Epidemiological study of mortality among underground gold mine workers (SIC-1041) was conducted. The cohort consisted of 3,328 white males who had been employed at the Homestake Mine, Lead, South Dakota for at least 1 year between January 1, 1940 and December 31, 1964. Total cohort exposure was 79,123 person years. The cohort was traced by reviewing company records, death certificates, social security and internal revenue data, and South Dakota state records. Mortality analyses were performed using a person year life table computer program. Previous surveys showed that the cohort was exposed to cummingtonite-grunerite, free silica (7631869), arsenic (7440382), and radon (10043922) daughters. The authors recommend further study of the incidence of chronic kidney disease mortality among underground miners, especially since other studies have found a similar correlation.