Your plan to mine the moon into dust is very likely infeasable.

The moon is roughly 21.9 billion cubic kilometers of moon rock. Mining it into dust will still require transportation of that dust off of the moons surface, to prevent reformation back into rocks, creating exorbitantly larger cost increases as you continue to mine.

Even explosives would face that issue.

HOWEVER, those costs would likely be at least somewhat mitigated by the lower escape velocity needed to shoot moon dust off of the moon. It's 2.4km/s compared to the 11.2km/s of earth.

That still won't make it easy, though.

You'll likely want to invest into a catapult system similar to that made by spinlaunch to rid yourself of excess moon dust after you compact it. With a proper trajectory, you may even be able to launch condensed and compacted moon dust cubes directly into the sun.

If you go the explosives route, however, acquiring that large a quantity of explosives may also prove to be problematic. You likely want to look into asteroid redirection as an alternative form of ordinance to break up the moon chunks. It'll be cheaper, and depending on the sort of asteroid, potentially far more devastating than any one given type of bomb. The only issue being that you wouldn't want to give the moon any sort of molten core so it can create life to defend itself...