Draft of the Great Coal Mine Near Mauch Chunk

This schematic, drawn by Isaac A. Chapman, shows a draft of the great Coal-Mine near Mauch Chunk “exhibiting the various branches of the Rail-road leading from it and the situation of the workings on the 18 of July 1827”. The different benches of the mine were measured along the direction of the dotted line F.M. and were found as follows. Bench D at F is the upper surface of the coal when measured. Bench C.C.C. at G is 10 feet below F. Bench B at H is 15 feet below G. the mine then gradually descends to I. Bench A on floor of the mine is 18 feet below I. The descent is the gradual from K to L. Bench marked N at M is 39 feet above L.