The Stage 1 feasibility study carried out during February-May, 1973 has included regional groundwater studies, pumping tests, logging and laboratory tests on drill cores, slope stability analyses, preliminary design of pit slopes and dewatering systems, and planning and estimating for the Stage 2 studies. A geotechnical assessment of a representative part of the orebody area (Area 106) was undertaken by surveying the existing water bores, measuring water levels and sampling local groundwaters, analysing historical rainfall records, drilling 3 cored holes to locate aquifers and provide samples for engineering tests, and conducting pump tests of 19 and 48 hours duration on the Unit 3 (Beverley Unit) sands, with water level monitoring in the pumped well and in 6 observation wells. This work has confirmed the general geological and groundwater situation already assumed, i.e. up to 100 m of very strong, clay-bound sands and gravels, and thinner clays overlying a lenticular sand bed which forms a pressure aquifer and also contains most of the ore. Mudstone with very weak rock properties occurs beneath this sand at depths of 120-135 m. Stability analyses indicate that slopes of 1.2:1 or about 40 degrees should be stable in the upper soils during the proposed period of mining. Flatter slopes of 1.75:1 are assumed for the lower sandy materials, but these might be steepened locally over short lengths during ore mining, and then stabilized by placing overburden at the toe. From the stability analyses and short duration pump tests it is considered that the main orebody sand will require dewatering, but the extent of dewatering will depend upon the type of excavation equipment to be used. For conventional equipment (scrapers, front-end loaders) the sands would best be well drained, probably requiring up to 8 deep wells pumping for 6 to 12 months prior to the pit excavation reaching the 100 m level. For excavators designed to handle wet materials the aquifer need only be de-pressured prior to the pit floor reaching this level, which probably requires a maximum of 3 deep wells pumping for about 2 months. Shallow wells drilled from a berm above the sands could be used to control water in the sands during their excavation. With either arrangement, some deep wells on the western side of the pit may need continual pumping at a low rate after the main pit area has been dewatered or depressured. Recommended ground investigations for Stage 2 include a pumping test of 4 to 5 weeks duration to check the feasibility of the two alternative dewatering proposals. Additional coring, laboratory testing and stability analyses are also recommended.