This is the boiler house for the Amygdaloid Mining Co. on the west edge of Delaware. The foundation and "street" are still there but the site is completely over grown. US 41 runs just south of the houses in the right middle of the picture. This dates to about 1915, as does the photo below.
This is a boiler house for the Delaware stamp mill that was located at the mine. It is now rubble but it can be found on the south side of US 41.
This is the shaft house at C&H's Frontenac exploration. I made this one about 1964 or so. After WWII, C&H did some extensive exploring at this mine and produced some copper. This is located south of Central. Mining was completed when this photo was taken. There were not any commercial deposits found. The gapping hole in the building is where they removed the rock crusher.