b'AEM 2023Short abstractsDesign of BIPTEM: an airborne B field IP and TEMUse of airborne electromagnetics for mineral system exploration and miningJames Macnae1, Terry Kratzer2, Duncan Massie3 andKatherine McKennaPaulRogerson4BHPMetals Exploration1. CD3D, Glen Iris, VIC, Australia The use of airborne electromagnetics (AEM) in mineral 2. BIPTEM, Melbourne, Vic, Australia exploration and mining has expanded over time. Initially with 3. Monex Geoscope, The Basin, Vic, Australia an objective of targeting, it is now also used for mapping, water 4. Thomson Airborne, Griffith, NSW, Australia delineation, structural identification, environmental monitoring, The BIPTEM project was funded by several companies andand the list is growing. It has been proven, AEM has had success developed a 1 MA m2 transmitter which was tested with ain identifying mineral deposits under cover, but the challenges concentric loop B field inductive magnetometer in 2017.come as we try to explore deeper. There is a need to achieve A report on the system was presented at AEM18. Withbetter resolution at shallower and deeper depths, to continue the rotation sensing and inertial navigation technologywith the creation of better and more meaningful inversions, to available at that time, motion noise corrections to theincorporate petrophysical and geological data and adapt to the collected data did not perform well enough to justifychanging expectations of exploration and mining. Examples of further substantial investment and the project washow AEM is used in mineral exploration and mining show the mothballed. Following improvements in fibre-opticdevelopment to date, the challenges of the interpretation and technology, and the announced future commercialthe way the results can be communicated to geological, geo-availability of breakthrough quantum rotation sensors,technical or environmental teams.Newmont funded research to improve the BIPTEM system and test its ability to map IP targets. System-scale airborne electromagnetic surveys in the Many experiments and flight tests were conducted, andlower Mississippi River Valley support multidisciplinary extensive software developments were undertaken toapplicationsbring the system to full operation. Parallel modelling andBurke Minsley , Ryan F Adams , William Asquith ,1 2 3ground experiments showed that the optimum systemBethanyL Burton , Bennett E Hoogenboom ,1 1for IP effect detection has a large Tx and a horizontalStephanie R James , Courtney Killian , Katherine J Knierim , 1 4 5component Rx (separated by about 300 m in the SlingramWade H Kress , Max Lindaman , Andy Leaf , J.R. Rigbyand2 6 7 8geometry JP Traylor9An airborne heterodyne sulphide exploration test at1. U.S. Geological Survey, Denver, CO, United StatesKempfield 2. U.S. Geological Survey, Nashville, TN, United States3. U.S. Geological Survey, Lubbock, TX, United StatesJames Macnae1 and Terry Kratzer2 4. U.S. Geological Survey, Bridgeville, PA, United States5. U.S. Geological Survey, Little Rock, AR, United States1. CD3D, Glen Iris, VIC, Australia 6. U.S. Geological Survey, Baton Rouge, LA, United States2. BIPTEM, Melbourne, Vic, Australia 7. U.S. Geological Survey, Madison, WI, United StatesWe continue to investigate an ancillary method to Induced8. U.S. Geological Survey, Oxford, MS, United StatesPolarisation for sulphide exploration, using analysis to measure9. U.S. Geological Survey, Lincoln, NE, United Statesheterodyne effects in time-domain Airborne ElectromagneticThe lower Mississippi River Valley spans over 200 000 km2 data. We investigate how a parameter named mixabiity canin parts of seven states, encompassing areas of critical characterise these effects in terms of frequency content andgroundwater supplies, natural hazards, infrastructure, composition, finding that with sufficiently low noise levels,and low-lying coastal regions. From 201822, the U.S. heterodyne effects could theoretically be observable in time- Geological Survey acquired over 82 000 line-km of airborne domain AEM data. electromagnetic, radiometric, and magnetic data over Analysing existing AEM survey data, we earlier found no spatialthis region to provide comprehensive and systematic correlation between known sulphide distribution and mixability.information about subsurface geologic and hydrologic We postulated that this is because potential heterodyneproperties that support multiple scientific and societal effects due to sulphides were being masked by two differentinterests. Most of the data were acquired on a regional grid limitations of the survey dataset we used; firstly, variableof west-east flight lines separated by 36 km; however, transmitter waveform asymmetry; and secondly, the decreasingseveral high-resolution inset grids with line spacing as signal levels from the fixed a ground-loop transmitter resultingclose as 200 m were acquired in targeted areas of interest. in increasing relative noise levels away from the transmitter. WeApproximately 8000 line-km were acquired along streams therefore conducted a airborne Slingram EM/IP survey with theand rivers to characterise the potential for surface water-BIPTEM system to address the identified limitations of existinggroundwater connection, and another 6000 line-km were test data. acquired along the Mississippi and Arkansas River levees to characterise this critical infrastructure. Here, we present We present results from an airborne test at Kempfield, the testa summary of the data along with several examples of site for definitive ground tests of the heterodyne method forhow they are being used to inform regional groundwater sulphide detection. The small mixability anomalies detectedmodel development, inferences of groundwater salinity, in the airborne data were not consistent with either drilledidentification of faults in the New Madrid seismic zone, and sulphides or mapped IP anomalies. levee infrastructure.AUGUST 2023 PREVIEW 60'