機器
macadam
activity
belt
business
cobblestone
concrete
construction
conveyor
dig
dirty
dust
earth
engineering
environment
equipment
excavation
extraction
factory
geology
gravel
heap
heavy
industrial
industry
iron
landscape
large
machinery
manufacturing
material
metal
mine
mineral
mountain
pit
quarry
quarrying
resource
rock
sand
sky
stack
steel
stone
technology
transportation
truck
work
working