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  • Airborne Electromagnetic data are being acquired by Geoscience Australia in areas considered to have potential for uranium or thorium mineralisation under the Australian Government's Onshore Energy Security Program (OESP). The surveys have been managed and interpreted by Geoscience Australia's Airborne Electromagnetic Acquisition and Interpretation project. In contrast to industry style deposit scale investigations, these surveys are designed to reveal new geological information at regional scale. The Frome Embayment AEM survey was acquired using the TEMPESTTM AEM system by Fugro Airborne Surveys under contract to GA. The survey covers a total of 32 300 line km and an area of 95 450 km2, the largest AEM survey by area ever flown in Australia. This data release contains the Phase-1 data, that is, contractor quality-controlled and quality-assessed data fas well as the Phase-2 data, that is Geoscience Australia layered earth inversion (GA-LEI) data and derived products for the Callabonna Uranium Infill Area. The data and products described in this report are available from the GA AEM website.

  • Between the 31st of March 2013 and the 15th of May 2013, Fugro Airborne Surveys Pty. Ltd., (FAS, now known as CGG Aviation (Australia) Pty Ltd) undertook a TEMPEST® airborne electromagnetic and magnetic survey over the South West Coastal Plain and the South Coast areas of Western Australia. There were four separate project areas: (1) Swan Coastal Plain, (2) Scott Coastal Plain, (3) Albany, (4) Esperance. The survey is designed to map groundwater resources and assess aquifer sustainability in four separate areas of southern WA. The survey areas are located in: 1. Esperance: Traverses spaced 300 & 600 metres apart in a north-south direction at 120 metres above ground level totalling 1,133 line km. 2. Albany: Traverses spaced 300 & 600 metres apart in a north-south direction at 120 metres above ground level totalling 2,163 line km. 3. Scott Coastal Plain: Traverses spaced 600 metres apart in a ne-sw direction at 120 metres above ground level totalling 2,980 line km. 4. Swan Coastal Plain: Traverses spaced 600 metres apart in a nw-se direction at 120 metres above ground level totalling 2,303 line km. The total coverage of the survey amounted to 8,579 line kilometres. The survey was flown using a Shorts Skyvan (SC3-200) aircraft, registration VH-WGT, owned and operated by FAS. The survey was commissioned by the Western Australia Department of Water, and was managed by Geoscience Australia. The Survey received funding from the WA Government's Royalties for Regions program to assess, plan and investigate regional water availability in Western Australia. The data release includes the final contractor supplied datasets. The data are available from Geoscience Australia's web site free of charge. Each data package includes: 1. Point-located electromagnetic data with associated position, altimeter, orientation, magnetic, and derived ground elevation data. These data are in ASCII column format with associated ASEG-GDF2 header files. 2. Point-located conductivity estimates derived using the EM Flow® conductivity depth imaging (CDI) algorithm with associated position, altimeter, magnetic, and derived ground elevation data. Data include the conductivity estimate for each 5 m interval and selected depth slices. These data are in ASCII column format with associated ASEG-GDF2 header files. 3. Gridded data, at 60 or 120 m cell size, for the conductivity depth slices derived from the EM Flow® CDI data, magnetics and elevation data in ER Mapper® binary raster grid format with associated header files. 4. Graphical multiplots, in PDF format, for each flight line showing EM Flow® CDI sections and profiles of electromagnetic data, magnetics, monitors, height and orientation data. 5. Operations Report. 6. Metadata and License files.

  • Identification of groundwater-dependent (terrestrial) vegetation, and assessment of the relative importance of different water sources to vegetation dynamics commonly involves detailed ecophysiological studies over a number of seasons or years. However, even when groundwater dependence can be quantified, results are often difficult to upscale beyond the plot scale. Consequently, quicker, more regional mapping approaches have been developed. These new approaches utilise advances in computation geoscience, and remote sensing and airborne geophysical technologies. The Darling River Floodplain, western New South Wales, Australia, was selected as the case study area. This semi-arid landscape is subject to long periods of drought followed by extensive flooding. Despite the episodic availability of surface water resources, two native Eucalyptus species, E. camaldulensis (River Red Gum) and E. largiflorens (Black Box) continue to survive in these conditions. Both species have recognised adaptations, include the ability to utilise groundwater resources at depth. A remote sensing methodology was developed to identify those communities potentially dependent on groundwater resources during the recent millennium drought in Australia.

  • Geoscience Australia (GA) has recently completed two regional-scale Airborne Electromagnetic (AEM) surveys: one in the Paterson Region, WA; and the other in the Pine Creek region, NT. These surveys provide AEM data at line spacings of 200 m to 6 km covering an area greater than 110 000 km2. The surveys were designed to promote more detailed investigations by the mineral exploration industry. An inherent risk in using AEM surveys is that the depth of penetration of the primary electromagnetic field is highly variable. Although forward modelling is undertaken before the AEM campaign, the depth to which we can reliably invert the AEM signal to generate conductivity models is not known until after the survey is flown. In order to estimate the penetration depth of the AEM surveys, we calculate the depth of investigation (DOI) based on the GA layered-earth inversion algorithm, which is influenced by both conductivity measurements and reference model assumptions. We define the DOI as the maximum depth at which the inversion is influenced more by the conductivity data than the reference model. We present the DOI as a 2D grid across both the Paterson and Pine Creek AEM surveys. Labelled the 'AEM go-map', the DOI grid helps to promote AEM exploration by decreasing risk when industry undertakes follow-up surveys within these regions.

