It said Hill-of-Gold was "likely to be positive" to Hasbrouck's economics but pointed out the historical 43,000 ounce resource had not been included in Hasbrouck's 2016 prefeasibility study.
The study had estimated low initial capex of US$47 million for an eight-year mine producing about 71,000oz of gold annually, with an after-tax NPV5 of $295 million and IRR of 92% using an $1,800/oz gold price.
However the company was in no rush to production, COO Sandy McVey had told Mining Journal in August, with West Vault's main owner Sun Valley Gold preferring to wait until the gold price rose significantly.
McVey since also became West Vault's interim CEO in September after Michael Jones resigned as president and CEO.
West Vault said it planned to truck material from Hill-of-Gold to its fully-permitted Three Hills deposit, which was phase one of its Hasbrouck mine plan and construction-ready according to a September update.
It had acquired Hill-of-Gold in February in exchange for a one-time payment of $250,000.
The company said in November its cash situation was "good for six years", having received $6 million through a gold and silver stream agreement with Sprott Private Resource Streaming and Royalty Corp in February.
Sprott has the option to add a Hill-of-Gold stream for $300,000.
Eric Sprott owns 5% of West Vault's stock, behind Ruffer with 17% and Sun Valley Gold with 46%.
West Vault shares (TSXV: WVM) have spanned C95c-$1.99 over the past year. They closed up 3% on Friday to $1.03 to capitalise it at $59.8 million (US$46.6 million).