Ramp plate placing machine, National Gypsum Company
The equipment shown is probably associated with the National Gypsum Company quarry near National City, Michigan. The National Quarry (Tawas Quarry, Tawas Mine?) is an open pit gypsum mine that was an important gypsum producer in Michigan for decades. The National Gypsum Company began working the gypsum deposit here in 1925 and the existing town was renamed National City.