smart(er) management of technical risk:

Transcription

1 New digital technologies for the smart(er) management of technical risk: Examples and added value Roussos Dimitrakopoulos COSMO Stochastic Mine Planning Laboratory -

2 Outline Introduction Optimizing mining complexes / mineral value chains with risk management Example from a gold mine: Higher value for lower risk New work: Waste management and risk Conclusions

3 Mining Complexes and Mineral Value Chains A mining complex may be seen as an integrated business starting from the extraction of materials to a set of sellable products delivered to various customers and/or spot market Mine A Critical facets of this integrated business are Mine B Mine C underlying uncertainties (stochasticity): materials produced from the mines metal s spot market price

4 CS 10th % CS 90th % Probability CS Average NPV Introduction - Risk Management and Risk Reporting % Deviation 120% 100% 80% 60% 40% 20% 0% -20% -40% -60% -80% Risk in Mining Australasian Examples New Celebration Jundee Mt Morgans Red Dome Union Reefs Plutonic Gwalia Nimary Yilgarn Star Core issue in deviations from expectations: Geological uncertainty (grades, material types..) Boddington Bluebird Kidston Macraes Flat Mt Muro Tanami Mine Copperhead Big Bell Paddington Granites Sunrise Dam Kanowna Belle Lihir Lawlers Yandan Baker and Giacomo (1998) Reporting Risk - Example: NPV Distribution NPV $ (million x 10)

5 Introduction Stochastic Workflow Stochastic Orebody Modelling Stochastic Mine Design & Production Scheduling Financial & Production Forecasts Sim. 1 s=1 Sim. 2 s=2 Sim. S s=s Simulated Orebody Models A set of simulations describe geological uncertainty and grade & material type variability Stochastic Design & Production Schedule Year A single mine design and production schedule accounting for and managing uncertainty Probabilistic Reporting If we can optimize mine designs with the established deterministic tools, we can also develop and optimize with stochastic optimizers: Stochastic Mine Planning 1. Lower risk in meeting financial and production forecasts. 2. Higher value for less risk. 3. Larger pit limits. 4. More metal. A better NPV is always obtained through the use of stochastic mine planning in comparison with conventional methods 5

6 Modelling Mining Complexes with Risk Management Production schedule Sulfides - Mine 1 Metal tonnes Total tonnes ξ s Sulfides - Mine 2 Metal tonnes Total tonnes No Economic Values for Mining Blocks Used Destination policies Processing streams Processing Stream A 1. Total metal 2. Total tonnes 3. Head grade 4. Recovery 5. Throughput 6. Metal recovered Decisions, GEOMET All move here Uncertainty can be quantified at any stage Product Value Customer #1 (Contract) 1. Metal 2. Metal value Customer #2 (Exchange) 1. Metal 2. Metal value

7 A Gold Mining Complex Mega Pit Extraction Capacity Sulphide piles Sage Autoclave Waste Dumps Other Sources TRJV Mill 5 Mag Blending is crucial! Vista Pit Oxide Leach Gold Juniper Mill Oxide stockpiles 7

8 Sources of Supply Uncertainty Other Sources Mega Pit TRJV Mill 5 Mag Stochastic simulations Sage Autoclave Historical data Sulphide Stockpiles Juniper Mill Vista Pit Oxide Leach Stochastic simulations 8

9 NPV Stochastic Schedule - Cumulative DCF Cumulative DCF - Cashflows 14% Year Mine s schedule P10 P50 P90 of Stochastic schedule 9

10 Au Stochastic Schedule - Recovered Gold Cumulative gold recovered 11% Year Mine s schedule P10 P50 P90 of Stochastic schedule 10

11 Acid Stochastic Schedule - Blending: Acid Consumption Acid consumption Year Limit for acid 12

12 Stochastic Schedule The Sequence is Also Different Stochastic Life-of-Mine schedule Full View Bench 4740 Bench 4520 The Mine s Conventional Life-of-Mine schedule Colors represent different mining periods (years) 13

13 Production Stochastic Schedule - More Ore, Larger Pit Simultaneous optimization of the mining complex decides the pit limits: 1 extra year of ore to the autoclave (Pit 11% larger) Conventional pit limit Stochastic pit limit CO3 Autoclave processed tons CO3 Year Conventional pit limit Stochastic pit limit 14

14 Stochastic Production Scheduling with In-pit Tailings and Waste Material Disposal Iron Ore Deposit (Section) Periods of extraction In-pit storage Period 0 Period 1 Period 2 Storage period 5 Storage period 6 Model: Accounts for uncertainty in chemistry of waste Uses the shape of the deposit Does not sterilize major ore zones Does not significantly affect the production Is practical with an evolving zone of storage Space saved

15 Conclusions A mining complex was seen as an integrated business starting from the extraction of materials to a set of sellable products delivered to markets New optimization technologies aim to maximize shareholder value, manage risk intelligently and address pertinent aspects of sustainability Improve reliability in an operation meeting production forecasts Generate larger amounts of metal to be produced from the same mineral resource Higher economic value than with existing approaches due to the ability of new smart technologies to directly manage risk