GEL 251 was one of 6 geothermal licences granted to Proactive Energy Developments Ltd (PED) covering areas of the central and northern Gawler Craton during 2006/2007. In early 2007 PED changed their name to Granite Power Ltd. GEL 251 was granted 17th Oct 2006 covering an area of 479km2 over the Prominent Hill area for an initial term of 5 years. No field activities were conducted but a review of the geothermal prospectivity of all geothermal tenements was completed by Earth Resources Australia (ERA). Target areas for a geothermal resource were nominally a cover sequence of sedimentary rocks of 2-4 km thickness overlying a high heat source such as radiogenic granites or iron oxide deposits. Based on available drill-hole data it was interpreted that the post Proterozoic cover was unlikely to exceed 250 meters. It was further deemed that it was unlikely that heat bearing granites occurred in the licence area. Based on these 2 issues, lack of cover depth and lack of heat producing granites saw the licence surrendered on 10th August 2007 before the end of the first licence year.