Allen Rueter wrote:  You might find this Bureau of Mines /Minerals yearbook 1950 interesting.

http://digicoll.library.wisc.edu/cgi-bin/EcoNatRes/EcoNatRes-idx?type=div&did=EcoNatRes.MinYB1950.WYoung&isize=XL

If one explores the "Sections" or "Contents" there is information on other minerals many still shipped by rail in 1950: e.g. cement, helium, carbon black, among others. All section are downloadable PDFs.

Bob Witt