Geometallurgical evaluation of a complex polymetallic depositGregory J Harbort

Location

Deposit Structure

• series of fine-grained dolomitic sandstones and siltstones

• Contains lenses of massive pyrite and carbonaceous pyrite

Mineralogy

• Copper in chalcocite, covellite and chalcopyrite

• Lead in galena

• Zn in sphalerite

• Cobaltiferous-pyrite contains cobalt, nickel, arsenic and silver replacement of iron in the pyrite lattice.

• The deposit varies from oxide to transition to primary ore at depth.

Element Association

Categories for Flotation Tests Copper dominant material

Lead dominant material

Zinc dominant material

Copper-lead material

Copper-zinc material

Lead-zinc material

Copper-lead-zinc material

Cobalt dominant material.

Model Development

• Model flowsheet

• Interaction hierarchy

• Selectivity functions

• Recovery and grade estimation

• Treatment of misplaced concentrates

Model Flowsheet• Five stage sequential flotation circuit

– Carbonaceous prefloat– Copper circuit– Lead circuit– Zinc circuit– Cobalt-nickel pyrite circuit

• Rougher, regrind and cleaning stages

Interaction Hierarchy

Selectivity Functions

Selectivity FunctionsRelationship between slope of selectivity curve and Cu:Pb ratio

Relationship between slope of selectivity curve and Y axis intercept

Example of Expanded Equation

RPb(CuRgh) = (β∙(γ∙α+δ)+ε) ∙ exp((γ∙α+δ)∙ζ)

Conclusions• A geometallurgical evaluation was conducted on

a mine plan from the Walford Creek polymetallic deposit using selectivity or upgrading curve equations, developed from testwork.

• The geometallurgical model provided a reasonable estimate of performance, based on test results and similar operations.