Safford deposit (Spalding; Lindsey and Anderson claims; Sanchez Copper deposit; Esperanza Mine), Sanchez, Lone Star Mining District (Safford Mining District; Dos Pobres Mining District), Graham County, Arizona, USAi

Regional Level Types
Safford deposit (Spalding; Lindsey and Anderson claims; Sanchez Copper deposit; Esperanza Mine)	Deposit
Sanchez	- not defined -
Lone Star Mining District (Safford Mining District; Dos Pobres Mining District)	Mining District
Graham County	County
Arizona	State
USA	Country

An underground Cu-Au mine located in secs. 25 & 26, T6S, R27E, 9 miles ENE of Safford, at Sanchez, on BLM-administered land. Lat-long is for approximate central point of the mineralized area - the old shaft in sec. 26 is at 32-52-57N, 109-32-43W; the prospect in sec. 25 is at 32-52-53N, 109-32-02W. Discovered 1899. Produced 1899 to the late 1930's. Owned and operated by the Azco Mining Inc., Lakewood, CO (1988). Also known as / designated: Maravilla Copper Co.; Lone Wolf shaft; Lead Hill; Kirtland Hill group; Iron King; Consolidated Metals MS 4590 claim; Clara; Bear Creek; United Nuclear; Nancy group; Arichise Copper Co.; Bellmon; Bob Carresco; Carpenter; Esperanza Sanchez; AZCO Minintg Inc. project; Kennecott Safford Mine; Carpenter Mine; Safford Inspiration Mine; and McBride. Unpatented mining claims extend into secs. 13-16 & 18-24, 26-28, and 34-36; and secs. 23-36, T5S, R26E.

Mineralization is a pipe-shaped porphyry copper deposit hosted in Safford Volcanics and breccia that is 762 meters long and 762 meters wide and 1066.8 meters thick, hosted in volcanic agglomerate and andesite. Ore centered on oldest of four monzonite porphyry intrusive phases but mostly hosted by andesite. Associated rock unit is the Lone Star pluton (monzonite). Concentration was hydrothermal and oxidation. Ore control was NE-trending shears intruded by dikes. Ore concentration was shearing and fracturing of older andesites, followed by intrusion of later igneous plugs and porphyries alogn shear zones. Shearing and fracturing continued, followed by alteration and iron and copper sulfide mineralization. The deposit later was enriched by formation of a chalcocite enrichment blanket. It was subsequently covered by volcanics. NW block faulting uplifted and tilted the Gila Mountains and further oxidized the deposit.

Alteration involves four hypogene alteration zones: 1) Sericitization & silicification in rhyolite, latite, and quartz latite; 2) Biotization in andesite; 3) Chloritization; and 4) Propylitic alteration. The ore body is in zones 1 & 2. Supergene enrichment has taken place to average dept of 440 feet.

Quartz monzonite is associated with the mineralization. The ore grade is highest in the main stock. The oxide zone extends to 1050 feet depth. Mixed oxide/native copper zone from 1050 to 1200 feet depth, sulfide below 1200 feet depth. A small chalcocite enrichment blanket formed in the breccia pipe but was later oxidized. The oxide zone consists of coatings of chrysocolla, neotocite, tenorite, minor native copper, and trace atacamite on fractures accompanied by goethite, minor hematite, and rare jarosite. Chrysocolla also occurs as disseminations in plagioclase. The mixed zone consists of Chrysocolla, neotocite, native copper, delafossite, cuprite (?), chalcopyrite, bornite, and minor molybdenite. The original total sulfide content averaged 1.5 vol. % with up to 5 vol. % in the breccia pipe. Protore grade was about 0.3% Cu.

Area structures include the Lone Star shear zone 6000 feet wide and 16000 feet long that strikes N50°-65°E, steep to vertical dip.

Workings include a shaft sunk by Carpenter on oxide Cu ore outcrop about 1910. Porphyry Cu potential recognized by Bear Creek Mining Co. (Kennecott) in the 1950's. The first hole cut about 1000 feet of 1% Cu. Subsequently explored bys several uranium, oil and mining companies of which Inspiration did the most work. Inspiration (late 1960's to early 1970's) identified sulphide copper mineralization below the oxide zone, but Azco was not pursuing the sulphide mineralization in 1989. In 1993, BLM approved the project after Azco completed a full environmental impact statement process. A total of 150 holes have been drilled with 190,000 feet of total footage.

Reserves amount to ore for at least 20 years of operation. Reserve-Resources: within the 250,000,000 st oxide reserve (1988) is an open pit minable block of 120,000,000 st at a grade of 0.37% Cu. Proposed open pit-heap leach operation. Development was to have begun in 1995. Plans to leach 100,000 to 150,000 tons/week.

Production: about 50,000 st bulk samples mined from open pits by Inspiration from 1969 to 1972. Azco mined additional bulk samples from the same pits.

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Link to USGS MRDS:	10026888

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References