Extensive literature and geological and geochemical field investigations of historic mines and prospects at the Mount Grainger and Oodla Wirra Goldfields have failed to disclose any remaining economic gold occurrences. The sparse native gold occurs within fine-grained Adelaidean sediments in a hydrothermal setting which appears to be lithologically controlled, possibly forming discontinuous blade-like orebodies. The narrowness of the ore zones and the random, small and thin host limonitic and sericitic quartz veins would require highly selective mining of what is uniformly very low grade ore (the highest assay value obtained from bulk sampling of mine dumps was 9.6 dwt/ton Au, from an isolated portion of the Dustholes line-of-lode). In general, the goldfield mineralisation is not nearly as extensive as the spread of past workings would indicate : to bear out this conclusion, there is no evidence of extensive wallrock alteration associated with the narrow gold-bearing veins, and little if any alluvial gold in the beds of creeks draining the major old mining sites.