Related Clues:

• Crater Lake's st
• Rich rock?
• Argentite, to silver
• Refinable resource
• It's the core of cores
• Miner's target
• Uraninite, to uranium
• 2,170-mi. trail terminus
• 32-Down contents
• Fodder for a smeltery
• Rock with value
• Stuff picked out in mines
• Material in the game Minecraft
• Extracted deposit
• Mining yield