機器
background
belt
black
chain
coal
construction
conveyor
conveyor belt
copper
dark
dirty
dust
energy
engineering
equipment
factory
fuel
geology
gold
grey
heavy
industrial
industry
iron
machinery
material
metal
mine
mineral
mining
modern
ore
pollution
power
production
quarry
rock
roller
sorting
steel
stone
technology
transport
transportation
tunnel
underground
work