Stratabound, metasedimentary iron ore was the principal target of exploration undertaken by BHP over a large area surrounding the Moonabie Range that extends along strike and borders the north-western side of Spencer Gulf. Base and precious metals were secondary targets. Following the acquisition of a 5500 line km regional aerial magnetic and radiometric survey in late 1976, and some 135 line km of detailed ground magnetic and gravity traversing of previously defined anomalous areas, an initial four vertical RAB percussion drillholes totalling 258 m tested the Myola aeromagnetic anomaly, 5 km east of Iron Baron. Gabbro, trachyte and metasediments were encountered, but no iron formations. Anomalously high background copper (420 ppm Cu) was found in acid volcanic interbeds to haematitic schist drilled in hole EEP 3. Subsequently, another 10 deep vertical rotary percussion drillholes totalling 698 m tested a number of similar magnetic targets which had been identified in the area east and south-east of Iron Baron. No iron ore was intersected in any of the holes, other than minor amounts of magnetite in gneisses and amphibolites, which were regarded as sufficient to cause the observed aeromagnetic anomalies. The last of these deeper drillholes, EEP 15 taken to TD 60.5 m, tested the Cowell aeromagnetic anomaly, 6 km west of Cowell. Coarse-grained magnetite in metajaspilite was intersected below 56 m of unconsolidated Cainozoic sediments, but because of the depth of cover, no further work was carried out. Reconnaissance geological mapping at 1:50,000 scale was carried out from Myola to south of Moonabie, and detailed mapping at 1:10,000 scale was performed in the vicinity of Moonabie Hill. A belt of hitherto unrecognised, mainly buried acid volcanic rocks, newly termed the "Myola Volcanics", which yielded the copper anomaly in drillhole EEP 3, was tested by 34 shallower vertical RAB holes (total 524 m) drilled to basement on 6 traverses across the northern part of the licence. This drilling revealed isolated background copper values to 600 ppm Cu, and anomalous arsenic was found in hole MY2. 239 geochemical samples of residual soils were also collected along 11 traverses chosen to give a complete coverage of the different rock types and stratigraphic units identified in the Moonabie-Myola area. However, assay values obtained for base metals and gold showed little variation above background levels. By late 1978, BHP concluded that its work in the Moonabie Range area had provided little encouragement for undertaking further iron ore or base metals exploration, and so it allowed licence tenure to lapse at expiry.