Someone else starts their own mines, everyone goes a little poorer.
except for oil, most countries aren't dependant on other countries just to survive in the near term (food is one of the few things countries will usually attempt to ensure they are selfsufficent in, if it's feasible)
The UK is far from self sufficient in food. You'd think they would have learned from their mistakes after they nearly starved to death due to the Axis blockade during WWII, but apparently not.
except for oil, most countries aren't dependant on other countries just to survive in the near term (food is one of the few things countries will usually attempt to ensure they are selfsufficent in, if it's feasible)