A giant sinkhole that closed a stretch of U.S. 24 north of Leadville on Monday has been determined to be a century-old railroad tunnel that collapsed decades ago and was exposed when the soil thawed.
A variety of engineers, maintenance supervisors and geological experts examined the sinkhole and now estimate its depth to be about 100 feet, according to a Colorado Department of Transportation news release. Much of the soil deep in the collapsed tunnel was still frozen until recently; when it thawed, the hole was exposed.
Read more: U.S. 24 sinkhole near Leadville determined to be old railroad tunnel - The Denver Post http://www.denverpost.com/news/ci_21048162/u-s-24-sinkhole-near-leadville-determined-be#ixzz20NsaaAXI
This isn't looking very good.
Looks like the east tunnel of the two here: http://mapper.acme.com/?ll=39.36347,-106.31011&z=15&t=T
The one just to the west has been mothballed since 1997, soon after the UP-SP merger.
Here's a newscast:
http://news.yahoo.com/blogs/lookout/giant-sinkhole-colorado-165704967.html
This has been repaired and completely reopened to traffic within the past few days. i understand it took 50,000 cans of Great Stuff (the expanding foam you spray in cracks around your home) to fix it.
Now, basically the same thing has happened on CO-67 just north of Cripple Creek. In this case, it wasn't a railroad tunnel but rather an old mineshaft. The detour when coming into Cripple Creek from the north isn't as major, since there's a paved county road that takes off north of this point and heads down to Victor where you can then pick up the very south end of 67 into Cripple Creek.