Related Clues:

• Vein settings
• Mine output
• Raw rocks
• Things tunnelers look for
• Tramcar contents
• They often get shafted
• Underground discoveries
• Contents of trams
• Miners' diggings
• Mine yields
• Mesabi loads
• Iron and manganese, e.g.
• They could use refinement
• They may be silver or gold
• Meteor materials