Bergen will make an initial investment of $4 million payment, followed by two further $4 million instalments over about eight months.
The investments will be made via an unsecured interest-free convertible security with a 24-month maturity.
Australian Mines had just under $9 million cash at the end of June and is fully funded through to a final investment decision on its Sconi cobalt-nickel-scandium project in Queensland, expected later this year.
Part of the Bergen proceeds will be used to complete the acquisition of the Flemington cobalt-scandium-nickel project in New South Wales.
A payment of $3.4 million is due to vendor Jervois Mining this month.
Australian Mines said the funds would strengthen the balance sheet during Sconi financing discussions.
"I am delighted to have attracted a significant investment in Australian Mines from a firm like Bergen, which has made a number of successful ASX investments over the years, alongside existing shareholders and management," Australian Mines managing director Benjamin Bell said.
"The issue of these convertible securities reinforces the significant investment interest we have received out of the United States over the past 12 months."
Australian Mines shares have been in freefall this month, starting September at 7.8c and falling by another 12.7% to 5.5c today. The stock peaked at 15.5c late last year.