Helvetia East

Past Producer in Pima county in Arizona, United States with commodities Copper, Silver, Gold, Molybdenum, Zinc, Lead

Geologic information

Identification information

Deposit ID 10210685
MRDS ID D000804
MAS/MILS ID 0040190010
Record type Deposit
Current site name Helvetia East
Alternate or previous names East Helvetia, Unit, Az, Usbm Ofr Mla ??-94., Rosemont, Helvetia, Helvetia-Rosemont, Coronado Nf, Part 12, Santa Rita Mt, Peach Elgin, Peach Mine, Copper World, Broad Top Butte
Related records 60000203

Geographic coordinates

Point of reference Ore Body
Geographic coordinates: -110.75878, 31.83263 (WGS84)
Elevation 1660
Location accuracy 500(meters)
Relative position 30 miles SE of the city of Tucson, AZ.
(click for info)

Geographic areas

Country State County
United States Arizona Pima

Public Land Survey System information

Meridian Township Range Section Fraction State
Gila and Salt River 018 S 015 E 36 NE Arizona

Commodities

Commodity Importance
Copper Primary
Silver Primary
Gold Secondary
Molybdenum Secondary
Zinc Secondary
Lead Secondary

Comments on the commodity information

  • Scheelite Traces Disseminated Throughout Mineralized Zone; Small Pockets Of Molybdenite; Malachite, Azurite, Cuprite Probably Secondary After Chalcopyrite

Materials information

Materials Type of material
Bornite Ore
Chalcocite Ore
Chalcopyrite Ore
Chrysocolla Ore
Cuprite Ore
Malachite Ore
Pyrite Ore
Azurite Ore
Molybdenite Ore
Pyrite Ore
Tenorite Ore
Gold Ore
Scheelite Ore
Sphalerite Ore
Quartz Gangue
Biotite Gangue
Feldspar Gangue
Diopside Gangue
Garnet Gangue
Magnetite Gangue
Epidote Gangue
Sericite Gangue
Wollastonite Gangue

Alteration

  • (Local) Thermal and Metamasomatic Alteration
  • (Local) Silification

Analytical data

Result Cores Yielded 0.01-0.014% M

Mineral occurrence model information

Model code 58
USGS model code 18a
Deposit model name Porphyry Cu, skarn-related
Mark3 model number 9

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Limestone
    Rock unit name Escabrosa Limestone, Horquilla Limestone, Earp Formation, Colina Limestone, and Epitaph Formation
    Stratigraphic age (youngest) Paleozoic
  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Quartz Monzonite
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Quartz Latite
    Chronological age 56
    Stratigraphic age (youngest) Tertiary
  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Sandstone
  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Dolomite
    Rock unit name Martin Formation; Abrigo Formation

Nearby scientific data

Ore Body (1) -110.75878, 31.83263

Geologic structures

Type Description Terms
Regional Homoclinal; Reg Trends: Tilting & Broad Open Folds S, Extensive Faulting N
Local Thrust & Normal Faulting-Fracture Zones

Ore body information

  • Area 2160HA
    Field Value
    Type of Orebody #1 REPLACEMENT
    Shape of Orebody #1 MASSIVE
    Type of Orebody #2 DISSEMINATED
    Type of Orebody #3 SHEAR ZONE
    Primary mode of Origin HYDROTHERMAL
    Secondary mode of Origin CONT METASOMATIC
    Primary Ore Control IGNEOUS
    Secondary Ore Control LITHOLOGY
    Degree of Wallrock Alter. INTENSE
    Type of Wallrock Alter. #1 CARBONATE SILIC
    Type of Wallrock Alter. #2 INTERM ARGILLIC
    Total Surface Area (HA) 2160
    Date of Last Modification 800411
  • General form Irregular Lenticular Zones, Bedded, Stringers and Pockets
    Strike N40E
    Dip 70SE
    Depth to bottom 18.29M
    Width 7.62M
    Length 73.15M

