I have recently found duplicate entries for Penrhyngerwin/Lovedon under the 2 different names. I added a note to the one to "see the other"
I think best way of dealing with that situation, but deletion of one the best in this case.
Of course, the Welsh mines can have alternative spellings, e.g. Alltycrib and Allt y Crib or Allt-y-Crib.
I am not Welsh and greatly respect the opinions of those who are.
My avatar is a poor likeness.