Modern Mining June 2019

REGIONAL FOCUS: WEST AFRICA

at nine different mine sites in six countries, with the longest service life of over 10 years on one of the largest bullion producers within the African continent,” comments Peter Lotz, Gold Process & Environment Manager with MMSA. “We’ve seen our process increase gold recoveries between 2 % and 19 % in gold-pro- ducing operations. Former Randgold Resources (now Barrick), a major client of MMS, is using Aachen™ equipment at its Loulo and Morila mines in Mali, at its Tongon operation in Côte d’Ivoire, and at the Kibali gold mine in the Democratic Republic of Congo.” Adds Cardinal’s CEO/Managing Director, Archie Koimtsidis: “These highly encourag- ing results from the metallurgical optimisation programme are potentially an opportunity to further enhance the Namdini project finan- cial outcomes and should be incorporated into the process flowsheet being designed by Lycopodium. “The metallurgical optimisation test results recently received and evaluated show prom- ising recovery, capital and operating cost improvements, which can be achieved over and above the current outcomes justifying incorpo- ration into the Feasibility Study.” As a result of the positive leach results, which are expected to enhance Namdini proj- ect economics, further testwork samples have been submitted. Located within the Birimian terrane of north- eastern Ghana approximately 60 km south of the Burkina Faso-Ghana border, the Namdini gold deposit has so far been delineated over a strike length of 1 150 m, up to 350 m wide and 700 m deep, and is situated within the Nangodi greenstone belt. Cardinal, listed on the ASX and TSX, released the results of a Preliminary Feasibility Study (PFS) on Namdini in September last year that demonstrated that the project has the potential to be developed into one of West Africa’s most significant gold mines with a throughput capac- ity of 9,5 Mt/a and an average yearly production of 361 000 ounces of gold over a 14-year mine life. Capex – assuming the 9,5 Mt/a throughput model is adopted – was estimated at US$414 million with the project generating a 38 % post- tax Internal Rate of Return (IRR) based on a gold price of US$1 250/oz. As detailed in the PFS, the processing flow- sheet incorporates conventional primary single stage primary crushing with a gyratory crusher, two-stage SAG/ball milling in closed circuit with cyclones, re-crush, flotation (to produce a 15 to 17 g/t Au concentrate), regrind and a car- bon-in-leach circuit comprising one pre-leach

tank and seven CIL tanks for gold and silver adsorption. A gravity concentration circuit has been incorporated given the presence of grav- ity recoverable gold (GRG) and will consist of a gravity scalping screen, a single 70-inch centrif- ugal concentrator and a CS4000 intensive leach reactor. A 3,5-tonne split AARL elution circuit, electrowinning and smelting will recover gold and silver and produce doré on site. Since the PFS, Cardinal has announced a new ore reserve estimate based on an optimi- sation of pit designs, wall angles and mining schedules. The new reserve totals 5,1 Moz from

A typical Aachen™ installation on a gold mine.

June 2019  MODERN MINING  31