#L2Dboomer

#metro

#metrostation

#L2Dboomer

Drill

and

Blasting

in

Tunnel:

The

controlled

use

of

explosives

and

other

methods,

such

as

gas

pressure

blasting

pyrotechnics,

to

break

rock

for

excavation.

#DrillnBlast

#tunnel

#L2Dboomer

#Himalaya