The Monson-Maine Slate Company was in operation from 1880 to 1947 and was located at the end of Chapin Avenue in Monson. This photograph shows the state of business around 1920.

The road running between the two open pits is now paved and fencing protects people and animals from falling into the water filled quarry. The rail cars seen on the left of the picture were used to transport the slate from the edge of the pit to the buildings in the center, which was the main manufacturing facility.