Mirny, April 23, 2019 - ALROSA extracted from the ground a large gem-quality diamond at its ‘International’ mine. The crystal weighing 118.91 carats was mined on April 16th. This is the largest gem-quality diamonds found at the ‘International’ pipe over the past two years.
The extracted rough diamond - with a light yellow overblown, has salient edges, one of them with cleavage, and small inclusions in the central zone.
“This crystal is unique as it has a large clean area despite the inclusions in the center - this makes it a gem-quality diamond. Well-known hallmarks of the diamonds from the ‘International’ kimberlite pipe are regular shapes and purity. That is exactly the pipe that most often brings ALROSA regular shape octahedrons with smooth edges,” explained Evgeny Agureev, Member of the Management Board, Director of the United Selling Organization at ALROSA.
The diamond was mined right on the eve of the launch of Zarya - a new deposit of ALROSA at Aikhal Mining and Processing Plant. The Company considers assigning the name Zarya to the new extracted crystal in honor of the launch event.
The mined crystal is one of the largest gem-quality diamonds extracted from the ground at the mine ‘International’ in recent years. Earlier, a similar large gem-quality diamond (109.61 carats) was mined here in summer of 2017.
The kimberlite pipe ‘International’ was discovered in 1969 by geologists of the Botuobinsky expedition. The open-cast mining (strip-pit) of the deposit was conducted from 1971 to 1981. The total depth of the pit is 284 m. The underground mining has been going on since 1999. By the time of the development, the reserves of the deposit ‘International’ were more than 100 million carats of diamonds. This field is the world leader in diamond content, which are of high quality. The average content in different periods of mining reached 12 ct/t, with an average content of 7 ct/t (in accordance with the recommendations of the JORC Code). This is the world's largest carat content per tonne of ore.