Crossword Genius

Water extraction device semi-crashed in operation, with workers attending (10,5)

Ross

I believe the answer is:

archimedes screw

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'water extraction device' is the definition.
The definition suggests a singular noun which matches the answer.

'semi-crashed in operation with workers attending' is the wordplay.
'in operation' indicates anagramming the letters (I've seen this in other clues).
'with' says to put letters next to each other.
'workers attending' becomes 'crew' (I can't explain this - if you can you should give a lot more credence to this answer).
'semi'+'crashed'='semicrashed'
'semicrashed' is an anagram of 'archimedess'.
'archimedess'+'crew'='ARCHIMEDES' SCREW'

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I've seen this clue in The Independent.
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