The Harding mine, Taos County, New Mexico
— Richard H. Jahns and R. C. Ewing

The Harding mine, in the western part of the Picuris Range about 20 miles southwest of Taos (Fig. 1), has yielded substantial amounts of commercial beryl, lepidolite, spodumene, and tantalum-niobium minerals over a period of half a century. It also has become widely known as a source of handsome mineral specimens, as a provocative locality for scientific studies, and as an attraction for those who appreciate spectacular exposures of pegmatite. It lies four miles southeast of the Rio Grande Canyon at an altitude of 7400 ft (sec. 29, T. 23 N., R. 11 E.), and it is readily accessible from a nearby point on State Highway 75 about 6 miles east of Dixon.

 

The mine property has been generously leased by the owner, Dr. Arthur Montgomery, to the University of New Mexico for preservation as one of the State's unusual natural assets. The University plans also to make this classic locality continually available for public inspection, study, and mineral collecting on a modest scale. Anyone with an interest in visiting the property should contact the Chairman, Department of Geology, University of New Mexico, Albuquerque, New Mexico 87131. A splendid collection of representative Harding minerals, donated by Dr. Montgomery, can be viewed in the University's Geology Museum.

 

The published record of the Harding mine comprises early general descriptions (Roos, 1926; Just, 1937) and mineralogic notes (e.g., Schaller and Henderson, 1926; Hirschi, 1928, 1931; Hess, 1933), summaries of extensive exploratory work by the U.S. Bureau of Mines in 1943 and 1948 (Soule, 1946; Berliner, 1949), descriptions of milling operations for tantalum minerals (Wood, 1946) and mining operations for beryl (Montgomery, 1951), and various discussions of mineralogic and structural relationships in the pegmatite bodies (e.g., Cameron and others, 1949; Montgomery, 1950; Page, 1950; Jahns, 1951; 1953a,b; Mrose, 1952; Rimal, 1962). The pur-pose of the present paper is briefly to describe the mining history and geology of the Harding locality, in part as an aid to those who visit the property or who view some of its characteristic minerals in Albuquerque at the Geology Museum. The treatment is based on detailed field studies that began in 1942 under the aegis of the U.S. Geological Survey and continued intermittently for more than two decades, and on mineralogical investigations in several laboratories.

 

We are indebted to John W. Adams and William P. Irwin of the U.S. Geological Survey and to Lauren A. Wright of The Pennsylvania State University for important contributions during the early periods of field work, and to Arthur Montgomery of Lafayette College and Lincoln R. Page and the late Waldemar T. Schaller of the U.S. Geological Survey for numerous penetrating discussions of the Harding mineral associations. We wish also to acknowledge the valued aid of Stuart A. Northrop of the University of New Mexico in compiling an authoritative list of minerals found in the Harding pegmatites. It is a special pleasure to recall, in connection with the field investigations, the hospitality and many courtesies received from Arthur Montgomery, John H. Soule of the U.S. Bureau of Mines, and Eliseo Griego, the late Flaudio Griego, and Lydia and "Doc" Zellers of Dixon.