Mine can be where the orchestra plays (3)
I believe the answer is:
pit
'mine' is the definition.
(down the pit)
'where the orchestra plays' is the wordplay.
I cannot really see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
The remaining letters 'pi' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'can be' is the link.
Can you help me to learn more?
(Other definitions for pit that I've seen before include "Stop to refuel" , "Cherry stone" , "Tip into hole" , "A hole as for coal" , "Big deep hole in the ground" .)