IC2 Experimental Coal Chunk for Minecraft 1.12.2, compressed in the Compressor to create one Industrial Diamond.
IC2 Guide
Run coal through a Macerator until you have at least 64 coal dust per planned Coal Chunk, since each chunk consumes 64 dust.
Surround a piece of Flint with 8 coal dust in the crafting grid to make one Coal Ball. Repeat eight times for one chunk.
Place each Coal Ball into a powered Compressor; each one becomes a Compressed Coal Ball that you'll need in the next step.
Arrange 8 Compressed Coal Balls around one block of Obsidian in the crafting grid to produce a single Coal Chunk.
Insert the Coal Chunk into the Compressor again; it converts into one Industrial Diamond ready for advanced IC2 recipes.
On Minecraft 1.12.2, the Coal Chunk recipe is one of the most stable chains in IC2 Experimental. Automate the Macerator and Compressor pair to get a steady stream of Industrial Diamonds.
Coal Chunk is an IC2 Experimental item crafted from 8 Compressed Coal Balls and 1 Obsidian; it is the direct precursor to an Industrial Diamond.
Place the Coal Chunk into a powered Compressor. After the cycle finishes, it outputs one Industrial Diamond.
Each chunk uses 8 Compressed Coal Balls (64 coal dust), 1 Flint and 1 Obsidian, so it represents the value of 64 coal plus the obsidian.
Yes, in IC2 Experimental for Minecraft 1.12.2 this chain is one of the standard ways to produce renewable Industrial Diamonds.