Silver Bell mine

Site Name

Primary: Silver Bell mine
Secondary: North Silver Bell pit
Secondary: El Tiro pit
Secondary: West Oxide pit
Secondary: East Oxide pit

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Commodity

Primary: Copper
Secondary: Silver
Tertiary: Molybdenum

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Location

State: Arizona
County: Pima
District: Silver Bell

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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.

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Holdings

Type: Patented

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Workings

Type: Surface

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Ownership

Owner Name: MITSUI AND CO LTD
Percent: 25.00
Info Year: 2009
Years: 1996 -

Owner Name: ASARCO INC (GRUPO MEXICO is 100% owner)
Home Office: 5285 East Williams Circle Suite 2000 Tucson AZ 85711 United States
Info Year: 2010
Years: 1999 -

Owner Name: Asarco (American Smelting And Refining Co.)
Company ID: 200134
Percent: 100.0
Home Office: New York
Info Year: 1972
Years: 1954 -

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Production

Year: 1998
Material type: Asarco 1998 10-K, p. A-15
Year: 2009
Mined: 347000.000 mt
Material type: Grupo Mexico 2009 AR, p. 26.
Year: 2005
Time Period: 1999-2005
Material type: Estimate based on SXEW production capacity of between 50 and 67 tpd Cu.
Year: 1997
Time Period: July-December
Material type: New leach mine and SXEW plant begin production. Asarco 1997 10-K, p. A3, A20.
Year: 1996
Material type: Asarco 1997 10-K, p. A20
Year: 1995
Material type: Asarco 1997 10-K, p. A20.
Year: 1991
Description: Cu Produced From Leach Ppt 3656 Mtpy Cu Produced
Year: 1989
Description: Cu Produced From Leach Ppt. 4544 Mtpy Cu Produced
Year: 1990
Description: Cu Produced From Leach Ppt. 3846 Mtpy Cu Produced
Year: 1988
Description: Cu Produced From Leach Ppt. 3928 Mtpy Cu Produced
Year: 1987
Description: Cu Produced From Leach Ppt. 5805 Mtpy Cu Produced
Year: 1986
Description: Cu Produced From Leach Ppt. 3300 Mtpy Cu Produced
Year: 1984
Description: 3170 Kgs Ag Produced
Year: 1985
Description: Cu Produced From Leach Ppt. 4000 Mtpy Cu Produced
Year: 1984
Description: Cu Produced From Mill Conc & Leach Ppt 14900 Mtpy Cu Produced
Year: 1984
Description: Mine Has Been Closed Since Aug 1984 2060000 Mtpy Ore Mined
Year: 1983
Description: 964 Kgs Ag Produced
Year: 1983
Description: Cu Produced From Mill Conc & Leach Ppt 8170 Mtpy Cu Produced
Year: 1983
Description: Mine & Mill Resumed Operation In Oct 83 780000 Mtpy Ore Mined
Year: 1982
Description: 342 Kgs Ag Produced
Year: 1982
Description: Mine & Mill Closed Dump Leach Operating 4720 Mtpy Cu Produced (Leach)
Year: 1981
Description: Mos2 Conc Grade: 41.7% Mo 257 Mt Mos2 Conc/Yr
Year: 1981
Description: Leach Ppt Grd: 75% Cu 4802 Mt Leach Ppt/Yr
Year: 1981
Description: Conc. Grd: 24% Cu, 92.7 G/Mt Ag 74145 Mt Conc/Yr
Year: 1981
Description: Fd Grd: 0.71%Cu, 0.012%Mo, 2.7g/Mtag 3346000 Mt Ore/Yr
Year: 1980
Description: Mos2 Conc Grade: 40.1% Mo 217 Mt Mos2 Conc/Yr
Year: 1980
Description: Leach Ppt Grd: 75% Cu 2658 Mt Leach Ppt/Yr
Year: 1979
Description: Mos2 Conc Grade: 43.0% Mo 454 Mt Mos2 Conc/Yr
Year: 1980
Description: Conc. Grd: 24% Cu, 66.8 G/Mt Ag 41049 Mt Conc/Yr
Year: 1980
Description: Fd Grd: 0.67%Cu, 0.012%Mo, 2.0g/Mtag 2000000 Mt Ore/Yr
Year: 1979
Description: Leach Ppt Grd: 75% Cu 4212 Mt Leach Ppt/Yr
Year: 1979
Description: Conc. Grd: 24% Cu, 79.5 G/Mt Ag 68536 Mt Conc/Yr
Year: 1979
Description: Fd Grd: 0.66%Cu, 0.013%Mo, 2.3g/Mtag 3375000 Mt Ore/Yr
Year: 1978
Description: Mos2 Conc Grade: 42.3% Mo 143 Mt Mos2 Conc/Yr
Year: 1978
Description: Leach Ppt Grd: 72% Cu 3963 Mt Leach Ppt/Yr
Year: 1972
Time Period: 1954-1972
Mined: 54200000.000 mt
Material type: Probably from old_MRDS Silver Bell District record D000333, source is probably Galey, 1979.
Year: 1978
Description: Fd Grd: 0.65%Cu, 0.017%Mo, 2.5g/Mtag 3239000 Mt Ore/Yr
Year: 1978
Description: Conc. Grd: 24% Cu, 86.3 G/Mt Ag 69312 Mt Conc/Yr

