An important weakness of REST is that we do not know the size of the detectable scent plume above landmines. The plume size will depend on many factors, including type of mine, soil properties, environmental factors, filter material, suction pressure and sampling technique. Practical field experience suggests that REST sampling will pick up mines from a minimum of 8 m distance. The reliability of this estimate is, however, unknown and it is necessary to fully determine variations in the detectable plume if the aim is to use REST for area reduction. NPA in Angola has been asked to manage a test project and undertake repeated sampling and analysis in a test field, which differs from most other test fields in that the minimum distance between landmines is 35 m to avoid cross contamination. The sampling and analysis involves 10 sampling sequences over a period of 12 months. Each sampling sequence will involve the use of 1600 filter cartridges. The results have been used to determine reliable detection distances for mines.
