Related Clues:

• Nickel in a pocket, say?
• Stuff of mine
• Raw material
• Cinnabar et al.
• Hard rock, maybe
• Smeltery input
• Some train cargoes
• They lack refinement
• Mined metal
• Bank deposit?
• Smelter's stuff
• Mine metal
• See 11-Down
• Products of a 16-Across
• Metallurgists' studies