Controls for ore emplacement

  • Faults, Fractures, and Favorable Silicated Limestone:
  • Guided By Faults and Favorable Beds:

Comments on the geologic information

  • Major.Units: Basin And Range ; Geol.Desc: Age Of Mineralization Believed To Be That Of The Quartz Latite Intrusive Of Drewes - 1971 ; Reg.Com: Structure In District Is Thrust Faulting And High Angle Normal Faulting And Folding
  • Ore Gen In Lime-Silicate Zones Controlled By Faults And Fractures. ; Geol.Desc: Age Of Mineralization Believed To Be That Of The Quartz Latite Intrusive Of Drewes - 1971. ; Reg.Com: Structure In District Is Thrust Faulting - High Angle Normal Faulting And Folding.
  • The Rosemont-Helvetia district mineralization lies in skarned Palaeozoic carbonate rocks associated with Laramide age quartz latite prophyry stocks, both controlled by Laramide folds and thrust faults, and disturbed by later Middle Tertiary normal faults. (Hardy 2000)

Economic information

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Significant Yes
Discovery year 1870
Mining method Open Pit
Year of first production 1890
Milling method Flotation

Mining district

District name Helvetia-Rosemont District

Mineral rights holdings

Type of mineral rights Patented
Type of mineral rights Fee Ownership
Type of mineral rights Located Claim

Land status

Ownership category Mixed
Ownership category National Forest
Ownership category Military Reservation

Ownership information

  • Type Owner-Operator
    Owner Anaconda Mining Company
    Interest 100
    First year 1963
    Last year 1973
  • Type Owner-Operator
    Owner Anamax
    Interest 100
    First year 1973
    Last year 1988
  • Type Owner-Operator
    Owner Asarco (American Smelting And Refining Co.)
    Interest 100
    Home office Arizona
    Year 1988
    First year 1988
    Last year 2004
  • Type Owner-Operator
    Owner Augusta Resource Corporation
    Interest 100
    Home office Vancouver, Canada
    Year 2009
    First year 2006

Production statistics

  • Year 1902
    Period 1899-1902
    Accuracy Estimate
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Cu Copper Copper 2wt-pct
    Secondary Ag Silver Silver 8g/mt
  • Year 1944
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Cu Copper Copper 4wt-pct
    Secondary Ag Silver Silver 63g/mt
  • Year 1951
    Period Start-1951
    Material Ore
    Ore mined 227,300mt
    Accuracy Accurate
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Cu Copper Copper 7,847mt
    Primary Ag Silver Silver 5,622,265g
    Secondary Zn Zinc Zinc 499mt
  • Year 1952
    Period 1882-1952
    Accuracy Estimate
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Cu Copper Copper 5wt-pct
    Secondary Ag Silver Silver 23g/mt
    Secondary Pb Lead Lead 2wt-pct
  • Year 1959
    Period 1900-1959
    Accuracy Estimate
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Cu Copper Copper 6wt-pct
    Secondary Ag Silver Silver 28g/mt
  • Year 1969
    Period 1877-1969
    Ore mined 402,000mt
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Cu Copper Copper 17mt
    Primary Ag Silver Silver 12mt
    Secondary Au Gold Gold 0mt
    Secondary Mo Molybdenum Molybdenum 13mt

