Photograph of a birdseye view of the Main Quarry of the Bell Asbestos Mines, Thelford Mines, Canada, July 1928. A long, jagged staircase leads down the rocky mountain side on the right to the mining site in the center. The mining site is a collection of cars riding on intersecting tracks throughout the site and into the mine on the right. The tracks run through a dusty ground covered in equipment and rock debris. In the foreground an intricate, four-wheeled pulley sits on high wires that extend above the site.