black
black gold
bucket
coal
coal pile
coal structure
combustible
contamination
darkness
dust filter
dust mask
energy
energy source
energy storage
extraction
filter
filter mask
flashlight
fossil
fossil fuel
fuel
gas mask
glow
hammer
hard
hard coal
hazard
helmet
industrial
industry
light
lump
metal bucket
metal clamp
mine
mineral
mining
night
pneumoconiosis
pollution
potential
raw material
rescue
shale
shines
solid
stone
unclean
underground
wealth