A programme of exploration was undertaken over an area located to the west of the Leigh Creek and Copley basins, aiming to find possible buried Leigh Creek - type Triassic coal measures within the Beltana Sub-basin. Due to sparse information about the existence, extent and nature of any concealed post - Palaeozoic strata in this area, a photogeological interpretation of likely controlling fault structures was made, followed by a regional gravity survey of 213 line km with stations at 200 m spacing. Based on the resulting gravity data, which identified three weakly prospective low anomalies, 7 exploratory rotary mud holes were drilled for 762 m total penetration, of which 3 intersected thin bands of Late Tertiary? - Early Quaternary black sandy mud and silty lignitic mud. No evidence of Triassic deposition was found, and no correlatable marker units could be recognised above the Palaeozoic basement which might reflect any geological structuring in the sub-basin, and its relationship to the sequence of deposition. However, a number of useful conclusions were made concerning sedimentary facies distribution and possible depositional environments, from both a geographical perspective and temporal basis.