There is potential for even more confusion here. What happens to mines (particularly collieries but not exclusively) where they started as individual mines, but then got incorporated into bigger ventures? Do they get listed under their individual names, or the group?
I think firstly, we need to have a naming protocol to cut out the Old Gunnislake/Gunnislake Old issue and then perhaps consider using the description to state "part of the ....."
In my own database, I use the adjective Old/North/New first, then the name of the mine, then the name/number of the pit or level. In the notes section, I add if it became part of .... at a later date.
Whatever, as long as we all use the same format, then it should cut down on the errors.
Where there's a mine or a hole in the ground.
That's where I'm heading for that's where I'm bound
So follow me down Cousin Jack
(Grateful thanks to Show of Hands)