So I took a long hard look at this thing and I can't help but to agree with some others here that it doesn't look like a resource miner to me - The concept is great and it I love it, but I still imagined something more massive and a bit more logical than a autobot that "picks up ore with a claw hand" - So I was thinking about it and I came up with an idea,
What I was thinking was something more along the lines of this:
It's a very rough sketch, but you should get the idea,
The idea was that the drillarm is replaced with this big drill module that consists of
1. The drillhead - it does the basic job of mining into the ground and finding resources
2. The rotor (orange bit) - a powerful gravitational engine around the drillhead that basically sucks all the mined stuff up (I don't know technical stuff, but it can probably be done with some scifi tech)
3. The separator (blue bit) - it separates the crap from the valuables and feeds it up
4. The collector - Valuables (Green) are transported to the resource sphere and Crap (Red) gets reintroduced to the surface (perhaps slowly creating ramparts/dirt walls around the MEKA, giving it a more drill-site feel)
Finally It'd be wise to stabilize out the rig with either Triple or Quad legs and have the other arm (now open) function as a sort of defense station, perhaps sporting a usable or automated turret (obviously can be upgraded)
Anyways this was my idea and I hope this gets as feedback as possible - I feel it would give the MEKA a more bulky and dangerous but also a more practical feel