The Worlds Fair Mine, located in Harshaw, Arizona was purchased by William Moran in 1883 then sold to Frank Powers of Custer County,Idaho in 1884 who maintained ownership until circa 1915. The Worlds Fair Mine produced silver-lead ore and was owned at times or in part, by the Worlds Fair Development Company; the Worlds Fair Mining Company; the Zero Mining Company and the Trench Company.
The collection consists chiefly of two account books kept by the World's Fair Mine in Harshaw, Arizona and records the purchase of supplies for the mining camp; charges for room, board, and personal provisions for employees; deliver of mail, payroll, assay cost, and notes on mining operations. The collections includes assay certificates, receipts, World's Fair Mine letterhead and partial time record, and a letter to Frank Powers from the Santa Cruz County Arizona Assessment Office. The account books make up the bulk of the collection.