I don't think that's an American prototype and I am not convinced it is actually even a coal mine structure. The nifty clerestory ventilators are just the sort of thing that coal mines in the U.S., especially small impecunious mines, would never purchase. The brick and stone base structure is also highly suspect; coal mines in the U.S. of small size were impermanent operations that had no spare cash for fixed plant of anything but the slipshoddiest construction.
As you point out it's highly incomplete, if indeed it's a coal mine structure.
Coal would MOST likely enter this structure through an elevated trestle (not shown) at floor level of B. That trestle would lead from either a portal into an adjacent hillside or from a headhouse from a shaft. The floor space in B is very small and only for miniscule quantities of coal would there be room for crushing or sorting -- really, all you can accomplish here is dump the car into a chute into a hopper or gon underneath. As for filling 2-3 cars an hour: it would be more like 2-3 cars per day in a mine this small if it's dumping mine cars. You could stick a conveyor belt in there and get better throughput, maybe 8 cars a day if you had a car puller to keep moving the cars forward. Or get a medium-sized Cat, Michigan or IH wheel loader, and after first using it to knock over this collection of sticks and shoving it into the nearest gully, use the space to load the hoppers directly.
The bays in E are so narrow you could hardly get anything bigger than a donkey-drawn 2-wheel cart into them. More likely that lump coal was dumped into them (3 bays, 3 sizes) and shoveled by hand into a wagon, cart, or pickup truck parked outside. Dropping lump coal is a really good way to turn it into slack coal, thereby destroying its value, so I'm dubious that this is really the purpose of the bays (again, not sure this is actually a coal mine!).
Coal picking (to size and clean coal) was entirely a hand operation until the 1920s even at very large mines. As labor costs grew and child labor laws and immigration restrictions cut out the lowest cost labor coal mines began mechanising to clean, crush, and size coal. These tend to be very big installations in order to achieve economy of scale, and there's hardly enough room in D to do anything but stick a small jaw crusher in there.
Slag is a byproduct of fusing (melting) rock to recover a desirable metal, or melting a metal in order to cast it. The impurities in coal that can be removed by hand or machine are rock, bone (carbonized rock), and tramp iron. Coal washing machinery can do all that plus reduce sulfur and ash content.
RWM
I would presume your letters are correct. A, B, C, D and E. Now here is a few tidbits.
You would want oil to spray onto the coal to keep dust down. Some mines did this and advertised it as such. Dustless coal etc.
The tipple loader GENERALLY had a pile of sorted coal to load into the hopper. USUALLY he had a chute to guide the coal into the hopper car. Most of the time the hopper car sat on a downgrade that is very gentle. There was a crewman on the ground that will have a iron bar and loosen the brake wheel of that hopper car to drift it as it is being loaded. Eventually that hopper car is drifted down to the loads outbound area.
Usually there are several more hoppers on that track BEHIND the tipple.
Mine trains came up in the morning, dropped the empties ready to be drifted under the tipples and departed with loads later in the day.
It would be a rather low output mine, but if you can find a bunch of mines along a branch .. say 4 of them suddenly that mine train is going to be groaning with coal coming back down.
Mine run coal had everything in it. Unsorted. Cheep.
Stoker coal I think were smaller pea sized coal.. probably sold for home coal heat/hot water units.
Baseball sized coal (Lump?) went to industry or shipping.
Other sizes got quite big but there I think was about 6 general differences in size with a specific family of end users for that size coal.
Most of the models we have of coal mines are single structures. I have this model, an N-scale one I picked up in eBay. I think it is an AHM, but I'm not sure.
Near as I can figure, A is the room that brings coal up the shaft and deposit it in B. In this room the slag and impurities are separated and the coal is sent to C where it is dropped into hoppers. I cannot imagine this operation filling more than 2 or 3 coal cars per hour due to the physical limitations if the size of the building. The slag is send down the chute to D where the lower grade coal is separated from the slag and it is dropped into one of the three E bays below. The slag is removed and the coal that can be sold is loaded into trucks or hoppers.
To me this seems to be an incomplete operation as there are no offices, rest rooms, equipment storage facilities, etc.
So the question are:
1) Am I right in my assumptions above?
2) What auxiliary structures would you expect to find in an operation this size?
3) Anything else needed to model the operation?
Chip
Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.