on a mine you have the man/material shaft that runs down. the deepest you can go on a single is 3920 meters. this is due to the hp of the winder and the size of the ropes. the ropes weigh about 3kg/m so going down 3000 meters the weight of the ropes alone are 6 tons. so you need a lot of power to lift that up. if you go deeper you need a sub vertical shaft. there is also most often a vent shaft. the mines follow the reef and in south africa the gold reef runs at 17 degrees from the centre of Joburg outwards. some of the mines tunnels can run 20 Km from the shaft barrel. down there they have workshop / stores and cantains just like a underground city. the man cage runs at 18mters per second. thats about 65 km/h a lot faster than you lifts in buildings