When in 1939 war did break out between Germany on the one hand, and Britain and France on the other, President Franklin D. Roosevelt dutifully invoked the Neutrality Acts. However, he believed that this was a fundamentally different war from World War I.
Another advanced coal technology is coal gasification, a process in which coal is converted to a gas (called syngas) before it is burned, making it easier to separate CO2 as a relatively pure gas before power is generated.
Coal is a rock that is a source of energy. Other rock types are useful as building stone, crushed stone and raw material for concrete. Still others serve for toolmaking, from the stone knives of our prehuman ancestors to the chalk used by artists today. All of these, too, are considered mineral resources.