"The Tipple."
The coal was brought to it raw from the pit to the structure on the far right. Each coal car was lifted and turned over to empty it. The coal was taken up a conveyor to the building on the left. There is was sorted by lump or egg and eventually stoker coal. Stoker was originally dumped as useless and too small till furnaces were developed to use this waste product. The coal was sorted by being dropped in a shaking bin with holes in the bottom. Successive bins with smaller holes sorted all of it by size. Then the coal was washed. The waste slag can be seen being dumped in the upper left hand corner. The coal could then be re-loaded into coal cars by size, and shipped by railroad. Before coal was sorted by size any slag or slate lumps were removed. Originally this was done by hand. Later the coal and slag or slate was shot through water, the slag would remain lower than the lighter coal which was channeled off leaving the heavier slag behind. Sort of the reverse idea of a gold sluice.