Airborne electromagnetic (AEM) data are an immensely useful tool for mapping cover thickness and under cover geology in Australia. The regional AEM surveys conducted by Geoscience Australia (GA) are an ideal starting point for integrating legacy AEM datasets across a range of scales with other information, e.g. borehole stratigraphy and shallow seismic data, to add to a national cover thickness map. Geoscience Australia is working towards this end as part of the UNCOVER Initiative.

A test site for airborne gravity (AG) systems has been established at Kauring, approximately 100 km east of Perth, Western Australia. The site was chosen using a range of criteria that included being within 200 km of Jandakot Airport in Perth where most of the airborne systems would be based at one time or another when operating in Australia, being free of low level flight restrictions, having minimal human infrastructure in the central 20 by 20 km area, and the presence of gentle to rolling terrain rather than deeply incised topography or an extensive flat plain with very low relief. In anticipation of catering for airborne gravity gradiometer (AGG) systems, the site was required to have a gravity gradient feature with clear response in the wavelength range of 100 m to 2 km in a 5 by 5 km core region. In addition to catering for AGG systems, the site may also be used in the future to demonstrate and compare various airborne magnetic systems (TMI, vector, and gradient tensor systems) and digital terrain mapping systems.

The Natural Fields EM Forum was held in Brisbane, Queensland, Australia, on February 26, 2012, in conjunction with the ASEG 22nd International Geophysical Conference & Exhibition 2012. The forum was organised to review the current state of development of natural field EM methods (NFEM), being those methods that utilise the ambient electromagnetic field rather than deploying an additional active source as an element of a survey. NFEM methods are used to acquire data from which various parameters can be obtained to help interpret the electrical characteristics of the subsurface.

Short article describing detection of interpreted unconformity between Coolbro Sandstone and Rudall Complex rocks near the Kintyre uranium deposit, Western Australia

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 Paterson airborne electromagnetic data were acquired at line spacings of between one and six kilometres, a total of 28 200 line km and covers an area of 47 600 km². The outcomes of the Paterson AEM survey include mapping of subsurface geological features that are associated with unconformity-related, sandstone-hosted and palaeovalley-hosted uranium mineralisation. The data are also capable of interpretation for other commodities including metals and potable water as well as for landscape evolution studies. The improved understanding of the regional geology resulting from the Paterson survey results will be of considerable benefit to mining and mineral exploration companies. This Data Package is for Archive to the internal area of the CDS and contains all data, grids, images, mxd, shape files, documentation, licenses, agreements, interpretations and scripts used to create the Paterson deliverables. At the projects completion (2012) all directories are required to be moved off the NAS. The reason to keep all the files is that more work is to be done on this data in the 2012-2015 period and these files may be needed in this future work.

The record is a presentation given by Adrian Fisher to staff of the Aditya-Birla Nifty copper mine and to staff at the Geological Survey of Western Australia, August 2007. It describes the planning behind the Paterson AEM survey, to be acquired in 2007-2008.

Geoscience Australia (GA) has recently released regional airborne electromagnetic data (AEM) in two survey areas of the Pine Creek region. The Woolner Granite-Rum Jungle survey in the western part of the region was flown using TEMPESTTM and the Kombolgie survey in the eastern part was flown using VTEMTM. These data assist in mapping geological features deemed to be critical for fertile unconformity-related uranium and sandstone-hosted uranium systems. These mapped features in combination with other datasets are used to assess the prospectivity of uranium systems.

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 covers an area of 74,000 km2 from Darwin to Katherine in the Northern Territory which hosts several world class deposits, including the Ranger Uranium Mine, Nabarlek, Mt Todd, Moline and Cosmo Howley. Aimed at regional mapping, uranium exploration, reducing exploration risk and promoting exploration activity, the program worked closely with industry partners to infill wide regional line spacing (5km) with deposit scale line spacing (less than 1km). The survey results are relevant in exploration for a variety of commodities and resources, including uranium, copper, lead, zinc, gold, nickel and groundwater. Geoscience Australia's interpretation products include sample-by-sample layered earth inversion products comprising located data, geo-located conductivity depth sections, depth slice grids, elevation slice grids, inversion report and an interpretation report. All data and products are available from GA as well as the Northern Territory Geological Survey Geophysical Image Web Server.

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.

Phase-1 data, that is, contractor quality-controlled and quality-assessed data for Kombolgie, were released during 2009. New EMFlow data, that is data generated using a new EMFlow version are included in this data release. The data and products described in this report are contained on the accompanying DVD. The main products included in this data package include: sections, conductance grids and an AEM Depth of Investigation grid. The data is provided in formats which can be viewed on most computer systems. They include, JPEG (.jpg) with associated world files for easy use in geographic information system (GIS) packages, ER Mapper grids (.ers), ESRI shape files (.shp) of the flight path, and point-located ASCII data with relevant metadata for derived products. The outcomes of the Pine Creek AEM Kombolgie survey include mapping of subsurface geological features that are associated with unconformity-related, sandstone-hosted Westmoreland-type and Vein-type uranium mineralisation. The data are also capable of interpretation for other commodities including metals and potable water as well as for landscape evolution studies. The improved understanding of the regional geology to greater than 1500m resulting from the enhanced EMFlow survey results will be of considerable benefit to mining and mineral exploration companies.