Barrick Gold Corp. has stopped new underground development at the Golden Sunlight gold-silver mine in Montana and will conduct the final mill run to process gold ore in May.

The company said March 21 that the mine's remaining gold reserves are almost depleted and mining is limited to existing areas only. However, it is evaluating different work streams at the operation.

In October 2018, Barrick secured approval for a new underground mine, known as Apex, that will extend operations at the Golden Sunlight mine until at least 2021.

Barrick said it will continue underground and surface exploration drilling at the operation with a focus on the southern extension of the Sunlight vein, and undertake metallurgical test work and a structural geological model associated with the Apex target.

Additionally, the company will look into reprocessing historic tailings, and conduct hydrological and geochemical studies to support ongoing water treatment and reclamation work, it noted.