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GE(W/sion <br /> geophysical services <br /> November 21, 2019 <br /> Project Number 19477 <br /> Junin Conaway <br /> Tam-Petra <br /> 700 S. Plower Start, Suite 2580 <br /> Los Angeles, CA 90017 <br /> Justilif <br /> Subject: Geophysical Investigation at N. Christman Rd and V. Crust Line Rd, <br /> Tracy, California <br /> My. (bnaway: <br /> A geophysical survey was conducted on November Ties, 2019 at the abovementioacd <br /> property. The purpose of the geophysical survey was to .saecn for am sleet-rash <br /> abandoned oil well in the western pan on of the site. The site consisted of an open dirt <br /> field bouml by Most Line Rd to the north and N. Christman Rd m the east. The <br /> geophysical method applied m this investigation cousisted of the magnetic teanique. <br /> METHODOLOGY <br /> The primary geophysical instrument used during this investigation consisted of <br /> Monarchies U858 optically pumped cesium-vapor nagnemmeler (U858). This <br /> magnerorocicr measures the intensity of the earths magnetic field in ramoteslas (nT) and, <br /> optionally, the ve adeal gradient of tile antb's magnetic field in nanonalas per metes <br /> infirm. Buried ferrous metallic objects give rise to anomalies in the call's magnetic <br /> jaidd These anomalies arc generally dipolar with a positive response south and a negative <br /> response north of the object. T'Ine ditmcnsioas and amplitude of a magnetic anomaly arc a <br /> function of the see, mass, depth, and magnetic lempatia of the source. Magacmmeters <br /> an typicahy locate an object the sire of a 550-gal[on lack to deplla aabout 10 fact <br /> providing Inckgmwd noise levels are nor too high and the tank is not calcosively <br /> comenod. Objects with more mass, like oil wells, an be located to greater depths. <br /> The magnetometer was used in conjunction with a UPS systan for spatial control. UPS <br /> data were collated in the geodetic ampoule system pad then converted to Califtmia <br /> State Plane 1983, NAD83 (Comas), Zone 3 (0403) in US Survey pee[, during data <br /> plmou,n ing. Positions were mken using a Spectra precision UPS system with Centerpoiat <br /> RTxcormaioms. <br /> 1124 alywac Dr. Calais. Cis 92M] ph. 951-549-1274 f 951-5494236 mvw.x:.welon�r <br />