Anjana K. Shah Chloe D. Gustafson Josip D. Adams Matthew A. Burgess Chelsea M. Amaral 20260420 tabular digital data Denver, CO U.S. Geological Survey Suggested citation:Gustafson, C. D., Shah, A.K., Adams, J.D., Burgess, M. A., Amaral, C., 2026, Radiometric data collected from an uncrewed airborne system and handheld meters at the Grand Junction Regional Airport radiometric calibration facility, 2023-2024: U.S. Geological Survey data release, https://doi.org/10.5066/P145CWYA. Primary contributors: Chloe D. Gustafson 0000-0001-8323-2568, Anjana K. Shah 0000-0002-3198-081X, Josip D. Adams, 0000-0001-8470-4141, Matthew A. Burgess, 0000-0003-3487-4972, Chelsea Amaral, 0000-0003-4632-4097. https://doi.org/10.5066/P145CWYA Chloe D. Gustafson Anjana K. Shah Matthew A. Burgess Josip D. Adams Virginia McLemore Evan J. Owen 20251101 publication The Leading Edge Society of Exploration Geophysicists Gustafson, C. D., A. Shah, M. A. Burgess, J. Adams, V. McLemore, E. J, Owens, 2025, Drone-based radiometric surveys provide high-resolution mine waste characterization, The Leading Edge 44 (11), 889-900 https://doi.org/10.1190/tle44110889.1 Measurements of K, Th, and U concentrations using gamma ray spectrometry (radiometric methods) were made using three different handheld spectrometers for different measurement periods and heights above ground at the radiometric calibration facility at Grand Junction Regional Airport. These measurements allow the user to observe the impact of station measurements over different time periods (1 minute, 2 minutes, and 3 minutes) and the potential decrease in measured concentration when the instrument is not in contact with the source (i.e. height attenuation), as may be done during a walking survey. For each measurement, radiometric processing was performed using the instrument internal software. This website includes the radiometric estimates taken by each handheld spectrometer in ASCII format (RadiometricData_HandhandMeters_GrandJunctionCalibrationSite.csv). The positions of the centers of each pad, where the measurements were all taken, are provided in ASCII format (RadiometricData_PadLocations_GrandJuctionCalibrationSite.txt), where the coordinates are referenced to World Geodetic System (WGS) 84 Universal Transverse Mercador (UTM) Zone 12N. These data were collected to better understand the impacts that various survey configurations such as measurement time and height above ground have on data collected with handheld radiometric sensors. They also provide a basis for comparison to a UAS-ready radiometric sensor. 20230327 20230328 ground condition Complete None planned -108.542200 -108.536790 39.134580 39.125530 ISO 19115 Topic Category geoscientificInformation None Geology, Geophysics, and Geochemistry Science Center GGGSC EarthMRI Earth Mapping Resources Initiative Mineral Resources Program MRP USGS U.S. Geological Survey USGS Thesaurus geospatial datasets radiometric surveying USGS Metadata Identifier USGS:6949a849d4be02509472e2f1 None Grand Junction, Colorado No access constraints. Please see 'Distribution Information' for details. These data are marked with a Creative Commons Zero v1.0 Universal (CC0-1.0) public domain dedication and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Anjana K Shah USGS - ROCKY MOUNTAIN REGION Research Geophysicist mailing and physical

