Here 'tis. Version 1.0. Well, really I should call it 0.8 or something since it's not really fleshed out into a full plan. But hopefully the gist is there.
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I was also thinking along the same lines as zedob about working some sort of crossing at the 36" corner. I then took it a bit further setting up a crossing at the other side and taking advantage of the remaining bits beyond the turnback curves along each wall.
Grade is 3%. Not ideal, but you probably aren't going to be running very long trains here so it shouldn't be a problem. Curves are 24" minimum. Plan is drawn to 3/4" = 1'.
There's one staging track (could be two at most on that shelf) beneath the mine 'switchback'. I envision the mine area as mountainous and rugged, standing in contrast to the urban area directly across the aisle.
On the other side, as the main line rises along the east wall, a spur descends behind the turntable and roundhouse and ducks beneath the mainline (vs. the mine branch on the opposite side climbing over the main) to serve either the gravel industry or the intermodal facility. I'm picturing much of the elevated track on bridges with the long straight section on something like the 'city' viaducts from ME (I think...or is it city classics?...) to keep the turntable accessible and visible.
Please note this plan is not at all fleshed out, it is just a rough sketch. Additional spurs could be added. Getting a yard on here, or any sort of passing track with good access is going to be tough, if not impossible as drawn. But already I'm thinking of a totally different option you may not like at all but would reflect a more realistic approach. SO chew on this plan and tell me what you think.
Galen