Wikia

The Nova Cataclysm is an upgrade from the Nova Catalyst. It is an explosive that captures all blocks it destroys and places a Loot Ball near the player who detonated it. Four Nova Cataclysms are equal to the blast radius of one Nuke. It does not damage players or mobs.

Due to such a low EMC value (4,849), the large blast radius, and its lossless drop rate, the Nova Cataclysm is an extremely efficient mining tool.

One suggestion for use: Bring around 10-20 Nova Cataclysms, 2 or 3 differently colored Alchemy Bags, a large amount of torches (at least 1 1/2 stacks), a redstone torch, and an iron pickaxe or two (or some other sort of mining tool), as well as some food, and explode around elevation 15. Light up the area, blow up the next one at the far end of the cavern, again, at elevation 15 (approximate), rinse and repeat. Depending on how many Nova Cataclysms you brought, you will have varying amounts of loot when you return. 10 uses of a Nova Cataclysm should fill about 1 1/2 Alchemy Bags with materials produced by the Nova Cataclysm. Usage of a Void Ring will pull in dropped items and condense them into items of higher EMC.