The West African miner believes a potential underground mining operation at Yaouré could target 595,000 ounces within 3 million tonnes grading 6.2 grams per tonne gold.
Perseus estimates it would need about US$15.5 million to drill out the resource out and complete a technical evaluation for the whole of the current underground target area.
The Yaouré project is flagged to start producing gold at the end of 2020 and has a current 8.5-year open cut operating life.
Yaouré has a capital cost of $264 million, with Perseus planning to fund development from corporate cash reserves, future cashflows and a debt facility.
Full-scale production is pegged to start early next year.
Yaouré will be the company's third (and major) operation in West Africa, taking Perseus' profile to about 500,000oz per annum at all-in sustaining costs of about $850/oz.
The company's September quarter revealed a near-300,000ozpa business producing gold at AISC of $950/oz.
Shares in Perseus closed last week at A37.5c capitalising the company at $388 million.
The stock was at 31c late in 2017 and at levels around 50c six months ago.