IGO (ASX:IGO) said the 100% ownership of Yeneena copper project in Western Australia has been reverted to Encounter Resources (ASX:ENR) after the company withdrew from the farm-in and joint venture agreement, according to a Wednesday Australian bourse filing.

Encounter will assess the technical datasets generated under the farm-in to refine and prioritise the next phase of exploration, including potential depth extensions to the project's BM1 high-grade copper oxide discovery and drill testing the large copper leakage anomaly identified at BM5.

The BM1 discovery includes 20 meters at 2% copper from 22 meters, including 12 meters at 3.2% copper from 32 meters.

Encounter said it will still prioritize its West Arunta Niobium Project in Western Australia while Yeneena presents "compelling" copper upside.