coal       
noun [ C or U ] uk/kəʊl/ us/koʊl/
C1 煤
a hard, black substance that is dug from the earth in pieces, and can be burned to produce heat or power, or a single piece of this
  How much coal was mined here? 这里出了多少煤? 
 a burning/red hot coal 燃烧的/灼热的煤块 
 - More examples
- Wood and coal are both combustible substances.
- The coal fire had discoloured the paintwork.
- Many miners have suffered from the effects of coal dust in their lungs.
- Wood, coal, oil, petrol and gas are all different kinds of fuel.
- We ordered a hundredweight of coal.
Idioms      
carry/take coals to Newcastleidiom UK 多此一举;徒劳无功
to supply something to a place or person that already has a lot of that particular thing
  Exporting pine to Scandinavia seems like carrying coals to Newcastle. 往斯堪的纳维亚出口松木似乎有点儿多此一举。 
 haul/drag someone over the coalsidiom  责备,申斥,责骂
to speak angrily to someone because they have done something you disapprove of
  He was hauled over the coals for coming in late for work. 他因为上班迟到而受到训斥。