Update: ores mined must be refined (9)
I believe the answer is:
modernise
'update' is the definition.
('update'->'modernize' is in my internal thesaurus and 'ize'->'ise')
'ores mined must be refined' is the wordplay.
'must be refined' indicates an anagram.
'ores'+'mined'='oresmined'
'oresmined' is an anagram of 'MODERNISE'.
(Other definitions for modernise that I've seen before include "Make up to date" , "to adapt to today's world" .)