Alex Doll: /* Sources, SAG 2015 conference */

2016-09-23T19:54:32Z

Sources, SAG 2015 conference

← Older revision		Revision as of 19:54, 23 September 2016
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	* Wi<sub>C</sub> 16.1 (metric)		* Wi<sub>C</sub> 16.1 (metric)
	* Wi<sub>RM</sub> 19.4 (metric, but based on non-standard liner geometry)		* Wi<sub>RM</sub> 19.4 (metric, but based on non-standard liner geometry)
			** Wi<sub>RM</sub> would be 15.0 (metric, Bond RM geometry) based on A×b = 36.1
	* Wi<sub>BM</sub> 17.6 (metric)		* Wi<sub>BM</sub> 17.6 (metric)
	* JKDWT: A×b 36.1, ta 0.40		* JKDWT: A×b 36.1, ta 0.40
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	Plant design criteria:		Plant design criteria:
	* primary crusher product (circuit F<sub>80</sub>) = 150 mm		* primary crusher product (circuit F<sub>80</sub>) = 150 mm
	* hydrocyclone overflow (circuit P<sub>80</sub>) = 75 mm		* hydrocyclone overflow (circuit P<sub>80</sub>) = 75 µm
	* ball mill using WRIM with Slip Energy Recovery and gearbox, assume 0.95 × 0.97 efficiency = 0.9215 conversion DCS power to shell.		* ball mill using WRIM with Slip Energy Recovery and gearbox, assume 0.95 × 0.97 efficiency = 0.9215 conversion DCS power to shell.

Alex Doll: Created page with "category: Benchmarking category: HPGR category: Bibliography ==Benchmarking: Bond/Rowland SSBM model - Tropicana HPGR circuit== ===Sources, SAG 2015 conference===..."

2016-04-18T19:50:22Z

Created page with "category: Benchmarking category: HPGR category: Bibliography ==Benchmarking: Bond/Rowland SSBM model - Tropicana HPGR circuit== ===Sources, SAG 2015 conference===..."

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[[category: Benchmarking]]
[[category: HPGR]]
[[category: Bibliography]]
==Benchmarking: Bond/Rowland SSBM model - Tropicana HPGR circuit==

===Sources, SAG 2015 conference===
''Koch, F., Siddall, L., Lovatt, I., Giddy, M. and DiTrento, M.'' '''RAPID RAMP-UP OF THE TROPICANA HPGR CIRCUIT''', SAG 2015 paper number 70.

''Gardula, A., Das, D., DiTrento, M. and Joubert, S.'' '''FIRST YEAR OF OPERATION OF HPGR AT TROPICANA GOLD MINE – CASE STUDY''', SAG 2015 paper number 69

* Primary crusher product (model F80) approximately 150 mm
* Secondary crushing circuit 1×XL900 crusher
* Tertiary crushing circuit 1×2.0 m by 1.85 m HPGR, with two 2.2 MW drives
* Fine screen aperture 4 mm, 57% passing 3 mm.
* Ball mill 24 ft diam by 43 ft long with twin-pinion 7 MW SER v/s drives

Average Primary Ore sample tested at ALS Ammtec gave following determinations:
* UCS 76.7 MPa
* WiC 16.1 (metric)
* WiRM 19.4 (metric, but based on non-standard liner geometry)
* WiBM 17.6 (metric)
* JKDWT: A×b 36.1, ta 0.40
* SMC test™ A×b 41.4, DWi 7.21
* Bond Ai 0.291

Plant design criteria:
* primary crusher product (circuit F80) = 150 mm
* hydrocyclone overflow (circuit P80) = 75 mm
* ball mill using WRIM with Slip Energy Recovery and gearbox, assume 0.95 × 0.97 efficiency = 0.9215 conversion DCS power to shell.

Plant DCS data Jan 2014 to Mar 2015:
* secondary crusher specific energy consumption 0.4 kWh/t
** assume product size 35 mm
** power draw back-calculates to 763 t/h × 0.4 = 305 kW (45% of available power)
* ball mill throughput 734 t/h (use this as overall throughput at 91.2% availability)
* HPGR specific energy consumption, EHPGR = 2.60 kWh/t
* energy associated to auxiliary equipment in sec crushing & HPGR = 0.70 + 1.08 = 1.78 kWh/t
* HPGR circuit product size assumed (T80) 3.5 mm
* ball mill drawing about 14 MW (assumed DCS, works out to 13.0 MW at mill shell)
* Eball = 16.77 kWh/t at shell (18.2 kWh/t at DCS)

==Modelling==
Use the '''Bond/Rowland single stage ball mill''' circuit model with the '''HPGR-BM''' flowsheet.

'''Ball mill model:'''
* Use the '''Nordberg wet overflow ball mill''' model
* Quantity 1
* Mill dimensions, diameter 24 ft, EGL 43 ft
* motor mechanical efficiency 0.97; motor efficiency to DCS 0.95
* Assume 6 inch liner thickness, 7.80 t/m3 ball density.
* Assume speed is 75% of critical and load is 32% v/v

'''Secondary crusher model:'''
* Quantity 1.
* XL900 crushers, use 900 HP motor.
* set mechanical efficiency to 0.45.
* ESecCrush of 0.40 kWh/t

'''HPGR model:'''
* Quantity 1
* HPGR motor 4400 kW (actually 2 × 2200 kW)
* Adjust the mechanical efficiency to get ETertCr of 2.6 kWh/t (EHPGR of 2.6 kWh/t),
** results is mechanical efficiency of 0.44.

'''Bond/Rowland SSBM Circuit model:'''
* Set the crusher product size to 3500 µm
* Circuit feed size 150 000 µm and product size 75 µm
* Adjust the '''Essbm calibration factor''' to zero (0)
* Result is 745 t/h circuit throughput with Etotal of 20.5 kWh/t (excluding auxiliary equipment)
* Predicts 1% increase in ball mill operating work index (17.75) versus laboratory Wi (17.5).

==Discussion==

===Essbm equation calibration===
No correction is made for the smooth liner in the rod mill work index apparatus. This rod mill work index will be conservative (probably high by more than 2 units).

===Microcracking/phantom cyclone/ball mill performance===
The predicted 1% increase in WiO fits nicely with the observation at Tropicana that "The range over five field tests was 0% to 8% higher power consumption when compared to the theoretical prediction."

===Secondary crushers, operating work index===
The Bond (impact) crushing work index is given as 16.1 based on a laboratory determination. Use the circuit survey data to compare the operating work index to this laboratory determination.

The reported specific power consumption of the XL900 crusher is 0.40 kWh/t. The secondary crusher is assumed to process a 150 mm primary crushed feed into a 35 mm secondary crushed product. Back-calculating the operating work index of the crusher gives:

<math>0.40 \text{ kWh/t} = Wi_{O} \left(\frac{10}{\sqrt{35000}} - \frac{10}{\sqrt{150000}} \right)</math>

Solving for WiO gives 2.8 kWh/tonne (versus laboratory determination 16.1 kWh/t).

Benchmarking: Bond - Tropicana - Revision history

Alex Doll: /* Sources, SAG 2015 conference */

Alex Doll: Created page with "category: Benchmarking category: HPGR category: Bibliography ==Benchmarking: Bond/Rowland SSBM model - Tropicana HPGR circuit== ===Sources, SAG 2015 conference===..."