The update used the expanded resource announced in February, which increased Chidliak's CH-6 kimberlite pipe inferred resource by 58% to almost 18 million carats at an average grade of 2.41c/t and took the project's total to 22.2Mct.

Compared with a 2016 PEA, the update increased diamond recovery 44% over the 13-year mine life to 16.7Mct.

It put the initial capex up 4.6% to C$455 million (US$354 million), the after-tax payback at 2.2 years with an IRR of 31.1% and increased the after-tax NPV by 44% to C$679 million (US$528 million).

The base case NPV used a discount rate of 7.5% and a reduced annual diamond price escalation of 1.75%, down from the 2.5% used in the 2016 PEA.

Peregrine president and CEO Tom Peregoodoff said the update validated the company's 2016 decision when it recognised the expansion opportunities at CH-6, which remained open at depth.

"The updated PEA clearly establishes Chidliak as Canada's next economic diamond development opportunity," he said.

Peregrine was "assessing various options to advance the project," founder and executive chairman Eric Friedland said.

The company had about C$1.7 million in working capital at May 10 and said at the time that further exploration and development would depend on funding through equity or debt financing, or joint ventures.

Peregrine shares closed more than 13% higher yesterday, gaining C2c to 17c and capitalising it just over $75 million.