background

bituminous

black

bucket

burning

central

clean

coal

cube

dark

deposits

dirty

ecology

effect

energy

environment

exploitation

extract

extraction

flip

fuel

gas

gloves

heap

heat

helmet

hot

industry

lignite

load

man

manufacturing

material

metallurgical

mine

miner

mineral

nature

pickaxe

pollution

power

resources

shovel

smoke

station

stone

things

tools

types

worker