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Deposit

Record Type: Deposit
Operation Category: Producer
Deposit Type: Porphyry Cu-Mo
Operation Type: Surface
Mining Method: Open Pit
Milling Method: Flotation
Year First Production: 1954
Discovery Year: 1909
Years of Production:
Organization:
Significant: Y

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Physiography

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

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Mineral Deposit Model

Model Name: Porphyry Cu-Mo

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Orebody

Not available

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Structure

Type: L
Structure: Fracturing

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Alterations

Not available

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Rocks

Name: Quartz Monzonite
Role: Host
Age Type: Host Rock
Age Young: Early Paleocene
Age Old: Late Cretaceous

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Analytical Data

Not available

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Materials

Ore: Molybdenite
Ore: Chalcopyrite
Ore: Chalcocite
Gangue: Cuprite

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Comments

Comment (Economic Factors): Waste Rock Feed Grade For Leach Was Calculated To Be 0.286% Rounded To 0.29% Cu. This Grade Was Calculated In The Same Manner That The Dump-Leach Reserve (Matrix 2) Was Calculated.

Comment (Reserve-Resource): M1c1=R2. Mo Grade Is Estimated To Be Grade Of Mill Feed Given In Bumines Production Statistics For 1981 (Last Year Of Cu-Mo Production). M9c4=R2. 2 Matrix 9, Col. 5 Represents Dump Leach Rock - M9c5=M2c1. Matrix 2 Quantity Equals Estimated Amount Of Waste Rock That Is Leached. (Company Officials In 1978 Stated 30% Of Waste Rock Mined Is Leached. Therefore, Reserve Equals 20,601,000 Mts X 1.9 (Strip Ratio) X 30%.) Calculated Assay Grade For Dump-Leach Waste Rock (Matrix 2) Is 0.286% Cu (Based On Known Cement Copper Output 9.07 Mtpd 75% Cu, Mill Recovery Of 40%, And Estimated Amount Of Waste Rock Leached Per Day, 5950 Mtpd) M3c1=R3. Asarco 1986 Ann. Rept., P 11.

Comment (Economic Factors): Mine Trans Cost Included In Mine Operating Costs.

