Against coal crush? No rumbling gusher? (7)

I believe the answer is:

volcano

I'm a little stuck... Click here to teach me more about this clue!

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

'against coal crush? no' is the wordplay.
'against' becomes 'v' (abbreviation for 'versus').
'crush?' is an anagram indicator (I've seen 'crushed' mean this).
'coal' anagrammed gives 'olca'.
'v'+'olca'+'no'='VOLCANO'

Can you help me to learn more?

(Other definitions for volcano that I've seen before include "Periodic smoker" , "Erupting fissure in the earth's crust" , "Etna, for example" , "eg Mount Etna" , "E.g. Vesuvius, Etna" .)

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

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