Saw everyone to do with operations except boss concerned with certain elements (13)

'concerned with certain elements' is the definition.

'saw everyone to do with operations except boss' is the wordplay.
'saw' becomes 'met' ('meet' can be a synonym of 'see').
'everyone' becomes 'all' (I've seen this before).
'to do with operations' becomes 'surgical' (I've seen this before).
'except boss' means to remove the first letter.
'surgical' with its first letter taken off is 'urgical'.
'met'+'all'+'urgical'='METALLURGICAL'