Research facility in front of assembly plant produces white mineral (9)
I believe the answer is:
alabaster
'white mineral' is the definition.
(I've seen this before)
'research facility in front of assembly plant' is the wordplay.
'research facility' becomes 'lab' (laboratory).
'in' means one lot of letters goes inside another.
'front of' suggests taking the first letters (the letter at the front of the word).
'plant' becomes 'aster' (aster is a kind of plant).
The first letter of 'assembly' is 'a'.
'a'+'aster'='aaster'
'lab' going within 'aaster' is 'ALABASTER'.
'produces' acts as a link.
(Other definitions for alabaster that I've seen before include "Blast area for white mineral" , "statue material" , "White mineral used for carving" , "Arabs tale (anag.)" , "White ornamental stone" .)