Crimson Marrow Extraction Process III

Step 3: Refinement
The diverted raw material rich in Crimson Marrow—labeled as "waste"—is transported through that concealed pipeline directly back to the underground Mining Zone to a secret facility sealed under strict security, inaccessible to ordinary personnel.
In this lightless underground chamber, the ore undergoes deep refinement to extract high-purity Crimson Marrow infused with Hruga Engram​.

The refined product—which Reiner referred to as "waste"—is temporarily stored in a hidden warehouse within the Mining Zone, awaiting the right moment to be smuggled out of the mine.