The starting point for creating a new geothermal reservoir is a deep well into hot, dry rock. Well NWG 55-29, drilled by Davenport Newberry in 2008, is well suited as the foundation for a geothermal reservoir. It is 10,060 feet (3066 m) deep into hot rock with very low water permeability.
On October 18 the pumping equipment was running and a water pressure of 1600 psi (10.9 MPa) was built up inside NWG 55-29. The diagnostics (pumping rate, microseismic detectors, etc.) indicated that hydroshearing and expansion of a network of cracks in the hot rock had begun. However, an unexpected night of freezing weather on October 20 damaged some of the auxiliary equipment, leading to a temporary shutdown of operations. AltaRock hopes to resume testing the stimulation process later this week. The following video gives a very good (if slightly lengthy) description of the project.