Related Clues:

• They may be driven to extraction
• Driveway material
• Vein bonanza
• Refinement targets
• Iron and copper, e.g.
• Miner samples
• Miner's strike
• Mine output
• Raw rocks
• Things tunnelers look for
• Tramcar contents
• Underground discoveries
• Contents of trams
• Metallic deposit
• Ore's locale