> thought I might have got it but alas no. Been thru the mines again a few times, counted my steps down to the black level and can get there in 9 moves without jumping down anywhere but still can't find the black level exit/catch up to mine cart. I always seem to access the black level after I have passed the stream on the red level, am I going wrong before I get to this point? I've tried making maps but can't seem to find anything new still. I'm beginning to think I must be missing something obvious.

Ah, if you pass by the stream on the red level, you went the wrong way, and you'll have to go up all the way to the white again to get on the right track. Try getting back to the start of the caverns (white level, just to the east of where you jump) and then going south first. From there, just don't take any of the downward jumps and you should be able to get down to the exit on the black level.