The Owen district is an uplifted fault block, halfway in elevation between the St Vincent Basin and the Mt Lofty Ranges. It is bounded on the west by the Redbanks-Owen Fault and in the east by the Alma Range Fault. This shallow Tertiary basin was considered by the ACI Industrial Minerals Div. to have a gently shelving environment of deposition, and hence to be prospective for very fine to fine-grained sands suitable for glassmaking. 56 shallow R/C-air holes totalling 1003 m were drilled along road verges in the area between Owen and Alma to determine the distribution of fine Tertiary sands. This prospecting work followed on from the drilling definition in late 1993 of the Halbury sand deposit, some 25 km to the north-northwest: the consultant's report on this activity and the results of assessment drilling of 33 holes remains confidential to ACI as the deposit is now the subject of a pegged Mineral Claim. A new fault (here named the East Owen Fault), with about 50 m vertical displacement, was located about 1.5 km east of Owen. East of this fault, drilling showed generally 4-6 m of Quaternary plastic clay overlying 10-17 m of yellow and orange silty fine sand of Tertiary age. Underlying these sediments are very weathered bedrock shales. Heading further east towards the Alma Range fault scarp, the Quaternary plastic clays increase in thickness to over 18 m. The Quaternary clays also increase in thickness southwards towards Hamley Bridge. On the western (downthrown) side of the East Owen Fault, the Quaternary is only 2-5 m in thickness and the Tertiary sediments exceed 28 m in thickness. Drilling also showed that Quaternary clay thicker than 18 m occurs west of the Redbanks-Owen Fault. Bulk samples were beneficiated by ACI to determine their suitability for glassmaking. 14 of 25 samples tested appear to be acceptable for amber-grade glass-sand. Other than the white-grade glass sand previously discovered at Halbury, no new white-grade glass sand deposits have yet been delineated by drilling within the exploration licence area.