On large maps with huge fleets of miners it gets really cumbersome if you run out of asteroids to improve before getting the next mining tech. This can lead to A LOT of clicking through notifications about a miner having its auto function disabled.
In fact, it would be nice if they just moved close to an asteroid belt (or skipped a turn) when there was nothing to improve, rather then shutting down auto and nagging you. The option to have it work that way (selected through the game options) would be very nice. That way when you finally DO get that next mining tech you dont have to go through and reactivate all the miners. Or if a mining base is destroyed someone would just fly there to rebuild it automatically.
Last game I played had 40 mining ships. and at times I would research only mining tech (despite it not being the ideal thing at the moment) just to prevent the total shut down of miners and having to manually reactivate them all later.