Bath dig in Roman Great Drain

Fascinating story in The Times about an archaeological investigation of the main Roman drain in Bath.
What will be revealed by sifting through the detritus of two millennia is anybody's guess.
Previous 'digs' have uncovered '33 carved cameo gemstones and a mysterious tin mask'.
The drain is in great condition but the local council need to inspect it to make sure it stays that way and that opens the way for the archaeologists.