SAGMILLING.COM - User contributions [en]

File:LinkedIN Regressions.png

2020-06-18T23:51:06Z

Munashe Kurisa:

File:LinkedIN WiRM vs SPIorSGI.png

2020-06-18T23:50:45Z

Munashe Kurisa:

File:LinkedIN SPIorSGI vs WiRM.png

2020-06-18T23:50:32Z

Munashe Kurisa:

File:LinkedIN SPIorSGI Axb.png

2020-06-18T23:50:22Z

Munashe Kurisa:

File:LinkedIN Axb vs SPIorSGI.png

2020-06-18T23:50:05Z

Munashe Kurisa:

Benchmarking: Amelunxen SGI - Agnico Eagle

2020-05-22T18:04:34Z

Munashe Kurisa: /* Results */

[[category:benchmarking]]
[[category:Amelunxen SGI Model]]
[[category:Bibliography]]
==Benchmarking: Amelunxen SGI Specific Energy Consumption - Agnico Eagle Laronde ==
''Starkey, J., Robitaille, J., Cousin, P., Jordan, J. and Kosick, G.'', '''Design of the Agnico-Eagle Laronde Division SAG mill'''. Proceedings of SAG 2001, pages III-165 to III-178.

Survey conducted shortly after start-up

Actual operating data, table 7 from the reference
* Throughput = 210 dry tonnes per hour
* SAG circuit F80 = 100 mm
* transfer T80 = 244 µm
* circuit P80 = 74 µm
* SAG power draw (at motor input) = 1350 kW (at mill shell = 1283 kW)
* SAG mill ball charge = 10.6 % vol
* SAG mill discharge % solids = 84% weight
* SAG mill speed 8.59 RPM (53.4% of critical)
* ESAG at mill shell = 1283/210 = 6.11 kWh/t
(to achieve DCS power of 1350 kW requires 14% vol mill load)
* ball mill power draw (sum of 2 mills, at motor input) = 1422 kW (at mill shell = 2 × 674 kW = 1348 kW)
* ball mill % solids = 83% weight
(to achieve 1424 kW, assume 30% vol mill charge, 17 RPM)
* Ebm at mill shell = 1348/210 = 6.41 kWh/t
* ball mill operating WiO relative to motor input = 13.0 kWh/t (= 13.7 kWh/t relative to mill shell)

==Design Criteria==
* SGI (actually SPI™) of ore (Oct 1, 2000 to - April 30,2001); assumed to be the 25th percentile = 24 minutes.
* WiBM assumed to be 10 kWh/tonne.
* Plant availability = 94.4%

Mill criteria
* SAG mill: 24 foot nom diam by 12 foot effective grinding length (EGL)
* ball mill: two 11 foot nom diam by 17 foot (assumed to be EGL)
* SAG mill single variable speed motor 4500 HP
* Ball mill single fixed speed motors 1000 HP (each mill)
* assume rubber liners in SAG, nominal 8½ inch liner thickness
* assume steel liners in ball mills, nominal 3¼ inch liner thickness

==Modelling==

The Amelunxen SGI model for SAB circuit is used.
* circuit F80 = 100 mm
* circuit P80 = 74 µm

SAG mill is modelled using following:
* full Morrell SAG grate C-model
* assume ore density 2.7 t/m³
* effective dimensions 6882 mm diam × 3657 mm EGL

Ball mill is modelled using following:
* full Morrell ball mill wet overflow C-model
* assume ore density 2.7 t/m³
* effective dimensions 3186 mm diam × 5181 mm EGL

The model defaults are used for:
* CFSAG = 1.0 (normal feed size, no pebble crushing)
* CFball = 1.10 (relationship for Los Bronces in Amelunxen et al, 2013)

== Results ==
[[file:Benchmarking-AgnicoEagle.png|thumb|right| Screenshot of Agnico Eagle circuit]]
Result for default Amelunxen SGI SAB model conditions:
{| class="wikitable" border="1"
|-
!
!Esag
!Epeb
!Ebm
!Etotal
!t/h
|-
| Predicted
| 6.5
| -
| 6.9
| 13.4
| 196
|-
| Survey
| 6.1
| -
| 6.4
| 12.5
| 210
|-
| Difference
| 0.4
| -
| 0.5
| 0.9
| 14
|-
| Difference
| model 7% high
| -
| model 8% high
| model 7% high
| model 7% low
|}

==Discussion==
The calibration factor for SAG milling, CFSAG, is given in Amelunxen et al (2013) as:
* 1.00 for "normal feed size with no pebble crushing",
* 0.90 for "fine SAG feed"
* 0.85 for "pebble crushing"
* 0.77 for both "fine SAG feed" and "pebble crushing"

Back-calculating the CFSAG for Laronde ore gives 0.94, mid-way between "normal" and "fine" in the list above. Amelunxen et al (2013) do not actually reveal what the basis is for determining if an ore is "fine", but 100 mm could be on the cusp of being fine or coarse. In reality, the CFSAG factor should be a continuous and smooth function of feed size and not a step-change.

The Starkey et al (2001) reference does not give a suitable range of ball mill work index values suitable for determining a 25th percentile. The operating work index is given as 12.3 kWh/t (13.0 kWh/t motor input basis). Back-calculating a CFball value is not really possible with the data provided.

If the model is run with a manual CFSAG = 0.95, the following results are returned:

Result for Amelunxen SGI SAB model with CFSAG = 0.95
{| class="wikitable" border="1"
|-
!
!Esag
!Epeb
!Ebm
!Etotal
!t/h
|-
| Predicted
| 6.4
| -
| 6.8
| 13.2
| 199
|-
| Survey
| 6.1
| -
| 6.4
| 12.5
| 210
|-
| Difference
| 0.3
| -
| 0.4
| 0.7
| 11
|-
| Difference
| model 4.9% high
| -
| model 6.3% high
| model 5.6% high
| model 5.5% low
|}

Benchmarking: Bond - Meadowbank

2020-05-22T17:32:38Z

Munashe Kurisa: /* Sick circuit simulation */

[[category: Benchmarking]]
[[category: Bond/Barratt Model]]
[[category:Bibliography]]
==Benchmarking: Bond/Barratt 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".

==Design criteria==

A survey was conducted on the "sick" mill in May, 2012 reported the following the following:

* A×b 38.6
* Ball mill work index 10.9 kWh/t
* Ore density 2.93 kg/L (contains magnetite)
* SAG mill feed F80 38 mm (pre-crushing)
* Cyclone overflow P80 79 µm
* Throughput 446 tonnes/hour

To run the Bond/Barratt model requires work index values for rod milling and crushing. The reported A×b (38.6) is similar to the "Design Criteria" sample at Phoenix (A×b of 37.5) published by J.Seidel et al, SAG 2006. Seidel also reported the following work index values that will be used as proxies for the Meadowbank ore:

* WiRM 17.2 kWh/t
* WiC 17.6 kWh/t

The "sick" mill corresponds to the May 2012 survey and the "healthy" mill corresponds to the September 2012 conditions in Figures 7 and 8.

The SAG mill uses a standard Austin model and the ball mill uses a Nordberg wet overflow model without density correction.

==Model parameter fitting, sick & healthy circuits==
The following tables back-calculate the "Essbm contingency" model fitting parameter for the Bond/Barratt SABC model (which includes allowance for phantom cyclone effects). Specific energy references the "mill shell" kW values.

