Bond Work Index. Testing Regime. Verification. Elliot Britvec. Hanna Steadman. Nathanael Williams. Dr. Corby Anderson. 1 ...
Bond Work Index Testing Regime Verification Elliot Britvec Hanna Steadman Nathanael Williams Dr. Corby Anderson 1
Bond Work Index Background • A measure of required energy to grind a material down to a set size • Developed by Fred Bond, a Colorado School of Mines alumni
• BWI is now used worldwide
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Scope of Work • “Mining projects are showing an average budget overrun of 62%” due to inadequate planning • The grinding process is one of the most energy intensive processes in mining • Correctly predicting energy costs is crucial to budgeting • Claim is that the new Sepor produces a higher, but more accurate, Bond Work Index over the older BICO mill 3
Energy Saving Opportunities
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Bond Grindability Test • Size analysis of feed • Smooth mill • 20.125 kg of balls of various sizes
Sepor Ball Mill
• Grind material to below 149 µm • Size analysis of product BICO Ball Mill 5
Experimental Material • Dr. Husni Usman Material – Dr. Usman calculated the BWI to be 13.03 kWh/ton
• Australian JKTech Round Robin Material – Average BWI value is 15.39 kWh/ton
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Dr. Usman Material Results Test Number
P1 (µm)
Grams/ Revolution
P80 (µm)
F80 (µm)
BWI (kWh/t)
BICO 1
149
1.848
118.8
1867
13.67
BICO 2
149
1.912
116.2
1867
13.10
Average:
13.39
Standard Deviation:
0.403
Sepor 1
149
1.616
118.0
1867
15.20
Sepor 2
149
1.636
112.0
1867
14.53
Average:
14.87
Standard Deviation:
0.474
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Statistical Analysis of Usman Material Bico
Sepor
Mean
13.37
14.86
Variance
0.134
0.185
Pooled Variance
0.160
t Stat
-3.347
t Critical one-tail
2.920
t Critical two-tail
4.303
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Australian Material Results Test Number
P1 (µm)
Grams/ Revolution
P80 (µm)
F80 (µm)
BWI (kWh/t)
BICO 1
149
1.687
109.8
2759
13.24
BICO 2
149
1.778
111.2
2759
12.77
Average:
13.01
Standard Deviation:
0.332
Sepor 1
149
1.413
102.6
2759
14.67
Sepor 2
149
1.419
104.1
2759
14.75
Average:
14.71
Standard Deviation:
0.057
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Statistical Analysis of Australian Material Bico
Sepor
Mean
13.00
14.71
Variance
0.088
0.002
Pooled Variance
0.045
t Stat
-7.298
t Critical one-tail
2.920
t Critical two-tail
4.303
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Economic Analysis • CAPEX: Capital Expenditures are the investments incurred by a mining company in their fixed assets to increase the value of that asset. • OPEX: Operational Expenditures are the recurring costs for operating the mine.
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Economic Analysis • The cost estimates for the Bond Work Index Ball Mill used for each BWi test:
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Economic Analysis • The six-tenths rule can approximated if the capital cost of a similar item of different size or capacity is known.
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Economic Analysis • Using the six-tenths rule and Cost Mine models, the cost estimate for a plant size Ball Mill was calculated based on the BWi testing:
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Economic Analysis • The operational power cost estimates for 80,000 tpd plant size Ball Mills were also based off of Cost Mine models and the BWi testing:
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Conclusions • The Sepor machine produces a statistically different and larger value for BWI in the Australian material • This could have effects on engineering design for future mining projects • A larger testing program would be needed to further quantify the difference
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Acknowledgements • Dr. Corby Anderson • Professor Bruce Yoshioka • Professor Erik Spiller • Mr. Bob Phillips • Mr. Drew Willis-Sepor • Mr. Matthew Weier-JKTech • Mr. Mark Strauss 17
References •
“Opportunities to Enhance Capital Productivity,” Ernest & Young, London, UK, 2015. http://www.ey.com/Publication/vwLUAssets/EY-opportunities-toenhance-capital-productivity/$FILE/EY-opportunities-to-enhance-capitalproductivity.pdf
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“Mining Industry Energy Bandwidth Study,” BCS, Incorporated, Laurel, MD, 2007. http://energy.gov/sites/prod/files/2013/11/f4/mining_bandwidth.pdf
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“Sensitivity Analysis for Mineral Processing Projects”, PEC Consulting, Saint Louis, MO, 2015.
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D. Willis, private communication, Apr. 2016.
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J. B. Leinart, “Mining Cost Service”, Cost Mine, Spokane Valley, WA, 2015. 18
Questions?
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