Benchmarking: Bond/Barratt - Selbaie - Revision history

Alex Doll: /* Circuit Simulation */

2022-11-11T15:49:47Z

Circuit Simulation

Alex Doll: /* Model Criteria */

2017-03-11T22:06:40Z

Model Criteria

Alex Doll: /* Additional model parameters */

2017-03-11T20:02:21Z

Additional model parameters

Alex Doll: /* Additional model parameters */

2016-12-29T00:44:28Z

Additional model parameters

Alex Doll: /* Circuit Simulation */

2016-12-29T00:40:10Z

Circuit Simulation

Alex Doll: /* Additional model parameters */

2016-12-29T00:18:44Z

Additional model parameters

Alex Doll at 00:04, 29 December 2016

2016-12-29T00:04:16Z

Alex Doll: Created page with "category: Benchmarking category: Bond/Barratt Model category:Bibliography ==Benchmarking: Bond/Barratt Specific Energy Consumption - Selbaie== ''Duval, L. and Woo..."

2016-12-28T23:29:07Z

Created page with "category: Benchmarking category: Bond/Barratt Model category:Bibliography ==Benchmarking: Bond/Barratt Specific Energy Consumption - Selbaie== ''Duval, L. and Woo..."

New page

[[category: Benchmarking]]
[[category: Bond/Barratt Model]]
[[category:Bibliography]]
==Benchmarking: Bond/Barratt Specific Energy Consumption - Selbaie==

''Duval, L. and Wood, K.'', '''Testing, Design and Operation of SAG Circuit at Les Mines Selbaie''', Proceedings of the SAG 1989 Conference, Vancouver, Canada, September 1989.

''Wood, K. and Duval, L.'', '''Mill Expansion at Les Mines Selbaie''', Proceedings of the 25th Anniversary Issue of the Canadian Mineral Processors, Ottawa, Canada (Paper № 8), January 1987.

==Design Criteria==

Two surveys was conducted in Nov 1988 and Dec 1988 and reported the following:
* Ore laboratory Bond rod mill work index: 16.5 metric
* Ore laboratory Bond ball mill work index, 104 µm closing mesh: 12.2 metric
* Ore laboratory Bond ball mill work index, 37 µm closing mesh: 13.2 metric
* MacPherson Autogenous work index (gross) of 20.1 metric (to 332 µm)
* MacPherson Autogenous work index (corrected) of 15.8 metric (to 332 µm)
* MacPherson ball mill operating work index of 13.8 metric (to 48 µm)
* MacPherson AB circuit operating work index of 16.1 metric (to 48 µm)
* Circuit FAG mill feed F80 117 mm
* Circuit transfer size T80</sub) 325 µm
* Circuit cyclone overflow P80 44 µm
* Circuit SAG operating work index of 20.0 metric (to 325 µm)
* Circuit ball mill operating work index of 13.8 metric (to 45 µm)
* Circuit total operating work index of 16.0 metric (117 mm to 45 µm)
* Target throughput: 5000 t/d at 90% availability
* Actual throughput:

The motors are described as:
* SAG mill is gear-driven with a DC variable speed motor having electrical efficiency of 0.925.
* SAG mill maximum speed (for "design" ore hardness) is 74% of critical speed.
* Ball mill is gear-driven with a fixed-speed synchronous motor (assume 0.96 electrical efficiency)

Additional data:
* SAG mill dimensions are given as 27 ft diameter by 11 ft long (not clear if this length is f/f or EGL)
** Checking the Metso installation list, a 27 ft by 12 ft f/f long SAG mill was delivered to Quebec in 1985.
** Duval & Wood (1989) say the discharge chamber is smaller than normal, so model a 10.5 ft EGL mill.
* Liner drawings show SAG mill hi/lo pattern with roughly 6 inch effective thickness.
* Ball mill dimensions are given in Wood & Duval (1987) as 16.5 ft diameter by 25.5 ft (?? f/f or EGL ??)
** Checking the Metso installation list, a 16.5 ft by 25.5 ft f/f long ball mill was delivered to Quebec in 1985.

