From The Mountain Mail (Joe Stone):
Enhanced geothermal systems require injecting fluid into hot underground rock to create fractures. After rock is fractured, water can be injected and pumped back to the surface after it has been heated by the hot rock.
Geophysics Field Camp supports the project by gathering data helping refine and validate imaging technology, [Mike Batzle, professor of geophysics at Colorado School of Mines] said. The imaging project will provide an overall understanding of the Mount Princeton geothermal system and “identify potential drill sites to optimize the geothermal yield of the valley,” according to the energy department on-line project description.
It gives students a real-world problem to which they must apply classroom knowledge, Batzle said. Students have used a variety of techniques to help map underground water and heat resources. Electrodes on the ground can identify hot water flow within 60 feet of the surface, including “one really big one up above Deer Valley Ranch near the (Chalk) Cliffs,” Batzle said. Batzle said the dramatic white cliffs consist not of chalk but kaolinite, “an alteration of granite that indicates a stable hydrothermal system active for thousands of years.” Field camp students have also been gathering data on deeper features using seismic and gravity imaging that can provide a subsurface map to the bottom of the basin, Batzle said. He said field camp studies are not directly concerned with hot water flow, but with deep geologic structure of the basin at the northern end of the Rio Grande Rift. The rift formed where tectonic plates were pulling apart. Near Mount Princeton, hot water reaches the surface along fractures at intersecting faults.
From a scientific viewpoint, Batzle said, researchers are “more interested in what’s happening in the center of the valley.” He said a deep borehole is needed to determine if the geothermal resource is hot enough to support generation of electricity. He said state-owned land near the center of the valley could be a potential location for drilling. Drilling on the Colorado-owned parcel would require state approval, but the location would have none of the split-estate issues that generated protests from landowners potentially affected by the Mount Princeton geothermal lease…
Copies of Geophysics Field Camp reports from 2007-2010 are available on-line at http://inside.mines.edu/GEO-Field-Camp