The simple implementation is to record the known ore reserves in
each belt and use this number, with impulse factor and mining
subskill, to work out the ore collected (and removed from the
known reserves) per action. A separate prospecting subskill is used
to increase the known reserves.
So at the extremes there are two styles of mining. In short-term "strip mining" players race into new areas and cream off the easiest ore, then move on before it gets difficult. In the long-term "sustainable" system players mix mining with prospecting to keep their yields reasonable in the same area indefinitly.
Prospecting should be difficult, especially at low skill levels, encouraging co-operating between separate mining and prospecting officers, whether within one ship or on different allied ships.
