Summer Prepro

I have been, very casually working on my summer project. I gathered some reference and did a quick concept, for a concept painting.

Here is some of the reference I gathered. I want the walls of the cave and the walkway to be some kind of granite. I really like the black granite for the color and the more cloudy pattern. Ideally I would like to blend the two big images on the left together for the walls of this space and the walkway.

As far as shapes on the walls inside of the cave space I would to go along the lines of this:

Some more shapes I found interesting:

Here's the quick concept blockout. I am trying to get better at the readability of my paintings. I treated this kind of like a thumbnail. I started with a blockout in UDK that I threw together last week. I quickly painted over it to try and get a readable image. The bridge spanning the abyss is coming from the left. In this shot you are inside the alcove, near water level, looking up at the rotating harvester device and the collector door (on the right). I am going to try and mess around with the composition some more, but I'm getting close to something I'd like to spend a while on painting.