6
CONCLUSION
The Bond ball mill work index test is empirically calibrated
to a very specific feed preparation and is sensitive to changes
in the product size. It is always desirable to conduct the test
“properly,” but for circumstances where that isn’t possible
(Eg. only a fine feed is available), correction algorithms are
available to salvage value from the tests.
The Morrell Mib parameter is even more sensitive to
these disturbances, and requires correction for product size
any time that the test P80 deviates from the model P80.
The Levin B value is another parameter that practitio-
ners can extract from a Bond ball mill work index deter-
mination. This metric is useful for performing Quality
Assurance on the laboratory tests, and is used in certain
Functional Performance efficiency bench-marks on ball
mill circuits.
ACKNOWLEDGMENTS
This paper was first published in the Procemin·GEOMET
2022 conference held October 5–7, 2022 in Santiago,
Chile. Minor changes have been made to this manuscript
for MineExchange.
The Authors wish to thank the following for providing
samples and laboratory assistance in generating the con-
cepts described in this paper.
• Centerra Gold, Mount Milligan mine (Canada)
• ALS Mineral Services (Canada)
• Milan Trumic at the University of Belgrade
NOMENCLATURE
–α—the exponent measured in a signature plot, interpreted
according to Hukki’s Conjecture (unitless)
B—the Levin B value that represents the amount of indus-
trial machine power consumed per rotation of a laboratory
mill (mWh/rev)
E—specific energy consumption (kWh/t)
F, F80—the 80% passing feed particle size (μm)
Ftest—the 80% passing size observed in the laboratory test
(µm)
Fd%passing—the percentage of the feed to the test that
already passes the closing screen size
G—net mass of undersize product per unit revolution of
the mill (g/rev)
K—coefficient measured in a signature plot, interpreted
according to Hukki’s Conjecture (unitless)
Mib—the Morrell ore hardness index for ball milling
(kWh/t)
P100—closing screen size (μm)
P, P80—the product 80% passing particle size (μm)
Ptest—the 80% passing size observed in the laboratory test
(µm)
Pdesired—the 80% passing size desired to run the work
index calculation at (µm)
Sd_bwi—the modified ball mill work index obtained from
the product of a SAGDesign laboratory SAG mill (metric
basis)
Wi—work index (treat as unitless, metric basis)
REFERENCES
Bond, F. (1952). The Third Theory of Communition.
Transactions of the American Institute of Mining, and
Metallurgical Engineers(193), 484–494.
Bond, F. (1962, February). More Accurate Grinding
Calculations. Preprint of the Transactions of the AIME.
Retrieved from www.onemine.org/document/abstract
.cfm?docid=15458 5
Doll, A., Morneau, A., Dupont, J.-F., &Michaud, D.
(2020, January). A Simple Method Of Assessing
Ball Mill Health Using Bond Tests And Functional
Performance. Proceedings of the 52nd Annual Canadian
Mineral Processors Operators Conference, 21–23.
Retrieved from sagmilling.com/articles/37/view/2020
CMP -Alex Doll.pdf?s=1
GMG. (2021). Determining the Bond Efficiency of
Industrial Grinding Circuits. GMG01-MP-2021,
Global Mining Guidelines Group. Retrieved from
gmggroup.org
GMG. (2021b). The Morrell Method to Determine
the Efficiency of Industrial Grinding Circuits.
GMG04-MP-2021, Global Mining Guidelines Group.
Retrieved from gmggroup.org
Hukki, R. T. (1962). Proposal for a solomonic settlement
between the theories of Von Rittinger, Kick, and Bond.
Transactions of the American Institute of Mining and
Metallurgical Engineers(223), 403–408.
Josefin, Y., &Doll, A. (2018). Correction of Bond Ball Mill
Work Index Test for Closing Mesh Sizes. Proceedings of
the 14th International Mineral Processing
Conference (Procemin·GEOMET), 200–216. Retrieved
from www.sagmilling.com/articles/36/view/Correction
of Bond Ball Mill Work Index Tests for Closing Sizes
.pdf?s=1
CONCLUSION
The Bond ball mill work index test is empirically calibrated
to a very specific feed preparation and is sensitive to changes
in the product size. It is always desirable to conduct the test
“properly,” but for circumstances where that isn’t possible
(Eg. only a fine feed is available), correction algorithms are
available to salvage value from the tests.
