Overview
Status | Closing / Closed |
Mine Type | Open Pit |
Commodities |
|
Processing |
- Heap leach
- Carbon in leach (CIL)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
The Status of Lone Tree Mine is closed.
On July 1, 2019, Phoenix was contributed to Nevada Gold Mines, a joint venture with Newmont. The Newmont contributed to NGM the non-operating Lone Tree mine, which is included in the Phoenix. |
Source:
p. 72
On March 10, 2019, Barrick entered into an implementation agreement with Newmont to create a joint venture, named Nevada Gold Mines.
On July 1, 2019, Phoenix was contributed to Nevada Gold Mines, a joint venture between Barrick and Newmont. The Newmont contributed to NGM the non-operating Lone Tree mine, which is included in the Phoenix.
Nevada Gold Mines include Barrick’s Cortez, Goldstrike, Turquoise Ridge and Goldrush properties and Newmont’s Carlin, Twin Creeks, Phoenix, Long Canyon and Lone Tree properties.
Barrick is the operator of the joint venture and owns 61.5%, with Newmont owning the remaining 38.5% of the joint venture.
Summary:
The Lone Tree gold deposit, Nevada is hosted in Paleozoic calcareous sedimentary rocks. Mineralization is dominantly controlled by high-angle normal faults and fracture sets, as is alteration. Mineralization occurs in the form of disseminations, micro and macro veins, and as a matrix to angular breccia clasts. The paragenesis of minerals indicate four stages of mineralization. The first stage is identified by brecciated quartz and minor pyrite. The second stage is the main gold stage of mineralization comprising quartz veins, kaolinite, pyrite, marcasite, arsenopyrite, gold, sphalerite, and chalcopyrite.This is overprinted by a third stage economic gold mineralization along with barite and pyrite. Free gold grains in stage 2 occur in a quartz and clay mineral assemblage in association with pyrite. The last stage is supergene mineralization producing covellite, chalcocite, native copper, hematite, and goethite.
Main alteration types are decarbonatization, silicification by multiple generations of silica, and argillization due to the development of kaolinite, illite/smectite, and alunite.
Gold mineralization at the Lone Tree deposit is primarily confined to fault zones and fracture sets, where sedimentary host rocks experienced decarbonatization, silicification (by repeated introduction of hydrothermal silica), and argillization (by development of clay minerals especially hypogene kaolinite).
Four stages of mineralization have been identified at the Lone Tree deposit. The first stage of mineralization is represented by brecciated quartz and minor pyrite. The second stage, main gold sulfide mineralization containing quartz veins, kaolinite, pyrite, marcasite, arsenopyrite, gold, sphalerite, and chalcopyrite is overprinted by a third stage of mineralization comprising barite, pyrite, and gold. Free gold grains occur in quartz and clay mineral assemblage in association with pyrite in stage 2 mineralization. The fourth stage is supergene mineralization and includes covellite, chalcocite, native copper, hematite, and goethite.
Fluid inclusion and gas composition data indicate multiple sources for the main gold stage mineralizing fluids as magmatic, crustal, and evolved meteoric waters. Fluid inclusion data indicates fluids had temperatures of 185 to 411 °C and salinity of 1.23 to 41.4 eq. wt. % NaCl. High salinity fluids (28.6-41.4 eq. wt. % NaCl) along with high N2/Ar ratios and high C02 concentrations demonstrate a magmatic input.
Summary:
Lone Tree is an open pit operation, located approximately 20 miles northwest of Battle Mountain, Nevada and can be accessed by paved highway. Lone Tree’s available mining fleet consists of two haul trucks, which range from 150 tons to 190 tons, to rehandle leach material for residual leaching operations.
Processing
- Heap leach
- Carbon in leach (CIL)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Source:
Summary:
Mining was completed in 2007, with residual heap leach processing and ongoing reclamation activities. The site also has an autoclave and flotation mill, which are currently on care and maintenance.
Reserves at December 31, 2018:
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
3,600 kt
|
Gold
|
0.29 g/t
|
30 koz
|
Heavy Mobile Equipment as of December 31, 2018:
HME Type | Quantity |
Truck (haul)
|
2
|
Mine Management:
Job Title | Name | Profile | Ref. Date |
.......................
|
.......................
|
|
Mar 29, 2021
|
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