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Lone Tree/Stonehouse Mine Area

Producer in Humboldt county in Nevada, United States with commodities Gold, Silver, Arsenic, Antimony, Mercury, Copper
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Alteration
  9. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Ore body information
  13. Controls for ore emplacement
  14. Economic information about the deposit and operations
  15. Mining district
  16. Land status
  17. Ownership information
  18. Bibliographic references
  19. General comments
  20. Reporter information

Geologic information

Identification information

Deposit ID 10310324
MRDS ID RE00041
Record type Site
Current site name Lone Tree/Stonehouse Mine Area
Alternate or previous names Wayne Zone (Lone Tree), NW-1, East Zone, Southeast Area (Stonehouse)
Related records 10055099, 10125353

Comments on the site identification

  • This record incorporates all material from earlier records for the same deposit: MRDS # RE00041 and RE00042 as well as additional material.

Geographic coordinates

Geographic coordinates: -117.21067, 40.83351 (WGS84)
Elevation 1390
Relative position The Lone Tree and Stonehouse deposits are located about a mile south of the Stonehouse Exit off Interstate 80, 34 miles SE of Winnemucca, Nevada, 4 miles NW of Dunphy, Nevada.

Site location context

Political divisions (FIPS codes)

Humboldt(county)

Nevada(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Valmy(quadrangle 1:24,000 scale)

Winnemucca(quadrangle 1:100,000 scale)

Winnemucca(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Middle Humboldt(hydrologic unit)

Humboldt(hydrologic accounting unit)

Black Rock Desert-Humboldt(hydrologic subregion)

Great Basin(hydrologic region)

Geographic areas

Country State County
United States Nevada Humboldt

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 34N 42E 11 13 14 Nevada

Comments on the location information

  • The Lone Tree and Stonehouse deposits are located at Lone Tree Hill within a mile of Interstate 80.

Commodities

Commodity Importance
Gold Primary
Silver Secondary
Arsenic Critical Tertiary
Antimony Critical Tertiary
Mercury Tertiary
Copper Tertiary

Comments on the commodity information

  • Ore Materials: Gold, arsenopyrite, pyrite.
  • Gangue Materials: chalcopyrite, marcasite

Materials information

Materials Type of material
Gold Ore
Arsenopyrite Ore
Pyrite Ore
Chalcopyrite Gangue
Marcasite Gangue

Alteration

  • (Local) Dominant alteration types affecting the host rocks are silicification, argillization, and pyritization.

Mineral occurrence model information

Model code 75
USGS model code 19c
Deposit model name Distal disseminated Ag-Au
Mark3 model number 18

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Quartzite
    Rock unit name Valmy Formation
    Stratigraphic age (youngest) Ordovician
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Conglomerate
    Rock unit name Antler Sequence
    Stratigraphic age (youngest) Early Permian
    Stratigraphic age (oldest) Middle Pennsylvanian
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Sandstone
    Rock unit name Havallah Sequence
    Stratigraphic age (youngest) Early Permian
    Stratigraphic age (oldest) Middle Pennsylvanian
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Siltstone
    Rock unit name Havallah Sequence
    Stratigraphic age (youngest) Early Permian
    Stratigraphic age (oldest) Middle Pennsylvanian
  • Host or associated Host
    Rock type Sedimentary Rock > Chemical Sediment > Chert
    Rock unit name Havallah Sequence
    Stratigraphic age (youngest) Early Permian
    Stratigraphic age (oldest) Middle Pennsylvanian
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Mafic Volcanic Rock > Basalt
    Rock type qualifier metabasalt
    Rock unit name Havallah Sequence
    Stratigraphic age (youngest) Early Permian
    Stratigraphic age (oldest) Middle Pennsylvanian
  • Host or associated Host
    Rock type Plutonic Rock > Porphyry
    Rock type qualifier quartz porphyry dikes
    Stratigraphic age (youngest) Tertiary
  • Host or associated Associated
    Rock type Plutonic Rock > Porphyry
    Rock type qualifier altered quartz porphyry dikes
    Stratigraphic age (youngest) Middle Eocene
    Chronological age 39
    Stratigraphic age (youngest) Late Eocene
    Chronological age 36

Nearby scientific data

(1) -117.21067, 40.83351
ListMap

Economic information

Ore body information

  • General form tabular to irregular

Controls for ore emplacement

  • The Power Line Fault is the principal ore host and is equivalent to the NW-1 structure identified at the Stonehouse Deposit to the south. Gold mineralization at Lone Tree occurs in all three units (Valmy Formation, Antler Sequence, Havallah Sequence) and is largely confined to a N-S trending zone of intense fracturing and faulting known as the Wayne Zone. The Wayne Zone dips steeply to the west and has been traced for nearly a mile along strike on the Lone Tree property. Major cross structures offset and pinch the Wayne Zone at the northern and southern ends of Lone Tree Hill.

