Old article unearthed and investigated (8)
I believe the answer is:
examined
'investigated' is the definition.
(examining is a kind of investigating)
'old article unearthed' is the wordplay.
'old' becomes 'ex' (prefix meaning former or onetime).
'article' becomes 'a' (the indefinite article in English).
'unearthed' becomes 'mined' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ex'+'a'+'mined'='EXAMINED'
'and' is the link.
Can you help me to learn more?
(Other definitions for examined that I've seen before include "Tested or scrutinised" , "Closely inspected" , "Inspected, studied" , "Questioned closely" , "Considered in detail" .)