{|class="wikitable" border="1"
! "Sick" SAG !!SAG!!BM!!Etotal
|-
| DCS kW||3,374||4,341||
|-
| Shell kW||3,190||4,105||
|-
| Throughput, t/h||446||446||
|-
| Specific Energy, kWh/t||7.15||9.20||16.36
|-
| Essbm||||||13.23
|-
| contingency||||||24%
|}

Note that no survey was done in this period, so the Essbm is assumed to be the same as the May 2012 value (the ore is the same hardness).

{|class="wikitable" border="1"
! "Healthy" SAG !!SAG!!BM!!Etotal
|-
| DCS kW||3,350||4,341||
|-
| Shell kW||3,168||4,105||
|-
| Throughput, t/h||500||500||Etotal
|-
| Specific Energy, kWh/t||6.34||8.21||14.55
|-
| Essbm||||||13.23
|-
| contingency||||||10%
|}

The default contingency for a Bond/Barratt SABC model is 10%. The "healthy" mill work out to exactly 10% - the model Etotal value fits perfectly.

==Healthy circuit simulation==
[[File:Benchmarking-Meadowbank-Healthy.png|thumb|Screenshot of the "healthy" Meadowbank circuit simulation]]
Combining the Bond/Barratt specific energy model, the Austin SAG model described in the [[Benchmarking: Meadowbank SAG|bibliography]] and the Nordberg ball mill model described in the [[Benchmarking: Meadowbank ball mill model|bibliography]] results in the following throughput predictions for a "healthy" milling circuit using the work index values above:

* 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): 3,085 kW / 4,186 kW
* Predicted nominal throughput: 500 tonnes/hour (no difference)

{|class="wikitable" border="1"
! !!SAG!!BM!!total
|-
| Measured specific energy consumption, kWh/t||6.34||8.21||14.55
|-
| Predicted specific energy consumption, kWh/t||6.18||8.38||14.55
|-
| Difference, kWh/t||-0.16||0.17||0.00
|-
| Difference, %||-2.5%||2.1%||0.0%
|}

The total specific energy consumption is exactly the same in the simulation as is observed in the plant, and the estimates for ESAG and Eball are very close to the plant observation. The model throughput prediction exactly matches the plant measurement.

==Sick circuit simulation==
[[File:Benchmarking-Meadowbank-Sick.png|thumb|Screenshot of the "sick" Meadowbank circuit simulation]]
Modelling the "sick" SAG mill is more difficult. The transfer size is forced to match the survey value by setting the upper limit to the surveyed value 1240 µm (and neglecting a phantom cyclone effect as it can not be calculated without a full size distribution). This forces the circuit into a SAG-limited situation which will restrict the throughput. The ball mill is modelled with a fixed speed (overgrinding versus the target P80), but is not important to the overall throughput. In reality, the ball mill is probably operating inefficiently under these conditions and the product will be coarser than predicted.

* Actual SAG/ball motor powers (at shell): 3,374 kW / 4,341 kW
* Actual daily average throughput: 446 tonnes/hour
* Predicted SAG/ball motor powers (at shell): 3,085 kW / 4,186 kW
* Predicted nominal throughput: 405 tonnes/hour (-9.2% difference)

{|class="wikitable" border="1"
! !!SAG!!BM!!total
|-
| Measured specific energy consumption, kWh/t||7.15||9.20||16.36
|-
| Predicted specific energy consumption, kWh/t||7.62||10.33||17.95
|-
| Difference, kWh/t||+0.47||+1.13||+1.59
|-
| Difference, %||+6.6%||+12.3%||+9.7%
|}

File:Benchmarking-Meadowbank-Sick.png

2020-05-22T17:27:37Z

Munashe Kurisa: Munashe Kurisa uploaded a new version of File:Benchmarking-Meadowbank-Sick.png

Bond/Barratt model of the "sick" Meadowbank grinding circuit

Benchmarking: Bond - Meadowbank

2020-05-22T17:26:21Z

Munashe Kurisa: /* Healthy circuit simulation */

[[category: Benchmarking]]
[[category: Bond/Barratt Model]]
[[category:Bibliography]]
==Benchmarking: Bond/Barratt 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".

==Design criteria==

A survey was conducted on the "sick" mill in May, 2012 reported the following the following:

* A×b 38.6
* Ball mill work index 10.9 kWh/t
* Ore density 2.93 kg/L (contains magnetite)
* SAG mill feed F80 38 mm (pre-crushing)
* Cyclone overflow P80 79 µm
* Throughput 446 tonnes/hour

To run the Bond/Barratt model requires work index values for rod milling and crushing. The reported A×b (38.6) is similar to the "Design Criteria" sample at Phoenix (A×b of 37.5) published by J.Seidel et al, SAG 2006. Seidel also reported the following work index values that will be used as proxies for the Meadowbank ore:

* WiRM 17.2 kWh/t
* WiC 17.6 kWh/t

The "sick" mill corresponds to the May 2012 survey and the "healthy" mill corresponds to the September 2012 conditions in Figures 7 and 8.

The SAG mill uses a standard Austin model and the ball mill uses a Nordberg wet overflow model without density correction.

==Model parameter fitting, sick & healthy circuits==
The following tables back-calculate the "Essbm contingency" model fitting parameter for the Bond/Barratt SABC model (which includes allowance for phantom cyclone effects). Specific energy references the "mill shell" kW values.

{|class="wikitable" border="1"
! "Sick" SAG !!SAG!!BM!!Etotal
|-
| DCS kW||3,374||4,341||
|-
| Shell kW||3,190||4,105||
|-
| Throughput, t/h||446||446||
|-
| Specific Energy, kWh/t||7.15||9.20||16.36
|-
| Essbm||||||13.23
|-
| contingency||||||24%
|}

Note that no survey was done in this period, so the Essbm is assumed to be the same as the May 2012 value (the ore is the same hardness).

{|class="wikitable" border="1"
! "Healthy" SAG !!SAG!!BM!!Etotal
|-
| DCS kW||3,350||4,341||
|-
| Shell kW||3,168||4,105||
|-
| Throughput, t/h||500||500||Etotal
|-
| Specific Energy, kWh/t||6.34||8.21||14.55
|-
| Essbm||||||13.23
|-
| contingency||||||10%
|}

The default contingency for a Bond/Barratt SABC model is 10%. The "healthy" mill work out to exactly 10% - the model Etotal value fits perfectly.

==Healthy circuit simulation==
[[File:Benchmarking-Meadowbank-Healthy.png|thumb|Screenshot of the "healthy" Meadowbank circuit simulation]]
Combining the Bond/Barratt specific energy model, the Austin SAG model described in the [[Benchmarking: Meadowbank SAG|bibliography]] and the Nordberg ball mill model described in the [[Benchmarking: Meadowbank ball mill model|bibliography]] results in the following throughput predictions for a "healthy" milling circuit using the work index values above:

* 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): 3,085 kW / 4,186 kW
* Predicted nominal throughput: 500 tonnes/hour (no difference)

{|class="wikitable" border="1"
! !!SAG!!BM!!total
|-
| Measured specific energy consumption, kWh/t||6.34||8.21||14.55
|-
| Predicted specific energy consumption, kWh/t||6.18||8.38||14.55
|-
| Difference, kWh/t||-0.16||0.17||0.00
|-
| Difference, %||-2.5%||2.1%||0.0%
|}

The total specific energy consumption is exactly the same in the simulation as is observed in the plant, and the estimates for ESAG and Eball are very close to the plant observation. The model throughput prediction exactly matches the plant measurement.