==Model parameter fitting==

No crushing work index is provided, but we can make an assumption it is similar to the MacPherson Autogenous Work Index measured at Hazen.

No power draw numbers or mill filling values are given for the SAG or ball mill; only specific energy and work index values are provided.
Assume for modelling:
* SAG mill filling is 25% v/v (gives about 85% of total power draw, sounds reasonable)
* ball mill filling is 32% v/v (gives about 95% of total power draw, sounds reasonable)

{|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%
|}

==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 [[Benchmarking: Santa Rita FAG|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%
|}

← Older revision		Revision as of 15:49, 11 November 2022
Line 74:		Line 74:
	\| Difference, %\|\| 2%\|\| 3%\|\| 4%		\| Difference, %\|\| 2%\|\| 3%\|\| 4%
	\|}		\|}
		+
		+	<math>\frac{kW}{t/h} = 10 \times Wi_{O} ( P_{80}^{-1/2} - F_{80}^{-1/2} ) </math>
		+
		+	rearrange to solve for Wi
		+
		+	<math>Wi_{O} = \frac{kW/(t/h)}{10 \times ( P_{80}^{-1/2} - F_{80}^{-1/2} )} </math>

@@ Line 22: / Line 22: @@
 * Circuit transfer size T<sub>80</sub> 325 &micro;m
 * Circuit cyclone overflow P<sub>80</sub> 44 &micro;m
-* Circuit SAG operating work index of 20.0 metric (to 325 &micro;m, measured at DCS)
+* Circuit SAG operating work index of 20.0 metric (to 325 &micro;m)
-* Circuit ball mill operating work index of 13.8 metric (to 45 &micro;m, measured at DCS)
+* Circuit ball mill operating work index of 13.8 metric (to 45 &micro;m)
-* Circuit total operating work index of 16.0 metric (117 mm to 45 &micro;m, measured at DCS)
+* Circuit total operating work index of 16.0 metric (117 mm to 45 &micro;m)
 * Target throughput: 5000 t/d at 90% availability (231 t/h)
 * Actual throughput: 5444 t/d at 93.5% availability (243 t/h)
@@ Line 38: / Line 38: @@
 ** Duval & Wood (1989) say the discharge chamber is smaller than normal, so model a 10.5 ft EGL mill.
 * Liner drawings show SAG mill hi/lo pattern with roughly 6 inch effective thickness.
-* Ball mill dimensions are given in Wood & Duval (1987) as 16.5 ft diameter by 25.5 ft (?? f/f or EGL ??)
+* Ball mill dimensions are given in Wood & Duval (1987) as 16.5 ft diameter by 25.5 ft (doesn't say f/f)
 ** Checking the Metso installation list, a 16.5 ft by 25.5 ft f/f long ball mill was delivered to Quebec in 1985.
 * SAG mill is normally operated at 8% v/v ball charge.

@@ Line 47: / Line 47: @@
 * use Wi<sub>C</sub> = 15.8 metric for modelling
-The ball mill work index P80 values are not provided (only the closing mesh sizes) so a detailed ball mill Wi calibration to P80 cannot be performed.  The target 44 &micro;m will be somewhere between the expected test P80s of 37 &micro;m and 105 &micro;m closing meshes.  Given the difference in work index is low (1.0 metric units), just model the arithmetic average of the two Wi<sub>BM</sub> tests.
+The ball mill work index P80 values are not provided (only the closing mesh sizes) so a detailed ball mill Wi calibration to P80 cannot be performed.  The target 44 &micro;m will be somewhere between the expected test P80s of 73 &micro;m and 105 &micro;m closing meshes.  Given the difference in work index is low (1.0 metric units), just model the arithmetic average of the two Wi<sub>BM</sub> tests.
 * use Wi<sub>BM</sub> = 12.7 metric for modelling