  • During 2008 and 2009, and under the Australian Government's Onshore Energy Security Initiative, Geoscience Australia acquired airborne electromagnetic (AEM) data over the Pine Creek Orogen of the Northern Territory. The survey area was split into three areas for acquisition. VTEM data was acquired in the Kombolgie area east of Kakadu National Park (this data set) between August and November 2008. TEMPEST data was acquired west of Kakadu National Park with the area split in two to facilitate the use of two aircraft: the Woolner Granite area in the north was acquired between October and December 2008; and the Rum Jungle area adjoining to the south, was acquired between October 2008 and May 2009. The main purpose of the surveys was to provide additional geophysical/geological context for unconformity style uranium mineral systems and thereby promote related exploration. The survey data will also provide information on depth to Proterozoic/Archean basement, which is of general interest to explorers, and will be used as an input into ground water studies in the region. This dataset includes the subscriber company data K1 K2 and K3.

  • The Pine Creek AEM survey was flown over the Pine Creek Orogen in the Northern Territory during 2008 and 2009 as part of the Australian Government's Onshore Energy Security Program at Geoscience Australia (GA). The survey provides pre-competitive data for enhancing uranium and other mineral exploration. Flight line spacing was 1666 m and 5000 m covering an area of 74,000 km2 (roughly the size of Tasmania) which hosts several uranium deposits, including the Ranger Uranium Mine, Rum jungle, Ranger and Nabarlek. The region is also prospective for metals including copper, lead, zinc, gold, tin, rare earths, tantalum, tungsten, molybdenum and nickel. The Pine Creek AEM survey comprises three areas: Kombolgie to the east of Kakadu National Park; Woolner Granite near Darwin; and, Rum Jungle to the west of Kakadu National Park. Collaboration with the National Water Commission and eight private infill companies brought an additional investment of approximately $1 m into the survey, with follow-up exploration equal to or exceeding this amount. The Woolner Granite and Rum Jungle survey area data were acquired using the TEMPEST fixed wing AEM system. The acquisition and processing were carried out by Fugro Airborne Surveys Pty. Ltd., under contract to GA. The Woolner Granite and Rum Jungle surveys were flown between August 2008 and May 2009 and the data were publicly released by GA in July and September 2009 respectively. In the Kombolgie survey area, the data were acquired a by Geotech Airborne Pty. Ltd. using the VTEM helicopter AEM system. The survey was flown between August and November of 2008, and additional calibration flights relating to the survey were flown in April 2009. The Kombolgie data were publicly released by GA in December 2009.

  • Conceptual MAR targets in the Broken Hill region were identified in previous investigations (Lewis et al., 2008; Lawrie et al., 2009a). In the BHMAR Phase 2 study, the project team is required to make recommendations on the presence and suitability of potential MAR sites with an 80% confidence level. While this will be attempted through a combination of AEM, borehole analysis and seismic reflection data acquisition, AEM is the prime dataset required to map the aquifer targets in 3D.

  • At present calcrete-hosted uranium deposits constitute only 1% of Australia's uranium resources. Most known deposits (nine out of eleven) are associated with Cenozoic drainage systems in the Yilgarn Craton, and similar drainage systems in the Gascoyne Province and Ngalia Basin. In the Paterson region calcrete-hosted uranium mineralisation has been reported only in the Lake Waukarlycarly area but no major deposit of this type has yet been found.

  • During 2008 and 2009, and under the Australian Government's Onshore Energy Security Initiative, Geoscience Australia acquired airborne electromagnetic (AEM) data over the Pine Creek Orogen of the Northern Territory. The survey area was split into three areas for acquisition. VTEM data was acquired in the Kombolgie area east of Kakadu National Park between August and November 2008. TEMPEST data was acquired west of Kakadu National Park with the area split in two to facilitate the use of two aircraft: the Woolner Granite area in the north (this data set) was acquired between October and December 2008; and the Rum Jungle area adjoining to the south, was acquired between October 2008 and May 2009. The main purpose of the surveys was to provide additional geophysical/geological context for unconformity style uranium mineral systems and thereby promote related exploration. The survey data will also provide information on depth to Proterozoic/Archean basement, which is of general interest to explorers, and will be used as an input into ground water studues in the region.

  • Data acquired as part of the Kombolgie VTEMTM Airborne Electromagnetic Survey have been inverted using a layered earth inversion algorithm. Interpretation products have been derived from the inversion results. The inversion results and derived products have been released by Geoscience Australia as a digital data package. The survey was funded under the Australian Government's Onshore Energy Security Program, and was managed and interpreted by Geoscience Australia's Airborne Electromagnetic Acquisition and Interpretation Project. The Kombolgie survey area, in the Pine Creek Orogen of the Northern Territory, covered sections of the Cobourg Peninsula, Junction Bay, Alligator River, Milingimbi, Mount Evelyn, Katherine, and Urapunga 1:250 000 map sheets. It covered a total of 8 800 line km and an area of 32 000 km2. The data were acquired under contract by Geotech Airborne Pty. Ltd. using its VTEMTM helicopter-borne electromagnetic system. The inversions were carried out using the GA-LEI layered-earth inversion software developed at Geoscience Australia. Products include the layer conductivities, depth and elevation slices, and sections. The products are in digital form in both point-located and gridded formats. They are available for download from the Geoscience Australia website.