Ore mining/Open Pit/Unlimited mining

[numbnutz]

get message X has run out. Says facility has run out, an open pit mine developes source
See construction menu.
I already researched all the mining options at the school, but dont have any new icons
on the construction menu and cant upgrade the existing mine, ie marble.

had 2 marble so deleted one to see if could biuld a new mine...nope...

So whats the trick to this? Some mines say go ahead and upgrade, others, like this
one says see construction menu to develop source.

[Opiliones]

To upgrade a mine, after you've done the necessary research, you simply select the old mine (don't remove it) and upgrade it like you would upgrade houses and markets (i.e. the arrow on the bottom-right of the screen). Make sure the mine is on a spot that is capable of deep mining!

[numbnutz]

i think what happened was ore ran out before i upgraded mine! live and learn... :P

once that reseach is done need to run round upgrading them all quick!

[Betty]

But you can only upgrade endless deposits... There the ore never runs out.

[Opiliones]

Aye, it doesn't matter if the ore runs out or not, if it's endless you can upgrade it even then. If you hold your mouse over the ore icon it will say "0t mineable" but that you can build an endless mine nevertheless...

[Howser]

How do you make a gold or gem mine?

[Opiliones]

How do you make a gold or gem mine?

Just like you'd make an ore mine, you have to get the necessary amount of Merchants first though. And of course you need mining spots that provide gems/gold.