Frank Schultz was the original discoverer, in 1879, but the main body of the deposits were discovered by Henry W. Nichols in 1942.
Faulting of the original ore body created two main segments, separated by an area of minor sulfides.
The mineralization is a porphyry copper deposit, with the ore body being tabular and 300 metres (980 ft) thick.
[1][2] Geologist J. D. Lowell who directed the program for Quintana Minerals Corporation and John M. Guilbert went on to develop this work into a general pattern for porphyry copper deposit exploration.
[3] The mine was operated by the Magma Copper Company before being bought out by BHP, which ultimately closed it.