Variety of mineral required for those working on the track (7)
I believe the answer is:
railmen
'for those working on the track' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'variety of mineral' is the wordplay.
'variety of' indicates anagramming the letters.
'mineral' with letters rearranged gives 'RAILMEN'.
'required' acts as a link.
Can you help me to learn more?
(Other definitions for railmen that I've seen before include "Train under their supervision" , "On-line workers" , "They've made tracks" .)