The proven and probable reserves are now at 14.7 million tonnes containing 814,900 ounces grading 1.72g/t, which extends the LOM to 2031.

This includes Youga deposit's reserves of 7.8Mt containing 372,200oz at 1.5g/t, the Ouaré deposit's reserves at 6.7Mt containing 403,000oz at 1.9g/t, and Balogo's reserves of 200,000t containing 39,700oz grading 5.7g/t.

The project also has a measured and indicated mineral resource of 22.16Mt containing 1.2 million ounces grading 1.67g/t and an inferred resource of 7.6Mt containing 377,000oz grading 1.5g/t.

Youga is forecast to recover 734,066oz over its LOM at an all-in sustaining cost of US$973 per ounce.

The project's total upfront capital is expected to be $17.7 million for the construction of the Ouaré to Youga haul road, tailings storage facility (TSF) upgrades and the mobilisation of contract operations, as well as sustaining capital costs of $17.8 million, including TSF expansion and mine closure.

Youga has a post-tax NPV of $142.6 million at a 5% discount rate with a $1,300/oz gold price and LOM free cash flow generation of $186.8 million.

CEO Serhan Umurhan said Avesoro had added 950,000oz to its combined mineral reserve inventory, net of mining depletion, through its 2018 exploration campaign in both Liberia and Burkina Faso.

In March, the company updated its reserve and resource estimates for its New Liberty gold mine.

"Each of our assets experienced an increase in mineral reserves, net of depletion, and as a result, we have substantially extended the lives of both our mines. I now expect the company to sustain group level gold production above 200,000oz per annum for each of the next four years as indicated by the updated mine plans," Umurhan said.

He said New Liberty and Youga now had a combined project level post-tax NPV of around $428.6 million after project and equipment finance debt repayments of $100 million, with the combined project level post-debt and post-tax LOM cash flows indicated as $556.8 million at a $1,300/oz gold price.

"We are continuing to assess a number of optimisation options, including ore sorting and heap leach scenarios, to further improve the economics of both projects in addition to the significant potential to add further economic ounces to the projects with additional drilling," he said.

Avesoro's shares (AIM:ASO) gained 3.7% Wednesday to £1.08 (US$1.41) per share.