Related Clues:

• Smithsonite, to zinc
• Strike with a pickax?
• Rock that's a nugget
• Good rock?
• It can be hard to process
• '-ite' mineral, often
• Strip mine yield
• 45-Across divisions
• Mine cart fill
• Really good rock
• It's mined
• Excavated stuff
• Krone fraction
• Dug-up commodity
• Contents of a seam