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Lakewood CO 80225 303-236-1218 ashah@usgs.gov Funding for this study was provided by the USGS Earth Mapping Resources Initiative and the USGS Mineral Resources Program; U.S. Geological Survey roles and contributions: Scientist-in-charge: Anjana K. Shah; Survey design and coordination: Anjana K. Shah, Chloe D. Gustafson, Josip D. Adams, Matthew A. Burgess; Data Collection: Anjana K. Shah, Chelsea M. Amaral, Josip D. Adams and Matthew A. Burgess; Data processing: Anjana K. Shah; Data preparation for release: Anjana K. Shah; Metadata preparation for release: Anjana K. Shah; Data Release Review: Dylan Connell; Warren C. Day 201909 publication Day, W.C., 2019, The Earth Mapping Resources Initiative (Earth MRI)—Mapping the Nation’s critical mineral resources (ver. 1.2, September 2019): U.S. Geological Survey Fact Sheet 2019–3007, 2 p., https://doi.org/10.3133/fs20193007. https://doi.org/10.3133/fs20193007 Several measurements were conducted more than once, allowing evaluation of meter accuracy. Data fall within expected ranges. Data are complete. Data were collected at three-minute, two-minute, and one-minute intervals for three different handheld gamma spectrometers laid directly on the five different calibration pads at the Grand Junction radiometric calibration facility. One Gamma Surveyor and two Gamma Surveyor Vario spectrometers (all by GF Instruments) were used. The pad on which the measurement was taken was noted. Data were processed for K, Th, and U using the intrument internal processing software. Measurements were repeated multiple times to observe any corresponding variations. 20230327 Using racks to keep the meters at fixed heights during the measurement, radiometric measurements were collected over three-minute intervals over the five different calibration pads (see photo in this data release). These data allow the user to observe attenuation with measurement height. The height above ground was measured from the base of the meter to the ground using a tape measure. One Gamma Surveyor and two Gamma Surveyor Vario spectrometers (all by GF Instruments) were used. Data were processed for K, Th, and U using the instrument internal processing software. The pad on which the measurement was taken was noted. Some measurements were repeated multiple times. 20230328 RadiometricData_HandhandMeters_GrandJunctionCalibrationSite.csv Comma Separated Value (CSV) file containing data. Producer Defined Date Date of measurement (mm/dd/yyyy) U.S. Geological Survey String showing date of measurement (mm/dd/yyyy) Meter Gamma Spectrometer Used U.S. Geological Survey GammaSurveyor A GF Instruments Gamma Surveyor Producer defined GammaVario1 A GF Instruments Gamma Surveyor Vario Producer defined GammaVario2 A GF Instruments Gamma Surveyor Vario Producer defined Mmt_duration_min Measurement duration U.S. Geological Survey 1 3 minutes Ht_above_gd_cm Height above ground (base of meter) U.S. Geological Survey 0 86 centimeters K_pct Potassium concentration U.S. Geological Survey 1.0 6.0 percent eU_ppm Uranium concentration U.S. Geological Survey 0.4 32.9 parts per million eTh_ppm Thorium concentration U.S. Geological Survey 3.7 51.0 parts per million DR_nGyph Dose rate U.S. Geological Survey 39.7 234.5 nanograys_per_hour Notes Description of pad on which the measurement was taken U.S. Geological Survey Background pad Background pad with concentrations K = 1.45%, Th = 6.3 ppm, U = 2.2 ppm Producer defined K pad Potassium pad with concentrations K = 5.14%, Th = 8.5 ppm, U = 5.1 ppm Producer defined Th pad Thorium pad with concentrations K = 2.01%, Th = 45.3 ppm, U = 5.1 ppm Producer defined U pad Uranium pad with concentrations K = 2.03%, Th = 9.2 ppm, U = 30.3 ppm Producer defined Mixed pad Mixed pad with concentrations K = 4.11%, Th = 17.5 ppm, U = 20.4 ppm Producer defined RadiometricData_PadLocations_GrandJuctionCalibrationSite.txt List of radiometric calibration pads at the Grand Junction Regional Airport radiometric calibration facility and their corresponding center locations. Producer Defined Pad Description of pad on which the measurement was taken U.S. Geological Survey Mixed Mixed pad Producer defined U Uranium pad Producer defined Th Thorium pad Producer defined K Potassium pad Producer defined Background Background pad Producer defined X_UTM UTM Easting - WGS84 UTM Zone 12N U.S. Geological Survey 712859.454 712913.346 Y_UTM UTM Northing - WGS84 UTM Zone 12N U.S. Geological Survey 4333888.212 4333969.557 RadiometricSensorOnRack_USGS2026.jpg - Photo of handheld radiometric sensor on a rack above one of the calibration pads. https://www.sciencebase.gov/catalog/item/6949a849d4be02509472e2f1 U.S. Geological Survey - ScienceBase mailing address

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Denver CO 80225 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P145CWYA None 20260420 Anjana K. Shah USGS - ROCKY MOUNTAIN REGION Research Geophysicist mailing and physical

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Lakewood CO 80225 303-236-1218 ashah@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998