Town hall department Liberal employed in looking for gold? (8)
I believe the answer is:
'town hall department' is the definition.
(as in town planning)
'liberal employed in looking for gold?' is the wordplay.
'liberal' becomes 'l' (abbreviation).
'employed in' is an insertion indicator.
'looking for gold?' becomes 'panning' (as in panning for gold).
'l' going within 'panning' is 'PLANNING'.
(Other definitions for planning that I've seen before include "Arranging beforehand" , "'Devising, designing (8)'" , "Preparation for future" , "Organisation" , "Intending or preparing" .)