Convict brought back raw material in abundance (6)
I believe the answer is:
galore
'in abundance' is the definition.
(thesaurus)
'convict brought back raw material' is the wordplay.
'convict' becomes 'lag' (I've seen this before).
'brought back' says the letters should be written in reverse.
'raw material' becomes 'ore' (I've seen this before).
'lag' reversed gives 'gal'.
'gal'+'ore'='GALORE'
(Other definitions for galore that I've seen before include "Lo, Reg, a change could be in abundance" , "In profusion" , "abundantly" , "Existing in great numbers" , "to spare" .)