Related Clues:

• Smelter stock
• Mine yields
• Rich source
• Certain deposit
• Mesabi loads
• Iron and manganese, e.g.
• They could use refinement
• Mine material
• Mother lode material
• Meteor materials
• See 12-Across
• Lead source
• Miner's pursuit
• Metals from the earth
• Raw metals, e.g.