Wisconsin Geological Natural History Survey Sphale
The last mine in the district to operate was the bear hole mine near shullsburg ne sw sec 22 t1n r2e which closed in 1978 the mill at shullsburg closed about 1 year later some sphalerite calcite marcasite and other minerals can still be found on the dump piles most of the mines were in t1n r1e near benton and new diggings