Curtin Mine (Humphrey Mine), Banner Mining District, Pinal County, Arizona, USAi

Regional Level Types
Curtin Mine (Humphrey Mine)	Mine
Banner Mining District	Mining District
Pinal County	County
Arizona	State
USA	Country

A Pb-Zn mine located about 1 mile east of the London-Arizona Mine and Chilito settlement, or 2½ miles east of the 79 Mine.

The Governor Curtin and 35 other claims in the vicinity were obtained by T.Z. Humphrey and associate in 1948. This ground was formerly part of the London-Arizona property.

Pennsylvanian Naco Limestone is intruded by porphyry dikes and overlain on the east by Cretaceous volcanics. The limestone beds prevailingly strike WNW-ly and dip 10º to 20º southward. About 1,200 feet west of the shaft is the O'Carroll fault, whose course is followed by a prominent southerly-trending gulch. This fault brings Mississippian Escabrosa and Devonian Martin Limestones on the west in contact with the Naco Limestone on the east. The main porphyry dikes strike approximately parallel to the limestone, but branches of them trend northeast, northwest and south. In general the dikes dip steeply northward, but in places they form sills more or less concordant with the limestone beds.

The ore deposits are irregular replacements in the Naco limestone. They occur mainly on the north or hanging wall side of the main dike and on the footwall side of sills. Certain impure limestone beds were relatively favorable for replacement. Most of the northeast fissures exposed underground show mineralization.

Workings include the Cutin vertical shaft, sunk to 325 feet prior to 1925. An inclined shaft 95 feet father north than the Cutin shaft had been deepened to 170 feet, and more than 1,000 feet of adit workings connecting with the shafts at the 70 foot level had been reopened. Production, mostly out of shallow workings in the vicinity, was 1,016 tons of lead ore and 51 tons of zinc ore.

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