Reserves and resources

  • Type In-situ
    Estimate year 1973
    Total resources 290,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.64 wt-pct Copper Major 1973
  • Type In-situ
    Estimate year 1973
    Total resources 18,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.55 wt-pct Copper Major 1973
  • Type In-situ
    Estimate year 1976
    Total resources 180,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.7 wt-pct Copper Major 1976
  • Type In-situ
    Estimate year 1977
    Total resources 10,884,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.75 wt-pct Copper Primary 1977
  • Type In-situ
    Estimate year 1977
    Demonstrated 21,000,000mt ore
    Total resources 21,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.55 wt-pct Copper Major 1977
  • Type In-situ
    Estimate year 1977
    Total resources 191,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.56 wt-pct Copper Major 1977
  • Type In-situ
    Estimate year 1977
    Total resources 20,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.55 wt-pct Copper Major 1977
  • Type In-situ
    Estimate year 1980
    Reserves 952,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.552 wt-pct Copper Primary 1980
    Silver Ag 8.8 g/mt Silver Primary 1980
    Gold Au 0.019 g/mt Gold Secondary 1980
    Molybdenum Mo 0.0055 wt-pct Molybdenum Secondary 1980
  • Type In-situ
    Estimate year 1988
    Total resources 280,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.62 wt-pct Copper Major 1988
    Molybdenum Mo 0.016 wt-pct Molybdenum Minor 1988
  • Type In-situ
    Estimate year 1988
    Total resources 23,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.78 wt-pct Copper Major 1988
  • Type In-situ
    Estimate year 1989
    Demonstrated 254,000,000mt ore
    Total resources 254,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.62 wt-pct Copper Major 1989
    Molybdenum Mo 0.016 wt-pct Molybdenum Minor 1989
  • Type In-situ
    Estimate year 1989
    Measured 20,900,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.78 wt-pct Copper Primary 1989
  • Type In-situ
    Estimate year 1995
    Reserves 430,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.6 wt-pct Copper Primary 1995
    Molybdenum Mo 0.014 wt-pct Molybdenum Secondary 1995
  • Type In-situ
    Estimate year 2008
    Reserves 2,240,000mt metal
    Remarks Contained Cu metal in 559.12 Mt reserves ore. Huss 2009 NI 43-101 p. 6-7.
    Commodity Subtype Grade units Group Importance Year
    Copper 100 wt-pct Copper Primary 2008
  • Type In-situ
    Name contained metal
    Estimate year 2008
    Reserves 73,000mt
    Remarks Contained Mo metal in 559.12 Mt reserves ore. Huss 2009 NI 43-101 p. 6-7.
    Commodity Subtype Grade units Group Importance Year
    Molybdenum 100 wt-pct Molybdenum Secondary 2008
  • Type In-situ
    Name contained metal
    Estimate year 2008
    Reserves 2,000mt
    Remarks Contained Ag metal in 559.12 Mt reserves ore. Huss 2009 NI 43-101 p. 6-7.
    Commodity Subtype Grade units Group Importance Year
    Silver 100 wt-pct Silver Primary 2008
  • Type In-situ
    Estimate year 2008
    Total endowment 952,000,000mt ore
    Remarks Helvetica deposit total endowment. 5.26 million mt contained Cu metal. Singer 2008 in PorCuEX2008.xls.
    Commodity Subtype Grade units Group Importance Year
    Copper 0.553 wt-pct Copper Primary 2008
    Gold 0.019 g/mt Gold Secondary 2008
    Molybdenum 0.0055 wt-pct Molybdenum Secondary 2008
    Silver 8.8 g/mt Silver Primary 2008

Comments on the reserve resource information

  • Includes Oxide Resource Of 21 Million Mt @ 0.78 % Cu.
  • M2c1 = R2 Gold And Silver Grades Estimated On Basis Of District Metal Production Ratios Of Au:Cu And Ag:Cu.
  • Assumed To Feed Helvetia East Mill To Help Supplement Feed. Oxide Resource Is 9.1 Million Mt @ 0.72 % Cu. Assume Also Known As Peach Elgin.
  • Assume R-Reserve Entry Is Sulfide Plus Oxide.
  • Resources described on adjacent properties - Broadtop Butte, Copper World and Peach-Elgin. (Huss, Conrad, 2009, NI 43-101 p 44-45)

