Hasbrouck Project Pre-feasibility Study

The 2016 pre-feasibility study was prepared by a team of Qualified Persons headed by Mine Development Associates (MDA) of Reno, Nevada, and presents a technically simple and economically robust project in a safe jurisdiction.

The Hasbrouck Gold Project consists of the Hasbrouck Mine and the Three Hills Mine plus surrounding land package, located near Tonopah, Nevada. All dollar values presented are U.S. dollars and are on a 100% project basis. Highlights include:

  • 594,000 recoverable gold-equivalent ounces
  • 74,000 gold-equivalent ounces annually for eight years
  • $661 Adjusted Operating Cost per gold ounce
  • $709 All-In Sustaining Cost per gold ounce
  • US$356 million NPV (5%) and a 109% IRR, after-tax, at $2,000 gold
  • US$47 million initial capital
  • Good exploration potential proximal to the Three Hills Mine
  • Fully-permitted Three Hills Mine, shovel-ready
  • Advanced permitting at Hasbrouck Mine

The Hasbrouck Project: comprised of the Three Hills and Hasbrouck deposits
The Hasbrouck Project: comprised of the Three Hills and Hasbrouck deposits
(Click to enlarge)

The Hasbrouck Gold Project is one of very few shovel-ready, high-margin gold projects in Nevada. Both deposits are all-oxide with low strip-ratios, minimal pre-strip, and no environmental or cultural factors which might impede permitting or operations. Both Mineral Resource and metallurgy have been advanced to a high level of reliability. Excellent infrastructure exists nearby in the form of the nearby town of Tonopah, grid electricity, paved highways, and multiple water sources. The Phase-1 Three Hills Mine is fully permitted, and permitting work is underway for the Phase-2 Hasbrouck Mine. For further information on permitting at Three Hills Mine please refer to the Company’s November 27, 2015 news release.

The 2016 PFS projects US$47 initial capital which will be used to build out the Phase-1 Three Hills Mine. Capital for the Phase-2 Hasbrouck Mine will come from free cash flow generated by operations at Three Hills. Six million tons of ore per year will be mined to produce on average 74,000 gold-equivalent ounces per year for eight years. Adjusted Operating Costs are projected at $661 per gold ounce, with All-in Sustaining Costs at $709 per gold ounce, both net of silver by-product credits.

The Three Hills and Hasbrouck deposits are 8 kilometers apart and located within a large land position hosting multiple near-surface and at-surface gold intercepts. Known gold intercepts are located proximal to current Mineral Resources; these are not included in the Mineral Resource model. These intercepts present exploration targets having the potential to increase and extend known Mineral Resources.

The 2016 PFS assumes Phase-1 production for two years at the Three Hills Mine followed by Phase-2 production for six years at the Hasbrouck Mine. Life-of-mine production is projected to be 594,000 gold-equivalent ounces. Stripping ratio is estimated at 1:1, and head-grade is estimated at 0.6 g/t gold (0.017 opt gold) while gold recovery from heap leaching is estimated at 76%. 

A Carbon-In-Columns (“CIC”) plant will be installed at the Three Hills Mine. Loaded carbon will be sent off-site for stripping and regeneration by a contractor. An Adsorption-Desorption-Recovery plant (ADR) complete with CIC circuit  will be installed at the Hasbrouck Mine, this being necessary due to the greater amount of silver occurring in the Hasbrouck Mine deposit.

The Hasbrouck Gold Project Updated Pre-feasibility Study

Mine Development Associates*, September 1, 2016 – in US dollars, based on 100% of the project (1)

