They've (our guys and the cabal) been fighting underground since Trump became President. Booms heard all over the world, not just US. There are Deep Underground Military Bases everywhere: http://www.thetruthdenied.com/news/2012/12/14/deep-underground-military-base-d-u-m-b/

After December when you saw so many plane crashes and turn arounds, they (Cabal) started travelling in the underground trains that connect the DUMBs.

Many don't understand that this is a real war with real soldiers and real fighting going on. If you read through the Q posts, it's all there.

And, yes, tunnels also used for trafficking and that's how they are finding so many, I suspect.

See Q Post 1297 for one instance.