機器
abandoned
activity
belt
cement
cobblestone
construction
conveyor
dig
dirt
engineering
environment
equipment
excavate
excavation
excavator
factory
gravel
grunge
heap
heavy
hydraulic
industrial
industry
large
machinery
manufacturing
material
mine
mineral
old
open
outdoors
pit
plant
quarry
rock
rust
sand
sky
soil
stack
steel
stone
transport
transportation
vintage
work
yellow