Aureus Mining New Liberty Project Mining February 2014
Contents Geotechnical • Pit optimisation • Pit design • Mining Contractor • Groundwater management • Water management •
Geotechnical, Mine design and Water management support AMC input on: – Updated Geotechnical assessment – Pit design and optimisation – Calculation of Reserves – Development of High level production schedules – Design of ROM Pad – Design and sequencing of Waste Rock Dumps • RPS Aquaterra input on: – Surface water assessment and pumping recommendations – Pumping tests on monitoring boreholes – Groundwater assessment and – Development of groundwater model • Knight Piesold input on: – Geotechnical stability of areas under TSF, WRD, MC Dams 3
New Liberty: Mining Schedule Highlights • Updated geotechnical model and slope LOM Production and Grade design 140 4.5 4 120 • Production evenly distributed over LOM – mining design has a high level of 3.5 100 confidence 3 80 2.5 • Reserves contained within open pit at depths of 180-220m below surface 2 60 1.5 40 • WRD wraps around pit and backfill into 1 Larjor pit 20 0.5 • Annual waste mining rate of 25Mt for four 0 0 years using mining contractor Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Production + Inferred (koz) Production (koz) - LHS Head Grade (g/t) - RHS 4
Key Mining Points • In situ reserves of 924koz gold at 3.4g/t (contained in 8.5mt) • Pit is 2km long, 420m wide and 220m deep • Mine life = 8 years W • Total ore mined = 8.5Mt • Total mined tonnage = 140Mt E • Stripping ratio = 15.5:1 • Mining cost $3.06/t mined* • Gold produced = 859koz * Includes cost of fleet 5
Experienced Mining Contractor: Banlaw Africa Ltd. • Combined executive management experience of over 50 years in similar West African environments • Mining at Bonikro gold mine (Newcrest) in Cote d’Ivoire • Experience on various projects in Ghana (Gold Fields), Burkina Faso (High River, Bissa), Cote d’Ivoire (Endeavour, Agbaou) and the DRC (Banro, Twangiza) • Banlaw’s management team are well known to the Aureus management & project team Mining Contract • Developed from the detailed AMC mine plan • All-in cost includes establishment & mobilisation, load & haul, drill & blast, pre- split, RC grade control and fixed costs for the life of mine • New mining fleet agreed 6
Material Movement by Stage Material Movement by Stage 8.0 7.0 Tonnes (Mt) 6.0 5.0 4.0 3.0 Mining 2.0 1.0 •2 km long open pit - operation, 220m deep Year 0 Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Stage 1 Stage 2 Stage 3 Stage 4 Stage 5 •Staged mining sequence Larjor planned Latiff Kinjor •High grade (3.4g/t) allows 3 for lower throughput, hence 4 2 1 Marvoe smaller plant – 1.1Mtpa 5 7
Ore Production Mined Ore Tonnes and Grade 0.5 6.0 0.4 5.0 0.4 Mined Ore Grade (Au g/t) 0.3 4.0 Mined Tonnes (Mt) 0.3 3.0 0.2 0.2 2.0 0.1 1.0 0.1 0.0 - Year 0 Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Mined Ore Tonnes Mined Grade (g/t) Mined Grade (g/t) FS 8
Waste mining and strip ratio Mined Tonnes and Strip Ratio 7.0 60.0 6.0 50.0 5.0 40.0 Mined Tonnes (Mt) 4.0 Strip Ratio 30.0 3.0 20.0 2.0 10.0 1.0 0.0 - Year 0 Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Mined Waste Tonnes Mined Ore Tonnes Strip Ratio 9
Ounces Produced Ounces Produced and Cumulative Ounces Produced 45 1,000 900 40 800 Cumulative Ounces Produced (koz) 35 700 30 Ounces Produced (koz) 600 25 500 20 400 15 300 10 200 5 100 0 - Year 0 Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Gold Produced (Au oz) Gold Produced (Au oz) FS Cumulative Ounces Produced FS Cumulative Ounces Produced 10
Cash flows and revenues Mining Cost and Cost Per Tonne Mined 18.0 3.5 16.0 3.0 14.0 Cost per Tonne Mined ($ millions/t) 2.5 12.0 Mining Cost (US$M) 2.0 10.0 8.0 1.5 6.0 1.0 4.0 0.5 2.0 0.0 - Year 0 Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Total Mining Cost Cost Per Tonne Mined 11
Grade Control Aim • Define mineralisation boundaries and minimise dilution • Define mining blocks Prior to mining • RC drill programme on 15x15m grid planned • Drill 1 year’s production in advance, ~ 8,000m/ year • Reconcile with orebody block model (based on a 30x30m grid) • Establish detailed distribution of gold and incorporate into mine planning 12
