MINING HISTORY OF THE AREA

The early history and production from the Rosemont Property has been described in Anzalone (1995), from which the following summary is taken.

In the 1880s the production of copper from mines on both sides of the northern Santa Rita Mountains supported the construction and operation of the Columbia Smelter at Helvetia on the west side of the Santa Rita Mountains and the Rosemont Smelter in the Rosemont Mining District on the east side of the Santa Rita Mountains. Copper production ceased in 1951 after the production of about 227,300 tons of ore containing 17,290,000 pounds of copper, 1,097,980 pounds of zinc and 180,760 ounces of silver. An unknown, but probably minor, portion of the production came from the Rosemont deposit.

In addition to the Rosemont deposit, the Peach-Elgin deposit was a significant resource in the area. Since shutdown in 1951, the area stretching from Peach-Elgin to Rosemont has seen a progression of exploration campaigns. Churn drilling at the Peach-Elgin prospect in 1955 and 1956 by Lewisohn Copper Company began the definition of that deposit. Drilling in 1956 by American Exploration and Mining Company initiated exploration of the Broadtop Butte prospect. Banner Mining Co. had acquired most of the claims in the area by the late 1950s, and drilled the discovery hole into the Rosemont deposit. Anaconda Mining Company acquired the claims in 1963 and carried out a major exploration program that identified the Rosemont deposit as a major porphyry copper body and advanced the Broadtop Butte and Peach Elgin prospects. The project carried on after Amax and Anaconda joined in the Anamax partnership until 1986 when Anamax sold the property to a real estate company during the dissolution of Anaconda. By the end of the Anaconda-Anamax programs, exploration drilling totaled in excess of 297,321 ft, of which approximately 232,000 ft defined the Rosemont deposit.

ASARCO purchased the property in 1988, renewed exploration of the Peach-Elgin prospect and initiated engineering studies. ASARCO drilling of the Rosemont deposit was limited to a small number of geotechnical diamond drill holes. ASARCO sold the entire property to real estate interests in 2004. Augusta acquired the Rosemont Property in 2005.