bituminous
black
central
clean
coal
coal burning
cube
dark
deposits
ecology
effect
energy
environment
exploitation
extract
extraction
fuel
fuels
gas
glove
hand
heat
heating
helmet
hold
hot
human
industry
laborer
lignite
load
loading
manufacturing
material
metallurgical
mine
miner
mineral
mines
mining
nature
power station
resources
show
smoke
stone
things
treasure
unclean
worker