Grade Control Production • RC drilling in dry season in advance of mining • Sample blastholes (10m benches) • In pit geological mapping – structures, bleaching, silicification, sulphides, mag sus. • Reconciliation of grade control work with both orebody model and plant figures • Marking out of grade blocks (minimum mining width of 2.5m) • Blast design to separate waste from ore • Selective mining - 2.5m flitches on 10m benches • Blending on ROM pad near crusher to ensure steady feed to plant • High, Medium & Low grade stockpiles and Mineralised waste 13
Waste Rock Dumps • The WRD is a wrap-around dump between 30-40m high • Protection provided below the MCDC dams – placing a barrier between the dams and the pit • Dumps are flat and cheaper to construct • Flatter dumps will be easier to rehabilitate and will be visually less obtrusive FS Nov 2012 • Dumps will help to limit the inflow of Waste Dump located surface water into the pit during the rainy to south of Pit season • Drainage on the dumps will be managed 14
End of Pre-strip (Year 0) Construction of; culverts and flood-ways, permeable bund locations. Construction of; Construction of; haul roads, Larjor drainage channels. perimeter safety bund/road. Latkin drainage channel. ROM Pad built up to crusher level Skyway built. 15
End of Year 1 Mining North, South East and Priority dumping in North and North West Waste Dump East Dump built up to Dump reduce haulage distances. abuts dam walls. control surface run-off Low-grade stockpile area to be built up to pad level with oxide. The oxide can be reclaimed for capping TSF at end-of-mine. 16
Geotechnical Data Work completed in 2013 Work undertaken: • New data acquired Campaign of targeted drilling into interpreted geological structures (7 holes) – Detailed geotechnical surveys on selected holes (20 holes) – • Structural model of pit updated & 8 domains defined Outcomes/ Conclusions: • No significant geotechnical risks highlighted • Quality of geotechnical database improved • Improved confidence in the geotechnical model and in slope designs • Likelihood of toppling failure is considered low • Satisfactory Factors of Safety achieved in the calculated slopes • 15m geotechnical berm introduced as additional safety measure • Slope design parameters outcomes: – Bench face angle 70⁰ & 75⁰ (steepened from 65⁰ in Feasibility study) – Overall slope angle 48⁰ (broadly similar to Feasibility Study) – Local areas of slope de-watering recommended 17
Water Management – work completed • Predominantly rainfall dominated system: Rainfall seasonal with wet season from July - September. Dewatering system designed to minimize pit days following storm events • Surface water management updated based on new waste dump and infrastructure • Storm event pit inflows revised based on new designs. 18
Water Management • Waste rock dump designed to minimize pit inflows Dumps profiled to drain water away from pit catchment • All flows within pit catchment dealt with by in-pit pumps • Main discharge channel and sedimentation basin developed by optimizing natural • drainage to south • Groundwater investigation completed • Numerical groundwater flow model developed • Groundwater pit inflows updated • Groundwater drawdown updated • Staged dewatering strategy and design • Depressurization modelling completed 19
Staged Pit Dewatering Strategy and Design: Phased plan for pump locations, sump locations and pipelines Year 1 Year 6 Year 2 Year 8 Year 3 Number of Sykes HH220i Pumps Final Pit Sump Pumps Transfer Station Pumps Year 4 High Head Pump or inclined dewatering Larjor bore(s) used following backfill of Larjor Pit Latiff 1 5 Kinjor 1 Marvoe 1 1 NB One extra sump pump will be required as a standby 20
Groundwater Modelling Drawdown and Inflows • 3D numerical groundwater flow modelling completed • Modelling estimates groundwater pit inflows and regional groundwater level drawdown • Groundwater pumping will generally range between 15 to 40L/s; less than 10% of the 210-240L/s capacity of the sump pumps which are required to deal with storm run-off GW Model Final Pit Drawdown GW Model Pit Inflows 21
Conclusions • Mining to be advanced in dry season, creating more flexibility in wet season • Mining rates and pit design optimised to minimise costs and maximise ore availability • Good grade control key to maximising recovery from ore • Increased geotechnical confidence - managing against pit failures • Surface water flows managed through runoffs and pumping • Groundwater managed through pumping, drain holes and pit design • Waste dump design minimises haulage costs, aids safety, water management and restoration potential 22
Thank you www.aureus-mining.com
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