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Pony Creek Project

Producer in Elko county in Nevada, United States with commodities Gold, Arsenic, Antimony
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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. Geologic structures
  13. Ore body information
  14. Controls for ore emplacement
  15. Economic information about the deposit and operations
  16. Mining district
  17. Land status
  18. Ownership information
  19. Bibliographic references
  20. General comments
  21. Reporter information

Geologic information

Identification information

Deposit ID 10310335
Record type Site
Current site name Pony Creek Project
Alternate or previous names Pony Creek/Elliot Dome Project, North Pony Creek

Geographic coordinates

Geographic coordinates: -115.99609, 40.35955 (WGS84)
Relative position The Pony Creek Project is located 28 miles southeast of the town of Carlin, Nevada.

Site location context

Political divisions (FIPS codes)

Elko(county)

Nevada(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Bailey Mountain(quadrangle 1:24,000 scale)

Ruby Lake(quadrangle 1:100,000 scale)

Elko(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Pine(hydrologic unit)

Humboldt(hydrologic accounting unit)

Black Rock Desert-Humboldt(hydrologic subregion)

Great Basin(hydrologic region)

Federal lands

Bureau of Land Management(Bureau of Land Management NV)

Bureau of Land Management NV BLM(Type of land area)

BLM(Federal land areas administered by BLM)

Geographic areas

Country State County
United States Nevada Elko

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 029N 053E 22 26 27 28 33 34 35 Nevada

Comments on the location information

  • The Pony Creek Project is currently divided into two claim blocks, with the main claim block, referred to as Pony Creek Property, consisting of 580 contiguous claims covering 11,600 acres. The second block of claims, located to the north of the Pony Creek Property near the Trout Creek gold deposit, is referred to as the Elliot Dome Property and consists of 95 claims, which were added to the project in September 2003 by Mill City International. The primary current exploration focus is on the Pony Creek Property, which is the site of all mineralization outlined on the Project to date. North Pony Creek is in sections 28 and 33.

Commodities

Commodity Importance
Gold Primary
Arsenic Critical Tertiary
Antimony Critical Tertiary

Comments on the commodity information

  • Ore Materials: gold
  • Gangue Materials: marcasite, pyrite, minor realgar and stibnite. Quartz, sericite, pyrite and limonite.

Materials information

Materials Type of material
Gold Ore
Marcasite Gangue
Pyrite Gangue
Realgar Gangue
Stibnite Gangue
Sericite Gangue
Pyrite Gangue
Limonite Gangue
Quartz Gangue

Alteration

  • (Local) Alteration within the rhyolite intrusive is characterized by quartz-sericite-pyrite mineralization associated with north and north-east-trending faults. The shear zones are fragmental and/or brecciated, containing very fine-grained quartz, sericite, and pyrite or limonite. Pyrite occurs secondary in fractures. Away from the shear zones the rhyolite gradually becomes fresher, grading outward from a rock with relict feldspar ghosts to one with a distinct porphyritic texture. In the center of the intrusion the rocks have a granular texture in which the feldspars have been altered, leaving open, clay-filled vugs. ?Sanded rhyolite? and ?rhyolite sand? are terms used by Newmont to describe a unique texture of the rhyolite often occurring in mineralized areas. The sanded rhyolite consists of medium-grained rounded clasts of glassy rhyolite breccia occurring near the margins and at the base of the intrusive. Sediments along the margins of the rhyolite intrusive and immediately beneath it have been silicified, decalcified and sulfidized. In and around the mineralized cells, the sediments have been extensively oxidized (hypogene).

Mineral occurrence model information

Model code 150
USGS model code 25c
Deposit model name Epithermal vein, Comstock
Mark3 model number 16

Host and associated rocks

  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock
    Rock type qualifier felsite breccias
    Stratigraphic age (youngest) Mississippian
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Rock type qualifier intrusive
    Stratigraphic age (youngest) Tertiary
  • Host or associated Host
    Rock type Plutonic Rock > Porphyry
    Rock type qualifier rhyolite
    Stratigraphic age (youngest) Eocene
  • Host or associated Host
    Rock type Sedimentary Rock > Mixed Clastic/Volcanic Rock
    Rock type qualifier adjacent to the intrusive
    Stratigraphic age (youngest) Permian
    Stratigraphic age (oldest) Mississippian

Nearby scientific data

(1) -115.99609, 40.35955
ListMap

Economic information

Geologic structures

Type of structure Local
Structure description Pinyon Range Anticline and Pinyon Graben
Type of structure Regional
Structure description The Pony Creek/Elliot Dome Project lies within the southern extension of the Carlin Trend, along the axis of Pinyon Range Anticline, paralleling the crest of the Pinyon Range. The Project area lies within a zone of convergence of two major structural trends which are the boundaries of a north-south series of grabens and half-grabens collectively referred to as the Pinyon Graben. Both the Pinyon Range Anticline and Pinyon Graben are estimated to be of late Mesozoic age.

