Mineral source
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mineral source</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ore that I've seen before include "Metal-bearing rock or mineral" , "coinage" , "Mined material" , "Danish currency" , "Mineral - Scandinavian monetary unit" .)