Yep, I read this a just a confirmation to confirm the calculation method. Not an test of the explosive, but the effects of that size of "bunker buster". The actually usage might be a strategic nuke that penetrates before the reaction.
Right. They are trying to evaluate the air effects of an explosive that size, at that depth.
That means we have a bunker buster nuke of 700 tons yield. We just want to make sure the radiation is contained.
I'm willing to bet the the soil used to fill over the explosive has some tracking agent in it. Then they could determine how much material was dispersed and how far.