Narragansett Mine (Narragansett claim; Narragansett Bay claim; Olcutt claim), Daylight-Narragansett Mines (Narragansett-Daylight Mines), Rosemont (Rosemont Camp), Helvetia-Rosemont Mining District, Pima County, Arizona, USAi

Regional Level Types
Narragansett Mine (Narragansett claim; Narragansett Bay claim; Olcutt claim)	Mine
Daylight-Narragansett Mines (Narragansett-Daylight Mines)	Group of Mines
Rosemont (Rosemont Camp)	Mining Area
Helvetia-Rosemont Mining District	Mining District
Pima County	County
Arizona	State
USA	Country

‡Ref.: Schrader, F.C. & J.M. Hill (1915), Mineral deposits of the Santa Rita and Patagonia Mountains, Arizona, USGS Bull. 582: 92, 128-129.

Elsing, M.J. and Heineman, E.S. (1936) Arizona Metal Production, Arizona Bureau of Mines Bulletin 140.

Creasey, S.C. & G.L. Quick (1955), Copper deposits of part of Helvetia Mining district, Pima County, Arizona, USGS Bull. 1027-F: 312, 318-319.

Arizona Bureau of Mines field notes (1971), vol. 1, no. 2.

Drewes, H.D. (1971) Geologic map of the Sahuarita quadrangle, southeast of Tucson, Pima County, Arizona: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-613, 1 sheet, scale 1:48,000.

Keith, Stanton B. (1974), AZ Bur. of Geol. & Min. Technology, Geol. Survey Br. Bull. 189, Index of Mining Properties in Pima County, AZ: 125 (Table 4).

Niemuth, N.J. & K.A. Phillips (1992), Copper Oxide Resources, Arizona Department of Mines & Mineral Resources Open File Report 92-10: 12 (Table 1).

Arizona Bureau of Mines file data.

MRDS database Dep. ID file #10039412, MRDS ID #M050046.

A former small underground Cu-Ag-Zn-Pb-Au claim located near the crest of the range in the SE ¼ sec. 24 & the NE ¼ sec. 25, T.18S., R.15E. (Sahuarita 15 minute topo map), 1½ miles ESE of Helvetia at an elevation of 5,500 to 5,600 feet and joins the Eclipse group on the east. Discovered in 1877 by J.K. Brown. Owned by J.K. Brown (circa 1915), and is about 28 miles SE of Tucson. Produced 1907-1961. Also owned at times, or in part, by the Lewisohn Copper Co.; Brown; Ramsdell; Narragansett Mines Co.; Holderness; Harold Steinfeld & Co., Tucson; Bennett; and the Wilson Mining Co.

Mineralization is copper carbonates with minor sulfides and local areas of lead and zinc minerals in irregular, pyrometasomatic replacement orebodies in intensely silicated and crushed Paleozoic limestone along folded series of thrust-faulted block segments. Minor amount of chalcocite and chalcopyrite. Malachite-azurite-chalcocite probably secondary after chalcopyrite. The ore bed is 20 feet thick and is formed on a fault plane. It seems to be a mass of crushed and altered limestone impregnated with copper carbonates and iron oxides. It is locally parallel banded. Host rock units are the Concha Limestone (cherty limestone), and the Scherrer Formation quartzitic sandstone.

Rocks are Paleozoic and Cretaceous sedimentary rocks. Paleozoic section represented by Bolsa Quartzite, Naco Limestone (restricted), lower Manzano equivalent & Snyder Hill formation of Stoyanow. The Paleozoic section overlies the Cretaceous sedimentary rocks on a fault contact. All major faults are vertical or dip westward. The Paleozoic limestone formations and the Naco limestone in part have been intensely silicated. The limestone is mostly crushed and altered.

The mine portal and most drifts and crosscuts are in the Cretaceous formation, which consists of bedded arkosic sandstones & shales.

The oreshoots lie along the axis of a south-plunging syncline in the folded, low-angle thrust fault that brings limestone of Paleozoic age over Cretaceous sedimentary rocks. The ore lies in a crushed zone 7 to 8 feet thick in the altered limestone hanging wall and consists of copper carbonates & minor sulfides, with a gangue composed principally of silicated limestone, iron oxides and some pyrite.

Local structures include thrust and normal faulting, fracture zones, homoclinal. Regional trends include tilting and broad open folds in the south and extensive faulting in the north.

Workings include several inclined shafts, tunnels, and winzes to a depth of nearly 300 feet. The main incline is 125 feet deep and dips 40ºSW. They also include 2,600 feet of drifts and crosscuts, 260 feet of inclined winzes and many stopes plus an adit. This mine worked intermittently from the late 1870's to 1961 and has produced over 90,000 tons of ore averaging over 4% Cu and 0.5 oz. Ag/T.

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Link to USGS MRDS:	10039412

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