Good looking mock up Christopher. It is interesting to see these stope mines. Where I grew up in MI the coalmines were all vertical shaft mines with a headstock building for the cable like this:
The building on the left is the headframe and hoistworks, you can see part of the headframe support on the outside of the building. A vertical shaft goes down to the level of the coal seam, and then horizontal stopes are cut into it from there. The building on the right is the boiler/power house along with the breaker facility and tipple to fill hoppers. This is Gage Coal Co shaft #8 in St Charles MI, and the headframe building still stands and is part of a "nature camp".
In the stope mines you are showing, how are the cars entering emptied? Hard to tell from these pics, but they seem to be gons, so there must be a car tipper in that building. Along with that question, I am curious exactly how they juggled the incoming gons. You can see a string of them entering, there must be a second track for the empties to leave by, otherwise only the first car in the string could be emptied. I wonder if the car tipper somehow lifts the car, dumps it and continues on over to a second track on the other side of it and sets it on the exit track? That building they are entering does not look wide enough for that, or even tall enough for a rotary car tipper. But, there is the open structure behind it too, that might have something to do with emptying the gons. I guess they might have shovelers emptying the gons too. I do not see any type of powerhouse which makes me inclined to think they are indeed using manpower to empty the gons from the mine, and also that means that they are using "breakerboys" instead of a mechanical breaker. A car tipper and /or breaker facility could be electrically driven I suppose, but then I do not see any sign of that either. I can see two grades of coal being loaded in the Raven pic, coarse on the two left tracks and fine on the right one.
These are just some thoughts about how this structure is operating. Not sure what you plan on doing as far as modeling the gons coming from the stope. I guess you could use HO track there.
Looks like a fun build,thanks for sharing and please keep us posted with your progress.