The PEA considered openpit mining only at Frontier's PAK and Spark deposits, plus a hydromet plant converting spodumene concentrate feeds to 23,174 tonnes of battery-quality lithium hydroxide monohydrate (LiOH-H2O) per year.
It put initial capex at US$685 million, the post-tax NPV8 at $974.6 million and IRR at 21% for the 26-year project.
It assumed an average LiOH-H2O selling price of $13,500/t and put all-in operating cash costs of $4,083/t.
"As western automotive companies rapidly electrify their product line-ups, we expect very strong demand for locally sourced premium lithium chemicals supply, and the Great Lakes region is the prime location as it is the largest auto manufacturing hub on the continent," president and CEO Trevor Walker said.
The company said both the PAK and Spark deposits were open in all directions and could provide potential resource expansion for the newly-begun preliminary feasibility study.
It also recently discovered a "significant pegmatite zone" dubbed Bolt between the two deposits.
Frontier Lithium started mini-pilot plant operations with Glencore's XPS Expert Process Solutions in January, to provide samples for marketing and data for the PFS.
The company raised just over C$1 million in November at 35c per unit to advance exploration at the PAK project.
Its shares (TSXV: FL) reached a one-year high intraday of C$1.39, before closing up 0.8% to $1.28 to capitalis it at $226.5 million (US$178.3 million).