University of Arizona

Students, faculty, staff, and the public are now welcome to visit Special Collections without an appointment from 9 am to 4 pm, Monday through Friday. 

Special Collections will close at 12 pm on Monday, December 5th for the event Satellites: bringing an astronomy archive to the stage.

Records of the Commonwealth Mine

The Commonwealth Mine of Cochise County, AZ was discovered by John Pearce in 1895. Later that year he formed a partnership with John Brockman, R.A.F. Penrose, and D.M. Barringer and organized Commonwealth Mining and Milling Company. By 1905, the high-grade ore had played out and the shaft collapsed. The mine was purchased by Montana Tonopah Mines Company in 1910. The later records seem to indicate that the mine was controlled by the Commonwealth owners. During its forty year existence, the mine produced $8 million worth of silver and $2.5 million in gold at a time when silver was priced around 50 cents an ounce, and gold was $20 an ounce.

The bulk of the Commonwealth Mine records document its activities from 1910 until 1930. Many of its earlier and later records were lost or destroyed between the closing of the mine in the 1940s and the salvaging of the records in 1960. Many records were destroyed in a fire and many of the remaining records are fragile and fragmentary. These remaining records best characterize the daily operations of the mine and its managers between 1910 and 1930. The broad themes of this collection outline the managerial and financial skills that kept the mine operating. 

The managers' correspondence highlights the business acumen and legal matters. There are also several subject files, entitled "Automobiles," "Cyanide," and "Insurance" which may represent the original filing systems used in the office. The financial files are mainly monthly account statements designating debits and credits for the company, outlining the cash flow of the mine and its operational status. The legal files consist largely of contracts, agreements, and deeds relating to structural improvements at the mine, railroad right-of-ways, leasing operations, smelting arrangements, equipment purchases, and mining claims. The tax files consist of annual and monthly reporting forms from the mine to the federal, state, and county offices. 

The directors of the Commonwealth Mine ventured into several other businesses in Pearce, AZ and the nearby communities. Fragments of records pertaining to the B.S.B. Egg Farm, Coronado Cattle Company, Glenn Land and Cattle Company, Midwest Sugar Company, and World's Fair Mine are present. A.Y. Smith was active on the Cochise County Highway Commission in 1919. The files contain minutes, reports, and correspondence of the Commission relating to a $1 million bond issue to construct and repair various roads in Cochise County. Additional files document the activities of the Sulfur Springs branch of the American National Red Cross, 1923 to 1927, and a Pearce social and recreational association, the Town and Country Club, 1914 to 1922.