OK, lets do the maths. It takes 15000 units of Gold Ore to fill a barge. New London buys it for 30sc/unit. That is 450000 new SC (45 million old SC). A mining ship used to get about 2000 (20)sc/unit and for 6x 5000k transports = 20 x 15000 - 30 million old Sirus credits or 300k new SC. This leaves just 10 million (100k today to transport and make a profit on.
There is no money in mining it seems either for the miner operator or the transport pilot.