‡Ref.: Hill, J.M. (1910), Notes on the placer deposits of Greaterville, Arizona, USGS Bull. 430: 11-22.
Schrader, F.C. & J.M. Hill (1915), Mineral deposits of the Santa Rita and Patagonia Mountains, Arizona, USGS Bull. 582: 164.
Wilson, E.D. (1927), Arizona Gold placers, 2nd. ed. (revised), University of Arizona Bull. 124: 38-40.
Arizona Bureau of Mines Bull. 135 (1933), Arizona Gold placers & placering: 58.
Keith, Stanton B. (1974), Arizona Bureau of Geology & Mineral Technology, Geological Survey Branch Bull. 189, Index of Mining Properties in Pima County, Arizona: 121 (Table 4).
Arizona Bureau of Mines File Data.
A Au-Ag placer deposit area located in Chispa Gulch, a small branch of Empire Gulch, on the eastern foot of the Santa Rita Mountains. Owned at times, or in part, or in places by the Stetson Co.; the El Oro Mining Co.; and the Greaterville Dredge Gold Mining Co.
Mineralization is mostly coarse flake and nugget gold with minor combined silver and some attached galena in medium-sized gravel along recent and older buried channels and terraces close to the mountain front.
Major operations were undertaken from 1875 to the early 1900's and small and sporadic since then. Estimated production for the entire area is some 30,000 oz. of gold, or more, with about 6,000 oz. of silver.
