英文關鍵字
background
belt
blue
building
business
cement
cone
construction
conveyor
crusher
dirt
dust
earth
environment
equipment
erosion
extraction
factory
gravel
heap
heavy
hill
industrial
industry
loading
machine
machinery
manufacturing
material
metal
mine
mineral
nature
open
outside
pebble
pit
processing
quarry
rock
rubble
rusty
sand
sorting
stone
sunny
technology
transportation
truck
work