ego -- must also contend with an angry mob of local yokels... (official distributor synopsis)