機器
big
car
career
coal
construction
copper
deep
digging
dredging
ecology
electric
engineering
environment
equipment
excavator
fossil
geology
gold
heavy
hole
industrial
industry
iron
land
landscape
large
machinery
metal
mine
mineral
mining
nature
open
ore
power
quarry
resources
road
sand
sky
steel
stone
surface
technology
transport
truck
vehicle
work
yellow