how actual resources like promethion, anti-matter, elerium mining works, if you would. Are they replenished over time, or are you only allowed one for each source that is mined for the duration of the game. Also if one of your ships so equipped gets destroyed, does that give you the resource back? It would seem to me that mining is a way to keep renewing your stock, but it doesn't seem to happen in the game. Info appreciated. Thanks