New Cornelia Ajo

Site Name

Primary: New Cornelia Ajo
Secondary: New Cornelia Mine
Secondary: Ajo Mine

---

Commodity

Primary: Copper
Secondary: Zinc
Secondary: Gemstone
Secondary: Silver
Secondary: Molybdenum
Secondary: Gold
Secondary: Semiprecious Gemstone
Tertiary: Iron
Tertiary: Niobium (Columbium)
Tertiary: Titanium
Tertiary: Rubidium

---

Location

State: Arizona
County: Pima
District: Ajo District

---

Land Status

Land ownership: Private
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.

---

Holdings

Type: Fee Ownership
Type: Patented

---

Workings

Type: Surface

---

Ownership

Owner Name: J.B. Johnson
Years: 1917 -

Owner Name: Phelps Dodge Corp, 2600 N Central Ave, Phoenix, Az 85004
Company ID: 200156
Percent: 100.0
Home Office: Arizona
Info Year: 1987

---

Production

Year: 1913
Year: 1957
Time Period: 1917-1957
Year: 1962
Time Period: 1917-1962
Mined: 255000000.00 mt
Year: 1985
Description: 182 Mt Cu Prod Frm Dump Leach
Year: 1984
Description: 91 Mt Mo Produced
Year: 1985
Time Period: 1911-1985
Mined: 418800000.00 mt
Year: 1984
Description: 417 Mt Cu Prod From Ppt
Year: 1984
Description: 21610 Mt Cu Prod From Ore
Year: 1984
Description: Mine Shutdown Indefinitely In Aug 1984 5255000 Mt Ore Mined
Year: 1983
Description: No Leach Ppt Cu Produced No Cu Ppt Produced
Year: 1983
Description: 72 Mt Mo Produced
Year: 1983
Description: Shutdown Without Production In Jan + Feb 7278000 Mt Ore Mined
Year: 1983
Description: 33838 Mt Cu Produced
Year: 1982
Description: 70 Mt Mo Prod From Ore
Year: 1982
Description: 9641 Mt Cu Prod From Ore
Year: 1982
Description: 300 Mt Cu Prod From Ppt
Year: 1982
Description: Mine Closed 4/82 - Cu Prices Depressed 1862000 Mt Ore Mined
Year: 1981
Description: Total Ore Mined 8715680 Metric Tons For The Year
Year: 1981
Time Period: 1917-1981
Mined: 390000000.00 mt
Year: 1979
Description: Total Ore Mined 9241320 Metric Tons For The Year
Year: 1980
Description: Total Ore Mined 6387280 Metric Tons For The Year
Year: 1978
Description: Total Ore Mined 7696820 Metric Tons For The Year
Year: 1973
Time Period: 1970-1973
Year: 1977
Description: Total Ore Mined 6194050 Metric Tons For The Year

---

Deposit

Record Type: Deposit
Operation Category: Past Producer
Deposit Type: Porphyry Cu
Operation Type: Surface
Mining Method: Open Pit
Milling Method: Flotation
Year First Production: 1917
Year Last Production: 1985
Discovery Year: 1750
Years of Production:
Organization:
Significant: Y
Deposit Size: L

---

Physiography

General Physiographic Area: Intermontane Plateaus
Physiographic Province: Basin And Range Province
Physiographic Section: Sonoran Desert

---

Mineral Deposit Model

Model Name: Porphyry Cu

---

Orebody

Name: Lenticular, Erratic

Name: Elliptical

---

Structure

Type: L
Structure: Fanglomerate and Volcanics Are Steeply Dipping

Type: L
Structure: NNW Fracture Zones, A Number of Major Faults With Large Displacements

---

Alterations

Alteration Type: L
Alteration: Oxidized Down to Water Table

Alteration Type: L
Alteration: Sericitic, Clay, Chloritization, Kaolinization, Silicification

---

Rocks

Name: Quartz Monzonite
Role: Associated
Age Type: Associated Rock
Age Young: Paleocene

Name: Quartz Monzonite
Role: Host
Age Type: Host Rock
Age Young: Paleocene

---

Analytical Data

Analytical Data: MOO3 IS ESTIMATED AT LESS THAN 0.1%. RUTILE OCCURS AS EQUANT GRAINS OVER 20 MICRONS AT ROUGHLY 0.1% IN K-FELDSPAR. RUTILE IS HIGH IN NB.
Analytical Data: 1928: 1.13% CU, 0.091 OZ/T AG, 0.006 OZ/T AU

