Attachment 3 Bat Cupola.pdf

This is a technical attachment document related to the Colorado Inactive Mine Reclamation Program for the PKAA Cottonwood Mine Closure Project. The attachment provides detailed specifications and engineering drawings for a bat cupola grating system designed for mine shaft closure. The bat cupola is a specialized ventilation structure that allows bats to exit sealed mine shafts while preventing other access. The design specifies a shaft grate constructed with 1¼" x 3/16" bearing bars spaced at 1³⁄16" on center, 1/4" round cross rods at 4" on center (type WXA 19-4-53), with alternate bearing bars tack welded to the grate frame. The cupola frame, constructed from 2"x2"x¼" angle iron, frames the opening in the shaft grate and extends a minimum of 24 inches above the grate, with a maximum cupola grating depth of 6 inches.

The technical specifications include detailed side view and plan view drawings that illustrate the precise construction methodology and material placement for the bat cupola installation. The cupola grating is welded to the framed opening to ensure structural integrity and create a sealed system. This component represents a specialized engineering solution within the mine reclamation project that balances environmental protection of bat populations with permanent mine closure requirements. The document serves as a reference specification for contractors bidding on or executing work associated with the Cottonwood Mine Closure Project.