b'AEGC 2023Short abstractslarger than a typical site collection of 10 to 20 palaeomagneticthe aggressive terrain mapping profile ideal for magnetics and cores. The method can be extended to more complex geometryradiometics surveying. This will be demonstrated with a repeat provided that geometry is captured and used in the inversions.line evaluation showing the residuals at 100s filtering to be The mapping can also be extended from individual profiles tounder 1.0 mGal at low-level flying. The tight line spacing that multi-profile mapping as in conventional magnetic field surveys.is also typical of these surveys (50-200 m) gives lots of data to The non-destructive nature of the measurements allows thestack to lower the final noise of the airborne gravity data. This method to be applied to archaeological sites where drilling ofwill be demonstrated using an odd-even difference analysis at palaeomagnetic cores is not acceptable and the method also hasvarious multiples of the line spacing of a test survey.Without application to detection and avoidance of lightning strikes forrequiring any changes to flight planning and also not adding palaeomagnetic sampling. much weight to the aircraft, the XGrav now allows gravity to be added as a staple in standard regional mapping projects and green fields exploration.Case study of application of hydraulic fracture monitoring in hard-rock mining.Falcon vs FTG - estimating precision and accuracy of Konstantin Galybin 1, Gabriel Amorer2, Gisela Viegas2 and Jonairborne gravity gradiometers.Lawrie1Chrisvan Galder1 Schlumberger Australia Pty Ltd 2 Newcrest Mining Ltd Xcalibur MultiphysicsHydraulic Fracture Monitoring (HFM) is a technique, commonlyThere are currently three types of commercial gravity used in unconventional Oil and Gas projects, aimed at locatinggradiometers used in airborne exploration: the FTG design, and characterising the fractures generated by hydraulicthe Falcon AGG design and the e-FTG design. All systems fracture operations of the subsurface. Nevertheless, hydraulicwere developed by Lockheed Martin and are rotating disc fracturing is often used in other industries such as mining. Thisgradiometer systems employing pairs of accelerometers equally paper presents a case study of application of HFM in hard-rockspaced around rotating discs.mining at the Cadia East mine, Australias top-producing goldPrecision and accuracy are terms that are often used mine, operated by Newcrest Mining Ltd. The Cadia East mineinterchangeably in exploration; however, they are different comprises several block caves, with ore extracted and processedqualities. The precision of the gradiometer data is estimated from a network of underground tunnels and chambers. There,by taking a measure of the repeatability of the dataset. The within the confines of the mine, hydraulic fracturing is usedprecision of the data will increase as the standard deviation to pre-condition the subsurface to mitigate seismic hazard,of the repeatability analysis decreases. The accuracy of the promote cave propagation and improve resource recovery. Agradiometer data is a measure of the closeness to the true value surface hydraulic fracturing trial has been commissioned byof the measurements. The accuracy will increase as the standard Newcrest and this necessitated verification of the effectivenessdeviation of a trueness analysis decreases. To fairly compare of the preconditioning. As such, a dual-well hydraulic fracturethese systems, we require both comparable examples of their monitoring technique was applied to enable accuratedata and common precision and accuracy estimation methods.microseismic event location and moment tensor inversion. The data were acquired by two accelerometer arrays, deployed inAt publication of this article, there are no open-source examples two different wells during hydraulic fracturing of a third, nearbyof eFTG data, so it will not be considered in the comparison. well. A total of 26 fracturing stages across three wells wereFor the FTG dataset, a 500 m line spaced survey was flown in monitored in an overall operating time of three weeks with2012 for Natural Resources Canada over the Bay St. George in zero HSE incidents, zero downhole failures, 100% operatingNewfoundland and Labrador, Canada (Bell 2013). For the Falcon efficiency and impeccable data quality. Moreover, remoteAGG dataset, a 500 m line spaced survey was flown in 2018 for operations were utilised for processing and interpretation ofthe Geologic Survey of Victoria over the Otway Basin in Victoria, the HFM data because the project took place during the heightAustralia (Xcalibur 2019). The comparison will demonstrate how of the COVID-19 pandemic in Australia in 2020, which allowedto check accuracy of the final data using LaPlaces equation and to reduce crew sizes on site. A collaborative approach betweenhow to check precision using an odd-even difference analysis.the mine operator and the various service providers enabled contemporaneous decision making and ensured successful completion of the preconditioning campaign. Investigation of coastal Perth Basin north for Jurien Bay town water supply with airborne electromagnetics.XGrav-Acquiring gravity data on a high resolutionKaren Gilgallon 1 and Anna Lach2magnetics platform. 1 Southern Geoscience Consultants Chrisvan Galder 2 Water CorporationXcalibur Multiphysics Jurien Bay is a small coastal town located 220 km north of Perth, Western Australia, and relies on groundwater for town Airborne gravity has long been acquired by flying throughwater supply (TWS). Water is sourced from a borefield located smooth conditions at higher than normal survey altitudes.4 km north-east of the town. The borefield is comprised of The aggressive flying required on low-level magnetic andthree production bores abstracting groundwater from a highly radiometric surveying platform is typically not conducive totransmissive superficial Tamala Limestone aquifer. The bores are acquiring viable gravity data as well.The new XGrav system hasrelatively shallow at about 16 to 22 m below ground level with 6 been designed to acquire good gravity data while still followingto 12 m screens in each bore. Jurien production bores recorded 99 PREVIEW FEBRUARY 2023'