---

Materials

Ore: Silver
Ore: Molybdenite
Ore: Chalcocite
Ore: Bornite
Ore: Gold
Ore: Chrysocolla
Ore: Malachite
Ore: Hematite
Ore: Covellite
Ore: Magnetite
Ore: Tenorite
Ore: Chalcopyrite
Ore: Shattuckite
Ore: Pyrite
Ore: Rutile
Ore: Ilmenite
Gangue: Quartz
Gangue: Talc
Gangue: Kaolin

---

Comments

Comment (Deposit): The Copper Concentrate Transportation Cost Was Updated To Jan. 1987 Dollars For The Economic Time Diagrams Included In The Update Report Backup. Property Update July 1987.

Comment (Reserve-Resource): Also Known As Ajo. Reserves Reported From Phelps Dodge Corp. '94. P. 14.

Comment (Production): Also Known As Ajo. Reserves Reported From Phelps Dodge Corp. 12/31/94. P. 14. 1982-1985 Production Taken From (1) Primary Copper Industry Of Arizona Special Repts Nos 6,8 & 9. Az Dept Of Mines & Min. Res. & (2) Phelps Dodge 1986 Ann Rept. P. 8. Mine Closed For Indefinite Period In Aug 1984. 1986 Ann Rept Stated That Mine Will Not Reopen Until Cu Price Rises Above 80 Cents Per Lb. (P. 9.)

Comment (Commodity): Carbonate Ore Is Mined Out, Only Sulfide Ore Remains. This Mine Is A Notable Locality For The Massive Deep Blue Shattuckite (A Hydrous Copper Silicate).

Comment (Geology): Contact Of Oxidized And Sulfide Ore Is Sharp. There Is No Leached Overburden. Gold Is More Closely Associated With Copper Sulfides Than With Pyrite. Units Present Include Quartz Monzonite, Quartz Diorite, Granodiorite, Equigranular Quartz Monzonite, Porphyritic Quartz Monzonite, Porphyritic Micro Quartz Monzonite.

Comment (Workings): Shallow Workings; Drilling To 1000 Ft In 1919 To 1921 Located No Further Ore.

Comment (Deposit): Associated Minerals: albite, alunite, anhydrite/gypsum, biotite, barite, bornite, brochantite, carbonate, chalcocite, chalcopyrite, chlorite, chrysocolla, covellite, cuprite, epidote, gold, hematite/specularite, ilmenite, jarosite, magnetite, malachite, molybdenite, pyrite, sericite, shattuckite, sphalerite, tetrahedrite/tennantite

Comment (Deposit): Associated Rocks: andesite dike, andesite porphyry dike, quartz diorite, quartz monzonite, quartz monzonite porphyry, pegmatite, rhyolite;gneiss;andesite flow, andesite breccia, fanglomerate, tuff

Comment (Deposit): Mineralization Is Disseminations & Veinlets. Ore Body Is Well Shattered. Iron Minerals Are Associated With Copper Mineralization. Molybdenite Is Widely Scattered In The Ore Body.

---

References

Reference (Deposit): Cox and others (2006), Dixon (1966), Gilluly (1946), Long (1995), McDowell (1971), Niemuth (1994), Trischka (1938), Wilkinson and others (1999)

Reference (Reserve-Resource): GILMOUR, P., 1982, GRADES AND TONNAGES OF PORPHYRY COPPER DEPOSITS: IN - ADVANCES IN GEOLOGY OF THE PORPHYRY COPPER DEPOSITS, SOUTHWESTERN NORTH AMERICA, ED. BY, S.R. TITLEY UNIV. AIR. PRESS, TUCSON, AZ, 1982.

Reference (Reserve-Resource): Damon, P.E. and Mauger, R.L., 1966, Epeirogeny-orogeny viewed from the Basin and Range Province; Society of Mining Engineers, AIME Transactions, v. 235, p. 99-112.