Ore body information

  • General form tabular; disseminated

Controls for ore emplacement

  • Ore mineralization is associated with brecciated shear zones.

Comments on the geologic information

  • Most of the Pony Creek Project is underlain by the Mississippian Webb Formation, which was thrust into current position by the Roberts Mountains Thrust Fault, overlying the Devonian Devils Gate Limestone but underlying the Diamond Peak and Chainman Shale Formations. The Webb Formation, consisting primarily of siliceous mudstone and calcareous siltstone, is the primary host rock for gold mineralization in the South Pinyon Range (as it is at the Rain, South Bullion and Trout Creek deposits. The Webb Formation remains untested at the Pony Creek/Elliot Dome Project. Middle to upper Devonian carbonate rocks through Permian clastic sedimentary are exposed at surface through the Pony Creek Property. Within the Pinon Graben, the south-plunging Pinon Range Anticline exposes progressively older units toward the north. Also within the Graben is a north-south trending, elongate rhyolite porphyry intrusive body of probable Eocene age. This sill-like body, which has intruded the Palaeozoic aged sedimentary rocks along the axis of the Pinyon Range Anticline, is composed of two lobes and contains rocks that have been variously described as rhyolite, felsite or felsic porphyry. Older, Tertiary sedimentary rocks of Palaeocene to Eocene age, composed of conglomerate, sandstone, siltstone and limestone are found to the northeast of the Pony Creek/Elliot Dome Project area.

Economic information about the deposit and operations

Operation type Surface
Development status Producer
Commodity type Metallic
Deposit size Medium
Significant Yes

Mining district

District name Robinson Mountain District
District name Larrabee District \n

Land status

Ownership category BLM Administrative Area
Area name Elko BLM Administrative District

Ownership information

  • Type Owner
    Owner Mill City International Corp. /Grandview Gold Inc.
    Year 2004
  • Type Operator
    Owner Grandview Gold Inc.
    Year 2004

Comments on the workings information

  • To date, no mineral production has been recorded from the Pony Creek Property and no workings larger than a few small prospect pits are known from the area.

Comments on other economic factors

  • In 1994, the Pony Creek property was reported to contain a geologic resource 1.1 million tons grading 0.057 opt gold. In 2006, the Pony Creek property was reported to have an inferred gold resource above 500 feet of 1,426,000 ounces contained in 32,410,000 tons with an average grade of 0.044 oz/ton Au. This shallow resource was calculated after compiling and reviewing all of the historic data on the property and is based on 151 drill holes from a property wide data base of 175 holes.

    In 2004, a new resource calclation was prepared as follows:
    Indicated Resources are 1,124,000 tons grading 0.058 ounces of gold per ton for a total of 65,000 contained ounces.
    Inferred Resources are 32,409,000 tons grading 0.044 ounces of gold per ton for a total of 1,426,000 contained ounces.
    Potential Resources are 58,750,000 tons grading 0.044 ounces of gold per ton for a total of 2,585,000 contained ounces.

