Related Clues:
- Claim valuables
- Underground treasures
- Pitchblende and cassiterite, for two
- Metal-bearing minerals
- Underground sources of income
- Smeltery needs
- Mineral sources
- Tram loads, often
- Prospectors' prizes
- Tram contents
- Bauxite and galena
- Metal-filled rocks
- They're mined and refined
- Smeltery material
- Refinery rocks