A largely soil and dune-covered area bordering the eastern side of the Nullarbor Plain near Lake Tallacootra was investigated initially for possible Precambrian metasedimentary iron ore ocurrences, that may be associated with a number of narrow regional north-east trending aeromagnetic anomalies which might be caused by shallowly subcropping banded iron formations. Contract photogeological office studies and follow-up field reconnaissance using a helicopter failed to locate any indications of ferruginous rocks, and confirmed a great paucity of outcrop in the district. It was decided to abandon the original exploration concept in favour of another, by conducting shallow stratigraphic drilling principally aimed at looking for potentially economic deposits of Tertiary or Permian coal within the scantly drilled local cover sediments. After lengthy planning and logistical delays, a programme of RC drilling (22 holes, total 1132 m) was carried out between April and June 1976 using a Schramm dual-tube (air/water blast) RC rig to try to circumvent several anticipated problematic ground conditions. The holes were geologically logged and sampled every metre, and were probed with a gamma ray tool for stratigraphic correlation purposes and to detect any possible uraniferous deposits. Basement, comprising granite and/or gneissic rocks, was encountered at the bottom of 8 drillholes, while coarse sands derived from these basement highs were reached in another 4 holes. No iron-rich basement rocks were found. The basement surface relief is markedly uneven, with a maximum variation of at least 80 m over 4 km being observed. Contouring of the limited depth-to-basement data suggests that the cover is deepest in the centre of the licence and deepens more going towards the south from the area drilled. Within the cover, the majority of the deeper unconsolidated sediments intersected by drilling appear to conform to paralic facies of the Middle Eocene Pidinga Formation. Poor quality lignite seams up to 3+ m thick were found in several of the BHP drillholes, notably T9, T14 and T20. Samples of the visually best lignite and of lignitic clays, silts and sands from the two former holes were proximate assayed for their percent bulk moisture, volatile matter, fixed carbon, and ash, while a lignite sample from hole T17 was also separately distilled in an autoclave to determine its hydrocarbon generative capacity through hydrogenation. The relatively low ash (< 20%) lignite from two seams in hole T9 returned an average 47.7% volatile matter and 38.4% fixed carbon. Hydrogenation testing yielded results very similar to those obtained using Loy Yang brown coal from the Gippsland Basin. Nevertheless, the apparently poor seam continuity in the lignite, its predominantly thin seams and its moderate to high ash content appeared to render it unsuitable for use as power station boiler fuel, so therefore BHP elected to surrender its interest in the area.