Bells of Coronado (1950) on Netflix

Plot summary

Thieves ambush the man who owns the El Coronado mine on the road into town and make off with a wagon of uranium ore. A crew of linemen for the power company finds him badly hurt, and he dies at the town doctor's office without regaining consciousness. With the mine now in the hands of Craig Bennett, a rancher and businessman, the claim for the lost ore brings Roy, an insurance investigator, to Coronado. The company wants to know whether the wagon left the roadway and dropped its load into the Coronado Dam reservoir. Roy signs on as a lineman for Bennett's power company, and he runs into an old friend, Sparrow Biffle, who works for Bennett's secretary, Pam Reynolds.