Letter from Carl Hayden to George Otis Smith asking his advice regarding the mining of asbestos deposits in the Grand Canyon.

Letter of introduction for Dwight B. Heard on the arrival of National Park Service Director Stephen T. Mather to Phoenix. Mather's visit includes trips to Roosevelt Dam and Tumacácori.

Letter from Carl T. Hayden to Alf Dickenson about mine locations within the park.

Letter from Carl T. Hayden to Louis C. Cramton about potential prosecution of people with mining claims within park boundaries.