==Sick circuit simulation==
[[File:Benchmarking-Meadowbank-Sick.png|thumb|Screenshot of the "sick" Meadowbank circuit simulation]]
Modelling the "sick" SAG mill is more difficult. The transfer size is forced to match the survey value by setting the upper limit to the surveyed value 1240 µm (and neglecting a phantom cyclone effect as it can not be calculated without a full size distribution). This forces the circuit into a SAG-limited situation which will restrict the throughput. The ball mill is modelled with a fixed speed (overgrinding versus the target P80), but is not important to the overall throughput. In reality, the ball mill is probably operating inefficiently under these conditions and the product will be coarser than predicted.

* Actual SAG/ball motor powers (at shell): 3,374 kW / 4,341 kW
* Actual daily average throughput: 446 tonnes/hour
* Predicted SAG/ball motor powers (at shell): 3,112 kW / 4,186 kW
* Predicted nominal throughput: 428 tonnes/hour (-4.1% difference)

{|class="wikitable" border="1"
! !!SAG!!BM!!total
|-
| Measured specific energy consumption, kWh/t||7.15||9.20||16.36
|-
| Predicted specific energy consumption, kWh/t||7.27||9.78||17.06
|-
| Difference, kWh/t||+0.12||+0.58||+0.70
|-
| Difference, %||+1.7%||+6.3%||+4.3%
|}

File:Benchmarking-Meadowbank-Healthy.png

2020-05-22T17:18:33Z

Munashe Kurisa: Munashe Kurisa uploaded a new version of File:Benchmarking-Meadowbank-Healthy.png

Bond/Barratt model of the "healthy" Meadowbank grinding circuit

File:Benchmarking-Santa Rita.png

2020-05-22T16:30:46Z

Munashe Kurisa: Munashe Kurisa uploaded a new version of File:Benchmarking-Santa Rita.png

Screenshot of Bond/Barratt model used for Santa Rita benchmarking

Benchmarking: Bond - Cadia East

2020-05-21T23:55:58Z

Munashe Kurisa: /* Model results */

[[category:benchmarking]]
[[category:Bond/Barratt Model]]
==Benchmarking: Bond/Barratt - Cadia==
''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 characterization===
* blased underground ore, secondary crushed to 80 mm.
** WiC = 30 (metric)
** WiRM = 26.5 (metric)
** WiBM = 21.4 (metric)
** DWI = 9.9
** density = 2.7 t/m³

The ore was reported blasted undergrond (block caving had not yet started). Particle size distribution given as two points which confirm a Bond-compatible "root-2" PSD.
* 80% passing 80 mm
* 20% passing 5 mm

===Modelling===

Details of the mill operating conditions are not given, but the power draw at the shell is given.
* 15.737 MW SAG mill power draw
* 19.509 MW ball mill power draw

Circuit operating conditions:
* F80 = 80 mm
* P80 = 140 µm
* instantaneous throughput = 1482 t/h

The mill load, ball charge and pulp density was tweaked to mimic these power draws, corresponding to:
* SAG operating 9% v/v balls, 25.5% v/v total filling and 78% of critical speed (Austin model has fixed %solids)
* ball mills operating 37% v/v total filling and 70% w/w solids (fixed speed mills, 72% of critical speed)

The ball load required to match the reported power draw is very high, and could only be achieved with a significant reduction in the trunnion diameter (using ball retaining rings). Moreover, the motors are predicted to be operating at 100.5% of their rated output power to achieve the indicated power draw.

===Model results===
{| class="wikitable" border="1"
|-
!
! ESAG
! Eball
! Etotal
! Throughput
|-
| Model
| 12.31 kWh/t
| 14.94 kWh/t
| 27.7 kWh/t
| 1243 t/h
|-
| Measured
| 10.6 kWh/t
| 13.2 kWh/t
| 23.8 kWh/t
| 1482 t/h
|-
| Difference
| 1.71 kWh/t
| 1.74 kWh/t
| 3.9 kWh/t
| -239 t/h
|-
| Difference
| 16.13%
| 13.18%
| 16.39%
| -16.13%
|}

<gallery>
File:CadiaEast.png|thumb|Cadia East circuit
File:CadiaEast-SAG.png|thumb|Cadia East SAG mill
File:CadiaEast-BM.png|thumb|Cadia East Ball mill
File:Cadia-Pebble.png|thumb|Cadia East Pebble crusher
</gallery>

The predicted transfer size needed to balance the power draw between primary & second mills is very coarse, 5 mm.

===Discussion===
There is a substantial difference between the survey and the predictions. Some observations:
* The rod mill work index was determined on an apparatus with smooth liners. This can cause a difference of 2-3 kWh/t versus the wave-liner apparatus specified by Bond. Using a rod mill work index of 24.0 kWh/t gives Etotal = 26.8 kWh/t; still 13% high.
* The Essbm predicts the energy required for a "standard" secondary crushing & ball milling plant that is believed to be one of the most energy efficient types of grinding circuits. This ore has Essbm = 24.3 kWh/t which is still less than the survey Etotal. Very odd result that a SABC circuit is more efficient than an SSBM (ergo, HPGR) circuit on such a hard ore.

File:Cadia-Pebble.png

2020-05-21T23:44:34Z

Munashe Kurisa: Screenshot of Cadia East Pebble crusher

== Summary ==
Screenshot of Cadia East Pebble crusher

File:CadiaEast-SAG.png

2020-05-21T23:44:05Z

Munashe Kurisa: Screenshot Cadia East SAG mill

== Summary ==
Screenshot Cadia East SAG mill

File:CadiaEast-BM.png

2020-05-21T23:43:43Z

Munashe Kurisa: Screenshot of Cadia East BM

== Summary ==
Screenshot of Cadia East BM

File:CadiaEast.png

2020-05-21T23:40:57Z

Munashe Kurisa: Uploading model of Cadia East circuit

== Summary ==
Uploading model of Cadia East circuit

File:ScreenGrab Selbaie.png

2020-05-21T17:30:52Z

Munashe Kurisa: Munashe Kurisa uploaded a new version of File:ScreenGrab Selbaie.png

Benchmarking screenshot for Selbaie simulation

File:BenchmarkingModel-FortKnox.png

2020-05-21T16:56:25Z

Munashe Kurisa: Munashe Kurisa uploaded a new version of File:BenchmarkingModel-FortKnox.png

Model conditions for the benchmarking against Fort Knox conditions reported by Magnuson et al, SAG 2001

File:CopperMtn-pit2.png

2020-05-20T17:27:50Z

Munashe Kurisa: Munashe Kurisa uploaded a new version of File:CopperMtn-pit2.png

== Summary ==
Benchmark screenshot for Copper Mountain Pit 2

File:CopperMtn-pit3.png

2020-05-20T17:26:34Z

Munashe Kurisa: Munashe Kurisa uploaded a new version of File:CopperMtn-pit3.png

== Summary ==
Benchmark screenshot for Copper Mountain Pit 3

Benchmarking: Bond - Copper Mountain

2020-05-20T16:13:38Z

Munashe Kurisa: /* Modelling */

[[category: Benchmarking]]
[[category: Bond/Barratt Model]]
[[category:Bibliography]]
==Benchmarking: Bond/Barratt - Copper Mountain==

===2011 SAG Conference, Mill & Motor===
''van de Vijfeijken, M., Filidore, A., Walbert, M. and Marks, A.'', '''Copper Mountain: Overview on the Grinding Mills and their Dual Pinion Mill Drives'''. Proceedings of the SAG 2011 Conference, September 25-28, 2011; Vancouver, Canada.

