This mine used to be served by part of the old Colorado Southern which became part of the BN many moons ago; I believe that the BN ran it as some kind of shortline if not under the BN colors to connect to the DRGW near Leadville. DRGW had a NG line up to Climax too, but that thing is long...looooong gone.
BN shutter down when the mine closed, and I imagine that the mine probably didnt pump out more than a couple dozen cars a week because the did the ore processing right there in Climax (thus the superfund thing to clean up all those acid ponds), so it wasnt like they were taking out tons and tons of raw ore and shipping it to a mill like you find elsewhere.
In the late 80's / early 90's, some folks bought the line from the BN for pennies. Got a couple of old GP9s outta the deal and set up a tourist line. Have not been over it in several years, but it was spectacular during the fall. I think it is still in operation; was called the Lake County or Leadville somethinguranother, would have to look it up. Google could help you there.
They will probably truck the ore out now; production is only going to be a fraction of what it was in the 1960's by what I have heard. Have a buddy with a house up there and he keeps on top of it because of the impact it might have on property values. On top of that, the DRGW is long gone, the UP has abandoned Tennessee Pass and it is long past the point where getting it back up to standard is worth a couple of carloads a week, even if they could run thru traffic from the Royal Gorge. That wouldnt happen either, when I was at UP there were some uppers who wanted that piece of rail back and there is a tourist line and a quarry shortline in there now that pretty much put the legal brakes on Uncle Pete ever getting his hands on that line again.
Hope it helps! Lots of good books on old CO railroads, probably wouldnt be too hard to find one on the CS that would dish out lots of information on Climax.