An area of the southern Flinders Ranges extending from Crystal Brook northwards to the Mount Remarkable Range has been explored for possible economic stratabound magnesite occurrences that may outcrop within Adelaidean metasediments. The known mineralised Collaby Hill area was selected by Magnesium Minerals for doing magnesite exploration and assessing the local potential for development of mining operations, due to its close proximity to transport and processing infrastructure, existing mining activity (benefit of possible shared utilities), and the land being less environmentally sensitive than other parts of the southern Flinders Ranges. During the first licence year, Magnesium Minerals Pty Ltd (MMPL) conducted geological mapping within the tenement, to ground truth its earlier assessment of the utility of Hymap hyperspectral thermal imagery to delineate places where past folding and structure movements may have locally increased the thickness of any sedimentary magnesite beds hosted by the Skillogalee Dolomite formation. Five traverses were made across the known Collaby Hill magnesite occurrence, which is situated on the western limb of a large north-south striking syncline that plunges gently southwards. The apparent thickness of the Skillogalee Dolomite on this fold's western limb is much greater than than it is on the eastern limb. Inspection of the western limb revealed that several parasitic Z-folds are present along it, resulting in structural thickening and repetition of dolomite beds. Direct mapping of the ten known magnesite beds was not possible, because of their limited outcrop due to the effects of prolonged weathering, and the obscuring effects of thick vegetative growth and transported soil cover. Nevertheless, it was possible to trace single thin (to 1.5 m wide) magnesite interbeds for a distance of up to 2 km, so it is thought that they must continue for much further than this. In the field, magnesite was often observed as weathered float rock. This rock has a bright (blue tint) white colour that makes it easily identifiable from a distance. The texture of the float rock is very similar to calcrete, however, the magnesite's brightness and higher density can be used to distinguish between the two. Often this float rock also has a cracked, desiccated-looking weathered surface. In several places float rock could be followed in narrow bands along strike, indicating the presence of a magnesite bed beneath. Occasionally, outcrops of fresh magnesite were observed, confirming the bed's presence as indicated. A section of the Skillogalee Dolomite exposed in an old quarry in the Beetaloo Valley, which is located on the eastern limb of the main syncline, was examined to provide an overview of the magnesite beds. Here, where formerly they had been mined to yield a reported 50 t of magnesite, they commonly grade from a white to creamy coloured cryptocrystalline mud at the base through to pebble conglomerate at the top. The conglomerate facies is almost 100% magnesite, with the pebbles and matrix formed of the same microcrystalline material. The clasts in the coarser conglomerates are generally elongate and plate shaped, up to 10 cm in length. The outcrop extends for a distance of about 70 m, and consists of reasonably fresh firm rock, apart from some softer siltier beds which show considerable weathering in places. A stratigraphic section was logged and measured, and the sedimentological characteristics of the magnesite were carefully noted and photographed. A discussion is presented comparing the current observations and interpretation of magnesite genesis with the findings of past researchers and mappers working on the host sequence throughout the Flinders Ranges. It was concluded that, due to chevron folding, the amount of magnesite present at near surface levels on the western limb of the main syncline may be triple that observed in the undeformed package examined in the quarry. During licence Year 2, the licensee undertook detailed structural mapping of magnesite beds and enclosing strata exposed along the western limb of the syncline. Interpretative geometric cross sections were drafted to show the disposition of the strata of interest as one moves down plunge along the fold. A detailed, 1:4250 scale geological map which was previously made in November 2003 by University of South Australia B.Sc.(Hons) student Robert Dart is included to show the full extent of local structures evident in the Skillogalee Dolomite sequence and the surrounding rock types. During licence Year 3, no work was done. Tenure of EL 4639 was allowed to lapse at expiry at year end.