Oil & coal are still being imported, to the USA.  The production of USA oil & coal, were stopped by POTUS Obama.  POTUS Trump has brought it back.  Windmill, watermill, solar power, have not made a real dent, with USA energy.

Foreign oil & coal were still being mined, for USA consumption.  The point being, whether it was foreign or domestic, it is still being used, and the environment has not really seen a significant dip in oil & coal usage.

By buying foreign oil & coal, we put the USA industries, out of business.  The price for foreign oil & coal, no longer had a USA competitive playing field.