The nickel deposits of Norilsk-Talnakh are the largest nickel-copper-palladium deposits in the world. The deposit was formed 250 million years ago during the eruption of the Siberian Traps igneous province (STIP). The STIP erupted over one million cubic kilometres of lava, a large portion of it through a series of flat-lying lava conduits lying below Norilsk and the Talnakh Mountains.
A couple of interesting pics.
[url]http://www.mining-technology.com/projects/norilsk/[/url]