Mineral deposit seen first on land (6)
I believe the answer is:
ashore
'on land' is the definition.
(synonyms)
'mineral deposit seen first' is the wordplay.
I cannot quite understand how this works, but
'mineral' could be 'ore' (ore is a kind of mineral) and 'ore' is found within the answer.
'deposit' could be 'ash' (I've seen this before) and 'ash' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ashore that I've seen before include "Beached" , "beach" , "on the coast" , "Hoarse being no longer at sea" , "Home for the sailor" .)