Technical Report for the Maricunga Gold Mine - Kinross Gold

Kinross Gold CorporationMaricunga Mine Technical Reportsolution / ore solids separation suits the SART process as clear solutions are fed directly tothe primary precipitation reactor. For mill plants the leach slurry may be washed via CCDwith the overflow pregnant solution feeding a SART plant prior to carbon adsorption. Whenthe leach slurry feeds a CIP plant, the CIP tails (barren) may be washed in a CCD circuit andthen fed to a SART plant.In summary, the process involves lowering the solution pH to release the cyanide associatedwith the copper cyanide complex, allowing it to be recycled back to the leach process as freecyanide. Sulphide reagent is added to the acidic solution to precipitate the copper as a solidhigh-grade copper sulphide precipitate which can be filtered, dried, bagged and shipped to asmelter to generate copper revenue. Lime has to be added back into the solution toneutralize the acid and gypsum (calcium sulphate) will be formed as by-product. Thisgypsum will be stored in lined ponds.The location of the SART plant was chosen to be near the existing ADR plant at the base ofthe heaps in order to maximize the use of existing roads and services. A SART plant of 750m3/hr capacity was determined as optimal to treat a bleed stream from the leach solution(2,150 m3/hr) from the heaps. In this way, the capital outlay for the plant is minimized andthe SART plant can be taken off line without affecting gold production. A copper sulphideprecipitate (Cu 2 S at about 65% Cu) will be produced at a rate of approximately 5 to 10tonnes per day and is planned to be sold to the Enami smelter near Copiapo. Figure 16-4shows the Marigunga modified flowsheet incorporating the SART process.A process to apply for environmental permitting has begun with preparation of DIAdocuments leading to a construction permit. This feasibility study has mapped out the DIAapplication process steps and contains the process technical information that will be requiredfor the application documentation. The installation of a SART plant at Maricunga will involvesome changes to the existing operation and a DIA permit will be required. Main changes tothe Maricunga operation are: supply of sulphuric acid (about 15 t/day) and NaSH chemicalsto the mine, dispatch of copper sulphide precipitate (about 5 t/day) from the mine anddisposal of a gypsum product on site in a lined facility at the mine (about 20 t/day). A newEIS for Maricunga will not be required for the plant. The estimated timing for the permittingprocess following submission of the DIA is expected to be about 8 months and will not be onthe project critical path.76