Comminution Energy and How to Reduce it. Tim Napier-Munn JKMRC (UQ) and CEEC

Transcription

1 Comminution Energy and How to Reduce it Tim Napier-Munn JKMRC (UQ) and CEEC

2 Comminution is the major consumer of energy on the minesite. It is a significant component of total global electricity consumption. It is an important component of project capex and opex, and GHGe emissions.

3 tonnes CO2 (e) Typical minesite comminution energy footprint 1999 Leinster Nickel Operations CO 2 Emissions 40,000 35,000 30,000 25,000 20,000 15,000 10,000 Sulphur Kerosene Coke LPG Petrol Diesel Electricity Natural Gas 5,000 0 Load & Trucking Drilling Tramming Services Crews Persy Cage Winder Persy Skip Winder Persy Underground Persy Ventillation Rocky's Reward Crushing (surface) Grinding Flotation Reagents Concentrate Drying Filters/Drier Area Tailings Conc. Transport Site Services,A... Engin & Maint. Compressed Air Process Water Potable Water Borefield Other,Admin etc Source La Nauze, Temos 2002

4 Source CSRP Energy use in the mining industry

5 blasting 14 Extraction digging 44 drilling 35 dewatering 5 ventilation 28 Materials Handling diesel electric crushing 25 Beneficiation & Processing grinding 356 separations Energy Savings Opportunity (Trillion Btu/Year) Source: Mining Energy Bandwidth Study (Draft 2007) Potential energy savings in the mining industry

6 Energy consumption in international mining industry

7 Comminution consumes 1-4 % of all electrical power generated in the world (7-10% in Australia) (Report of the US NRC Committee on Comminution and Energy Consumption, 1981; Prof. Fuerstenau, Berkeley University, 2003; etc.) About 50% of minesite energy consumption is in comminution Consumption of electrical energy

8 Ore Grade Average Ore Grades Over Time 8 7 Copper Grade (%) Lead Grade (%) Nickel Grade (%) 6 Gold Grade (g/t) Year Things are only going to get worse

9 Energy (kwh/t) Energy & grind size 100,000 1.E+05 10,000 1.E+04 1,000 1.E+03 1.E E E+00 1 The abyss Future Current operations 1.E E E E E E E+03 1,000 10, E+04 Source: Hukki RT, 1961 Particle Size (micron) Things are only going to get worse

10 Grinding is expensive in capex, opex and GHG emissions. It has very low energy efficiency: perhaps 20% in practical terms and only 3-5% in fundamental terms.

11 The march of technology

12 Newcrest Cadia SAG mill, 40, 20 MW

13 Citic AG mills, 40, 26 MW (x 6)

14 Oyu Tolgoi ball mills (6 x 11.4 MW)

15 Very big mills on order

16 What are the solutions?

17 Incremental improvements Barrick Gold Findings : Energy and GHG Reductions from Three Improvement Events 60,000 MWh annual savings 0.5% net efficiency improvement for Barrick global 43,000 tonnes of CO 2 (e) annual reduction Average improvement of 5.3% for 3 mine sites total energy. $5.2 million annual direct electrical savings $1.1 million potential future annual savings with CO 2 projected at $25/tonne Reference: Buckingham et al, 2011; Improving Energy Efficiency in Barrick Grinding Circuits

18 Smart blasting

19 Don t grind: pre-concentrate Jig Electromagnetic sorter

20 Novel flowsheets

21 Novel flowsheets

22 Novel flowsheets 60% reduction in total energy 3% increase in metal recovery

23 Do we need AG/SAG mills at all?

24 Plasma Mill HPGR Isamill SelFrag New comminution technology

25 Researching the fundamentals Courtesy N. Djordevic, JKMRC Finite element modelling of rock fracture

26 Researching the fundamentals Courtesy CSIRO Discrete element modelling of milling

27 Optimising the value chain - geometallurgy Each Model Cell to Contain Metal Content (Ounces) CO 2 Produced (CO 2 /Oz) Total Water Consumption (Ml/Oz) Total Energy Consumption (kwhr/oz) Total Cost (oz) Courtesy CSIRO Courtesy CRC Ore

28 THE MET S VIEW WHAT S a 2? MINING ENGINEER METALLURGIST GEOLOGIST

29 Professional development

30 The Coalition for Eco-Efficient Comminution Vision To accelerate implementation of energy-efficient comminution strategies through promotion of research, data and industry benefits Not for profit company, supported by donations

31 CEEC Sponsors

32

33 How? information and awareness Key papers & reports posted to website. LinkedIn technical discussions. Presentations at conferences. Media. CEEC Medal. CEEC workshop, June 2012.

34 Stretch Targets 20% energy reduction now 40% by % by 2050

35 The takeaway message 1. Comminution is very expensive. 2. We need smart ideas to reduce comminution capex, opex and GHG. 3. There is no shortage of smart ideas. 4. But we need a synthesis: whole > sum. 5...and investment in innovation.

36 Acknowledgements Elizabeth Lewis-Gray (Gekko/CEEC) Sarah Boucaut (CEEC) Prof. Malcolm Powell (JKMRC) Suzy Lynch-Watson (formerly JKTech, now Metso) Dr Mike Daniel (CMD Consulting/CEEC) Dr Zeljka Pokrajcic (Worley Parsons/CEEC) Diana Drinkwater (JKTech) CEEC s sponsors

37 The measure of a man is what he does with power - Plato ( BCE)