Comments on development

  • Mineral exploration in southwest Elko County has been occurring since the late 1850s when various prospectors, on their way to the California gold fields, passed through Nevada. In 1869, silver, gold, copper, lead and zinc were discovered 13 miles to the north of the Pony Creek/Elliot Dome Project in the Railroad mining district. This district was worked heavily for
    copper, lead and silver through the late 19th century and into the early 20th century, with an estimated US$4.7 million in lead, copper, silver, gold and zinc being produced between 1869 and 1968.In 1980, during a search for additional gold deposits along the Carlin Trend, Newmont completed a regional stream sediment sampling program, which returned anomalous gold and arsenic values associated with a large, rhyolitic intrusive igneous body on what is now the Pony Creek Property. Newmont subsequently located 100 claims to cover the prospect during the same year and added a further 80 claims in 1982 to cover additional ground in the Property area. Following the completion of over 50,000 feet of drilling between 1981 and 1989, Newmont
    outlined a significant gold resource on the Pony Creek Property located within 500 feet of the surface, hosted by the rhyolite intrusive and silicified Mississippian to Permian sediments located immediately beneath and adjacent to the intrusive. Newmont estimated the gold resource in the Upper and Lower Bowl areas (the southern portion of the claim boundary) to be 1.124 million tons grading 0.058 ounces per ton, for approximately 65,000 ounces of contained gold . This estimate did not include any additional mineralization outside of the Bowl area. Newmont continued to explore the Pony Creek Property up until 1990 when they entered into a joint venture agreement with Westmont Mining, Inc. Since 1980, approximately US$5.0 million has been spent on exploration of the Pony Creek/Elliot Dome Project, during which time a number of different companies have completed
    exploration and development work on the Project.
    In July 2003, the Pony Creek Property was acquired by Mill City. A document outlining the Property?s gold potential prepared by the company in March 2004, resulted in the calculation of new resource estimates for gold mineralization known to occur over an area of 2.4 miles long by 2,000 to 4,800 feet wide ? an area well beyond the Bowl area mineralization. Based on available data, an inferred gold resource of 32.4 million tons at a grade of 0.044 ounces of gold per ton was calculated, equivalent to 1.43 million ounces of contained gold. Based on the known geologic and grade continuity of this type of deposit in north-central
    Grandview Gold Inc. has the option to earn a 60% interest in the Pony Creek/Elliot Dome Project (the ?Project?) located in the southern extension of the Carlin Trend. Since 1980, approximately $5.0 million has been spent on exploration of the Pony Creek Project. Past work conducted by companies including Newmont, Barrick, Uranerz and Homestake has included stream sediment sampling, soil sampling and geochemistry, mapping, geophysical surveys, data compilation and analysis and RC drilling. A total of 175 drill holes (95,511 feet) have been drilled on the Pony Creek Property to date. From 167 drill holes, for which information is available, 88 drill holes (50.3%) have gold intercepts of at least 5.0 feet grading 0.010 ounces of gold per ton.
    Grandview Company believes that, based on the geologic setting at Pony Creek, considerable potential exists for the identification of additional resources at depth, below the 500 foot level.

Reference information

Bibliographic references

  • Deposit

    LaPointe and others, 1991, NBMG Bull 106

  • Deposit

    Long, K.R., DeYoung, J.H., Jr., and Ludington, S.D., 1998, Significant deposits of gold, silver, copper, lead, and zinc in the United States: U.S. Geological Survey Open-File Report 90-206A, 33 p.; 98-206B. one 3.5 inch diskette.

  • Deposit

    NBMG MI-96 through NBMG MI-02

  • Deposit

    Coats, NBMG Bull 101

  • Deposit

    Quest International 1996 SEC Form 20-F; 1998

  • Deposit

    Ruby Lake Land Status, 1978

  • Deposit

    www.millcityinternational.com

  • Deposit

    NBMG Pony Creek Mining District file # 74, Item 31.

  • Deposit

    Amer. Mines 1996-2000

  • Deposit

    http://www.standardmining.com

General comments

Subject category Comment text
Deposit All significant gold mineralization outlined to date on the Pony Creek Property appears to be directly related to felsite breccias formed within a rhyolite intrusive. Over 90% of the mineralization on the property lies within 500 feet of the surface and occurs primarily along north and north-east trending structures within the rhyolite intrusive body and in silicified and altered Mississippian to Permian clastic rocks immediately beneath and adjacent to the intrusive.
Gold mineralization is directly related to felsite breccias formed within the rhyolite intrusive body either by phreatomagmatic processes, faulting, or both. Over 90% of the mineralization on the property lies
within 500 feet of the surface and occurs primarily along north and north-east trending structures within the rhyolite intrusive body and in silicified and altered Mississippian to Permian clastic rocks immediately beneath and adjacent to the intrusive. Mineralization in the southern portion of the Pony Creek claim boundary (known as the Bowl area) is located within the southern lobe of the rhyolite intrusive and consists of an assemblage of marcasite and pyrite with minor realgar and stibnite. Two continuous zones of
mineralization have been recognized within the Bowl area. The first is a tabular mineralized zone. Presumed to be flat-lying, this zone occurs near the base of the felsite body. The second zone occurs in a steeply dipping, north-trending structure. Gold mineralization is developed along fractures and disseminated in permeable zones in the intrusive and in the matrix of felsite breccias. Past drilling completed by Newmont has indicated that gold in the Bowl area occurs within a large cell of alteration approximately 5,000 feet long by 2,500 feet wide, containing widespread low-grade gold mineralization in the 0.010 to 0.045 ounce per ton range.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-NOV-2006 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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