Comment (Reserve-Resource): Two Entries Are Made Under The Same Suquence Number In Order To Account For Both The Sulfide And Oxide Ore Bodies. Oxide Resource Is 11.7 Million Mt @ 0.29 % Cu. Mine Is Presently Under Development To Mine For Leach Oxide Copper Ore Using An Sx-Ew Circuit

Comment (Deposit): Original Evaluation Done In 1978. Updated 1983. Location - Silver Bell Consists Of Two Open Pits (Oxide & El Tiro Pit). The El Tiro Pit Is About 10,000 Ft.(3050 M.) Northwest Of Oxide Pit. El Tiro Location: Utm: North 3586800 East 449300 Lat 32 Deg. 25 Min. 8 Sec. North Lon 111 Deg. 32 Min. 21 Sec. West NW Qtr, Sec. 4 T. 12s R. 8e Silver Bell Mine Has Been Closed Since Dec 1981 And Has Not Reopened As Of Jun 1983. This Data Base Represents A Proposed Operation Assuming The Mine Reopened In Jan 1982 And Operated At Design Capacity Thru 1987. Property Updated 7/87.

Comment (Production): 1978-1981 Production Data From U. S. Bureau Of Mines Production Statistics. Production In 1982 - 1984 From 1984 Asarco Ann Rept. P. 10. Mine & Mill Have Been Closed Since Aug 1984. Dump Leach Operation Has Continued To Operate. Molybdenum Has Not Been Recovered Since 1981. Production In 1985 - 1986 From Asarco 1986 Ann Rept. P. 12.

Comment (Identification): The Silver Bell Mine is part of the Silver Bell Distric. Also included in this district are the North Silver Bell Mine (10039895), Oxide Mine (10039685), El Tiro Open Pit Mine (10039684)

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References

Reference (General): Grupo Mexico Annual Report for 2009, 88 p. Accessed on 8/30/2010. http://www.gmexico.com/investors/reports.php
URL: http://www.gmexico.com/investors/reports.php

Reference (Age): Kendrick, M.A., Burgess, R., Pattrick, R.A.D. and Turner, G., 2001, Halogen and Ar-Ar age determinations of inclusions within quartz veins from porphyry copper deposits using complementary noble gas extraction techniques; Chemical Geology, v. 177, p. 351-370.

Reference (Age): Barra, F., Ruiz, J., Valencia, V.A., Ochoa-Landin, L., Chesley, J.T. and Zurcher, L., 2005, Laramide porphyry Cu-Mo mineralization in northern Mexico: age constraints from Re-Os geochronology in molybdenite; Economic Geology, v. 100, p. 1605-1616.

Reference (Reserve-Resource): Browne, Q. J. and Miller, M. A., 2002, Use of geologic parameters for development of low-grade copper reserves, Silver Bell Mine, Arizona; In Society of Mining Engineers Annual Meeting and Exhibit, 2002, Technical Program, Society of Mining Engineers, p. 68.

Reference (Reserve-Resource): Long, K.R., 1995, Production and reserves of Cordilleran (Alaska to Chile) porphyry copper deposits; in Pierce, F.W. and Bolm, J.G., eds., Porphyry Copper Deposits of the American Cordillera, Arizona Geological Society, Digest 20, p. 35-68

Reference (Deposit): Huttl, John B., Silver Bell A S and R'S New Arizona Copper Project Starts Production, Engr. and Mining J., V. 155, N.7, Pp. 72-9.

Reference (Deposit): Engr. and Mining Journal Flowsheet Portfolio, Dec., 1957,P.166

Reference (Deposit): Sheffer, Herman W., And Lamar G. Evans, Copper Leaching Practices In The Western United States, U.S. Bur. Of Mines I C 8341, 1968, Pp. 10-11, 19-23.

Reference (Deposit): Silver Bell - Asarco Makes A Mine At A Known Deposit, Mining World, April, 1958, Pp. 40-5.

Reference (Deposit): Skillings, David N., Jr., Asarco'S Silver Bell Unit,July 25, 1970. Pp. 3-5.