* SAG mill inside (shell) diameter: 34 ft (10.363 m)
* SAG mill effective grinding length: 17.5 ft (5.334 m)
* SAG mill design speed (corresponding to motor peak torque/power): 10.08 RPM
* SAG mill motor (original) power output: 17,000 HP (12,677 kW)

* Ball mill inside (shell) diameter: 24 ft (7.315 m)
* Ball mill effective grinding length: 39 ft (11.886 m)
* Ball mill design speed (corresponding to motor peak torque/power): 11.89 RPM

===2011 SAG Conference, Process Design===
''Marks, A., Sams, C. and Major, K.'', '''Grinding Circuit Design for Similco Mines'''. Proceedings of the SAG 2011 Conference, September 25-28, 2011; Vancouver, Canada.

{| class="wikitable" border="1"
|-
! Sample
! Density, g/cm3
! A×b
! ta
! WiRM
! WiBM
|-
| Pit 2
| 2.75
| 22.9
| 0.19
| 20.1
| 22.3
|-
| Pit 3
| 2.87
| 20.1
| 0.16
| 20.2
| 22.2
|}

* Circuit F80: 150 mm

===Presentation to District 6 CMP ===
''Morrison, R.'', '''Current Plant Conditions at Copper Mountain'''. Presentation to the BC/Yukon Branch Canadian Mineral Processors, November 29, 2012; Vancouver, Canada.

* Ore blend is 80% Pit 3; 20% Pit 2.
* SAG mill motors have been upgraded to total 13.8 MW by adding cooling to drive transformers (6.9 MW per motor).
* SAG mill operating with 17% v/v ball charge and 27% to 28% v/v total filling
* SAG mill operating typically 10.2 RPM.
* Ball mills operating 34% to 35% v/v total filling
* Circuit P80=150 µm (was 180 µm before SAG motor upgrade)
* Circuit throughput: 1600 t/h

===Modelling===
[[file:CopperMtn-pit2.png|thumb|Screenshot of pit 2 model]]
[[file:CopperMtn-pit3.png|thumb|Screenshot of pit 3 model]]
* Assume the crushing work index is similar to the rod mill: 20 (metric).
* Default SSBM contingency for SABC circuit is 0.10.
* Assume liner thickness of 6 inches in SAG, 4.5 inches in ball mill.
* Model predicted throughput: 1499 t/h on Pit 3 ore and 1488 t/h on Pit 2 ore.

Result for default model conditions:
{| class="wikitable" border="1"
|-
! !! Pit 2 !! Pit 3
|-
| Model || 1488 t/h || 1499 t/h
|-
| Measured || 1600 t/h || 1600 t/h
|-
| Difference || 112 t/h || 101 t/h
|-
| Difference || 7% || 6.3%
|}

===Discussion===
* It is noted that the SAG mill model is drawing less than 92% of available power and the ball mill model is drawing over 95%. Power measurements for these mills haven't been published to check against the model.
** The ball mills are likely operating at close to this power draw.
** The SAG mill actual power draw (measured at the shell) is most probably higher than 92%.
* The liner effective thickness is unknown and may be thinner than assumed — this would increase the power draw in the mills and increase the tonnage. Changing the effective liner thickness of the SAG mill to 4.5 inch and the ball mills to 3.0 inches results in 1490 t/h throughput prediction (7.1% difference versus the measured throughput).
* The assumed crushing work index (20) suggests a very competent ore compared to most in British Columbia — this matches comments at the SAG conference. Assuming a lower work index of 10 results in a throughput of 1505 t/h (6.1% difference versus the measured throughput).
* Raising the SAG speed to 78% of critical speed (10.4 RPM) has little effect due to the drop-off in power observed in a Loveday model using Barratt's published Power Numbers above 76% of critical speed.
* The model predicts a '''negative''' phantom cyclone effect. This is an odd result, but does match one observation on a hard ore (Boddington circuit; private communication with M. Sherman).

Benchmarking: Bond - Copper Mountain

2020-05-19T23:52:25Z

Munashe Kurisa: /* Modelling */

[[category: Benchmarking]]
[[category: Bond/Barratt Model]]
[[category:Bibliography]]
==Benchmarking: Bond/Barratt - Copper Mountain==

===2011 SAG Conference, Mill & Motor===
''van de Vijfeijken, M., Filidore, A., Walbert, M. and Marks, A.'', '''Copper Mountain: Overview on the Grinding Mills and their Dual Pinion Mill Drives'''. Proceedings of the SAG 2011 Conference, September 25-28, 2011; Vancouver, Canada.

* SAG mill inside (shell) diameter: 34 ft (10.363 m)
* SAG mill effective grinding length: 17.5 ft (5.334 m)
* SAG mill design speed (corresponding to motor peak torque/power): 10.08 RPM
* SAG mill motor (original) power output: 17,000 HP (12,677 kW)

* Ball mill inside (shell) diameter: 24 ft (7.315 m)
* Ball mill effective grinding length: 39 ft (11.886 m)
* Ball mill design speed (corresponding to motor peak torque/power): 11.89 RPM

===2011 SAG Conference, Process Design===
''Marks, A., Sams, C. and Major, K.'', '''Grinding Circuit Design for Similco Mines'''. Proceedings of the SAG 2011 Conference, September 25-28, 2011; Vancouver, Canada.

{| class="wikitable" border="1"
|-
! Sample
! Density, g/cm3
! A×b
! ta
! WiRM
! WiBM
|-
| Pit 2
| 2.75
| 22.9
| 0.19
| 20.1
| 22.3
|-
| Pit 3
| 2.87
| 20.1
| 0.16
| 20.2
| 22.2
|}

* Circuit F80: 150 mm

===Presentation to District 6 CMP ===
''Morrison, R.'', '''Current Plant Conditions at Copper Mountain'''. Presentation to the BC/Yukon Branch Canadian Mineral Processors, November 29, 2012; Vancouver, Canada.

* Ore blend is 80% Pit 3; 20% Pit 2.
* SAG mill motors have been upgraded to total 13.8 MW by adding cooling to drive transformers (6.9 MW per motor).
* SAG mill operating with 17% v/v ball charge and 27% to 28% v/v total filling
* SAG mill operating typically 10.2 RPM.
* Ball mills operating 34% to 35% v/v total filling
* Circuit P80=150 µm (was 180 µm before SAG motor upgrade)
* Circuit throughput: 1600 t/h

===Modelling===
[[file:CopperMtn-pit2.png|thumb|Screenshot of pit 2 model]]
[[file:CopperMtn-pit3.png|thumb|Screenshot of pit 3 model]]
* Assume the crushing work index is similar to the rod mill: 20 (metric).
* Default SSBM contingency for SABC circuit is 0.10.
* Assume liner thickness of 6 inches in SAG, 4.5 inches in ball mill.
* Model predicted throughput: 1499 t/h on Pit 3 ore and 1488 t/h on Pit 2 ore.

