The PEA estimated annual production of 20,000 tonnes per year of battery-quality lithium hydroxide (LHM) over 20 years, with initial capex put at US$602 million.

After-tax NPV8 was $819 million and IRR of 27%, using a forecast LHM price of $14,079/t and all-in operating costs of $3,656/t.

Production was based on recovering lithium from brines in the Leduc Aquifer and E3 said there was room for expansion across the Clearwater resource area and in E3's adjacent Exshaw and Rocky resource areas.

"The combination of electrochemically-produced lithium hydroxide, targeted process re-cycle streams, and relatively low cost of energy in Alberta provides for a very attractive trade-off between opex and capex," president and CEO Chris Doornbos said.

The company struck a joint venture agreement with Livent Corp a year ago, with the leading lithium producer to contribute up to US$5.5 million to assist in the development and pilot of E3's direct lithium extraction process. 

Doornbos said the PEA provided a robust opex capable of withstanding lithium hydroxide price fluctuations.

The company said the future average selling price of $14,079/t was consistent with other publicly released economic assessments of other lithium projects in the past four months.

"We are very excited to be moving forward with the project development work into 2021 as we progress on the path to a pre-feasibility study," Doornbos said.

Clearwater's inferred resource was updated to 410,000t, or an increase of 14%, which E3 said using a conversion factor of 5.323 equated to 2.2 billion tonnes of lithium carbonate equivalent.

E3 raised C$1.3 million in October at 40c per share, to begin preparations to advance Clearwater into 2021.

Its shares (TSXV: ETMC) touched a one-year high of $1.73 intraday before closing up 18.8% to $1.45, capitalising it at $44.2 million (US$33.8 million).