Dogs
The use of dogs to detect mines is very fast and efficient. Dogs have the ability to learn to sniff out certain smells, and also certian combinations of smells. This gives dogs the ability to detect mines the may normally be missed by conventional methods. Also, dogs are able to navigate terrain that could be unreachale by other methods.
http://www.humanitydog.se/minedog.htm
Hyperspectral Imaging
Hyperspectral imagining is a method in which objects on the ground that might not be seen by the naked eye can be deteced from overhead. The visible and infrared spectrum is broken down into hundreds of different pieces. This data can then be analyzed the compare differences in ground characteristics.
http://www.ccmat.gc.ca/Achievements/nb_005/index.html
http://www.tracam.com/hmd.htm
Georgia Tech Acoustic Waves and Radar
A transducer is used to create seismic waves that causes the ground they travel through to be slightly displaced. These tiny displacement can be measured by a radar system. The displacement of a mine causes by these seismic waves is quite different than the soil surrounding it, thus, the data can be analyzed to determine if a mine is present in the ground.
http://www.gtri.gatech.edu/res-news/MINES.html
Ground Probing Radar
A radar signal enters the ground, and is reflected back by the soil and underground objects. The signal passes through some substances, is absorbed by some, and also reflected back by others to anf antenna. When the signal is recieved, it is processed to determine how long and how far it traveled after it was sent. Since different substnaces either reflect or absorb the signal, the makeup of the ground can be determined.
http://www.era.co.uk/CASE/CS9804.HTM
http://www.geomodel.com/gprtext.htm
http://diwww.epfl.ch/w3lami/detec/gpr96.html