Reference (Deposit): New Corenelia Copper Co. 1911-30 Annual reports; Phelps Dodge 1971-85 SEC Form 10K; USBM Minerals Yearbooks 1911-85; PCIA 1979-85

Reference (Reserve-Resource): Phelps Dodge 1984 SEC Form 10K

Reference (Development): The Metals Economics Group (MEG) webpage for the Ajo Mine contains information about this deposit. Accessed on 8/17/2010. http://www.metalseconomics.com/
URL: http://www.metalseconomics.com/

Reference (Geology): The Porter GeoConsultancy webpage for Ajo, New Cornelia contains a description of the geology. Accessed on 8/17/2010. http://www.portergeo.com.au/
URL: http://www.portergeo.com.au

Reference (Other Database): CIMRI

Reference (Deposit): Dixon D W 1966 - Geology of the New Cornelia Mine, Ajo, Arizona: in Titley S R, Hicks C L 1966 Geology of the Porphyry Copper Deposits, Southwestern North America University of Arizona Press, Tucson pp 123-132 Hagstrum J T, Cox D P, Miller R J 1987 - Structural reinterpretation of the Ajo mining district, Pima County, Arizona, based on paleomagnetic and geochronologic studies: in Econ. Geol. v82 pp 1348-1361

Reference (Deposit): BELL, 1930, USBM IC 6303.

Reference (Deposit): HARDWICK, 1960, USBM IC 7938.

Reference (Deposit): WADSWORTH, 1968, ECON GEOL, V. 63, NO. 2.

Reference (Deposit): DIXON, 1966, IN TITLEY & HICKS, UNIV OF AZ PRESS, P. 123-132.

Reference (Deposit): GILLULY, 1946, USGS PP 209.

Reference (Deposit): WORLD MINING. SEPT. 1981, P. 50, & SEPT. 1982, P. 70. (1977-1981 PRODUCTION)

Reference (Geology): Hagstrum J T, Cox D P, Miller R J 1987 - Structural reinterpretation of the Ajo mining district, Pima County, Arizona, based on paleomagnetic and geochronologic studies: in Econ. Geol. v82 pp 1348-1361

Reference (Deposit): PHELPS DODGE TODAY (CORP. QUARTERLY PUB.). AJO'S NEW "MOLY" PLANT GOES INTO PRODUCTION. MARCH 1981, FRONT COVER AND P. 2.

Reference (Deposit): 1981 ANNUAL REPORT. P. 5.

Reference (Deposit): PHELPS DODGE CORP. 1979 ANNUAL REPORT. PP. 6-7.

Reference (Deposit): ARIZONA PAY DIRT (SUPPLEMENT). AJO, IN PHELPS DODGE--A COPPER CENTENNIAL, 1881-1981. SUMMER 1981, PP. 64-68, 70-71, 90-91, AND 180-181.

Reference (Deposit): PHELPS DODGE BRINGING COPPER MINE, MILL AT AJO BACK ON LINE. FEBRUARY 1983, FRONT COVER AND P. 5A.

Reference (Deposit): PHELPS DODGE IS CONSTRUCTING MOLY PLANT AT AJO. APRIL 1980, P. 22.

Reference (Deposit): SW PAY DIRT, 8-90, P.7A.

Reference (Deposit): PHELPS DODGE CORP 1994 10-K, P.14.

Reference (Deposit): ARIZONA PAY DIRT. PHELPS DODGE ANNOUNCES PIT EXPANSION THAT WILL CARRY AJO MINE THROUGH 1980S. AUGUST 1979, P. 30.

Reference (Deposit): MINING METHODS AND COSTS AT THE NEW CORNELIA BRANCH, PHELPS DODGE CORPORATION, AJO, ARIZ.-U.S.B.M. I.C. 6666,OCT,1932

Reference (Deposit): GEOLOGY OF THE PORPHYRY COPPER DEPOSITS SOUTHWESTERN NORTH AMERICA BY TITLY AND HICKS, 1966.

Reference (Reserve-Resource): PHELPS DODGE CORP 1995 ANNUAL REPORT, P.23.

Reference (Reserve-Resource): PHELPS DODGE CORP SEC FORM 10-K REPT. DEC 31, 1993. P. 14.

Reference (Deposit): AJO'S NEW WASTE DUMP SYSTEM AND THE D-10 DOZER. SEPTEMBER 1981, P. 8.

Reference (Reserve-Resource): Porter, T.M., 1998, An overview of the World's porphyry and other hydrothermal copper & gold deposits and their distribution; in Porter, T. M., ed., Porphyry and Hydrothermal Copper and Gold Deposits: a global perspective, PACRIM '98 Conference Proceedings, Australian Mineral Foundation, p. 3-17.

---

Arizona Gold

"Where to Find Gold in Arizona" looks at the density of modern placer mining claims along with historical gold mining locations and mining district descriptions to determine areas of high gold discovery potential in Arizona. Read more: Where to Find Gold in Arizona.