← Older revision		Revision as of 00:44, 29 December 2016
Line 55:		Line 55:
	* ball mill filling is 32% v/v (gives about 95% of total power draw, sounds reasonable)		* ball mill filling is 32% v/v (gives about 95% of total power draw, sounds reasonable)

		+	Duval & Wood do not specifically say if the reported work index values are relative to the motor output power (mill shell) or the measured DCS motor input power. Given that the paper does provide motor efficiency values and that comparisons to laboratory work index tests (which are based on motor output "pinion" power), it is reasonable to assume that the reported operating work index values are corrected to either the motor output or the mill shell. For purposes of comparison, we will assume the operating work index is equivalent to the "mill shell" specific energy values in SAGMILLING.COM; possibly predictions are low by 1.5% due to pinion mechanical efficiency).
−
−	{\| class="wikitable"
−	\|-
−	\| align=center\|
−	\| align=center\| '''SAG WiO, metric '''
−	\| align=center\| '''Ball mill WiO, metric '''
−	\| align=center\| '''Total WiO, metric '''
−	\| align=center\| '''F80'''
−	\| align=center\| '''T80'''
−	\| align=center\| '''P80'''
−	\| align=center\| '''Esag'''
−	\| align=center\| '''Ebm'''
−	\| align=center\| '''Etotal, kWh/t'''
−	\|-
−	\|\| Operating work index at DCS
−	\| \| 20.0
−	\| \| 13.8
−	\| \| 16.0
−	\| \| 117000
−	\| \| 325
−	\| \| 45
−	\| \| 10.51
−	\| \| 12.92
−	\| \| 23.43
−	\|-
−	\|\| Electrical efficiency
−	\| \| 0.925
−	\| \| 0.960
−	\| \| 0.946
−	\|\|
−	\|\|
−	\|\|
−	\|\|
−	\|\|
−	\|\|
−	\|-
−	\|\| Mechanical efficiency
−	\| \| 0.985
−	\| \| 0.985
−	\| \| 0.985
−	\|\|
−	\|\|
−	\|\|
−	\|\|
−	\|\|
−	\|\|
−	\|-
−	\|\| Operating work index at shell
−	\| \| 18.22
−	\| \| 13.05
−	\| \| 14.91
−	\| \| 117000
−	\| \| 325
−	\| \| 45
−	\| \| 9.58
−	\| \| 12.21
−	\| \| 21.79
−	\|-
−	\|}

	==Circuit Simulation==		==Circuit Simulation==

@@ Line 116: / Line 116: @@
 ==Circuit Simulation==
-[[File:Benchmarking-Santa_Rita.png|thumb|Screenshot of the Santa Rita circuit simulation]]
+[[File:ScreenGrab_Selbaie.png|thumb|Screenshot of the Selbaie circuit simulation]]
 Combining the Bond/Barratt specific energy model, the Austin SAG model and the Nordberg wet overflow ball mill model results in the following throughput predictions using the work index values above:
@@ Line 122: / Line 122: @@
 ! !!SAG!!BM!!total
 |-
-| Predicted specific energy consumption, kWh/t|| 11.99|| 12.37|| 24.37
+| Predicted specific energy consumption, kWh/t|| 11.99 || 12.37 || 24.37
 |-
-| Predicted operating work index, metric|| 20.32|| 14.20|| 16.67
+| Predicted operating work index, metric|| 20.3|| 14.2 || 16.7
 |-
-| Measured operating work index, metric|| || ||
+| Measured operating work index, metric|| 20.0 || 13.8 || 16.0
 |-
-| Difference, metric Wi units|| || ||
+| Difference, metric Wi units|| 0.3 || 0.4 || 0.6
 |-
-| Difference, %|| %|| %|| %
+| Difference, %|| 2%|| 3%|| 4%
 |}

@@ Line 54: / Line 54: @@
 * SAG mill filling is 25% v/v (gives about 85% of total power draw, sounds reasonable)
 * ball mill filling is 32% v/v (gives about 95% of total power draw, sounds reasonable)
 {| class="wikitable"
 |-
 |}