The workers in the mine have nothing but allspice (7)
I believe the answer is:
pimento
'allspice' is the definition.
(I've seen this in another clue)
'the workers in the mine have nothing' is the wordplay.
'the workers' becomes 'men' (men can mean staff or employees).
'in the' indicates putting letters inside.
'mine' becomes 'pit' (down the pit).
'have' says to put letters next to each other.
'nothing' becomes 'O' (looks like zero - 0).
'men' put into 'pit' is 'piment'.
'piment'+'o'='PIMENTO'
'but' acts as a link.
(Other definitions for pimento that I've seen before include "Sweet red pepper" , "Type of pepper" , "Vegetable" , "Something spicy" , "Spicy berries" .)