Benchmarking: Specific Energy Consumption Models

Benchmarking: Bond/Barratt - Cadia East (underground)

Engelhardt, D., Robertson, J., Lane, G., Powwel, M.S. and Griffin, P., Cadia Expansion - From open pit to block cave and beyond. Proceedings of MetSoc 2012.

• Design criteria and plant trial of underground Cadia East ore
• Ore was blasted underground and had F₈₀ = 80 mm on surface

Result for default Optimized Bond/Barratt SABC model conditions:

	ESAG	Eball	Etotal
Model	12.2 kWh/t	15.1 kWh/t	27.7 kWh/t	1294 t/h
Measured	10.6 kWh/t	13.2 kWh/t	23.8 kWh/t	1482 t/h
Difference	1.6 kWh/t	1.9 kWh/t	3.9 kWh/t	-188 t/h
Difference	15%	14%	16%	-13%

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Benchmarking: Bond/Barratt - Cadia

Dunne, R., Morrell, S., Lane, G., Valery, W. and Hart, S., Design of the 40 foot diameter SAG mill installed at the Cadia gold copper mine. Proceedings of SAG 2001, pages I-43 to I-58.

Lane, G., Foggiatto, B. and Bueno, M, Power-based comminution calculations using Ausgrind. Proceedings of Procemin 2013, Chapter 2, paper 2.

• Survey conducted shortly after start-up

Result for default Optimized Bond/Barratt SABC model conditions:

	Esag	Epeb	Ebm	Etotal	t/h	T80, mm
Predicted	8.6	0.3	8.5	17.4	2000	2.06
Survey	8.6	-	8	16.6	2065	1.34
Difference	0	0.3	0.5	0.8	-65	0.72
Difference	0%	-	6%	5%	-3%	54%

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Benchmarking: Bond/Barratt SABC Circuit Specific Energy Consumption - Copper Mountain

• Morrison, R., Current Plant Conditions at Copper Mountain. Presentation to the BC/Yukon Branch Canadian Mineral Processors, November 29, 2012; Vancouver, Canada.

Result for default Optimized Bond/Barratt model conditions:

	Tonnage
Model	1455 t/h
Measured	1600 t/h
Difference	145 t/h
Difference	9.5%

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Benchmarking: Bond/Barratt SAG Mill Specific Energy Consumption - Esperanza

• Villanueva, F. and Soto, L., SEC and the impact on a mills selection for DMC project. Proceedings of the XXVII International Mineral Processing Congress, October 2014, Santiago, Chile. C14-23.

Paper describes modelling of two expansion cases (Esperanza Sur and Encuentro). Some operating data for the current Esperanza pit & plant are provided as they were used to tune the comminution models used for the expansion cases.

	Average ore
Measured SAG specific energy consumption, kWh/t	5.5
Predicted SAG specific energy consumption, kWh/t	5.9
Difference, kWh/t	0.4
Difference, %	model predicts 7% high

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Benchmarking: Bond/Barratt SABC Circuit Specific Energy Consumption - Fort Knox

• Magnuson, R.; Hallow, J.; Mosher, J.; Major, K., The Fort Knox Mill: Design, Commissioning and Operation. Proceedings of the SAG 2001 Conference, Vancouver, Canada.

Optimized Bond/Barratt SABC circuit (10% Essbm calibration factor).

Result for default model conditions:

	Etotal	WiO		Tonnage
Model	11.43	15.90	kWh/t	1,607	t/h
Measured	10.50	14.61	kWh/t	1,733	t/h
Difference	0.93	1.29	kWh/t	126	t/h
Difference	8.9%	8.8%		7.3%

Model predicts 8.9% harder than survey resulting in predicted throughput 7.3% lower than survey.

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Benchmarking: Bond/Barratt SABC Circuit Specific Energy Consumption - Kanowna Belle

Lunt, D.J., Thompson, A. and Ritchie, I. The Design and Operation of the Kanowna Belle Milling Circuit, SAG 1996, Pages 81-96.

