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Morenci Mine (Morenci pit; Phelps Dodge Morenci Mine; Morenci-Metcalf), Morenci, Copper Mountain District (Clifton-Morenci District), Shannon Mts, Greenlee Co., Arizona, USA

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Latitude & Longitude (WGS84): 33° 5' 26'' North , 109° 21' 57'' West
Latitude & Longitude (decimal): 33.09056,-109.36611
GeoHash:G#: 9tfhprfn2
Other regions containing this locality:Sonoran Desert, North America
Owned/operated by:Freeport-McMoRan (72%), Sumitomo Metal Mining Co., Ltd. (28%)
Locality type:Mine (Active) - last checked 2018
Köppen climate type:Csb : Warm-summer Mediterranean climate

An open pit and underground Cu-Mo-Au-Ag-Pb-Zn-U-Re-REE-Gemstone-Gypsum-Talc/soapstone-garnet mine located in secs. 8, 9, 15, 17 and in the N½ sec. 16, T4S, R29E (Clifton 15 minute topo map), at Morenci, 4.5 miles NW of Clifton. First produced 1942.

Mineralization is an elliptically shaped ore body in a porphyry copper-molybdenum deposit. The ore zone is 1341.12 meters long, 853.44 meters wide with a depth to top of 76.2 meters and a depth to bottom of 701.04 meters, and a thickness of 259.08 meters, and plunges E. Ore control was NE-trending fisures, veining, and crackling. Ore concentration was complex as progressively more silicic intrusions carried sulfide phases into fractures created by older pulses. Alteration was hydrothermal with kaolinization, sericitization, calc-silicate or pelitic hornfels and skarn.

The district is zoned with a chalcopyrite-rich core surrounded by a pyrite envelope which is surrounded by protore. Ag and Au are more abundant in less altered areas. The greatest Mo concentrations are in granite porphyry, less in Precambrian Granite.

The enrichment blanket ranges from 50 to 1000 feet thick and thickens from W to E. Turquoise found in the oxidized part of the deposit. Massive andradite is found in a skarn deposit at the southwest corner of the large open pit.

Area structures include the NW-trending Copper Mountain Fault, which dsplaces enrichment blanket 200 feet. Also NE-trending fissures may have localized porphyry emplacement.

The workings are 2133.6 meters long and 1219.2 meters wide. The open pit work started in 1937. Molybdenite runs 400 to 2000 ppm of Re.

Commodity List

This is a list of exploitable or exploited mineral commodities recorded from this region.

Mineral List

Mineral list contains entries from the region specified including sub-localities

74 valid minerals.

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org

2.588 - 5.333 Ma

ID: 3192320
Cenozoic volcanic rocks

Age: Pliocene (2.588 - 5.333 Ma)

Lithology: Volcanic rocks

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

Ypresian - Campanian
47.8 - 83.6 Ma

ID: 2778472
Early Tertiary to Late Cretaceous granitic rocks

Age: Phanerozoic (47.8 - 83.6 Ma)

Description: Porphyritic to equigranular granite to diorite emplaced during the Laramide orogeny. Larger plutons are characteristically medium-grained, biotite +/- hornblende granodiorite to granite. Smaller, shallow-level intrusions are typically porphyritic. Most of the large copper deposits in Arizona are associated with porphyritic granitic rocks of this unit, and are thus named 'porphyry copper deposits'. (50-82 Ma)

Comments: Laramide metaluminous; associated with porphyry Cu deposits

Lithology: Major:{granite,granodiorite,diorite}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License

Localities in this Region
Show map

  • Arizona
    • Greenlee Co.
      • Shannon Mts
        • Copper Mountain District (Clifton-Morenci District)

This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


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Lindgren, W. (1903), The copper deposits of Clifton, Arizona, Engineering and Mining Journal: 75: 705.
Lindgren, W. (1904), The genesis of copper deposits, Engineering and Mining Journal: 78: 987.
Lindgren, W. (1905), The copper deposits of the Clifton-Morenci district, Arizona, USGS PP 43;
Guild, F.N. (1910), The Mineralogy of Arizona, The Chemical Publishing Co., Easton, PA.
University of Arizona Bull. 41 (1916-17), Mineralogy of Useful Minerals in Arizona: 50.
Butler, B.S. & Wilson E.D. (1938), Arizona Bureau of Mines Bull. 145: 72-80.
Moolick, R.T. & J.J. Durek (1966), The Morenci district, in S.R. Titley and C.L. Hicks (editors), Geology of the porphyry copper deposits, southwestern North America, Universty of Arizona Press, Tucson: 221-231.
Langton, J.M. (1973), Ore Genesis in the Morenci-Metcalf District, A.I.M.E. Transactions: 254: 247-257.
Paydirt (1981) Phelps Dodge, A Copper Centennial, 1881-1981.
Engineering and Mining Journal (1987) Phelps Dodge Has Something to Smile About, August, 1987: 24-31.
Phillips, K.A. (1987), Arizona Industrial Minerals, 2nd. Edition, Arizona Department of Mines & Minerals Mineral Report 4, 185 pp.
Minerals Yearbook (1988) - Mining & Quarrying Trends: 31;
Peirce, H. Wesley (1990), Arizona Geological Survey Industrial Minerals card file.
Phillips, et al (1990).
Walenga, Karen (1990) SX-EW Production Doubled to 200 Million PPY, Southwestern Pay Dirt, 4/90: 4A-6A.
Dillard, Gary (1991) Four Major Orebodies will Shoulder the Load. Southwestern Pay Dirt, 11/91: 4A-14A.
Epler, Bill (1991) Phelps Dodge Finds 150 Million More Tons of Ore at Morenci. Southwestern Pay Dirt, 1/91: 3A.
Epler, Bill (1991) Phelps Dodge Relocates Highway at Morenci Mine. Southwestern Pay Dirt, 7/91: 4A-6A.
Blair, G. (1992), The Rockhound's Guide to Arizona: Helena, MT, Falcon Press.
Carter, Russell A. (1992) Expansion Almost Complete at Arizona’s Mission and Morenci Mines. Engineering and Mining Journal, 2/92: C14-C16.
Niemuth, N.J. & K.A. Phillips (1992), Copper Oxide Resources, Arizona Department of Mines & Mineral Resources Open File Report 92-10: 8 (Table 1).
Dillard, Gary (1994) Phelps Dodge is Contemplating SX-EW Expansion at Morenci. Southwestern Pay Dirt, 5/94: 3A, 8A.
Snider, T.R. (1994) Morenci Southside will Add 150 million pounds of Cathode. Southwestern Pay Dirt, 8/94: 3A.
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.: 124, 125, 163, 166, 193, 198, 233, 261, 292, 314, 345, 368, 388.
Merritt Stephen Enders (2000) The Evolution of Supergene Enrichment in the Morenci Porphyry Copper Deposit, Greenlee County, Arizona. PhD Thesis, University of Arizona
Singer, D.A., Berger, V.I., and Moring, B.C. (2005): Porphyry Copper Deposits of the World: Database, Map, and Grade and Tonnage Models. USGS Open-File Report 05-1060.
Grant, Raymond W., Richard A. Bideaux & Sidney A. Williams (2006), Minerals Added to the Arizona List 1995 to 2005: 1.
USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10027138, MRDS ID #M002216; and file ID #10282444.
U.S. Bureau of Mines, Minerals Availability System (MAS) file ID #0040110018.

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