A detailed spatial analysis recently performed by the Geological Survey of South Australia (GSSA) shows that at Mintabie, after approximately 40 years of mining carried out to look for opal, an area totalling less than 2 square km has been intensively mined. But a conservative estimate made by GSSA of the areal extent of ground with greatest opal prospectivity which lies within the bounds of the Mintabie Precious Stones Field (MPSF) is 20 square km. Within this high prospectivity area, it is predicted that searching for undiscovered opal occurrences will support mining activities for 400 years at the levels of intensity already experienced in its working lifetime to date. A complementary geospatial analysis, performed in 2002, revealed that further prospective areas totalling 44 square km lie within the MPSF. The total value of the opal mined at Mintabie to 2016 has been estimated by the South Australian Government to be 412 million Australian dollars (A$412M). An area-based analysis conducted herein concludes that this amount of production is less than 10% of the likely total contained opal at Mintabie. The opal resource in Mintabie, including the opal already found, is therefore estimated to have a raw opal value of >A$4B.