	Survey	Optimized Model	Difference
ESAG	12.55 kWh/t	13.27 kWh/t	+5.7%
Eball	9.70 kWh/t	10.24 kWh/t	+5.6%
Epeb	0.99 kWh/t	1.04 kWh/t	+5.2%
Etotal	23.24 kWh/t	24.55 kWh/t	+5.6%

Two possible circuit models were tested, and the Optimized Bond/Barratt SABC model better matches the survey than the Raw Bond/Barratt model.

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Benchmarking: Bond/Barratt SABC Circuit Specific Energy Consumption - Meadowbank

• Muteb, P. & Allaire, J., Meadowbank Mine Process Plant Throughput Increase, Proceedings of the Canadian Mineral Processors Annual General Meeting, Ottawa, Canada, January 2013.

Paper describes a "sick" SAG mill and the changes made to "bring it to health". The "healthy" mill conditions benchmark as follows:

• Actual SAG/ball motor powers (at shell): 3,168 kW / 4,105 kW
• Actual daily average throughput: 500 tonnes/hour
• Predicted SAG/ball motor powers (at shell): 3,096 kW / 4,182 kW
• Predicted nominal throughput: 500 tonnes/hour (0% difference)

	SAG	Ball Mill	total
Measured specific energy consumption, kWh/t	6.34	8.21	14.55
Predicted specific energy consumption, kWh/t	6.19	8.36	14.55
Difference, kWh/t	-0.15	0.15	0.00
Difference, %	-2.3%	1.8%	0.0%

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Benchmarking: Bond/Barratt SABC Circuit Specific Energy Consumption - Macraes

Barns, K., Lane, G., Osten, K. & Scagliotta, N., Benchmarking Energy Efficiency - A Case Study at Macraes Gold Mine, Proceedings of the AusIMM MetPlant conference, Perth, Australia, September 2004.

Difference between model results and plant surveys:

		Survey 5	Survey 4	Survey 3	Survey 2	Survey 1	Overall Average
SAG specific power		-5.3%	-5.0%	6.3%	0.5%	2.2%	-0.2%
ball mill specific power		-6.3%	-4.7%	3.6%	1.9%	3.2%	-0.5%
total specific power		-6.8%	-3.8%	5.4%	1.4%	2.9%	-0.2%

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Benchmarking: Bond/Barratt ABC Circuit Specific Energy Consumption - Santa Rita

Latchireddi, S. & Faria, E., Achievement of High Energy Efficiency in Grinding Mills at Santa Rita, Proceedings of the Canadian Mineral Processors Annual General Meeting, Ottawa, Canada, January 2013.

Faria, E. & Latchireddi, S., Commissioning and Operation of Milling Circuit at Santa Rita Nickel Operation, Paper #137: Proceedings of the International Autogenous Grinding, Semiautogenous Grinding and High Pressure Grinding Roll Technology Conference, Vancouver, Canada, September 2011.

	FAG	BM	Pebble Crusher	total
Measured specific energy consumption, kWh/t	9.55	7.28	0.34	17.18
Predicted specific energy consumption, kWh/t	9.78	8.33	0.39	18.50
Difference, kWh/t	0.23	1.05	0.05	1.32
Difference, %	2.4%	14.4%	14.7%	7.7%

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Benchmarking: Bond/Rowland SSBM Circuit Specific Energy Consumption - Boddington

The Bond/Rowland SSBM model was fit to the observed operation of the Boddington HPGR circuit. The fitting parameters are:

• E_ssbm calibration factor: (-0.13)
• Mechanical efficiency of HPGR crushers: 0.28.

Because the model is specifically fit to the Boddington data, it doesn't make any meaningful throughput predictions, but the following predictions are available:

• Ball mill operating work index reduction versus laboratory: 5% (microcracking/phantom cyclone effect)
• Secondary crusher WiO is 18.1 kWh/tonne (versus laboratory determination 27.7 kWh/t).

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