The Morrell Mib parameter is even more sensitive to
these disturbances, and requires correction for product size
any time that the test P80 deviates from the model P80.
The Levin B value is another parameter that practitio-
ners can extract from a Bond ball mill work index deter-
mination. This metric is useful for performing Quality
Assurance on the laboratory tests, and is used in certain
Functional Performance efficiency bench-marks on ball
mill circuits.
ACKNOWLEDGMENTS
This paper was first published in the Procemin·GEOMET
2022 conference held October 5–7, 2022 in Santiago,
Chile. Minor changes have been made to this manuscript
for MineExchange.
The Authors wish to thank the following for providing
samples and laboratory assistance in generating the con-
cepts described in this paper.
• Centerra Gold, Mount Milligan mine (Canada)
• ALS Mineral Services (Canada)
• Milan Trumic at the University of Belgrade
NOMENCLATURE
–α—the exponent measured in a signature plot, interpreted
according to Hukki’s Conjecture (unitless)
B—the Levin B value that represents the amount of indus-
trial machine power consumed per rotation of a laboratory
mill (mWh/rev)
E—specific energy consumption (kWh/t)
F, F80—the 80% passing feed particle size (μm)
Ftest—the 80% passing size observed in the laboratory test
(µm)
Fd%passing—the percentage of the feed to the test that
already passes the closing screen size
G—net mass of undersize product per unit revolution of
the mill (g/rev)
K—coefficient measured in a signature plot, interpreted
according to Hukki’s Conjecture (unitless)
Mib—the Morrell ore hardness index for ball milling
(kWh/t)
P100—closing screen size (μm)
P, P80—the product 80% passing particle size (μm)
Ptest—the 80% passing size observed in the laboratory test
(µm)
Pdesired—the 80% passing size desired to run the work
index calculation at (µm)
Sd_bwi—the modified ball mill work index obtained from
the product of a SAGDesign laboratory SAG mill (metric
basis)
Wi—work index (treat as unitless, metric basis)
REFERENCES
Bond, F. (1952). The Third Theory of Communition.
Transactions of the American Institute of Mining, and
Metallurgical Engineers(193), 484–494.
Bond, F. (1962, February). More Accurate Grinding
Calculations. Preprint of the Transactions of the AIME.
Retrieved from www.onemine.org/document/abstract
.cfm?docid=15458 5
Doll, A., Morneau, A., Dupont, J.-F., &Michaud, D.
(2020, January). A Simple Method Of Assessing
Ball Mill Health Using Bond Tests And Functional
Performance. Proceedings of the 52nd Annual Canadian
Mineral Processors Operators Conference, 21–23.
Retrieved from sagmilling.com/articles/37/view/2020
CMP -Alex Doll.pdf?s=1
GMG. (2021). Determining the Bond Efficiency of
Industrial Grinding Circuits. GMG01-MP-2021,
Global Mining Guidelines Group. Retrieved from
gmggroup.org
GMG. (2021b). The Morrell Method to Determine
the Efficiency of Industrial Grinding Circuits.
GMG04-MP-2021, Global Mining Guidelines Group.
Retrieved from gmggroup.org
Hukki, R. T. (1962). Proposal for a solomonic settlement
between the theories of Von Rittinger, Kick, and Bond.
Transactions of the American Institute of Mining and
Metallurgical Engineers(223), 403–408.
Josefin, Y., &Doll, A. (2018). Correction of Bond Ball Mill
Work Index Test for Closing Mesh Sizes. Proceedings of
the 14th International Mineral Processing
Conference (Procemin·GEOMET), 200–216. Retrieved
from www.sagmilling.com/articles/36/view/Correction
of Bond Ball Mill Work Index Tests for Closing Sizes
.pdf?s=1