There's some film in this programme (after 16 minutes) - all of which is fascinating. There's also a Roman aqueduct later on which is instantly recognisable as an early coffin level.

The 3000 tonnes of silver gained from the workings paid for the ships etc.  and the long walls.

https://www.bbc.co.uk/iplayer/episode/b0bk67wc/ancient-invisible-cities-series-1-2-athens

Agree.  It was a fascinating programme altogether but this section was really interesting.

Athenian coffin levels are something else again!