Comment 29 for bug 977980

> to place minig resources on the border between mountain and grass. However, in those location it is typically not possible to build mines. So the player sees more resources but cannot use them.

I think this is not correct. A mine has an action radius so such resource would be within reach of a mine and thus mineable.

> If changing a terrain leads to removed resources, they are not recreated when you undo the terrain change.

Interesting side effect .... but I personally am OK with this, I dont want to ask you for additional work....

I am also satisfied with mentioned two rules. As long as it is consistent.....