Interviews explore the development of the mining industry in northern Mexico from the 1930s to the present. Topics include life in mining camps, working conditions, labor unrest, the function of foreign capital, political events that influenced the industry, and mining technology. These interviews, in both English and Spanish, constitute a significant archive providing rich primary source material to researchers and scholars in a variety of disciplines.

Some vols., 1920-1949, contain collections of papers according to subject.