01023cam a22002651 4500 gs 60000249 DLC 20260227111409.0 780920s1960 nmuab b 000 0 eng c gs 60000249 (OCoLC)4238656 U.S. Geol. Survey. Libr. NmU-L OCoLC DLC premarc TN24.N6 A235 no. 54 Bertholf, William Earl, 1915- Magnetite taconite rock in Precambrian formations in Rio Arriba County, New Mexico. Socorro, State Bureau of Mines & Mineral Resources, New Mexico Institute of Mining & Technology, 1960. iv, 24 p. illus., map, diagrs., tables. 28 cm. New Mexico. Bureau of Mines and Mineral Resources. Circular, 54 Errata slip inserted. Bibliography: p. 24. Magnetite New Mexico Rio Arriba County. Rocks Analysis. Circular (New Mexico. Bureau of Mines and Mineral Resources) ; 54. 29470 29470