The Hasbrouck Gold-Silver Project is located in Nevada, USA. (Credit: West Vault Mining)
Gold ore. (Credit: James St. John/Wikipedia)
Exploration results on various zones of the project. (Credit: West Vault Mining)

The Hasbrouck Gold-Silver Project is an open-pit gold-silver mine owned 100% by West Vault Mining in Esmeralda County in Nevada, USA.

The project is the second phase of the Hasbrouck Gold Project consisting of the Three Hills Mine (phase one) and the Hill of Gold (phase three).

West Vault received a Federal Permit from the Bureau of Land Management (BLM), USA to construct and operate the mine in November 2020.

According to the 2023 Preliminary Economic Assessment (PEA), the gold-silver project has a mine life of 7 years.

Currently, the project is in the permitting stage. The construction of the project will commence in the second year after the completion of the permitting stage followed by the operations in the third year.

Hasbrouck Location and Site Access Details

The Hasbrouck Gold-Silver Project is located 8.04km south of Tonopah in Nevada. Tonopah is a historical mining town located in Nevada.

The project consists of 28 patented lode mining claims covering an area of approximately 9,390 acres.

The project will be accessible off US Highway 95, an all-weather all-season road, and US Highway 6.

Hasbrouck Ownership History

The gold-silver mineralisation was first discovered in 1902 on the Hasbrouck Mountain with recorded production of 740 tons of ore in 1923 and 1924 by the Tonopah Hasbrouck Mining Company.

Cordex conducted sampling, drilling, mapping, mineral resource estimate, and metallurgical test work on the project in 1974.

In 1985, Franco-Nevada optioned the project from Cordex. Franca-Nevada drilled 20 vertical reverse-circulation drill holes and completed metallurgical test work.

FMC optioned the project and drilled 76 reverse-circulation and vertical drill holes in 1988. After 1990, Euro-Nevada completed a 19,000m (19km) geophysical survey and reconnaissance surface rock chip surveys on the project.

Euro-Nevada optioned the property to Corona in 1992. Corona was acquired by Homestake in 1993 which transferred its interest to Prime Equities International.

In the same year, Euro-Nevada regained 100% interest in the project and planned for further exploration.

In 1996, Euro-Nevada completed an 18-hole reverse circulation drilling program on specific targets on the project.

Euro-Nevada merged with Newmont in 2002. In May 2003, Vista Gold received the project from Newmont.

Allied Nevada was formed in 2007 after separating from Vista Gold becoming the owner of the project.

Allied conducted various sampling and drilling campaigns from 2010 to 2013 including data verification, metallurgical studies, and a PEA.

In April 2014, West Kirkland Mining completed a 75% acquisition of the project from the subsidiaries of Allied Nevada through its subsidiary WK Mining (USA).

Allied sold 25% interest in the mine to Clover Nevada, a wholly owned subsidiary of Waterton Precious Metals Fund II Cayman, in June 2015 after approval from the United States Bankruptcy Court for the District of Delaware.

West Kirkland changed its name to West Vault Mining in July 2020. The remaining 25% interest in the project was acquired by West Vault in August 2020 from Clover Nevada.

West Vault became the 100% owner of the project after this transaction.

Geology and Mineralisation

The Hasbrouck Gold-Silver Project is a low-sulfidation mine hosted by tuffs and sediments of the Siebert Formation. The mine has limited mineralisation within the underlying Fraction Tuff.

The project has gold and silver mineralisation consisting of discontinuous silica-pyrite veinlets, sheeted veinlets, and stockworks associated with hydrothermal breccia. The sulphide minerals are largely oxidised.

The mineralisation of the project is accompanied by silicification, adularia, and pyrite. The mineralisation is open at depth and from the east and northwest to a limited extent.

Mineral Resource Estimate

The measured mineral resource estimate of the Hasbrouck Gold-Silver Project is 6.98Mt containing 134Koz gold at a grading of 0.019oz gold/ton and 2,752Koz silver at a grading of 0.39oz silver/ton.

The indicated mineral resource estimate of the mine is 35.04Mt containing 516koz gold at a grading of 0.015oz gold/ton and 9,404Koz silver at a grading of 0.27oz silver/ton.

