It is the largest Diamond Mine in the world: The open pit Mir Diamond Mine, located in the Eastern part of Siberia, in the town Mirny.
Because of its depth (525 m / 1722 ft deep) its airspace is closed for helicopters as they will get sucked in by the downward air flow.
As most of the time the soil is frozen due to the permafrost, engineers used jet engines to defreeze the location they were working on. Those machines might have looked similar to this one.
Those who found a Kimberlite pipe
- hhgygy
- Dan Watson
- Ivar Bonsaksen
- lardarz
- Paul Franson
- blacbronco
- José Miguel Díaz
- Rolando Marín Monge
- ACG
- Chris Nason
- Chris M.
- Javier Abadia
- Thomas Egan
- Milosh, Serbia
- Andy McConnell
- Carvas, Portugal
- Josh Muehe
- Steve Jaycocks
- Camargo, California
- D Hall
- Dennis S.
- Taliesin
- ewen
- Elrober
- Graham Foxall
- Sarah G
- Stephen Hope
- David Kozina
-Hint-
- Andy M, USA
- Michael T
- Max_Power
A very interesting article on this:
http://io9.com/5689785/a-proposal-for-a-domed-city-in-a-kilometer+wide-siberian-diamond-mine