NCJ Number
117872
Date Published
1989
Length
3 pages
Annotation
The metal detection principles used to detect weapons are also being used in the precious metals industry to prevent thefts of gold and other previous metals.
Abstract
However, the precious metals detectors differ from weapons detectors in application, design, and operation. Weapons detectors must discriminate between larger ferrous iron objects like guns and knives and smaller ordinary objects like keys, coins, and similar objects that people normally carry. In contrast, precious metal detectors are more concerned with detecting tiny amounts of nonferrous materials like gold and silver. Distinguishing such small objects against the background metal content of the human body requires a calibrated standard value for each person entering the metal detector. Therefore, each employee of a gold mine, a gold refinery, or a jewelry manufacturer is tested through a portal to receive a standard reading. Subsequent daily readings can be compared with the standard reading, and a handscanner can be used to examine any deviations. Digital values and the use of a computer simplify the process. The computer further removes the possibility of collusion between security personnel and employees. The metal detecting system acts mainly as a deterrent, but its accuracy, repeatability, and simplicity also make it useful for theft control. Recently mandated restrictions on the use of lie detectors make it likely that the use of metal detectors will increase. (Author abstract modified)