英文關鍵字
below
black
business
cave
cavern
coal
control
copper
copy
corridor
damp
dangerous
dark
deep
dig
diminishing
dirt
dirty
employment
engineering
entrance
gold
gravel
historical
history
industrial
industry
inside
interior
job
labor
lighting
mine
mineral
mining
nobody
old
path
perspective
rough
safety
shaft
skill
solitude
stone
tunnel
tunneling
underground
wall
working