Reference (Geology): Richard K, Courtright J H 1966 - Structure and mineralization at Silver Bell, Arizona: in Titley S R, Hicks C L 1966 Geology of the Porphyry Copper Deposits, Southwestern North America University of Arizona Press, Tucson pp 157-163

Reference (Geology): Graybeal F T 1983 - Geology of the El Tiro area: in Titley S R 1983 Advances in Geology of the Porphyry Copper Deposits, Southwestern North America University of Arizona Press, Tucson pp 487-505

Reference (Geology): Lopez J A, Titley S R 1995 - Outcrop and capping characteristics of the supergene sulfide enrichment at North Silver Bell, Pima County, Arizona: in Pierce F W, Bolm J G (Eds), Porphyry Copper Deposits of the American Cordillera Arizona Geol. Soc. Digest 20 pp 424-435

Reference (Deposit): Engineering And Mining Journal, 9-90, P.111.

Reference (Deposit): The Mining Record, 9-5-90, P.20.

Reference (Deposit): The Mining Record, Vol 108., #9, Feb. 26, 1997, P14.

Reference (Deposit): Sw Pay Dirt, 7-94, P.2a.

Reference (Deposit): Asarco Inc., 1994 10-K, P. A18.

Reference (Deposit): The Northern Miner, 11-11-91, P.17.

Reference (Deposit): Asarco Inc. 1993 10-K, P.A15.

Reference (Deposit): Asarco News Letter, 6-30-89.

Reference (Deposit): Sw Pay Dirt, 8-90, P,6a.

Reference (Deposit): Mining Engineering, 9-90, P.1052.

Reference (Deposit): Titley, Spencer R., Univ. Of Az Press, 1982, P.167.

Reference (Deposit): Graybeal, Frederick T., Univ. Of Az Press, 1982, P.487.

Reference (Deposit): Schiffer, Craig. American Metal Market, V104 N28, 2-8-96, P.1.

Reference (Deposit): Sw Pay Dirt,4-92, P.12a.

Reference (Geology): Geology Of The Porphyry Copper Deposits, Southwestern North America, 1966 Pp. 157-163.

Reference (Geology): Richard, K.E., and J.H. Courtright, Structure and Mineralization At Silver Bell, Arizona, Aime Trans., 1954, Pp. 1095-1099.

Reference (Reserve-Resource): Asarco S.E.C. Form 10-K, 1977.

Reference (Reserve-Resource): World Mining, Sept., 1977, P. 174.

Reference (Deposit): Asarco Inc. 1986 Annual Report, P. 11.

Reference (Geology): The Porter GeoConsultancy webpage for Silver Bell contains a description of the geology. Accessed on 8/31/2010. http://www.portergeo.com.au/
URL: http://www.portergeo.com.au

Reference (Deposit): Hardwick, W.R., Open Pit Copper Mining And Concentrating Methods and Costs, Silver Bell Unit, American Smelting And Refining Co., Pima County, Arizona, U.S. Bureau Of Mines I C 8153, 1963, 72 Pp.

Reference (Geology): Watson, Barry N., Updating The Geology And Structural Ore Controls At Silver Bell, Arizona, Pres. At Arizona Aime Spring Meeting, Mining Geology Div., May 20, 1968, 11 Pp.

Reference (Reserve-Resource): Asarco 1986 Sec Form 10-K Report, P. 11.

Reference (Reserve-Resource): Asarco Inc. 1995 Annual Report, P.7.

Reference (Reserve-Resource): Asarco 1981 Form 10-K Annual Report, 1982, P. 20.

Reference (Reserve-Resource): Asarco 1993 Ann. Rept. P. 5.

Reference (Reserve-Resource): Asarco S.E.C. Form 10-K Report, Dec. 31, 1976, Pp. A3-A5.

Reference (Production): GALEY, 1979, SOC ECON GEOL, PORPHYRY CU FIELD CONF, 18 P.

Reference (Development): Asarco's Silver Bell Mining webpage has timeline history and operation information. Accessed 8/30/2010. http://www.asarco.com/silverbell.html
URL: http://www.asarco.com/silverbell.html

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