Underground column’s wasted time at POW camp (10)
I believe the answer is:
stalagmite
'underground column's wasted time at pow camp' is the definition.
I can't judge whether this defines the answer.
'wasted time at pow camp' is the wordplay.
'wasted' is an anagram indicator.
'at' says to put letters next to each other (I've seen this in other clues).
'pow camp' becomes 'stalag' (I've seen this before).
'time' anagrammed gives 'mite'.
'mite' put after 'stalag' is 'STALAGMITE'.
Can you help me to learn more?
(Other definitions for stalagmite that I've seen before include "A mound of calcium carbonate" , "Column made by dripping water" , "found on floor of cave" , "something on floor of underground passage" , "Upward-rising cave deposit" .)