Cyanide Attenuation Modeling

Cyanidation tailings disposed in a surface impoundment experience a loss of cyanide due to natural attenuation, which frequently reduces the cyanide concentration to low levels. Estimating the rate of cyanide loss as a function of impoundment geometry, local weather conditions and tailings chemistry can be conducted via computer modeling. Models are structured from “first-principles” using the impoundment water balance and detailed speciation of cyanide complexes within the decant pond. In the latest version of the attenuation model, the USEPA equilibrium model “MINTEQA2” was adapted for calculating aqueous equilibrium.

Site-specific models are developed to take into account:

• Total, WAD and free cyanide attenuation
• Iron-cyanide photolysis
• Integration of attenuation models into larger models of the tailings management system (CCD wash thickeners, cyanide detoxification, decant reclaim/treatment, etc.)

Read more about how natural cyanide attenuation is modeled in Modeling of Natural Cyanide Attenuation in Tailings Impoundments.

Read more about a case study for modeled versus actual cyanide attenuation at an operating mine in Africa in Cyanide Attenuation Modeling for the Newmont Golden Ridge Ltd Akyem Project.

Actual vs. Modeled Cyanide Concentrations

Surface Tailings Impoundment