Ackerman wonders about them:
“I’ve disassembled mines in the Falklands islands, a very harsh climate,” says Colin King, a former British Army bomb-disposal officer, “and the last ones I did were more than 30 years [older] than the event, and some of those were in perfect condition 30 years on. I’ve seen some in Cambodia and in Jordan, particularly in Cambodia where you’ve got a wet climate and poor quality mines, which were nonfunctional very, very quickly. But there are very few IEDs that are going to last for years.”
Science and experience indicates as much. But the data, alas, is lacking.