CNN Forensic Files June 22, 2014 07:49:00
>> but there was so much trash out there, so much farm equipment, this is the place where they would throw the garbage along with the tin foil and toothpaste tubes and all the junk went out there. so the challenge was working through 130 years of trash and picking up the single .25-caliber automatic shell casing that we were looking for. >> modern metal detectors use computer processors to measure levels of conductivity. which enables them to identify the type of metal and the depth of the objec...
Source: archive.org