I've been wondering this, but can a terrain square run out of raw materials, totally and completely? Like if you mine a deposit dry and then prospect it again and don't find anything, can you just keep prospecting and eventually you will find another deposit, or is that square now empty forever? The rules left me a little unclear on how exactly this works. I basically want to know if a terrain square can be a continuous source of some raw material or another or if there comes a point where it's useless for mining?
Whether the RM deposit requires too high a sensor value, or is commpeletely empty, is unknown to us. However either way at the moment repeated prospecting without a higher compops/sensor combo will not reveal a new deposit.