{| class="wikitable"
|-
! !! Measured !! Pit 2 !! Difference !! Pit 3 !! Difference
|-
| ESAG || xx kWh/t || 8.2 kWh/t || x% || 8.23 kWh/t || +%
|-
| Eball || xx kWh/t || 16.86 kWh/t || x% || 16.75 kWh/t || +%
|-
| Epeb || xx kWh/t || 0.34 kWh/t || x% || 0.34 kWh/t || +%
|-
| Etotal || xx kWh/t || 25.4 kWh/t || x% || 25.31 kWh/t || +%
|}

Result for default model conditions:
{| class="wikitable" border="1"
|-
! !! Pit 2 !! Pit 3
|-
| Model || 1488 t/h || 1499 t/h
|-
| Measured || 1600 t/h || 1600 t/h
|-
| Difference || 112 t/h || 101 t/h
|-
| Difference || 7% || 6.3%
|}

===Discussion===
* It is noted that the SAG mill model is drawing less than 92% of available power and the ball mill model is drawing over 95%. Power measurements for these mills haven't been published to check against the model.
** The ball mills are likely operating at close to this power draw.
** The SAG mill actual power draw (measured at the shell) is most probably higher than 92%.
* The liner effective thickness is unknown and may be thinner than assumed — this would increase the power draw in the mills and increase the tonnage. Changing the effective liner thickness of the SAG mill to 4.5 inch and the ball mills to 3.0 inches results in 1490 t/h throughput prediction (7.1% difference versus the measured throughput).
* The assumed crushing work index (20) suggests a very competent ore compared to most in British Columbia — this matches comments at the SAG conference. Assuming a lower work index of 10 results in a throughput of 1505 t/h (6.1% difference versus the measured throughput).
* Raising the SAG speed to 78% of critical speed (10.4 RPM) has little effect due to the drop-off in power observed in a Loveday model using Barratt's published Power Numbers above 76% of critical speed.
* The model predicts a '''negative''' phantom cyclone effect. This is an odd result, but does match one observation on a hard ore (Boddington circuit; private communication with M. Sherman).

File:CopperMtn-pit3.png

2020-05-19T23:33:58Z

Munashe Kurisa: Benchmark screenshot for Copper Mountain Pit 3

== Summary ==
Benchmark screenshot for Copper Mountain Pit 3

File:CopperMtn-pit2.png

2020-05-19T23:33:22Z

Munashe Kurisa: Benchmark screenshot for Copper Mountain Pit 2

== Summary ==
Benchmark screenshot for Copper Mountain Pit 2

Benchmarking: Bond - Copper Mountain

2020-05-19T23:29:57Z

Munashe Kurisa: /* Modelling */

[[category: Benchmarking]]
[[category: Bond/Barratt Model]]
[[category:Bibliography]]
==Benchmarking: Bond/Barratt - Copper Mountain==

===2011 SAG Conference, Mill & Motor===
''van de Vijfeijken, M., Filidore, A., Walbert, M. and Marks, A.'', '''Copper Mountain: Overview on the Grinding Mills and their Dual Pinion Mill Drives'''. Proceedings of the SAG 2011 Conference, September 25-28, 2011; Vancouver, Canada.

* SAG mill inside (shell) diameter: 34 ft (10.363 m)
* SAG mill effective grinding length: 17.5 ft (5.334 m)
* SAG mill design speed (corresponding to motor peak torque/power): 10.08 RPM
* SAG mill motor (original) power output: 17,000 HP (12,677 kW)

* Ball mill inside (shell) diameter: 24 ft (7.315 m)
* Ball mill effective grinding length: 39 ft (11.886 m)
* Ball mill design speed (corresponding to motor peak torque/power): 11.89 RPM

===2011 SAG Conference, Process Design===
''Marks, A., Sams, C. and Major, K.'', '''Grinding Circuit Design for Similco Mines'''. Proceedings of the SAG 2011 Conference, September 25-28, 2011; Vancouver, Canada.

{| class="wikitable" border="1"
|-
! Sample
! Density, g/cm3
! A×b
! ta
! WiRM
! WiBM
|-
| Pit 2
| 2.75
| 22.9
| 0.19
| 20.1
| 22.3
|-
| Pit 3
| 2.87
| 20.1
| 0.16
| 20.2
| 22.2
|}

* Circuit F80: 150 mm

===Presentation to District 6 CMP ===
''Morrison, R.'', '''Current Plant Conditions at Copper Mountain'''. Presentation to the BC/Yukon Branch Canadian Mineral Processors, November 29, 2012; Vancouver, Canada.

* Ore blend is 80% Pit 3; 20% Pit 2.
* SAG mill motors have been upgraded to total 13.8 MW by adding cooling to drive transformers (6.9 MW per motor).
* SAG mill operating with 17% v/v ball charge and 27% to 28% v/v total filling
* SAG mill operating typically 10.2 RPM.
* Ball mills operating 34% to 35% v/v total filling
* Circuit P80=150 µm (was 180 µm before SAG motor upgrade)
* Circuit throughput: 1600 t/h

===Modelling===
[[file:BenchmarkingModel-CopperMt.png|thumb|Screenshot of model]]
* Assume the crushing work index is similar to the rod mill: 20 (metric).
* Default SSBM contingency for SABC circuit is 0.10.
* Assume liner thickness of 6 inches in SAG, 4.5 inches in ball mill.
* Model predicted throughput: 1499 t/h on Pit 3 ore and 1488 t/h on Pit 2 ore.

{| class="wikitable"
|-
! !! Measured !! Pit 2 !! Difference !! Pit 3 !! Difference
|-
| ESAG || xx kWh/t || 8.2 kWh/t || x% || 8.23 kWh/t || +%
|-
| Eball || xx kWh/t || 16.86 kWh/t || x% || 16.75 kWh/t || +%
|-
| Epeb || xx kWh/t || 0.34 kWh/t || x% || 0.34 kWh/t || +%
|-
| Etotal || xx kWh/t || 25.4 kWh/t || x% || 25.31 kWh/t || +%
|}

Result for default model conditions:
{| class="wikitable" border="1"
|-
!
! Tonnage
|-
| Model
| 1455 t/h
|-
| Measured
| 1600 t/h
|-
| Difference
| 145 t/h
|-
| Difference
| 9.5%
|}

===Discussion===
* It is noted that the SAG mill model is drawing less than 92% of available power and the ball mill model is drawing over 95%. Power measurements for these mills haven't been published to check against the model.
** The ball mills are likely operating at close to this power draw.
** The SAG mill actual power draw (measured at the shell) is most probably higher than 92%.
* The liner effective thickness is unknown and may be thinner than assumed — this would increase the power draw in the mills and increase the tonnage. Changing the effective liner thickness of the SAG mill to 4.5 inch and the ball mills to 3.0 inches results in 1490 t/h throughput prediction (7.1% difference versus the measured throughput).
* The assumed crushing work index (20) suggests a very competent ore compared to most in British Columbia — this matches comments at the SAG conference. Assuming a lower work index of 10 results in a throughput of 1505 t/h (6.1% difference versus the measured throughput).
* Raising the SAG speed to 78% of critical speed (10.4 RPM) has little effect due to the drop-off in power observed in a Loveday model using Barratt's published Power Numbers above 76% of critical speed.
* The model predicts a '''negative''' phantom cyclone effect. This is an odd result, but does match one observation on a hard ore (Boddington circuit; private communication with M. Sherman).

Benchmarking: Bond - Kanowna Belle

2020-05-19T21:02:17Z

Munashe Kurisa: /* Modelling, Raw Bond/Barratt SABC model */

[[category: Benchmarking]]
[[category: Bond/Barratt Model]]
[[category:Bibliography]]
==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.

Paper describes the design criteria for the circuit and one survey.

