Materials suitable for concrete aggregate, railway ballast, road base course, protection of salt field sea wails and rock fill will be required should construction of the petrochemical plant and appurtenant works proceed at Redcliff, 25 km south-southeast of Port Augusta. Results of the auger drilling and back hoe trenching which extended over sections 12, 16, 17, 18, 19, 99, 100, 101, 102, 103, 104, 105, 134 and 170 Hundred Winninowie, are described in this report. No laboratory tests were carried out. Quality assessments of potential construction materials were based only on visual estimation. Further investigation for construction sand is not warranted within the site area. Reconnaissance backhoe trenching east of Mount Grainger intersected a sequence of interbedded sandstone and quartzite, presumed to be part of the Upper Proterozoic A.B.C. Range Quartzite, beneath a blanket of Middle Pleistocene ?Bakara Calcrete and Recent dune sand (Fulham Sand). The calcrete and stronger sandstone are considered suitable for road base and sub-base, embankment slope protection and general rockfill. The quartzite should be acceptable for concrete aggregate and railway ballast. Close-spaced trenching of the proposed quarry site revealed good quality quartzite suitable for all aggregate requirements. Calcrete, soil and talus overburden is less than 0.8 m. Over a strike length of 200 metres, 56,000 cubic metres or 147,000 tonnes of quartzite are indicated in situ above R.L. 27 m, with 8,800 cubic metres or 23,000 tonnes of quartzite available per vertical metre below this level. Quarrying to R.L. 27 M will involve removal of 14000 cubic metres of overlying sandstone, calcrete and dune sand. Deepening to R.L. 17 metres will require benching and the removal of a further 58,000 cubic metres of sandstone. However, portion of the sandstone may prove acceptable for some material requirements. Diamond core drilling of the proposed quarry site is required to test the quality of the quartzite overlying sandstone at depth and to define reserves.