Workings at the site

  • Type of workings Surface
    Area 300HA
    Field Value
    MAS Development Schedule # 1
    Mining Record # 1
    Status of Mining Method PROPOSED
    Mining Method OPEN PIT
    Swell Factor .61
    Percent Waste Rock 70
    Primary Material Cover M-HARD ROCKS
    Percentage 100
    Hardness of Ore M-HARD ROCKS
    Avg. Bench Height (meters) 15
    Max. Pit Slope (degrees) 37
    Capacity 30000
    Capacity Units MT ORE/DAY
    Preprod. Stripping Vol. 27500
    Unit Production Cost 2.9
    Units of Production $/MT ORE
    Operating Days per Year 357
    Operating Shifts per Day 3
    Year of Information 1979
  • Type of workings Surface
    Field Value
    MAS Development Schedule # 1
    Mining Record # 2
    Status of Mining Method PROPOSED
    Mining Method OPEN PIT
    Primary Material Cover M-HARD ROCKS
    Percentage 100
    Hardness of Ore HARD ROCKS
    Avg. Bench Height (meters) 15
    Max. Pit Slope (degrees) 37
    Capacity 3725
    Capacity Units MT ORE/DAY
    Operating Days per Year 357
    Operating Shifts per Day 3
    Year of Information 1979
  • Type of workings Surface/Underground
    Area 0.004HA
    Overall depth 103.63M

Comments on development

  • Rosemont will begin production in 2012 at 221 million lbs (100 tonnes) Cu per year, about 10% of the US capacity. (Augusta Resource Corp website, 8/12/2010) http://www.augustaresource.com/section.asp?catid=2051

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
U.S. Bureau of Mines Minerals Availability System MAS 0040190010
USGS Mineral Resources Data System MRDS D000804 MAS references MRDS
U.S. Bureau of Mines Minerals Availability System MAS 0040190492 DUP
USGS Mineral Resources Data System MRDS TC10136 DUP
U.S. Bureau of Mines Minerals Availability System MAS 0040190428 DUP
U.S. Bureau of Mines Minerals Availability System MAS M050159 DUP
U.S. Bureau of Mines Minerals Availability System MAS 0040190357 DUP
USGS Mineral Resources Data System MRDS M050164 DUP
U.S. Bureau of Mines Minerals Availability System MAS 0040190204 DUP
USGS Mineral Resources Data System MRDS M050039 DUP
U.S. Bureau of Mines Minerals Availability System MAS 0040190226 DUP
U.S. Bureau of Mines Minerals Availability System MAS 0040190276 DUP
USGS Mineral Resources Data System MRDS M050049 DUP
U.S. Bureau of Mines Minerals Availability System MAS 0040190086 DUP
USGS Mineral Resources Data System MRDS M030541

Bibliographic references

  • Deposit

    SAWYER, M.B., GURMENDI, A.C., DALEY, M.R., AND HOWELL, S.B., 1992, PRINCIPAL DEPOSITS OF STRATEGIC AND CRITICAL MINERALS IN ARIZONA: U.S. BUREAU OF MINES SPECIAL PUBLICATION, 334 P.

  • Geology

    Huss, Conrad, 2009, NI 43-101 Technical Report For The Rosemont Copper Project Updated Feasibility Study, Pima County, Arizona, USA, for Augusta Resource Corporation, M3-PN08036; January 14, 2009, Amended March 17, 2009, 138 pages plus appendices.

  • Other Database

    CIMRI

  • Deposit

    SCHRADER, F.C., 1915, USGS BULL. 582.

  • Geology

    Anzalone, S.A., 1995, The Helvetia area porphyry systems, Pima County, Arizona; in Pierce, F.W. and Bolm, J.G., eds., Porphyry Copper Deposits of the American Cordillera, Arizona Geological Society, Digest 20, p. 436-441.

  • Reserve-Resource

    Lowell, J.D. Trends And Techniques In Southwest Porphyry Exploration. World Mining, Oct. 1976, Pp. 56-57.

  • Deposit

    Anzalone (1995), Long and others (1998), Niemuth (1994), Titley (1993), Titley and Anthony (1989)

  • Geology

    Titley, S.R., 1993, Characteristics of porphyry copper occurrence in the American Southwest, in Kirkham, R.V., Sinclair, W.D., Thorpe, R.I., and Duke, J.M., eds., Mineral deposit modeling: Geological Association of Canada Special Paper 40, p. 433-464.

