Insights Session HPGR in the Iron Ore Industry Presented by Karri Dorrington, Process Engineer Mineral Engineering Technical Services Pty Ltd PO Box 5778 St Georges Tce WA 6831 P: (+61 8) 9421 9000 F: (+61 8) 9325 8311 ABN 66 009 357 171 W: www.metsengineering.com E: info@metsengineering.com > M i n e r a l P r o c e s s i n g > E n g i n e e r i n g D e s i g n > T r a i n i n g > S p e c i a l i s t S e r v i c e s
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Outline What is HPGR? Benefits of HPGRs Iron ore types around the globe HPGR use in the iron ore industry HPGR in iron ore plant design Testwork
What is HPGR High Pressure Grinding Rolls (HPGR) Similar to the typical fixed roll crusher Force applied to push one roll towards the fixed roll and raise pressure between the rolls Force on the material mainly compressive Source: Mine Engineer Website (2012) Introduces micro cracking favourable for further comminution Higher reduction ratios than fixed rolls
HPGR Reduced power consumption hard ores 10 to 15% Requires secondary crushed feed Reduced BWI Replaces SAG mill-smaller ball mill CAPEX similar 10% moisture in feed Source: Technomine Website (2012)
HPGR Source: World of Mining Professionals Website (2012) Source: Weir Minerals Website (2012)
HPGR vs Cone Crusher HPGR and Cone Crusher Product
Assay, % Magnetic Recoverey, % Benefits to Magnetic Separation 80 70 HPGR Coarse Cob Cone Coarse Cob 60 50 40 30 20 10 100 90 80 70 HPGR Coarse Cob Cone Coarse Cob 0 MgO Al2O3 SiO2 Fe Wt. 60 50 40 30 20 10 0 MgO Al2O3 SiO2 Fe Wt.
HPGR vs Cone Crusher More even size distribution Finer size distribution Lower magnetic recovery of gangue minerals such as MgO, Al 2 O 3 and SiO 2 Lower mass recovery Typically a higher iron grade (and other metallics)
Iron Ore Types Around the World Canada: Hematite, Magnetite USA: Hematite, Magnetite East Africa: Itabirite, Hematite Russia: Hematite India: LG Itabirite China: LG Hematite Brazil: Itabirite, Hematite South Africa: Hematite, Magnetite Australia: Hematite, Magnetite
HPGR in Iron Ore Processing Applied to iron ore industry mainly for regrinding of pellet feed to improve properties in the pelletising process Over time has been applied to other iron ore processes to improve concentrates Australia Magnetite (Karara) Vanadiferous, Titaniferous Magnetite (Future: Mount Peake) South Africa Hematite (Khumani) Brazil Itabirite (Samarco)
Karara Project JV project Long life magnetite concentrate operation (30+ years) Low-grade magnetite to produce a high-grade premium concentrate Have issues getting the power efficiency to the SAGs and therefore optimum operating 2011 installation of HPGR Installed downstream of the secondary crusher HPGR significantly lifted feed rates
Karara Project
Karara Project
Mount Peake Project FS Underway Polymetallic ore body Two stage HPGR installed after the secondary crusher Lower operating cost Efficient in producing the required feed size (two stages required) Micro-cracking Reduced mass recovery on coarse cobbing Changes to the process HPGR still beneficial
Mount Peake Project (Scoping Study)
Khumani Mine High grade hematite deposit in South Africa Formally BKM Project (Bruce, King and Mokaning) 10 Mt export quality iron ore per annum increasing to 16 Mt Civil construction began in 2006 December 2007 first delivery to Bruce primary crusher Late 2007 construction of jigs and HPGR HPGR utilised to reduce middlings particle size
Khumani Mine
Khumani Mine Single HPGR located after Jigging of the Lump Size reduction from -32.0 +6.0 mm to -6.0 mm More efficient than cone crusher Source: International Mining (2008)
Samarco Project JV between BHP Billiton and Vale Low grade itabiritic ore Ore Reserve = 451 Mt (wet) as of 2008 Conveyor belts transport the ore to the beneficiation plant, whilst a 396 km slurry pipeline transports the pellet feed to the pellet plant on the coast HPGR prior to grinding, de-sliming and flotation
Samarco Project
Samarco Project
Samarco Project
HPGR Plant Design Normally HPGR is located after the primary/secondary crushing Can replace tertiary crushing with SAG mill, where a ball mill is still required Can replace secondary/tertiary/quaternary crushing Not suitable for all ore types High fines/clays lead to impaired comminution High ore competency and abrasiveness will lead to increased wear rates High moisture (>10%) will cause washout of the autogenous layer
HPGR vs. SAG Mill Design 1. Original circuit design SAG/AG mills and ball mills (Huckleberry SABC circuit), however very energy intensive and also energy inefficient accounting for ~80% of the overall process plant energy (depending on the overall process) 2. Changes to design lead to HPGR and ball mill circuits, thus lowering the energy consumption costs slightly 3. Further examination, HPGR and stirred mills circuits demonstrated it is technically feasible and showed promising benefits over traditional options 1 2 3 Source: E&MJ News (2013)
Why Choose HPGR? What are the Drivers? Benefits to downstream processing magnetic separation, flotation, leaching Better energy efficiency lowering costs Replacement of equipment to increase grinding efficiency Willing to investigate with testwork to see if ore is amenable
Testwork Prior to selection of HPGR testwork is required Testwork involves: Pressure tests Roll speed tests Roll gap tests Testwork reveals if the ore is amenable to HPGR HPGR settings influence throughput, product size distribution and micro-cracking
References Karara Mining Ltd (2013) Energy Efficiency Opportunities KML Expansion Project TNG Limited (2012) Executive Summary Mount Peake Project Pre-Feasibility Study Moore, P (2011) Samarco An Iron Ore Pioneer, International Mining, Dec 2011 Burchardt, E (2013) HPGRs in Hard Rock Mining, Mining Magazine Wang, C., Nadolski, S., Mejia, O., Drozdiak, J., Klein, B (2013) Energy and Cost Comparisons of HPGR-Based Circuits, E&MJ News Morley, C (2010) HPGR-FAQ, Journal of the Southern African Institute of Mining and Metallurgy
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