===Design Criteria===
The reported mill conditions during the survey are,
* throughput: 170 tonnes/hour
* SAG feed size, F80: 150 mm
* BM cyclone product size, P80: 71 µm
* SAG: 2134 kW power draw at mill shell (ESAG = 12.6 kWh/t)
* Ball mill: 1649 kW power draw at mill shell (Eball = 9.70 kWh/t)
* transfer size: 300 µm
The pebble crusher isn't described, assume it is a 7-foot cone crusher with 300 HP motor drawing 168 kW (Epeb = 1.0 kWh/t). Total circuit specific energy consumption Etotal is 23.2 kWh/t.

Several samples are given in the text. It is assumed that the survey period looks similar to "Lowes West", the 'median' hardness sample of the non-oxidized samples. The Lowes West sample gives similar predictions to the "Pilot Plant" sample tested at A.R. MacPherson, which is claimed to have been selected to be representative of the sulphides.

Lowes West sample {pilot plant sample}:
* WiC 26.7 (metric) {not tested}
* WiRM 22.7 (metric) {19.3 metric}
* WiBM 16.1 (metric) {18.3 metric}
Density isn't given, assume 2.7 t/m3

===Modelling, mill power draw===
Adjust the SAG and ball mill models to get the shell power draws reported in the paper. Actual conditions don't matter because there isn't enough detail to properly model the mills -- treat them just as sources of output kW.

===Modelling, Optimized Bond/Barratt SABC model===
The Lowes West sample is predicted to have Essbm of 22.3 kWh/t, add 10% to give Etotal prediction of 24.6 kWh/t. Based on the split of SAG + BM power, the T80 needed to balance the circuit is about 1370 µm. The 'pilot plant' sample predicts a T80 prediction of 540 µm and an Etotal of 26.8 kWh/t.

{| class="wikitable"
|-
! !! Survey !! Model, Lowes West sample !! Difference !! Model, Pilot Plant sample !! Difference
|-
| ESAG || 12.55 kWh/t || 13.27 kWh/t || +5.7% || 14.49 kWh/t || +15.4%
|-
| Eball || 9.70 kWh/t || 10.24 kWh/t || +5.6% || 11.19 kWh/t || +15.4%
|-
| Epeb || 0.99 kWh/t || 1.04 kWh/t || +5.2% || 1.14 kWh/t || +15.4%
|-
| Etotal || 23.24 kWh/t || 24.55 kWh/t || +5.6% || 26.82 kWh/t || +15.4%
|}

<gallery>
File:Kanowna-Lowe.png|thumb|Screenshot of the Model, Lowes West sample
File:Kanowna-PilotPLant.png|Screenshot of the Model, Pilot Plant sample
</gallery>

===Modelling, Raw Bond/Barratt SABC model===
The Lowes West sample is predicted to have Etotal of 29.1 kWh/t. Based on the split of SAG + BM power, the T80 needed to balance the circuit is about 530 µm. The 'pilot plant' sample predicts a T80 prediction of 377 µm and an Etotal of 29.5 kWh/t.

{| class="wikitable"
|-
! !! Survey !! Model, Lowes West sample !! Difference !! Model, Pilot Plant sample !! Difference
|-
| ESAG || 12.55 kWh/t || 15.70 kWh/t || +25.1% || 15.93 kWh/t || +26.9%
|-
| Eball || 9.70 kWh/t || 12.12 kWh/t || +24.9% || 12.30 kWh/t || +26.8%
|-
| Epeb || 0.99 kWh/t || 1.23 kWh/t || +24.5% || 1.25 kWh/t || +26.5%
|-
| Etotal || 23.24 kWh/t || 29.05 kWh/t || +25.0% || 29.48 kWh/t || +26.8%
|}

<gallery>
File:Kanowna-raw-Lowe.png|thumb|Screenshot of the Model, Lowes West sample
File:Kanowna-raw-PilotPlant.png|Screenshot of the Model, Pilot Plant sample
</gallery>

===Discussion===

The rod mill work index values in this survey were based on results from Amdel which is believed to have used a non-standard rod mill using a smooth liner. Bond rod mill work index determinations are supposed to be done in a mill employing a wave liner. The "pilot plant" sample rod mill work index was determined at the A.R. MacPherson - Hazen laboratory in the USA which has a wave liner. The ratio of WiRM:WiBM for the Pilot Plant sample (1.05) is dramatically different from the ratio for the samples tested in Australia (avg 1.40). In spite of this, the Lowes West sample, which is an "average sulphide" sample for Kawnowna Belle, gives similar throughput predictions to the Pilot Plant sample.

The predicted phantom cyclone effect is very significant, depending upon which sample is used for the "laboratory" work index value:
* for the Lowes West sample, WiO is 30% less than laboratory value
* for the Pilot Plant sample, WiO is 20% less than laboratory value
The pilot plant's 20% reduction is large, but believable. The Lowes West sample is too large, suggesting the ratio of WiRM:WiBM isn't really that representative of the plant feed during the survey.

The transfer size observed is very fine, 300 µm. The Raw Bond/Barratt model prediction is closer to the observed value (530 µm versus 1370 µm). Measured transfer sizes will always be finer than the "Bond-type" transfer sizes used in the model due to the extra fines present in the SAG product (the phantom cyclone effect). The difference between the survey and the Raw Bond/Barratt model could possibly be explained by the extra fines, but the difference versus the Optimized Bond/Barratt is probably too great to explain by fines correction alone. The 'pilot plant' sample, where the ratio of rod mill work index to ball mill work index is more "normal" gives an Optimized Bond/Barratt T80 prediction of 540 µm which is much closer to the survey than the Lowes West sample. The Raw Bond/Barratt model also gives a very fine T80 prediction on the Pilot Plant sample.

Overall, it appears that the Lowes West sample total energy prediction is close to what was observed during the survey, but the ratio of the rod mill and ball mill work index values (1.4) is probably not correct. The ratio observed in the pilot plant (1.05) give a better match to the internal model parameters (T80, phantom cyclone effect) even though the total hardness of the pilot plant sample exceeds that observed in the survey.

File:Kanowna-raw-PilotPlant.png

2020-05-19T21:00:57Z

Munashe Kurisa: Raw Model for Kanowna Belle's Pilot Plant

== Summary ==
Raw Model for Kanowna Belle's Pilot Plant

File:Kanowna-raw-Lowe.png

2020-05-19T21:00:14Z

Munashe Kurisa: Raw model benchmark for Kanowna's Lowe

== Summary ==
Raw model benchmark for Kanowna's Lowe

Benchmarking: Bond - Kanowna Belle

2020-05-19T18:26:53Z

Munashe Kurisa: /* Modelling, Optimized Bond/Barratt SABC model */

[[category: Benchmarking]]
[[category: Bond/Barratt Model]]
[[category:Bibliography]]
==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.

Paper describes the design criteria for the circuit and one survey.

===Design Criteria===
The reported mill conditions during the survey are,
* throughput: 170 tonnes/hour
* SAG feed size, F80: 150 mm
* BM cyclone product size, P80: 71 µm
* SAG: 2134 kW power draw at mill shell (ESAG = 12.6 kWh/t)
* Ball mill: 1649 kW power draw at mill shell (Eball = 9.70 kWh/t)
* transfer size: 300 µm
The pebble crusher isn't described, assume it is a 7-foot cone crusher with 300 HP motor drawing 168 kW (Epeb = 1.0 kWh/t). Total circuit specific energy consumption Etotal is 23.2 kWh/t.

Several samples are given in the text. It is assumed that the survey period looks similar to "Lowes West", the 'median' hardness sample of the non-oxidized samples. The Lowes West sample gives similar predictions to the "Pilot Plant" sample tested at A.R. MacPherson, which is claimed to have been selected to be representative of the sulphides.

