If we have to pick a natural resource to exploit for fuel, iron is a good choice: https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Crust https:/

If we have to pick a natural resource to exploit for fuel, iron is a good choice: https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Crust https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elem...