Resin in mine, evidently low, eventually at first rising (5)
I believe the answer is:
Here is my best explanation:
'resin' is the definition.
(elemi is a kind of resin)
'in mine evidently low eventually at first rising' is the wordplay.
'at first' indicates taking the first letters.
'rising' says the letters should be written backwards (going up in a down clue).
The initial letters of 'in mine evidently low eventually' is 'imele'.
'imele' backwards is 'ELEMI'.
(Other definitions for elemi that I've seen before include "Fragrant resin used as incense - Emile (anag)", "Tree resin; ie, elm (anag.)", "Fragrant tree resin used as incense - I'm Lee (anag)", "Fragrant substance", "Resin", "Resinous stuff", "A fragrant resin", "Oleoresin", "aromatic resin" and "Extract".)