Coal mining was an important part of the local economies in the Colorado Front Range through the first half of the 20th century. Many of the towns in our area, including Superior, Louisville, Lafayette and Erie, as well as Frederick, Firestone, and Dacono to the east in Weld County, began as coal mining towns. Nearly 50,000 acres were undermined along the Front Range.
This becomes a concern for home buyers because underground shafts can collapse and cause subsidence on the surface. If this subsidence were to occur under the foundation of your new home, you might have problems. The State Geological Survey has mapped these mines. In Boulder County, geological studies have been conducted, resulting in detailed maps indicating risks of surface level subsidence. These maps are available at most local planning offices. If you find your new home is located in a risk area, you might call the mining section at the State Geological Survey (303-866-2611).
Currently, this is not a significant resale issue in our area. There have been few if any reported cases of home damage resulting from surface subsidence, so most people are unaware of the issue. However, if a subsidence event did occur while you were trying to sell a home in a high-risk subsidence zone, you might have problems. It’s worth checking. The state has a subsidence insurance program available, but there are restrictions, particularly on the age of the home (800-44-MINES).