機器
belt
blue
business
cement
cobblestone
cone
construction
conveyor
dirt
dust
electric
environment
equipment
erosion
factory
gravel
growth
heap
heavy
high
hill
industrial
industry
machinery
manufacturing
material
mine
mineral
motor
nature
outdoors
pebble
pit
plant
quarry
refinery
rock
rubble
rusty
sand
site
sky
stack
stone
sunny
transport
transportation
work