(a) The following words and phrases when used in this article shall have, unless the context clearly indicates otherwise, the meanings given to them in this section: "Coal." Coal produced from mines in Pennsylvania or any mixture or synthetic derived, in whole or in part, from coal produced from mines in Pennsylvania.
"Mixture derived, in whole or in part, from coal." Includes, but is not limited to, both the intermittent and the simultaneous burning of natural gas with coal or a coal derivative if the intermittent or simultaneous burning of natural gas would:
(1) lower the cost of using coal or a coal derivative produced from mines in Pennsylvania; or(2) enable coal or a coal derivative produced from mines in Pennsylvania to be burned in compliance with present and reasonably anticipated environmental laws and regulations.