  Units Three Hills

Head-grade Au opt (Au g/t) 0.018 (0.62) 0.017 (0.57) 0.017 (0.58)
Ore million tons 10 36 45
Stripping Ratio waste:ore 0.9 1.1 1.1
Annual Ore Processed million tons 5 6 6
Processing Rate tons per day 15,000 17,500 15,986
Gold Grade Au opt (Au g/t) 0.018 (0.62) 0.017 (0.57) 0.017 (0.58)
Silver Grade Ag opt (Ag g/t) NA 0.30 (10.2) 0.23 (8.0)
Contained Gold koz 175 588 762
Contained Silver koz NA 10,569 10,569
Contained Gold-equivalent (1) koz 175 610 784
Gold Recovery % 81.5% 74.0% 75.7%
Silver Recovery %   11.0% 11.0%
Recoverable Gold koz 142 435 577
Recoverable Silver koz NA 1,163 1,163
Recoverable Gold-equivalent
koz 142 452 594
Average Annual Gold Production koz 69 71 71
Average Annual Silver Production(2) koz NA 194 194
Average Annual Gold-equivalent Production koz 69 74 74
Gold Price US$/oz $1,275 $1,275 $1,275
Silver Price US$/oz $18 $18 $18
Initial Capital US$ million $47    
Growth Capital US$ million   $83  
Sustaining Capital US$ million   $13  
Life of Mine Capital US$ million     $143
Contingency (included) US$ million $6 $15 $21
Contingency (included) % 14% 19% 17%
Adjusted Operating Cost per Ton of Ore (3) US$/ton ore $7.40 $8.71 $8.43
Mining US$/ton ore $3.18 $3.74 $3.62
Processing US$/ton ore $2.55 $3.93 $3.63
G&A US$/ton ore $0.44 $0.46 $0.46
Other (4) US$/ton ore $1.23 $0.58 $0.72
Adjusted Operating Cost per Ounce(3) US$/oz Au net of by-products $502 $714 $661
All-In Sustaining Cost per Ounce (5) US$/oz Au net of by-products $510 $774 $709
Life of Mine year 1.7 7.1 8.8
NPV (5%) - after tax US$ million     $120
IRR - after tax %     43%
Payback Period year     3.1


  1. Gold-equivalent calculations are made using the ratio of recovered silver / gold and metal prices
  2. Silver production is averaged over the Hasbrouck mine life only
  3. World Gold Council - Adjusted Operating Costs include:
    On-site mining and G&A, royalties and production taxes, permitting and community cost related to current operations, 3rd party smelting, refining and transport costs, stock-piles and inventory write-downs, site-based non-cash remuneration, operational stripping costs and by-product credits
  4. Other category includes royalties, production taxes, permitting, refining, and by-product credit
  5. World Gold Council All-in Sustaining Costs includes:
    Adjusted Operating Costs (above) plus corporate G&A, reclamation & remediation—accretion & amortization, expenditures sustaining exploration and study costs, capital exploration, capitalized stripping and sustaining capital
  6. World Gold Council All-In Cost includes:
    All-In Sustaining Costs (above) plus community, permitting, and reclamation and remediation costs not related to current operations and non-sustaining exploration and study costs, capital exploration, capitalized stripping and capital expenditure
  7. Project economics are presented for 100% of the project which is jointly owned by WKM (75%) and Waterton Precious Metals Fund(25%)

Three Hills section showing gold domains and geology
Three Hills section showing gold domains and geology
(Click to enlarge)

Hasbrouck section showing gold domains and geology
Hasbrouck section showing gold domains and geology
(Click to enlarge)

After-Tax Sensitivity to Gold Price

Gold Price NPV5 IRR
  US$M CDN$M  
$1,200 $92 $122 35%
$1,400 $165 $219 56%
$1,600 $232 $309 74%
$1,800 $295 $392 92%
$2,000 $356 $473 109%


  • * Exchange rate C$1.33 = US$1.00

Hasbrouck Project Mineral Reserves

Proven and Probable Mineral Reserves total 45.3 million tons containing 762,000 ounces gold and 10.6 million ounces silver:

Hasbrouck Project Mineral Reserves, June 3, 2015, Mine Development Associates (1, 2)
(k tons)
(k oz)
(k oz)
Three Hills Mine          
0.005 opt
Au cutoff
Proven - - - - -
Probable 9,653 0.018 175 - -
P&P 9,653 0.018 175 - -
Hasbrouck Mine        
Variable (3) Proven 6,242 0.020 127 0.410 2,562
Probable 29,374 0.016 461 0.273 8,007
P&P 35,617 0.017 588 0.297 10,569
  Total Hasbrouck Project          
Variable (3) Proven 6,242 0.020 127 0.410 2,562
Probable 39,028 0.016 635 0.205 8,007
P&P 45,270 0.017 762 0.233 10,569


