The Dudley pegmatite, located a short distance inland near the eastern tip of Kangaroo Island, ~10.5 km south-east of Penneshaw township, was worked historically during the 1890s and early 1900s for gem tourmaline, ceramic-grade feldspar and silica, and for kaolin to use in brickmaking. Recently, the remaining potential of this outcropping and subcropping rock body for yielding commercial quantities of semi-precious gem tourmaline has been re-assessed by a Queensland-based mineral specimen selling, lapidary supply and jewellery company, Entia Gems and Jewellery. Inspection and sampling work has been carried out there under tenure of an Exploration Licence, following the successful conclusion of negotiations made with the current private landowner regarding obtaining approval for access and the payment of compensation for causing temporary land disturbance. Based on their prior extensive literature research about the Dudley pegmatite, and on contemporary knowledge of the usual spatial nature of pegmatite mineral zoning, the licence operators identified multiple shallowly buried, potentially gem pocket - bearing rock zones trending parallel to the strike of the previously mined pegmatite mass. These mostly appeared to lie along (but were not limited to) the outer margins of the Dudley pegmatite. Historical mining records indicated that gem tourmaline was consistently produced from clay-filled vughs, often encountered at a depth of 2 metres or greater. One such productive area, named the “Gem shaft”, not only produced gem tourmaline to a mined depth of 50 feet below surface, but also yielded more gem pockets within adjacent zones in the subsurface that were worked by tunnels driven along the strike of the pegmatite. The licence operators also recognised that to date, the vast majority of historic mine pits and the more recent prospectivity appraisal trenches has been sited somewhat haphazardly, were only very shallow, or had been dug across the strike of the pegmatite. In response to the future work recommendations made in 1987 by John Keeling of the SADME Mineral Resources Branch in his consultancy report RB 87/119 prepared for a previous explorer, Roebuck Resources, who examined the deposit over the period 1987-1989, Entia Gems and Jewellery has recently tested the potential for deeper gem tourmaline zones to exist running parallel to the strike of the Dudley pegmatite. The new work consisted of digging several exploratory costeans using a 25 ton hydraulic excavator, at five selected target locations guided by interpretations of historical mine data plus the field mapping which had been undertaken by Roebuck Resources. Trenching began in January 2016, on target zones E2 and E4 located in an open farm paddock. Heavily weathered pegmatite was struck, with no coloured tourmaline evident in either excavation. Both trenches were subsequently backfilled and rehabilitated. Next, the E1, E3 and E5 target zones all located within the fenced-off historic mining area were trenched. Here the undisturbed pegmatite is fresh but friable below 1 m depth. Zones E3 and E5 were also found to be barren of coloured tourmaline, so the trenches dug there were immediately backfilled and rehabilitated. Target zone E1, centred on the Gem shaft and surrounding pitted area, needed some minor preparatory earthworks to be completed before the deeper undisturbed level there could be investigated. Initially, regrowth scrub and dead vegetation had to be cleared out of the abandoned main open cut to allow better access for the excavator. A series of benches were cut around the walls of the open cut to make the area safer, and then historical mine tailings were removed from the base of the open cut to expose its floor. Remnants of previously mined quartz-lined cavities were discovered in the walls of the open cut, while occurrences of coarse muscovite mica and vuggy quartz were frequently encountered in both its walls and floor. A rock breaker was used to open up cracks in the pegmatite around these areas, in the hope that gem tourmalines might be discovered. This proved successful, with two areas of coarse grained pegmatite found to contain several collapsed vugh fill occurrences of coloured tourmaline crystals ranging from fractured green pieces to small gem quality green stones (rare), plus dark blue/indigo tourmaline crystals. 3.2 kg of friable grey/red clay uniformly mixed with decomposed feldspar, quartz, muscovite mica and tourmaline fragments was removed from these vughs for gem mineral processing and evaluation. Upon completion of the sampling, the open cut was backfilled with the historical tailings. The sampled rock material was processed via mechanical sieving through 0.2 cm, 0.5 cm and 1 cm metal sieves, with accompanying high pressure water washing. After sorting through the residual washed and sieved mineral crystals, the following grades of gem tourmaline were separated: - 472 g of fractured/weathered green (elbaite) or dark blue/indigo (indicolite) crystals ranging in size from 0.2 cm to 3 cm; - 122 g of partly fractured elbaite and indicolite crystals ranging from 5 mm to 25 mm in maximum length; - 61 g of un-fractured elbaite and indicolite “needles” ranging in size from 1 to 2.5 mm diameter, and up to 20 mm long. One, 10.2 mm X 5 mm gemmy green elbaite weighing 0.6 g was isolated from this fraction and was later faceted to produce a high grade jewel. As a discrete monomineralic gem find within the E1 zone, one collapsed vugh produced 306 g of fractured indicolite only crystals, the largest being 55 mm X 34 mm and weighing 87 g. In addition to the collapsed vugh fill material, 1.1 kg of highly fractured pegmatite matrix mineral specimens were collected from the E1 zone. These were composed primarily of quartz, feldspar and muscovite mica, associated with fractured elbaite crystals ranging in size up to a maximum of 7 mm X 22 mm. [ N.B. Scaled colour photographs of all of the recovered gem crystals and tourmaline-bearing rock material described above are included in the EL 5474 second annual report ]. The licence operators have concluded that the Dudley pegmatite holds some potential for producing a quantity of gem tourmaline from rock located within (and adjacent to) the Gem shaft open cut. They recommend that further investigation of the E1 target zone be undertaken by carefully prospecting the walls and floor of the open cut for occurrences of coarse mica and smoky quartz, which are regarded as indicators for hidden tourmaline mineralisation. They also state that the tourmaline samples recovered by the latest trench sampling, if given further lapidary processing steps such as cutting, polishing or mineral specimen preparation techniques, could be used in the jewellery industry or as collectible mineral specimens.