Sunday, October 16, 2011

The World's Largest Open Pit Diamond Mine

By on Sunday, October 16, 2011 2 Comments

Somewhere in the middle of Siberia is one huge hole in the ground. The Mirny or Mir Mine is the second largest excavated hole in the world and the largest open pit diamond mine.

It's 525 meters (1,722 ft) deep and has a diameter of 1,200 m (3,900 ft). The mine is so deep that it's a no fly zone for helicopters after some were sucked down due to the downward draft of the air currents!

The mine was discovered in the 1950's as the Soviets were trying to find their own source of industrial diamonds.  De Beers, which controls the diamond cartel, had embargoed the Soviet Union and they had no other access.

View Mirny, Siberia in a larger map

There couldn't have been a more inhospitable place to mine for diamonds than in Russia (or Canada!). The winter temperatures average at -40C and lasts 7 months. It's so cold, keeping machinery and vehicles going is a challenge. Rubber tires would shatter, oil would freeze and the steel rigging would snap.  The land the rest of the year is just a sea of mud so the nearby buildings had to be built with steel pilings so they wouldn't sink into the sludge.

The city of Mirny with its mineCity of Mirny near the mine via Wikipedia

The Soviets also resorted to using jet engines or dynamite to burn or blast their way into the permafrost. As water freezes, they were forced to use dry crushing methods for their ore processing. Not much else was known about their mining techniques although it wasn't for lack of trying.

Transport station in the mineTransport station via Wikipedia

The mine produced more than $17 billion worth of diamonds in nearly 50 years.  Large quantities of gem grade diamonds - a fifth of total production in the 1960's - were also discovered and ironically sold to De Beers.  De Beers was forced to buy all the Russian diamonds because they feared the flooding of the market with these "Silver Bears" as the gems were called, would decrease the price of diamonds.

In the 1970's De Beers actually sent two representatives to Russia to find out more about the Russian diamond production.  The wily Soviets wined and dined the pair and generally stalled so much that only a 20 minute mine tour was possible before their visas expired. 

Lake in the Mir mineLake at the bottom via Wikipedia

Russian speaking readers will be able to understand this tv news report but it does show fascinating historical clips of Mirny Mine and its amazing diamond yields.

About 10 years ago, declining yields and safety concerns permanently shut the open pit mine down. Today, the miners dig for diamonds in the area's underground tunnels.  

A Brief History of the World's Largest Open Pit Diamond Mine
BBC's At the Heart of Russia's Diamond Industry 

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  1. Fascinating! I wish I could speak Russian. Thanks for this very interesting piece.

  2. Interesting but sad what we do to this lovely planet to obtain precious gemstones and metals. The quest for gold has decimated vast expanses of land and once the source dries up it is abandoned leaving huge scars of deep pits and mutilated forests. Maybe someday we'll have the means of creating synthetic gold and silver ... hey we're working on synthetic diamonds so nothing's impossible. :)