The entrance depends on the location. Some areas of Appalachia have folded and tilted rocks, and the coal seams follow the slopes, while others have more or less horizontal layers, and mines can go straight in. We live in one of the flatter areas, and although there isn't much coal close to us today, it was mined here years ago.
The map is very typical of older mines back here, and the layout long predates strip mines and conveyors. The entire trackage would be shoehorned into the bottom of a canyon, possibly with a crooked, narrow road on the other side, and the storage tracks would hold just enough cars to keep the mine running until the next train. Depending on the geography, there could be more or less tracks on either side, with two storage and one load being about as likely.
Even in the pre-conveyor days the mine itself, the actual hole in the ground, could be out of site, around a bend in the "holler", with only a tramway, probably electric with a trolley wire originally, leading to the tipple. By the 60s, battery trams were common, so all you'd need is the track. Back here, strip mines came later than in the West. If you really want to be adventuresome, model Keystone, WV, with its aerial tramway to the tipple.
Or, if you like trucks, model a truck dump at the tipple, and have a long line of coal trucks waiting to unload.
