What is your dilemma? A dilemma presents at least two permissible choices, both of which are likely to cause some form of harm, and the where correct or best option is not immediately apparent without some analysis. (Sorry, it's the pedant in me, but I used to teach a course in ethics where ethical dilemmas were to be analyzed in two major assignments.)
Model building in our hobby is always contingent upon space, funds, time, and other resources. We all have to compromise on some aspect of our dreams. If I were you, I would have a 24" deep shelf, the main component, with a switching complex and the mine. Leading out to the crushing plant and ore loading facility, would be a single track mini-shelf going around a corner and taking up another wall. Try for curves in the 22"-24" range so you can run a Mikado as a switcher, or maybe a Fairbanks-Morse H series, or if you are modern era, a SD-40 or GP-38, or whatever. You would only need maybe 6 #5 or #6 turnouts to make it interesting and involved.