Tin ore smelted by colleague from the east (10)

I believe the answer is:

orientally

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'tin ore smelted' is the definition.
I can't tell whether this definition defines the answer.

'by colleague from the east' is the wordplay.
'by' says to put letters next to each other.
'colleague' becomes 'ly' (I am not sure about this - if you are sure you should believe this answer much more).
'from the east' becomes 'oriental' (I've seen this in another clue).
'ly' after 'oriental' is 'ORIENTALLY'.

Can you help me to learn more?

I've seen this clue in The Independent.

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