What Technology is used to mine coal?
Trucks, cranes and explosives.
Aluminum is easier to handle and form, is lighterBrass is fine for models, trinkets, shimsSteel is sturdierStainless steel will not rustCopper is good for roofingGold, silver and platinum are for jewelry, coins, instrumentationAs you can see, it depends upon the use, the budget, and the tooling to make things.
