Gold deposits at the Podgolechnoye mine in Yakutia are more impressive than earlier understood.
New explorations show that deposits are 19 per cent higher, and ore 20 per cent higher.
The mine is run by Russian holding Seligdar and is believed to have a further eight years of production capacity.
Seligdar is a Siberian operation formed in 2008 after a merger of assets by Russian Funds Investment Group and Seligdar Prospectors Artel.
Gold production is seen as hitting around 700 kilograms annually.