Lowes West sample {pilot plant sample}:
* WiC 26.7 (metric) {not tested}
* WiRM 22.7 (metric) {19.3 metric}
* WiBM 16.1 (metric) {18.3 metric}
Density isn't given, assume 2.7 t/m3

===Modelling, mill power draw===
Adjust the SAG and ball mill models to get the shell power draws reported in the paper. Actual conditions don't matter because there isn't enough detail to properly model the mills -- treat them just as sources of output kW.

===Modelling, Optimized Bond/Barratt SABC model===
The Lowes West sample is predicted to have Essbm of 22.3 kWh/t, add 10% to give Etotal prediction of 24.6 kWh/t. Based on the split of SAG + BM power, the T80 needed to balance the circuit is about 1370 µm. The 'pilot plant' sample predicts a T80 prediction of 540 µm and an Etotal of 26.8 kWh/t.

{| class="wikitable"
|-
! !! Survey !! Model, Lowes West sample !! Difference !! Model, Pilot Plant sample !! Difference
|-
| ESAG || 12.55 kWh/t || 13.27 kWh/t || +5.7% || 14.49 kWh/t || +15.4%
|-
| Eball || 9.70 kWh/t || 10.24 kWh/t || +5.6% || 11.19 kWh/t || +15.4%
|-
| Epeb || 0.99 kWh/t || 1.04 kWh/t || +5.2% || 1.14 kWh/t || +15.4%
|-
| Etotal || 23.24 kWh/t || 24.55 kWh/t || +5.6% || 26.82 kWh/t || +15.4%
|}

<gallery>
File:Kanowna-Lowe.png|thumb|Screenshot of the Model, Lowes West sample
File:Kanowna-PilotPLant.png|Screenshot of the Model, Pilot Plant sample
</gallery>

===Modelling, Raw Bond/Barratt SABC model===
The Lowes West sample is predicted to have Etotal of 29.1 kWh/t. Based on the split of SAG + BM power, the T80 needed to balance the circuit is about 530 µm. The 'pilot plant' sample predicts a T80 prediction of 377 µm and an Etotal of 29.5 kWh/t.

{| class="wikitable"
|-
! !! Survey !! Model, Lowes West sample !! Difference !! Model, Pilot Plant sample !! Difference
|-
| ESAG || 12.55 kWh/t || 15.70 kWh/t || +25.1% || 15.93 kWh/t || +26.9%
|-
| Eball || 9.70 kWh/t || 12.12 kWh/t || +24.9% || 12.30 kWh/t || +26.8%
|-
| Epeb || 0.99 kWh/t || 1.23 kWh/t || +24.5% || 1.25 kWh/t || +26.5%
|-
| Etotal || 23.24 kWh/t || 29.05 kWh/t || +25.0% || 29.48 kWh/t || +26.8%
|}

===Discussion===

The rod mill work index values in this survey were based on results from Amdel which is believed to have used a non-standard rod mill using a smooth liner. Bond rod mill work index determinations are supposed to be done in a mill employing a wave liner. The "pilot plant" sample rod mill work index was determined at the A.R. MacPherson - Hazen laboratory in the USA which has a wave liner. The ratio of WiRM:WiBM for the Pilot Plant sample (1.05) is dramatically different from the ratio for the samples tested in Australia (avg 1.40). In spite of this, the Lowes West sample, which is an "average sulphide" sample for Kawnowna Belle, gives similar throughput predictions to the Pilot Plant sample.

The predicted phantom cyclone effect is very significant, depending upon which sample is used for the "laboratory" work index value:
* for the Lowes West sample, WiO is 30% less than laboratory value
* for the Pilot Plant sample, WiO is 20% less than laboratory value
The pilot plant's 20% reduction is large, but believable. The Lowes West sample is too large, suggesting the ratio of WiRM:WiBM isn't really that representative of the plant feed during the survey.

The transfer size observed is very fine, 300 µm. The Raw Bond/Barratt model prediction is closer to the observed value (530 µm versus 1370 µm). Measured transfer sizes will always be finer than the "Bond-type" transfer sizes used in the model due to the extra fines present in the SAG product (the phantom cyclone effect). The difference between the survey and the Raw Bond/Barratt model could possibly be explained by the extra fines, but the difference versus the Optimized Bond/Barratt is probably too great to explain by fines correction alone. The 'pilot plant' sample, where the ratio of rod mill work index to ball mill work index is more "normal" gives an Optimized Bond/Barratt T80 prediction of 540 µm which is much closer to the survey than the Lowes West sample. The Raw Bond/Barratt model also gives a very fine T80 prediction on the Pilot Plant sample.

Overall, it appears that the Lowes West sample total energy prediction is close to what was observed during the survey, but the ratio of the rod mill and ball mill work index values (1.4) is probably not correct. The ratio observed in the pilot plant (1.05) give a better match to the internal model parameters (T80, phantom cyclone effect) even though the total hardness of the pilot plant sample exceeds that observed in the survey.

Benchmarking: Bond - Kanowna Belle

2020-05-19T18:20:02Z

Munashe Kurisa: /* Modelling, Optimized Bond/Barratt SABC model */

[[category: Benchmarking]]
[[category: Bond/Barratt Model]]
[[category:Bibliography]]
==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.

Paper describes the design criteria for the circuit and one survey.

===Design Criteria===
The reported mill conditions during the survey are,
* throughput: 170 tonnes/hour
* SAG feed size, F80: 150 mm
* BM cyclone product size, P80: 71 µm
* SAG: 2134 kW power draw at mill shell (ESAG = 12.6 kWh/t)
* Ball mill: 1649 kW power draw at mill shell (Eball = 9.70 kWh/t)
* transfer size: 300 µm
The pebble crusher isn't described, assume it is a 7-foot cone crusher with 300 HP motor drawing 168 kW (Epeb = 1.0 kWh/t). Total circuit specific energy consumption Etotal is 23.2 kWh/t.

Several samples are given in the text. It is assumed that the survey period looks similar to "Lowes West", the 'median' hardness sample of the non-oxidized samples. The Lowes West sample gives similar predictions to the "Pilot Plant" sample tested at A.R. MacPherson, which is claimed to have been selected to be representative of the sulphides.

Lowes West sample {pilot plant sample}:
* WiC 26.7 (metric) {not tested}
* WiRM 22.7 (metric) {19.3 metric}
* WiBM 16.1 (metric) {18.3 metric}
Density isn't given, assume 2.7 t/m3

===Modelling, mill power draw===
Adjust the SAG and ball mill models to get the shell power draws reported in the paper. Actual conditions don't matter because there isn't enough detail to properly model the mills -- treat them just as sources of output kW.

===Modelling, Optimized Bond/Barratt SABC model===
[[File:Kanowna-Lowe.png|thumb|Screenshot of the Model, Lowes West sample]]
[[File:Kanowna-PilotPLant.png|thumb|Screenshot of the Model, Pilot Plant sample]]

The Lowes West sample is predicted to have Essbm of 22.3 kWh/t, add 10% to give Etotal prediction of 24.6 kWh/t. Based on the split of SAG + BM power, the T80 needed to balance the circuit is about 1370 µm. The 'pilot plant' sample predicts a T80 prediction of 540 µm and an Etotal of 26.8 kWh/t.

