Related Clues:

• Mine treasure
• Refiner's supply
• Gold container, perhaps
• Stuff to refine
• Subject of an assay test
• It might have a silver lining
• Prospector's strike
• Mined mineral
• See 111 Across
• Hopper load
• State that's home to Nike H.Q.
• Raw metal source
• Prospecting yield
• Seam stuff
• Mountain treasure