M is for Mine, a subject I love to study -- both photographically, and historically. This is the Quincy Mine Number 2 shaft-rockhouse, which is 101 years old. It was a combined shafthouse (covering the shaft opening) and rockhouse (processing the rock brought up from underground).
The long beams in the foreground are batter braces -- strong beams designed to oppose the forces of the hoisting rope, which entered the building near the top. The hoist would bring rock-laden cars up from more than 9000 feet into the earth, which required enormous speeds and forces. After being unloaded near the top, the rock was sorted, processed, and ultimately dropped into waiting train cars near the bottom.