GEL 258 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 258 was granted 22nd March 2007 covering an area of 491km2 over the Phillipson Trough 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 kms thickness overlying a high heat source such as radiogenic granites or iron oxide deposits. The maximum recorded depth in the Phillipson Trough has been 1317m in the Arkeeta 1 drill hole. Based on available seismic data and other drill hole data the maximum depth for the Phillipson Trough is unlikely to exceed 1500m. 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.