Economic information about the deposit and operations

Operation type Surface
Development status Producer
Commodity type Metallic
Deposit size Medium
Significant Yes
Discovery year 1989
Discoverer Santa Fe Pacific Minerals
Year of first production 1991
Year of last production 2005
Production years 1991 - present (2005)

Mining district

District name Battle Mountain District
District name Buffalo Mountain District

Land status

Ownership category BLM Administrative Area
Area name Winnemucca BLM District

Ownership information

  • Type Owner-Operator
    Owner Newmont Gold Corp.
    Year 2005

Comments on the workings information

  • The project area incorporates all or part of four sections which were 100% owned by Lone Tree Mining, Inc., a subsidiary of Santa Fe Pacific Minerals, until it was taken over by Newmont mining in 1997. Ore is segregated into oxide heap leach, sulfide mill, and run-of-mine heap leach. Conventional heap leaching methods are utilized to recover up to 90% of the gold in the oxide heap leach ore. Run-of-mine heap leach recovery is only expected to be 40%, but the low cost of this process allows treatment of the lower grade ore at a profit. Sulfide ore is being stockpiled. Expected mine life in 1992 was 12 years.

Comments on other economic factors

  • Production from Lone Tree and Stonehouse from 1991-2002 was 2,149,832 ounces of gold, and 208,326 ounces of silver in 1995 and 1998-02.
    In 2002 the deposits contained proven and probable reserves of 21 million tons of ore grading 0.069 ounces of gold per ton. There was also measured and indicated mineralized material of 2 million tons grading 0.057 ounces of gold per ton. There was an additional million tons of inferred mineralized material grading 0.047 ounces of gold per ton.

Comments on development

  • Drilling at Lone Tree was conducted near the completion of a much larger drilling program in the South Valmy Area. Holes at Lone Tree were sited in part on drilling results at the Stonehouse Deposit immediately to the south and in part on geologic factors considered since 1987. The discovery hole, TH-79, was drilled in July, 1989. It intersected 35 feet of ore grading 0.12 ounces of gold per ton starting at a depth of 140 ft. A follow-up reverse circulation drilling program of 10 holes was begun in August, 1989. These were angle holes drilled mainly as east-west fences in the vicinity of TH-79. Of these 10 holes, only 1 failed to intersect significant au mineralization. By December, 1989, the known strike length of the au-bearing structure extended nearly 0.5 mile on Santa Fe Pacific property. An accelerated drilling program beginning in January, 1990, used as many as 17 drill rigs simultaneously. The goal was to delineate an oxide resource by June, 1990. The presence of power lines on the property was a hindrance to the siting of the drill holes. Prior to mine development, these power lines were moved at a cost of $4 million. The production decision was made May, 1990, construction began in December, 1990, full scale mining began April, 1991, and the first dore was poured august, 1991. Over 400 drill holes had been completed at Lone Tree as of April, 1992. The project capital cost was $52.9 million, excluding initial exploration. Cash costs in 1991 were $103.45/oz. Au. A mill equipped with a low temperature, low pressure autoclave to treat sulfide ore was built in 1994 at an estimated cost of $67 million. Newmont acquired Santa Fe Pacific Gold Corporation in 1997, adding Lone Tree and other deposits near Winnemucca to its portfolio.

Reference information

Bibliographic references

General comments

Subject category Comment text
Deposit At Lone Tree, the Power Line Fault is the principal ore host and is equivalent to the NW-1 structure identified at the Stonehouse Deposit to the south. Gold mineralization at Lone Tree occurs in all three rock units (Valmy Formation, Antler Sequence, and Havallah Sequence) and is largely confined to a N-S trending zone of intense fracturing and faulting known as the Wayne Zone. The Wayne Zone dips steeply to the west and has been traced for nearly a mile along strike on the lone tree property. Major cross structures offset and pinch the Wayne Zone at the northern and southern ends of Lone Tree Hill.In sulfide ore, gold is associated mainly with arsenopyrite and to a lesser extent with one or two generations of pyrite. Overburden ranges from 1 foot to 200 feet thick.
At Stonehouse, the NW-1 structure is the most economically important structure. Gold mineralization occurs in three main areas: the main NW-1 structure has been defined over almost 1.5 miles, strikes NNW, and dips 70-75 west. East Zone mineralization lies east of NW-1, in its footwall. The east zone is a series of horsetail structures that strike approx. N-S and have steep west to almost vertical dips. The Southeast zone is offset approximately 1000 feet from the NW-1 structure. Gold values have been encountered over a broad area in the Southeast zone with some suggestion of a relatively flat-lying ore body. Mineralization in the Southeast zone tends to be erratic, low grade, and refractory.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-FEB-2005 LaPointe, D.D. Nevada Bureau of Mines and Geology
Editor 01-SEP-2007 Schruben, Paul G. U.S. Geological Survey Converted from S&A FileMaker format to Oracle. Edit checks on rocks, units, and ages with Geolex search, and other fields.

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

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Authoritative Nevada resources

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