actually Moops, using turns such as digging won`t do anything to the minerals that are above the limit... ONLY if you`re using turn/s to build ship/s then it will go back to the max cap value...
in fact, when you`re having planets with certain minerals, you can have more that certain minerals even above the limit when you`re using turn/s UNLESS you start to build ship.... i`m not sure about turns for research levels since i`ve maxed it... but digging won`t effect at all for minerals above the limit...
a good tip not to waste minerals above the limit... sell some of them until you reach below the max limit b4 building any ship... :)