GEL 157 was granted to Petratherm Ltd on 23rd Nov 2004 and this was followed by the granting of an adjacent licence GEL 179 on 28th January 2005. Both licences were contiguous and are located in the Lake Callabonna area at the northern end of the Arrowie Basin. Initially granted for 5 years, the work programmes for both licences were amalgamated and together they formed the Callabonna Hot Rock Project. The exploration target for this area was uraniferrous granitic rocks with associated high heat production rates and all covered by up to 3000 meters of sedimentary rocks acting as an insulating blanket. New gravity data was collected over a distinctly anomalous gravity low and PACE Funding was granted to support the drilling and logging of Yerila 1 which was drilled to 693.5 m within the Callabonna Gravity Low. An MT survey was recorded during the 2nd year of tenure (June 2006) but the final traverse length was only 1600m due to severe electrical storms. A full length MT was run in Dec 2007 for a total distance of 5.0kms in the hope that results may be indicative of a granitic basement at 2000-3000m depth. Modelling of the data produced conflicting results but a depth of 2000m to basement was accepted. Modelling of absolute temperatures and thermal conductivities produced a result the indicated the project was economically unviable. Tenements were finally surrendered on 16/7/2009.