study of the effect of blast pattern design on autogenous ... adjusting blasting to increase sag...
TRANSCRIPT
Study of the Effect of Blast Pattern Design on
Autogenous and Semi-Autogenous Mill Throughput at Gol-e-Gohar Iron Ore Mine
Authors: A.Hakami, H.Mansouri, M.A.Ebrahimi Farsangi, M.R.Dehghan and
F.Faramarzi
Presenter: Farhad Faramarzi
• Previous works
• About Gole-e-Gohar iron ore mine (Mine No.1)
• Fragmentation measurement
• SAG power index (SPI) test
• Conventional blast pattern vs. new blast pattern
• Mills performance before and after implementation
• Conclusions
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Table of contents
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Previous works
• The Mine to Mill concept (McKee, 1990)
• The relationship between fragmentation in mining and comminution circuit
throughput (McKee, 1995)
• Exploring the effect of blast design on throughput at KCGM (Kanchibotla et al., 1998)
• Blasting for reduced process plant costs at Argyle diamond mine (Bulow et al., 1998)
• Mine to mill blasting to maximize the profitability of mineral industry operations (Kanchibotla., 2003)
• Blast fragmentation for maximising the SAG mill throughput at Porgera gold mine (Grundstrom et al., 2001)
• Effect of Blasting on the Strength of Rock Fragments (Kemeny., 2003)
• Optimum blasting? Is it minimum cost per broken rock or maximum value per
broken rock? (Kanchibotla., 2003)
• Optimisation of the Cadia Hill SAG mill circuit (Hart et al., 2001)
• Adjusting blasting to increase SAG mill throughput at the Red Dog mine (Paley et al.,
2001)
• Mine to mill optimisation for conventional grinding circuits – a scoping study (Jankovic and Valery ., 2002)
• Process integration and optimisation; a case study in productivity improvement (Dance et al., 2007)
• The influence of blasting on Kemess hypogene ore milling (Hikita, 2008)
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Previous works
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Throughput gains of 5-15% have been recorded and confirmed at operations
with SAG mills such as (Jankovic and Valery ., 2002):
• Highland Valley Copper (Canada)
• Minera Alumbrera (Argentina)
• Cadia (Newcrest Mining in Australia)
• Escondida (Chile)
• Porgera (Placer Dome in Papua New Guinea)
• OK Tedi (BHP in Papua New Guinea)
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Previous works
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About Gole-e-Gohar iron ore mine (Mine No.1)
Gyratory Crusher
Crusher Stock piles
Bins
Line 3- AG 9m×2.05m
Line 1- SAG 9m×2.05m
Line 2- AG 9m×2.05m
Line 4- HPGR
Thickener Concentrate Stock piles
Crusher closed side set was 20 cm SAG : Operated at 5% ball charge Critical speed for SAG/AGs: 85% Mills are operated in dry mode Mills are air swept
Muck pile and Mills’ feed size distribution:
• Split-Desktop was used to carry out image analysis.
• Delineation was done manually and the 100% fines correction option used.
• Photos were taken by a digital camera during the excavation of muck piles.
• Stock pile distribution was also photographed before, during and at the
end of implementation.
• It was not possible to stop the belts for sampling and sieving belt cuts.
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Fragmentation measurement
• MinnoveEX SPI test developed by Starkey and Dobby, 1996. • It’s a laboratory batch test to evaluate comminution behavior
rocks and also SAG mills specific energy (Amelunxen et al., 2014).
• Why SPI? It was the only available equipment for evaluation ore hardness at Gol-e-Gohar laboratory.
• How SPI was done? The time required to; 2kg sample (F80<12.7mm) 2kg sample (P80<1.7mm)
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SAG power index (SPI) test
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Mills performance before and after implementation
Throughput: 30% Energy : -21% Throughput: 5%
Energy : -4% Throughput: 14%
Energy : -14%
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Mills performance before and after implementation
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524 472 485
549 538
0
100
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400
500
600
700
1 2 3
Trou
ghpu
t (t/h
)
Mill Number
Old blast pattern New blast patternNew Blasts
April May June July August September October November December January February March
• For the first time in Iran, a mine to mill blasting approach
implemented at Gole-e-Gohar iron ore mine No.1, “ A Good Start”.
• By increasing powder factor from 1.65 to 2.48 kg/m3 by a tighter
blast pattern and so finer ROM distribution; up to 30% increase in
throughput and also up to 21% decrease in the mills’ energy
consumption achieved, “A Good Result”.
• Studies should continue at Gol-e-Gohar iron mine by more blast
practices and comminution tests; if key decision makers accept the
concept/changes “A Sweet Hope” .
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Conclusions
Shahid Bahonar University of Kerman
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Acknowledgements
Gole-e-Gohar Mining and Industrial Company
Gol-e-Gohar Iron and Steel Research Institute