What is "muck iron"

Muck \Muck\, n. [Icel. myki; akin to D. m["o]g. Cf. Midden.]

1. Dung in a moist state; manure.
   --Bacon.

2. Vegetable mold mixed with earth, as found in low, damp places and swamps.

3. Anything filthy or vile.
   --Spenser.

4. Money; -- in contempt.

   The fatal muck we quarreled for.
   --Beau. & Fl.

5. (Mining) The unwanted material, especially rock or soil, that must be excavated in order to reach the valuable ore; also, the unwanted material after being excavated or crushed by blasting, or after being removed to a waste pile. In the latter sense, also called a muck pile.

   Muck bar, bar iron which has been through the rolls only once.

   Muck iron, crude puddled iron ready for the squeezer or rollers.
   --Knight.

   muck pile see muck pile in the vocabulary.