"The study outcomes fully justify additional investment on extension drilling at both deposits where an increase in mineral resources could significantly enhance projected returns," PolarX said.

As it currently stands, a pre-production capital investment of US$111 million yields a project with a net present value of $72 million and an internal rate of return of 26% - both pre-tax.

PolarX pointed out a 300,000t (or 14%) increase in mined ore from one of the two deposits to be exploited could add $31 million to the NPV.

And a 500,000t increase in material mined at both the Zackly and Caribou Dome deposits could yield a $52.5 million increase in projected pre-tax NPV.

A copper price of $9000/t and gold price of $1800/oz was used in scoping metrics.

As well as resource extension work being constructive, PolarX said additional metallurgical test work is warranted and may deliver better copper recovery and concentrate grade, particularly for Caribou Dome, and better gold recovery for Zackly.

The Alaska Range project is 250km northeast of Anchorage in central Alaska, US and has current resources containing 131,000t of copper and 213,000 ounces of gold (plus 1.6 million ounces of silver).

The two deposits would be processed over 6.5 years.

PolarX got involved in the project eight years ago, with the resources estimates made around five years ago.

PolarX initiated a second project in Nevada (Humboldt Range) at the start of last year to ensure company newsflow all year round - given the seasonal nature of work in Alaska.

Managing director Dr Jason Berton moved into the role in July, having come from the company that previously owned Humboldt Range.

PolarX had about A$1.95 million at the end of the June quarter, with its last fund raising(s) pricing new share at 2.1c each.

Shares in PolarX were up 11% to 1c, capitalising the company at just over $8 million.