Difference between revisions of "Benchmarking: Fimiston Ball Mills"

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(Benchmarking: Ball Mill Power Draw - Fimiston)
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* ''Nelson, M; Valery, W; Morrell, S'', '''Performance Characteristics and Optimisation of the Fimiston (KCGM) SAG Mill Circuit''', Page 233 - 248, SAG 1996 Conference, Vancouver, Canada.
 
* ''Nelson, M; Valery, W; Morrell, S'', '''Performance Characteristics and Optimisation of the Fimiston (KCGM) SAG Mill Circuit''', Page 233 - 248, SAG 1996 Conference, Vancouver, Canada.
 
** Diameter inside shell = 5.49 m (18 ft)
 
** Diameter inside shell = 5.49 m (18 ft)
** Diameter inside liners = 5.35 m (17.5 ft, 3.0 inch effective liner thickness)
+
** Diameter inside liners = 5.35 m (17.5 ft, 70 mm effective liner thickness)
 
** Belly length inside liners (EGL) = 7.60 m (25 ft)
 
** Belly length inside liners (EGL) = 7.60 m (25 ft)
 
** Centre-line length = 8.76 m
 
** Centre-line length = 8.76 m
 
** Top ball size = 80 mm
 
** Top ball size = 80 mm
  +
** Ore density 2.93 t/m<sup>3</sup>
 
Table 5 presents results of a single ball mill survey. The survey measured motor input power. Drives are assumed to have an efficiency of 0.96 and gearbox+pinion efficiency of 0.970, so the model shell power draw is converted to motor input power by dividing by 0.9312. The predicted power draw of '''Example''' project circuit number 7 (Fimiston) using sample '''MLE''', based on the KCGM paper published by Campbell, J. et al; 1998 AusIMM Annual Conference.
 
Table 5 presents results of a single ball mill survey. The survey measured motor input power. Drives are assumed to have an efficiency of 0.96 and gearbox+pinion efficiency of 0.970, so the model shell power draw is converted to motor input power by dividing by 0.9312. The predicted power draw of '''Example''' project circuit number 7 (Fimiston) using sample '''MLE''', based on the KCGM paper published by Campbell, J. et al; 1998 AusIMM Annual Conference.
   
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| Survey 1
 
| Survey 1
 
| '''3,864'''
 
| '''3,864'''
| <del>66.7</del> 68.3 <sup>&dagger;</sup>
+
| <del>66.7</del> 68.4 <sup>&dagger;</sup>
 
| 38.7
 
| 38.7
 
| 72.0
 
| 72.0
 
| '''3,933''' / ''3,776''
 
| '''3,933''' / ''3,776''
| '''3,592''' / ''3,345''
+
| '''3,619''' / ''3,370''
 
|}
 
|}
 
<sup>&dagger;</sup> The appendix of the paper lists the mill speed as 12.5 RPM. The mill is fixed speed, so the %critical speed is only a function of mill effective diameter (as liners wear). Doing the math (neglecting the balls) gives a 68.3% critical speed.
 
<sup>&dagger;</sup> The appendix of the paper lists the mill speed as 12.5 RPM. The mill is fixed speed, so the %critical speed is only a function of mill effective diameter (as liners wear). Doing the math (neglecting the balls) gives a 68.3% critical speed.

Revision as of 04:18, 24 November 2013

Benchmarking: Ball Mill Power Draw - Fimiston

  • Nelson, M; Valery, W; Morrell, S, Performance Characteristics and Optimisation of the Fimiston (KCGM) SAG Mill Circuit, Page 233 - 248, SAG 1996 Conference, Vancouver, Canada.
    • Diameter inside shell = 5.49 m (18 ft)
    • Diameter inside liners = 5.35 m (17.5 ft, 70 mm effective liner thickness)
    • Belly length inside liners (EGL) = 7.60 m (25 ft)
    • Centre-line length = 8.76 m
    • Top ball size = 80 mm
    • Ore density 2.93 t/m3

Table 5 presents results of a single ball mill survey. The survey measured motor input power. Drives are assumed to have an efficiency of 0.96 and gearbox+pinion efficiency of 0.970, so the model shell power draw is converted to motor input power by dividing by 0.9312. The predicted power draw of Example project circuit number 7 (Fimiston) using sample MLE, based on the KCGM paper published by Campbell, J. et al; 1998 AusIMM Annual Conference.

Survey Survey Power,
kW at input
Mill speed,
%critical
Total load,
%v/v
Pulp %solids,
w/w
Morrell SAG Model,
kW at input / shell
Nordberg Model,
kW at input / shell
Survey 1 3,864 66.7 68.4 38.7 72.0 3,933 / 3,776 3,619 / 3,370

The appendix of the paper lists the mill speed as 12.5 RPM. The mill is fixed speed, so the %critical speed is only a function of mill effective diameter (as liners wear). Doing the math (neglecting the balls) gives a 68.3% critical speed.

The ball mill belly length can be achieved with a 18 degree head angle and 1.9 m trunnion diameter.