Milestone clot is resulting from certain internal operations (15)

I believe the answer is:

tonsillectomies

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'certain internal operations' is the definition.
The definition suggests a plural noun which matches the answer.

'milestone clot is resulting from' is the wordplay.
'resulting from' indicates an anagram.
'milestone'+'clot'+'is'='milestoneclotis'
'milestoneclotis' anagrammed gives 'TONSILLECTOMIES'.

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I've seen this clue in the Sydney Morning Herald.

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