Near Graham's mill, on the east side of Grand river, the coal was shafted and is reported twelve to fourteen inches thick. It was not being worked when visited. A number of drifts and shafts have been operated in the vicinity for over forty years. The Mulberry coal at these mines, as at other places in the county, seems to be rather irregular both in distribution and thickness, varying between fourteen and twenty-four inches. The roof is a shale containing remains of plants.
Mining is done on a modified longwall method.
The floor is in places a limestone, but in others as much as four feet of shaly clay lies between the bottom-rock and the coal. The coal is hoisted by horse-power and consumed locally and at Chillicothe. A short distance north of the Cox mines the only rock exposed is sandstone. Coal has been mined at a number of places on the south bluffs of Grand river near Utica. Near the old mill site, the limestone at the top of the Henrietta formation outcrops about fifteen feet above water.