Dug up part of chateau near the Dordogne (9)
I believe the answer is:
unearthed
'dug up' is the definition.
(I've seen this before)
'part of chateau near the dordogne' is the wordplay.
'part of' says the answer is hidden in the clue.
'UNEARTHED' can be found hidden inside 'chateau near the dordogne'.
(Other definitions for unearthed that I've seen before include "Discovered something hidden by digging" , "Excavated, brought to light" , "found" , "unsafe condition of electrical apparatus" , "Dug up" .)