Study of the Effect of Blast Pattern Design on Autogenous ... Adjusting blasting to increase SAG...
Transcript of Study of the Effect of Blast Pattern Design on Autogenous ... Adjusting blasting to increase SAG...
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
2
Table of contents
3
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)
4
Previous works
4
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)
5
Previous works
6 6
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.
7 7
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)
8 8
SAG power index (SPI) test
10
Mills performance before and after implementation
Throughput: 30% Energy : -21% Throughput: 5%
Energy : -4% Throughput: 14%
Energy : -14%
11
Mills performance before and after implementation
374
524 472 485
549 538
0
100
200
300
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” .
12
Conclusions
Shahid Bahonar University of Kerman
13
Acknowledgements
Gole-e-Gohar Mining and Industrial Company
Gol-e-Gohar Iron and Steel Research Institute