  • Reserve-Resource

    World Mining. Copper: A Future Of Ample And Secure Supply. Sept. 1977, P. 110.

  • Geology

    Titley, S.R., and Anthony, E.Y., 1989, Laramide mineral deposits in Arizona, in Jenney, J.P., and Reynolds, S.J., eds., Geologic evolution of Arizona: Tucson, Arizona Geological Society Digest 17, p. 485?514.

  • Reserve-Resource

    Asarco Incorporated 1988 Annual Report. P. 6, 8.

  • Deposit

    Anamax Mining Company. An Environmental Inventory Of The Rosemont Area In Southern Arizona. Contract Study By University Of Arizona, R. Davis And J. R. Callahan, - Editors, 1977, 2 Volumes, 341 Pp.

  • Geology

    Hardy, J.J., 2000, SUPERIMPOSED LARAMIDE AND MIDDLE TERTIARY DEFORMATIONS IN THE ROSEMONT-HELVETIA DISTRICT, SOUTHEASTERN ARIZONA; Denver Region Exploration Geologists' Society abstracts2000. http://www.dregs.org/abs2000.html

  • Reserve-Resource

    Southwestern Pay Dirt, 8/95, P.5a.

  • Deposit

    Arizona Pay Dirt. Usfs Working On Anamax Land Swap At Rosemont. October 1977, P. 57.

  • Reserve-Resource

    American Metal Market. Asarco Buys Helvetia Deposit As Long-Term Copper Reserve. Aug. 19, 1988, P. 2.

  • Deposit

    Bennett, H. J., L. Moore, L. E. Welborn, And J. E. Toland. An Economic Appraisal Of The Supply Of Copper From Primary Domestic Sources. Bumines Ri 8598, 1973, 156 Pp.

  • 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.

  • Deposit

    Bowman, A. B. History, Growth, And Development Of A Small Mining Company. Min. Eng., June, 1963, Pp. 42-49.

  • Reserve-Resource

    Niemuth, N.J., 1994, The primary copper industry of Arizona, 1992: Arizona Department of Mines and Mineral Resources SR-20, 58 p.

  • Deposit

    Caterpillar Tractor Company. Caterpillar Performance Handbook, 9th Edition, Cat Publication, October 1978, 592 Pp.

  • Deposit

    Cummins, A. B., And I. A. Given. Sme Mining Engineering Handbook, A.I.M.E., New York, 1973, 2 Volumes, Pp. 17-1 To 17-180, 18-1 To 18-90.

  • Deposit

    Drewes, H. Cenozoic Rocks Of The Santa Rita Mountains, Southeast Of Tucson, Arizona. U.S. Geological Survey Professional Paper 746, 1972, 66 Pp.

  • Deposit

    Drewes, H. Geochemical Reconnaissance Of The Santa Rita Mountains, Southeast Of Tucson, Arizona. U.S. Geol. Survey Bulletin 1365, 1973, 67 Pp.

  • Deposit

    Drewes, H. Mesozoic Stratigraphy Of The Santa Rita Mountains, Southeast Of Tucson, Arizonia. U.S. Geol.

  • Deposit

    Mountains, Southeast Of Tucson, Arizonia. U.S. Geol. Survey Professional Paper 658-C, 1971, 81 Pp.

  • Deposit

    Drewes, H. Structural Geology Of The Santa Rita Mountains, Professional Paper 748, 1972, 35 Pp.

  • Deposit

    Drewes, H.L And T. L. Finnell. Mesozoic Stratigraphy And Laramie Tectonics Of Part Of The Santa Rita And Empire Mountains Southeast Of Tucson, Arizona. Southern Arizona Geol. Society Guidebook Iii, S. R. Titley, Editor; Geol. Society Of America Cordilleran Section, 64th Annual Meeting, Tucson, Arizona, 1968, Pp. 315-324.

  • Deposit

    Engineering And Mining Journal. In The U.S.--Arizona. June 1975, P. 301.

