Posted: Mar 7, 2013 7:21 AM by Maddie Garrett
After a man in Florida was swallowed by a sinkhole that opened underneath his house, experts here say sinkholes also can occur in Colorado, but for different reasons and on a smaller scale.
The deadly chasm in Florida was caused by shifting limestone and water. Here in Colorado there's very little limestone, but a lot of underground mines.
Below the streets and homes of Colorado Springs lies an underground network of mines that stretches for miles and covers thousands of acres.
"For example, the Rockrimmon area, there's 3,000 acres of these (mine) shafts, and upwards to 50 to 70 miles of shafts around the Colorado Springs area, so it's a substantial amount," said Dave Futey, Manager of the Western Museum of Mining and Industry.
The mines, a huge part of Colorado Springs history, might be abandoned and long forgotten, But Futey explained how the mines have a way resurfacing in present day.
"Horizontal shafts still remain below ground and are obviously unfilled, and if the roofs of those shafts collapse then you have a funneling effect. And depending on how close those shafts are to the surface you can have an impact on the surface," said Futey.
Those effects can take form as sinkholes, depressions in the ground, or even cracks in your home and tilted foundations. And the experts say these results are not uncommon.
and the experts say --- these effects aren't uncommon.
"In the past in Colorado Springs there have been a lot of little sinkhole problems opening up in yards and driveways in these high risk areas where the mines are fairly close to the surface," said Bruce Stover, Director of the Office of Active and Inactive Mines with the Colorado Division of Reclamation, Mining and Safety.
But unlike the unpredictability of Florida, Colorado state officials know where the network of mines are and are even starting to fill in some of the high risk areas to prevent sinkholes.
Stover said there are about 3,600 homes in Colorado Springs that are considered at risk of mine subsidence, the collapsing of part of a mine.
But most of those are categorized as "low risk." Only 271 homes are "high risk" and 265 are considered at "moderate risk."