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

Result for default model conditions:

	ESAG	Eball	Etotal
Model	kWh/t	kWh/t	kWh/t	t/h
Measured	10.6 kWh/t	13.2 kWh/t	23.8 kWh/t	1482 t/h
Difference	kWh/t	kWh/t	kWh/t
Difference	%	%	%

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Benchmarking: Bond/Barratt - Cadia (pre-crushing)

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

• SAG feed is pre-crushed to 98 mm

Result for default model conditions:

	Tonnage
Model	t/h
Measured	2065 t/h
Difference	t/h
Difference	%

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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 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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