Due to the… potentially temperamental and dangerous nature of various explosives, safely transporting “military grade” explosives can get expensive and has safety concerns. So rather than deal with the risks and expenses of transporting old ordinance, disposing of it is often the cheaper and safer solution. Besides, we get to see a massive explosion this way.
Watch for the shockwave.
To put in some perspective, they were 1.7 miles from the explosion. That is a massive explosion to say the least. It’s like the grand canyon – no way to fully comprehend it unless you’re there.
Here’s a longer video with more info about the demolition.
If you want to just watch the explosion portion to get the delay and the noise, skip ahead to about 2:35.