Impoundment Design for Precious Metal Tailings

Miller, Roger G.; Moldt, Steven F.; Johnson, Kathryn; ,

Impoundment Design for Precious Metal Tailings

by Roger G. Miller, Miller Consulting Engineers, Sheboygan, WI, USA,
Steven F. Moldt, Miller Consulting Engineers, Sheboygan, WI, USA,
Kathryn Johnson, Miller Consulting Engineers, Sheboygan, WI, USA,

Document Type: Proceeding Paper

Part of: Environmental Engineering

Abstract:

An engineering study and design of impoundments for the disposal of mill tailings in central Nevada is presented. Mill process waste is generated as flotation tailings and cyanide residue. Permeable site soils and environmental considerations required the prevention of infiltration of cyanide residue leachate into the subgrade. The cyanide residue impoundment was designed using a four-layer liner, utilizing on-site soils and chemical soil additives. Geochemical modeling of flotation tailings indicated potential for high concentrations of nickel to be present in the flotation tailings leachate. Analysis also indicated that placement of a thin layer of oxidized surface soils, high in soluble sulfates, on the bottom of the flotation tailings impoundment would be sufficient to react with tailings leachate and cause precipitation of ferric oxide and the associated removal of nickel, permitting flotation tailings leachate to dilute acceptably with groundwater. (Edited author abstract. )

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