Such engines can be used in a process for ore (4)

I believe the answer is:

aero

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'such engines can be used' is the definition.
I can't judge whether this definition defines the answer.

'a process for ore' is the wordplay.
'process for' indicates anagramming the letters (I've seen 'processing for' mean this (I've seen this in other clues)).
'ore' anagrammed gives 'ero'.
'a'+'ero'='AERO'

'in' acts as a link.

Can you help me to learn more?

(Other definitions for aero that I've seen before include "Prefix denoting air" , "Prefix meaning air or aircraft" , "bar" .)

I've seen this clue in the Evening Standard.

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