@Cjsplash123: with rotor and wheel settings as-is, it won't dig down. In fact, it takes repeated passes and patience just to get it even.
If I want to start a controlled downward dig, adjust the rotor's lower limit to go just 1 or 2 degrees further, excavate until I've got a gentle downward slop, then set the rotor back to default -9° to continue digging at that angle.
Give it a try. While not perfect, it's surprisingly capable and forgiving for such a simple build.

I could never get mining rovers to work as i found that I couldn't control how it dug the terrain it then drove on and they all usually ended up in vertically nose down in a hole. How do you stop that?

LOVE!!!

N.O.M. vehicle blueprint on the workshop: https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1939417356

Scenario (VERY hard, not for beginners, also a 1GB download because of all the mods): https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1913859973
Splitsie's video series of playing this scenario (ongoing): https://www.youtube.com/playlist?list=PLfMGCUepUcNyhjLopHOlIrmz9xeepJWl7