Related Clues:

• Combustible mineral
• Rocks with metal
• It's all in your mine
• Mine layer
• Fruit of a miner's labors
• ___-black
• Gold in them thar hills?
• Frosty's 'eyes'
• Feldspar, e.g
• Underground resource
• Mineral in a wall, perhaps
• Stove filler
• 10-Down source, e.g
• Forty-niner's pay dirt
• Stoking supply