The Probability Of Magnetic Or Electromagnetic Detection Of A X+-Gallon Drum As A Function Of Line And Station Spacing

A simplified elliptical footprint of a %-gallon drum for electromagnetic and magnetic detection as a function<br>of depth is defined. The signal-to-noise ratio for field measurements is used to scale this ellipse. For a given<br>ellipse, the probability of detection at various line and station spacings is calculated.<br>Representative numbers indicate that with a line spacing equal to the major axis of the ellipse and a station<br>spacing equal to the minor axis, the probability of detection of a 1:2 (minor:major axis) ellipse by at least one<br>station is 0.66, but only 0.12 for the recording of two anomalous values.<br>Compound probability enters the problem if more than one target is present. If location rather than detection<br>is the goal, more that one anomalous station is required. If the number of stations is proportional to cost,<br>location or characterization will certainly increase the costs. This paper provides information to disqualify<br>specifications tendered by procurement departments who often request badly aliased surveys.