Autominers only work when they are loaded in. If you go too far from them they will stop until you come back, where they will increase production to make up for the resources which should've been mined while you were away.
I thought you'd watched and commented on my video about this topic? Did it not help?:
Yeah, the Auto-miners will only spit out resources while you're within about 500 meters of them. But if you've been beyond that for a long time they should produce resources 3 times faster until they catch up with what they should have made while they were unloaded.