Where were coal mines in Hamilton county Iowa?

Coal mines in Hamilton County Iowa

I know that one coal mine was located in section 10 of Webster Township. It was the Stockdale Mine on land owned by L.L. Peese in 1896. A man named Jim Thompson operated the mine, and three or four helpers were employed to run it. The mine was located on both sides of the ravine. The mining was done first on the north side of the ravine until the vein ran out. Then the operation was switched to the south side. This was the only mine in the county that mined from a tunnel and it had a higher sulfur content than other coal in the area. The others mines in the county were strip mines but I am not sure where those were located. The Stockdale Mine was closed up by the 1930's.