COMPLIANCE INFO 1987-2003 - Laserfiche WebLink

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WZ1 INC 3.4 FIELD PROCEDURES 3.1 Equipment The magnetometer used was a cesium vapor type (model G-858) manufactured by ' Geometrics Inc. This is a digital recording instrument configured to measure the earth's total magnetic field at a sampling rate of ten times per second. Magnetic information is utilized to map objects that contain iron or other objects that may exhibit magnetic susceptibility contrasts. Objects commonly found to contain iron are buried pipelines, underground fuel storage tanks, and wells. The instrument recorded each reading in a data logging unit that was later transferred to a personal computer for location processing. ' The apparent ground conductivity was measured with a Geonics model EM31 instrument. This instrument measured both the inphase and quadature components in east-west and north-south boom configurations. The quadature component represents the apparent conductivity, while the inphase component is designed for detection of conductive objects. Conductive objects may include pipeline, underground fuel storage tanks, aluminum objects, and in some cases, form backfilled trenches. The pipe locator utilized for the investigation was a Radiodetection RD600 instrument. The pipe locator is able to trace individual buried pipelines by energizing the line with a signal and using a remote unit to trace out the surface location. The EM31 ground conductivity survey has an advantage over the magnetometer survey in defining linear objects (pipes, trenches) and conductive objects within areas of high magnetic interference. The principal electromagnetic and magnetic instrument interference is high voltage lines, buildings and chain link fencing within or adjacent to the ��. survey area. The EM31 instrument first transmits an electromagnetic field into the ground in which the instrument receiver measures the primary magnetic field {quadature 05340410.001 3