Two large vertical openings are in the octagonal portion, each 12.5 by 60 feet (3.8 m × 18.3 m), on its east-southeast and south-southwest sides.

[3] Its cylindrical portion plus the top 5 feet (1.5 m) of the octagon are encircled by many large steel rods (called bands) for reinforcement.

[8][D] The lowest part of the stack is a concrete foundation or footing that is built on sloped ground with a grade of 21% (12°) because it is just below the top of a hill.

The floor of the stack is generally conical leading 17 feet (5.2 m) down below the brick chimney to a 5-by-33-foot (1.5 m × 10.1 m) rectangular grate, then into a 5-foot (1.5 m) square horizontal duct that exits the stack at the center of the downhill side of the foundation on its south-southeast side.

This allowed any valuable metal dust particles left in the flue gases that precipitated down to that conical floor to be collected by a car on a track within the duct and sent back to the smelter for more processing.

[E] The stack's brick portion is about 6 inches (15 cm) taller than the monument's 2015 height.

[9] The stack was designed to discharge exhaust gases from the various roasting and smelting furnaces at the smelter.

[6] The flue system and stack combined to provide a natural draft capable of carrying 3–4 million cubic feet (85,000–113,000 m3) per minute of exhaust gases.

Although the site of the smelter underwent some environmental cleanup, the general public is not allowed access to the stack itself because the soil around it is still hazardous due to contamination by the toxic metalloid arsenic as well as copper, cadmium, lead and zinc.