A word with variant forms ᴱQ. mulda and mulina and the gloss “powdery” from the Qenya Lexicon of the 1910s, an adjectival form of ᴱQ. mul (muld-) “fine powder”, ultimately derived from the early root ᴱ√MULU “grind (fine)” (QL/63).
Neo-Quenya: In notes from the late 1950s or early 1960s, Tolkien gave Q. mulë for “meal” = “✱coarsely ground flour”, so it seems ✱√MUL “grind” either survived or was restored. This may make it possible to retain ᴺQ. mulda “powdery” for purposes of Neo-Eldarin as descriptive of ground up things.
A verb appearing as ᴱQ. mul- “grind” in the Qenya Lexicon of the 1910s under the early root ᴱ√MULU “grind (fine)” (QL/63). In a nearby comparative list of roots it was given as mulu- “grind”.
Neo-Quenya: The 1968 word Q. mulë “meal” (PE17/115) indicates ✱√MUL survived in Tolkien’s later writing, so I would retain ᴺQ. mul- “to grind” for purposes of Neo-Quenya.