機器
balcan stream
bucket
building
bulldozer
clay
construction
crane
dig
earthwork
earthworks
equipment
excavation
excavator
extraction
fuel
gas
gas main
gas supply
gaspipeline
hydraulic
line
natural gas
oil
oil pipeline
oilfield
petroleum
pipe
pipeline
power
serbia
site
steel
structure
supply
technology
transportation
trench
tube
tubular
vehicle
welding
work
working
yellow