Greatland Resources (ASX:GGP) said results from a feasibility study at its Havieron project in Western Australia confirmed further upside potential and generated an internal rate of return post-tax of 22.5%, according to a Monday filing with the Australian bourse.

The results also showed a steady state average annual production target of 266,000 ounces of gold and 9,600 tonnes of copper, the filing said.

It updated the project's ore reserve to 38.5 million tonnes at 2.63 grams per tonne gold and 0.33% copper, for 33 million gold ounces and 128,000 copper tonnes, the filing added.

The feasibility study mine shows an initial mine life of 17 years, and the company now expects first gold at the project around 2.5 years from the final investment decision, the company said.

Shares of the company rose 10% in recent Thursday trade.