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English: Abandoned mines can pose serious health and safety hazards, such as landslides, erosion, surface instability, and burning coal refuse, which is why the government is required to inspect Abandoned Mine Land (AML) sites and identify any needed remediation. This means that State and Federal AML departments must spend significant amounts of time and money driving to remote sites through rough terrain in order to perform these inspections. Therefore, in September 2012 a proof of concept mission was performed to determine if the Raven sensors could be used to record the area and identify any AML features, such as portals and other dangerous openings. The ability to use Raven data to perform thorough site inspections would significantly decrease the time and expense needed, as well as help inspectors determine the best course for any needed remediation.

This mission was performed by the USGS National UAS Project Office, in cooperation with the Office of Surface Mining, at the Coal Basin mining operation, Pitkin County, Colorado. The topographic basin where the mine facilities were located covers 236 acres and is on the divide that separates the North Fork of the Gunnison watershed from the Crystal River watershed, and drainage from the east side of Huntsman Ridge flows through several tributaries into Coal Creek. All mine portals and surface facilities in the basin are located in Pitkin County, primarily within the White River National Forest, with some interspersed private lands. The underground mine areas extended to the west under Huntsman Ridge into Gunnison County.

Mining of the Coal Basin deposits began in 1895 and continued until 1908, and then in 1956 the Mid-Continent Resources began producing coking coal at this location. The Coal Basin Mine consists of five adjacent underground mines, a rock tunnel entry, a preparation plant, two coal waste piles, one development waste pile, an extensive road system and numerous ancillary facilities. There were five drift mines, driven from the outcrop down-dip through the western flank of Coal Basin and under Huntsman Ridge, that were all interconnected. Coal, men and equipment were brought to the surface through one bore of the rock tunnel. The Coal Basin area also has diverse climate characteristics caused by its precipitous rise in elevation, the lowest point was the coal preparation plant at 8,000 feet, while the highest point is along Huntsman Ridge at 11,852 feet. As a result, temperature, precipitation, and wind conditions are quite variable throughout the disturbed area.

During this mission a GoPro Hero 2 camera mounted on the Raven was used for the first time. After successfully acquiring this new imagery, it was later evaluated for use in 3D photogrammetric modeling software. As a result it was determined that this type of image data provided a better way to use structure from motion techniques.

Overall, this mission successfully demonstrated the value of utilizing sUAS technology with mounted cameras to assist in the extremely vast and difficult job of monitoring and inspecting AML areas. Several technical advances were also shown as part of this mission including the ability to use a retrofitted camera on a Raven and the ability to fly at elevations above 10,000 feet, which is very important to support the many high elevation DOI lands in the western United States.