  1. The estimation and classification of Proven and Probable Reserves have been prepared by Thomas L. Dyer, P.E., of Mine Development Associates following CIM standards
  2. Reserves are estimated based on $1,225/oz gold and $17.50/oz silver
  3. Cutoff grades used for Reserves are: Three Hills 0.005 oz Au/ton, Hasbrouck Upper Siebert 0.008 oz Au/ton, and Hasbrouck Lower Siebert 0.007 oz Au/ton

Hasbrouck Project Mineral Resources

Mineral Resources are reported inclusive of Mineral Reserves.

Hasbrouck Deposit Reported Mineral Resources* November 3, 2014,

Mine Development Associates (0.006oz AuEq/ton Cutoff)

Class Ore (tons) Gold (opt) Gold (oz) Silver (opt) Silver (oz)
Measured 8,261,000 0.017 143,000 0.357 2,949,000
Indicated 45,924,000 0.013 595,000 0.243 11,147,000
M+I 54,185,000 0.014 738,000 0.26 14,096,000
Inferred 11,772,000 0.009 104,000 0.191 2,249,000

Notes: oz AuEq/ton = oz Au/ton + (oz Ag/ton x 0.000417)

Three Hills Deposit Reported Mineral Resources* August 4, 2014,

Mine Development Associates (0.005oz Au/ton Cutoff)

Class Tons oz Au/ton oz Au
Indicated 10,897,000 0.017 189,000
Inferred 2,568,000 0.013 32,000


  1. CIM definitions are followed for classification of Mineral Resources
  2. Mineral Resources are estimated using a gold price of $1,300 per ounce and a silver price of $22 per ounce
  3. Totals may not represent the sum of the parts due to rounding
  4. The Mineral Resources have been prepared by Paul Tietz, C.P.G of Mine Development Associates in conformity with CIM “Estimation of Mineral Resource and Mineral Reserves Best Practices” guidelines and are reported in accordance with the Canadian Securities Administrators NI43-101. Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. There is no certainty that all Mineral Resources will be converted into Mineral Reserves


West Vault will continue permitting work on Phase-2 Hasbrouck Mine in order to further de-risk the project, and will make a construction decision at Three Hills Mine when market conditions dictate. West Vault will engage with its major shareholders on such a construction decision. 

The reader is cautioned that a production decision might be made on the 2016 PFS and that the Company may proceed to production without completion of a feasibility study. There is an increased risk associated with making a production decision based on a pre-feasibility study.

Authors and Qualified Persons Statement

The 2016 PFS was prepared in conformance with NI 43-101 by Mine Development Associates (MDA). Technical work, analysis and findings were completed by Thomas L. Dyer, P.E. and Paul Tietz, C.P.G. of MDA, with contributions by Herb Osborne, Metallurgical Eng., SME, of H.C. Osborne & Associates (metallurgy), Ryan Baker, P.E., of Newfields (civil and heap leach) and Carl Defilippi, SME, of Kappes Cassiday & Associates (process design). Each person is a "Qualified Person" under NI 43-101 and has reviewed and approved the information in this news release relevant to the portion of the 2016 PFS for which they are responsible. MDA has reviewed and verified the data disclosed in this news release to conform to CIM “Estimation of Mineral Resource and Mineral Reserves Best Practices” guidelines and to NI 43-101. West Vault will file an NI 43-101 technical report in support of the technical disclosures made in this news release on SEDAR within 45 days.

Sandy McVey, P.Eng., Chief Operating Officer for West Vault, and a non-independent Qualified Person as defined by NI 43-101, has also reviewed the foregoing information and has verified the data.

Sample Preparation, Analyses, and Security

It is MDA’s opinion that the sampling, assaying, and security procedures used at Three Hills and Hasbrouck deposits follow industry standard procedures, and are adequate for the estimation of the current Mineral Resources and Mineral Reserves.

Data Verification

MDA completed audits of the database, performed a site visit, reviewed QAQC data and confirmed historic assays. After performing their review, they consider the assay data to be adequate for the estimation of the current Mineral Resources and Mineral Reserves.

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