This report details geothermal resource exploration done for Arizona Public Service and the U.S. Department of Energy in 2005 to evaluate the geothermal resources of the Clifton Hot Springs area in Greenlee County, eastern Arizona for electric power production. The intent of the evaluation was to determine the local geologic controls of the geothermal system and, using publicly available data and original mapping performed for this project, to recommend locations for Controlled Source Audiomagnetotelluric (CSAMT) cross sections. The results of the geophysics were then combined with the geologic mapping to site three gradient holes, two of which were drilled to depths of 635 feet and 1,000 feet, respectively.

This summary report overviews a State of Arizona and U. S. Department of Energy funded drilling project to determine if near-term hot dry rock (HDR) geothermal potential exists in the eastern portion of the White Mountains region of Arizona. A 4,505 feet deep slim-hole exploratory well, Alpine1/Federal, was drilled within the Apache-Sitgreaves National Forest at Alpine Divide near the Alpine Divide camp ground about 5 miles north of Alpine, Arizona in Apache County (Figure 1). A comprehensive technical report, in two parts, details the results of the project. Part 1, Alpine1/Federal, Drilling Report, discusses the drilling operations,
logging program, permitting and site selection for the hole. Part 2, Temperature Gradients, Geothermal Potential, and Geology, summarizes the temperature gradients, heat flow, geothermal potential, and subsurface geology.