  • Deposit

    Hopkins, W. R., And A.J. Lynch. The Twin Buttes Ozide Project. A.I.M.E. Reprint, 1976 Sme-Aime Fall Meeting, 1976, 30 Pp.

  • Deposit

    Keith, S. B. Index Of Mining Properties In Pima County, Arizona. Arizona Bureau Of Mines Bulletin 189, 1974,

  • Deposit

    Lovering, T. G., J. R. Cooper, H. Drewes, And G. C. Cone. Copper In Biotite From Igneous Rocks In Southern Arizona As An Ore Indicator. U.S. Geological Survey Research 1970 (Professional Paper 700-B), 1971, Pp. B1-B8.

  • Deposit

    Pay Dirt. Anamax Files For Forest Land Swap For Helvetia. June 30, 1975, Pp. 73-74.

  • Deposit

    Pay Dirt. Scenes In Old Arizona. August 24, 1970, Pp. 3-4.

  • Deposit

    Pfleider, E. P. Surface Mining. A.I.M.E., New York, 1968, 1061 Pp.

  • Deposit

    Rampacek, C., And J.T. Dunham. Copper Ore Processing --U.S. Practices And Trends. Min. Cong. J., February 1976, Pp. 43-50.

  • Deposit

    Schwartz, G. M. The Nature Of Primary And Secondary Mineralization In Porphyry Copper Deposits. Chapter In Geology Of The Porphyry Copper Deposits - Southwestern North America, S. R. Titley And C. L. Hicks, Editors, University Of Arizona Press, 1966, Pp. 41-50.

  • Deposit

    Skillings' Mining Review. Anamax Mining Company Acquires Empire Ranch In Arizona. January 18, 1975, P. 16.

  • Deposit

    World Mining. Copper Deposits To Be Developed. August 1970, P. 47.

  • Deposit

    Anzalone And Brown, 1992, Geology Of The Helvetia Copper Deposit, Sme Preprint 92-61.

  • Deposit

    Sw Pay Dirt, 12-95, P.12a.

  • Deposit

    Randol Mining Directory 1996/97, P. 136.

General comments

Subject category Comment text
Deposit Evaluation In April 1979by I.F.O.C., Denver, Colorado. Evaluation Update Done In Sept 1983
Deposit Some Disseminated Cu Mineralization In Shattered Pal Quartzite; Most Ore In Lime Silicate Zones Controlled By Faults And Fractures.
Deposit Ore Zone In Limestone At Granite-Limestone Contact; Lime Silicate Zones Controlled By Faults And Fractures
Deposit All Figures Calculated From A.A. Mathews Capital And Operating Cost Estimating System Handbook. Mo, Ag, And Au Are Possible Trace Elements In Ore. No Grade For Mo, Ag, Or Au Found In Literature. Pit Location Based On Literature And Assumptions. Due To Lack Of Information Or Mng Plan Cost Could Vary.
Deposit Associated Rocks Include: quartz latite porphyry, quartz monzonite, skarn;andesite, chert;arkose, conglomerate, dolomite, granodiorite, limestone, quartzite, sandstone, shale, siltstone
Deposit Ore Bodies Tend To Associate With The Lime-Silicate Zone

Reporter information

Type Date Name Affiliation Comment
Reporter 24-SEP-96 Tad/Ras U.S. Bureau of Mines
Reporter 01-JUL-72 Keith, William J. U.S. Geological Survey
Updater 01-DEC-93 Orris, Greta J. U.S. Geological Survey
Reporter 07-OCT-94 Intermountain Field Operations Center (IFOC) U.S. Bureau of Mines
Reporter 01-MAR-83 Peterson, Jocelyn A. U.S. Geological Survey
Reporter 24-SEP-96 Br U.S. Bureau of Mines
Reporter 04-NOV-83 ADMR U.S. Bureau of Mines
Updater 12-AUG-09 Anderson, Claire U.S. Geological Survey
Editor 16-AUG-10 Schruben, Paul U.S. Geological Survey new reserves info, paraphrased some comments