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.

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.

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.