Russian diamond producer Alrosa has shifted operations at its Udachnaya pipe, one of the oldest kimberlite pipes in Western Yakutia, from open-pit to underground mining.
Opened in June 1955, the Udachnaya mine is 640m deep, has been developed since 1967 by drilling and blasting methods and has a surface area of 1,600m x 2,000m.
In June 2014, the initial stage of the underground mine was commissioned and its design capacity of four million tonnes of ore a year is expected to be reached in 2019.
According to the company, the mine will produce around 0.78 million carats of rough diamonds in 2015 with volume set to increase to over five million carats in 2019.
Alrosa president Andrey Zharkov said: "The Udachny open-pit made a great contribution to Alrosa's development, and its conservation represents a milestone in the history of the company.
"The Udachny underground mine successfully ramps-up capacity, and its indicative planning horizon is 50 years.
"The Udachny mining and processing division will remain one of the key production divisions of Alrosa and play a significant part in the implementation of the company's long-term development programme, which provides for the increase of diamond output to 41 million carats."
The company conducted the last blasting operations at the Udachny open-pit mine in the first half of 2015.
Last year, output at the mine, which was considered as the flagship diamond mine in Western Yakutia, amounted up to 12.8 million tonnes of ore a year.
Image: Udachnaya mine is 640m deep and has been developed by drilling and blasting methods. Photo: © OJSC ALROSA.