Fantastic Lego mind that brings wealth (8)

I believe the answer is:

goldmine

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'wealth' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.

'fantastic lego mind' is the wordplay.
'fantastic' is an anagram indicator.
'lego'+'mind'='legomind'
'legomind' anagrammed gives 'GOLDMINE'.

'that brings' is the link.

Can you help me to learn more?

I've seen this clue in The Sun.

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