Description: The ventilator tunnel begins at floor level in the center of the south kiva wall. From here it extends under the south wall for at least 90 cm to the point where it intersects the vertical shaft which rises to the ground surface. The floor of the tunnel is bedrock. It slants uphill at a slight (10-15°) angle, following the natural plane of the bedrock. The walls of the tunnel are made of sandstone blocks, and the roof of the tunnel was once formed by wooden lintels. The tunnel opening is roughly circular and measures 30 cm in diameter. Its length is known to be greater than 90 cm, but its total length is presently unknown, as it was not completely excavated.
Across the opening of the tunnel, the Anasazi excavated a narrow slot 35 cm long, 3 cm wide, and 1 cm deep into the bedrock. This slot was dug to accomodate a slab that, when placed in an upright position, sealed the tunnel. This effectively "shut down" the ventilator system and prevented drafts from entering the kiva.