Roxgold acquired Séguéla for US$30 million earlier this year from Australia's Newcrest Mining (ASX: NCM), which had established an inferred 5.8 million tonne resource grading 2.3g/t gold for 430,000 ounces.
Canada-based Roxgold last week announced a maiden indicated resource for Séguéla of 6.5Mt at 2.4g/t for 496,000oz, plus an inferred resource for the satellite Antenna deposit of 400t at 2.4g/t for 34,000oz.
It maintained the proven and probable reserves of 658,000oz at 8.2g/t for its flagship Yaramoko mine in Burkina Faso despite production of 260,000oz in 2017 and 2018.
The company said its total measured and indicated resources now stood at 1.3Moz at 4.8g/t, a 79% increase on the December 2016 estimate.
"With the newly-defined indicated mineral resources at Séguéla and our upcoming drill programme, we believe there is an encouraging line of sight to further increases in the company's near-surface mineral resource inventory in the coming years," president and CEO John Dorward said.
Roxgold is aiming to release a preliminary economic assessment for Séguéla in the December quarter.
The company expects Yaramoko to produce 145,000-155,000oz of gold this year at all-in sustaining costs of $765-$795/oz.
Its shares are close to the 52-week peak reached a year ago of C$1.15, last trading at $1.08 to capitalise it about $400 million (US$308 million).