While I like the quality of the game graphics very much, there is one usability issue concerning the two miners.
The silver resource is light gray, and the ore is brown. But the silver miner is wearing a brownish shirt, while the ore miner is wearing a light gray one. This is counterintuitive and makes it harder to learn how each colonist looks like.
Switching the two graphics might confuse some current players a bit, but will make it easier for all the upcoming players.
The colours of the miners was changed a while back. Closing.