It used an initial reserve of 12.1 million tonnes grading 2.8g/t for 1.1Moz, which Roxgold said positioned Seguela among the highest-grade openpit gold projects globally.
Peak production was forecast at 151,000oz in year four, with average annual production of 120,000oz.
Roxgold acquired Seguela from Newcrest Mining in 2019 and is aiming for first gold in 2022.
"Seguela has rapidly become a cornerstone asset for Roxgold, with the potential to more than double the company's production profile within a short time frame," president and CEO John Dorward said.
Roxgold's Yaramoko mine in Burkina Faso produced 35,308oz of gold in the March quarter and was on track to achieve guidance of 120,000-130,000oz this year.
The Seguela study kept initial capex at US$142 million, the same as a 2020 preliminary economic assessment, which had tipped total production of 841,000oz over 8.2 years.
Under the feasibility study, all-in sustaining costs rose from the PEA's $749/oz to $832 over the life of mine which increased slightly to 8.6 years.
After-tax NPV5 attributed to Roxgold's 90% interest was $380 million and IRR 49%, with a payback period of 1.7 years using a base case gold price assumption of $1,600/oz.
This increased to $451 million and 56% using a spot price of $1,750/oz.
The PEA had put after-tax NPV5 attributable to Roxgold of $268 million and IRR at 66% using a $1,450/oz gold price.
The feasibility study was based on mining Antenna and satellite deposits Koula, Ancien, Agouti and Boulder.
Roxgold pointed to further potential at Seguela, including the new Sunbird discovery about 1km from Antenna.
Next steps included finalising a debt financing agreement.
"We expect to be able to deliver this without the need for equity dilution," Dorward said.
The company had started early works in December in anticipation of a positive development decision and had named Lycopodium as preferred contractor for the CIL plant in March.
Roxgold shares reached a multi-year high of C$2.08 intraday before closing down 4.4% to $1.95, valuing it at $731 million (US$585 million).
