When you have a research center, you have a chance to "mine" technology cards daily - some of these cards are worth a LOT of money (miner operation cards, etc).
So anything mined could then be sold - in addition to all the daily rewards earned, etc
When you have a research center, you have a chance to "mine" technology cards daily - some of these cards are worth a LOT of money (miner operation cards, etc).
So anything mined could then be sold - in addition to all the daily rewards earned, etc