Dirt Bomb

This is the undo button for explosive mining. Throw one into a hole and the empty space fills in without touching anything that was already there. That makes it the fast way to patch a meteorite crash site, close a shaft you no longer want, or drop a floor across a gap you cannot be bothered to bridge by hand.

The best use is emergency work in a hellevator. A wall of lava opening into your shaft is normally a long, careful repair. One of these closes it from a safe distance in a single throw, because the fill goes in around liquid rather than replacing it. It will hold water the same way, and mining that dirt back out lets the water straight through again, so patch first and think about drainage afterward.

One bomb puts down more dirt than it took to build, and it puts down the most when it goes off in open air with nothing nearby soaking up the fill. That makes it a dirt generator rather than a way to move dirt around, and since dirt becomes mud and mud grows Chlorophyte Ore, the supply chain has no ceiling.

Standing on top of one when it goes off gives you the ordinary explosion instead: full damage, no fill. Clear the area the same way you would with any other bomb.