This weekend's news included the story about three more Canadian soldiers being killed in Afghanistan.

I haven't researched the event in detail, but apparently they were working on clearing a highway of explosives.

That got me wondering: if they were minesweeping, how did they miss the explosive? Do Canadian soldiers tasked with seeking and nullifying explosives not have the proper equipment to do the job?

Or was the explosive launched at them from elsewhere? Was it remotely detonated?