As has been pointed out, IED's are not simply mines in the traditional sense. They are, in fact, quite cleverly conceived devices of death. There is no "silver bullet" for their location because their composition, placement and triggering are, ultimately, dependent entirely upon the imagination of human beings.
The suggestion that there can be a foolproof method for their detection is one that, really, only a fool can make. Taking into account the number of different, commonly available, compounds that can be used to create an explosive mix multiplied by the number of compounds that could be used to mask said compounds multiplied by the number of ways the explosive could be used at greater range to effect damage, (claymore, shaped charges, larger explosions), multiplied by the number of ways they can be initiated one quickly realizes that the combination's are myriad and, therefore, reliable detection becomes proportionately less likely and rapidly approaches impossible unless you restrict the detection device to only a small subset of the whole thus defeating the premise of a universal detection solution.
There is no viable solution to the problem of IED's with our current level of technology, (nor in the forseeable future), other than not deploying foot soldiers and vehicles into areas where they might be encountered. Clearly, that is not an option.