The total (measured + indicated) mineral resource estimate of the mine is 42.02Mt containing 651koz gold at a grading of 0.015oz gold/ton and 12,156Koz silver at a grading of 0.29oz silver/ton.

The inferred mineral resources of the project are 5.16Mt containing 56koz gold at a grading of 0.011oz gold/ton and 986koz silver at a grading of 0.19oz silver/ton.

Hasbrouck Mineral Reserves

The proven mineral reserves of the Hasbrouck Gold-Silver Project are 6.13Mt containing 126KOzs gold at a grading of 0.021oz gold/ton and 2,558KOzs silver at a grading of 0.417oz silver/ton.

The probable mineral reserves of the mine are 28.23Mt containing 452KOzs gold at a grading of 0.016oz gold/ton and 7,946KOzs silver at a grading of 0.281oz silver/ton.

The total (proven + probable) mineral reserves of the project are 34.37Mt containing 578KOzs gold at a grading of 0.017oz gold/ton and 10,504KOzs silver at a grading of 0.306oz silver/ton.

Mining Methods and Processing of Ores

The Hasbrouck Gold-Silver Project is planned to use open-pit, truck, and loader operations. Two additional waste rock storage areas have been designed for the mine.

The production schedules of the project were completed based on the production requirement of 17,500 tons per day (tpd) of ores. There is a need to use some pre-stripping for the ores located on the surface.

The Upper Siebert ores were assigned a 55.6% operational gold recovery and a 24% operational silver recovery.

The Lower Sibert ores were assigned a 76.1% operational gold recovery and a 17% operational silver recovery.

The project will undergo construction after the commencement of production at the Three Hills Mine. The Three Hills Mine will stop production after two years.

The Hasbrouck Mine will use a conventional heap-leaching method to process ores mined from the mine. The ores will undergo three stages of crushing.

The ores will enter two secondary cone crushers after passing through a primary jaw crusher and will enter the high-pressure grinding-roll unit.

The ores will be stacked on the heap after agglomeration with cement. The dilute cyanide solution will leach gold and silver which will be recovered by an on-site carbon adsorption-desorption-recovery (ADR).

The ADR process will produce Doré bars.


The infrastructure of the Hasbrouck Gold-Silver Project will consist of water supply and related facilities, power infrastructure, warehouses, mine operations, and an assay laboratory etc.

The project is planned to receive water from the two wells drilled near the Three Hills Mine. The water from a 500,000-gallon water storage tank at the Three Hills Mine will be transferred to the project via High-Density Polyethylene (HDPE) pipelines.

A potable water system will be developed and installed at the project site. During operations, three trailers will be installed for training, conferences, safety, and offices.

A 1,500ft2 reagents storage building and a 145*42*44ft high ADR plant will be built on the mine site. An additional 14*25*20ft high section for the caustic area will be attached to the ADR.

A 79.5*44.5*22.7ft high refinery will be installed on the project site sharing a wall with the ADR building.

Power Transmission

The Hasbrouck Gold-Silver Project will be grid power supplied by NV Energy. The estimated power load at the mine is 6.5MW with an average of 4.1MW.

An 8,000kV substation will be built at the mine site consisting of a transformer with a step-down voltage from 120kV to 4,160V.

The overhead power lines will deliver the electricity across the equipment on the site at 4,160V. The voltage will be reduced to 480V from 4,160V by transformers and will be fed to the distribution panels and MCC (s).

Additional power requirements will be met by small dry-type transformers which will step down the voltage from 480V to 220-127V.

The backup power will be supplied by a 750kW and 480V diesel-powered backup generator for emergencies.

Key Contractors

RESPEC prepared the 2023 PEA of the Hasbrouck Gold-Silver Project. Before this PEA, Mine Development Associates prepared the technical report and Pre-Feasibility Study (PFS) of the project.

Westland Engineering & Environmental Services prepared the environmental section of the 2023 PEA.

The preliminary design and costs to supply electricity to the mine was prepared by NV Energy. The work included a 120kV switching station (Siebert Switching Station), communication equipment, upgrades, and metering at the substation.

The preliminary designs and costs for the onsite electrical distribution was provided by KCA.

Alpha Advisory Services was selected in January 2017 to provide investor relations and advisory services for the project.