Is this the Nice Spice? Yea, probably so, your answer WAS helpful!! Thanks for the info on re-occuring resources.)
As I understand it from an Editor prespective, it is a simple random function for the disapperance of a resource. They all have a value, (in some cases a zero value, as would explain Mr. Spice's report that Rubber never dissapears). Every turn the program "rolls the die" and if a number less then the given value occurs, the resource dissapears. (Since you can't get less then a zero, rubber cannot dissapear ... makes sense, if rubber starts with a zero value for the "disapperance probability".) This from looking around in the editor and surmise.
But it tells us nothing about the way the re-apperance location is determined.
And note that since this is a numerically random even each turn, there is no way for a player to recieve a "warning" that the resoursce is "about" to go away.
As an aside, in my current game, last night, (ah, timeleness ...)
I have a civ which has (had ...) 3 iron deposits. In Anno Dommini 1745, one of them becomes "exhausted" and "poof", now I have only 2 sources of iron. Of my 3 remaining opponents, two have 3 each, and the last, just one. My vanished iron appears not elsewhere on my main continent (where it had been), but on another, within the nation that only has one iron up to then.
The very next turn, 1750 AD, ANOTHER iron deposit of mine "becomes exhasuted". It's on my second, partially conquered continent (which the Babylonians share with me - they are the civ that just went from one iron to two). This second vanished iron also reappears on a new, seperate continent from where it had initially been- unfornatuely for me, on the continent of my main rival the Iroquois. They now have 4 irons and I am down to just one.
All in just two turns!
Am I unlucky or what!
You can see why I might be concerned that my clearing ALL jungle from my main continent (my second, partial continent has no jungle), might leave me with no rubber ...
I will very surely be glad to get Infantry ... IF I do have rubber ... will not know for sure until I research Replaceable parts ... it will be a tense wait ...
I think I might need to conquer the Babylonians to get back some iron, if that last one I have were to dissapear ...
Sealman might like that option, too!