{| class="wikitable"
|-
! !! Survey !! Model, Lowes West sample !! Difference !! Model, Pilot Plant sample !! Difference
|-
| ESAG || 12.55 kWh/t || 13.27 kWh/t || +5.7% || 14.49 kWh/t || +15.4%
|-
| Eball || 9.70 kWh/t || 10.24 kWh/t || +5.6% || 11.19 kWh/t || +15.4%
|-
| Epeb || 0.99 kWh/t || 1.04 kWh/t || +5.2% || 1.14 kWh/t || +15.4%
|-
| Etotal || 23.24 kWh/t || 24.55 kWh/t || +5.6% || 26.82 kWh/t || +15.4%
|}

===Modelling, Raw Bond/Barratt SABC model===
The Lowes West sample is predicted to have Etotal of 29.1 kWh/t. Based on the split of SAG + BM power, the T80 needed to balance the circuit is about 530 µm. The 'pilot plant' sample predicts a T80 prediction of 377 µm and an Etotal of 29.5 kWh/t.

{| class="wikitable"
|-
! !! Survey !! Model, Lowes West sample !! Difference !! Model, Pilot Plant sample !! Difference
|-
| ESAG || 12.55 kWh/t || 15.70 kWh/t || +25.1% || 15.93 kWh/t || +26.9%
|-
| Eball || 9.70 kWh/t || 12.12 kWh/t || +24.9% || 12.30 kWh/t || +26.8%
|-
| Epeb || 0.99 kWh/t || 1.23 kWh/t || +24.5% || 1.25 kWh/t || +26.5%
|-
| Etotal || 23.24 kWh/t || 29.05 kWh/t || +25.0% || 29.48 kWh/t || +26.8%
|}

===Discussion===

The rod mill work index values in this survey were based on results from Amdel which is believed to have used a non-standard rod mill using a smooth liner. Bond rod mill work index determinations are supposed to be done in a mill employing a wave liner. The "pilot plant" sample rod mill work index was determined at the A.R. MacPherson - Hazen laboratory in the USA which has a wave liner. The ratio of WiRM:WiBM for the Pilot Plant sample (1.05) is dramatically different from the ratio for the samples tested in Australia (avg 1.40). In spite of this, the Lowes West sample, which is an "average sulphide" sample for Kawnowna Belle, gives similar throughput predictions to the Pilot Plant sample.

The predicted phantom cyclone effect is very significant, depending upon which sample is used for the "laboratory" work index value:
* for the Lowes West sample, WiO is 30% less than laboratory value
* for the Pilot Plant sample, WiO is 20% less than laboratory value
The pilot plant's 20% reduction is large, but believable. The Lowes West sample is too large, suggesting the ratio of WiRM:WiBM isn't really that representative of the plant feed during the survey.

The transfer size observed is very fine, 300 µm. The Raw Bond/Barratt model prediction is closer to the observed value (530 µm versus 1370 µm). Measured transfer sizes will always be finer than the "Bond-type" transfer sizes used in the model due to the extra fines present in the SAG product (the phantom cyclone effect). The difference between the survey and the Raw Bond/Barratt model could possibly be explained by the extra fines, but the difference versus the Optimized Bond/Barratt is probably too great to explain by fines correction alone. The 'pilot plant' sample, where the ratio of rod mill work index to ball mill work index is more "normal" gives an Optimized Bond/Barratt T80 prediction of 540 µm which is much closer to the survey than the Lowes West sample. The Raw Bond/Barratt model also gives a very fine T80 prediction on the Pilot Plant sample.

Overall, it appears that the Lowes West sample total energy prediction is close to what was observed during the survey, but the ratio of the rod mill and ball mill work index values (1.4) is probably not correct. The ratio observed in the pilot plant (1.05) give a better match to the internal model parameters (T80, phantom cyclone effect) even though the total hardness of the pilot plant sample exceeds that observed in the survey.

File:Kanowna-PilotPLant.png

2020-05-19T18:02:16Z

Munashe Kurisa: Benchmarking screenshot for Kanowna Belle's pilot plant

== Summary ==
Benchmarking screenshot for Kanowna Belle's pilot plant

File:Kanowna-Lowe.png

2020-05-19T18:01:22Z

Munashe Kurisa: Lowe model prediction for Kanowna Belle

== Summary ==
Lowe model prediction for Kanowna Belle

Benchmarking: Bond - Santa Rita

2020-04-30T20:30:36Z

Munashe Kurisa: added EGL for both the SAG and Ball Mill

[[category: Benchmarking]]
[[category: Bond/Barratt Model]]
[[category:Bibliography]]
==Benchmarking: Bond/Barratt 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.

==Design Criteria==

A survey was conducted on July 15, 2010 and reported the following:
* Ore A×b 50.2
* Ore ball mill work index 18.4 kWh/tonne
* Circuit FAG mill feed F80 141 mm
* Circuit cyclone overflow P80 146 µm
* SAG mill: 30 foot diameter by 15.4 foot effective grinding length (EGL)
* Ball mill: one 20 foot by 28.4 foot (assumed to be EGL)

To run the Bond/Barratt model requires work index values for rod milling and crushing. The reported A×b (50.2) is similar to these values:
* WiRM 15.0 kWh/tonne
* WiC 15.0 kWh/tonne

The motors are not described in detail, but the paper does mention a problem with "SER", which usually stands for "slip energy recovery", suggesting that the SAG mill uses a gear drive with an induction motor. Assume that the ball mill also has an induction motor with gear drive, so for both mills use 0.97 for mechanical efficiency between the motor output and the mill shell, and a motor efficiency of 0.96 between the motor input and output.

==Model parameter fitting==

The following tables back-calculate the "Essbm contingency" model fitting parameter for the Bond/Barratt SABC model (which includes allowance for phantom cyclone effects). Specific energy references the "mill shell" kW values (note that specific energy values in the references relate to power at the DCS).

{|class="wikitable" border="1"
! !!FAG!!BM!!Peb Crusher!!Etotal
|-
| DCS kW||6,667||5,082||||
|-
| Shell kW||6,208||4,732||224||
|-
| Throughput, t/h||650||650||650||
|-
| Specific Energy, kWh/t||9.55||7.28||0.34||17.18
|-
| Essbm||||||||16.82
|-
| contingency||||||||2.1%
|}

The default model contingency is 10%, so this circuit is operating more efficiently. Note that the lack of actual work index measurements in the rod mill and crushing size classes means there is uncertainty in the Essbm measurement used to estimate the contingency.

==Circuit Simulation==
[[File:Benchmarking-Santa_Rita.png|thumb|Screenshot of the Santa Rita circuit simulation]]
Combining the Bond/Barratt specific energy model, the Austin FAG model described in the bibliography and the Nordberg wet overflow ball mill model described in the [[Benchmarking: Santa Rita ball mill model|bibliography]] results in the following throughput predictions using the work index values above:

* Actual FAG/ball motor powers (at shell): 6,208 kW / 4,732 kW
* Actual daily average throughput: 650 tonnes/hour
* Predicted FAG/ball motor powers (at shell): 5,555 kW / 4,734 kW
* Predicted nominal throughput: 568 tonnes/hour (14.4% difference)

Additional criteria for modelling:
* SAG mill loading 33.18% v/v (autogenous, no balls)
* ball mill loading 27.5% v/v
* DCS to shell conversion 0.97 × 0.96 = 0.9312
* SAG liner thickness not given, assume 4.5 inches
* circuit F80 141 mm; P80 146 µm

{|class="wikitable" border="1"
! !!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%
|}

The model specific energy consumption estimates are 7.7% higher than the actual values, and the mill model power draw estimates are about 6% lower than actual. The net effect is the throughput estimates are 14% lower for the model versus the survey.