Bibliography: Benchmarking

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Bibliography: Benchmarking of models

The following list of references show data useful for benchmarking against the different models.

Benchmarking: Circuit Specific Energy Consumption

Benchmarking: SAG 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 = 10.970 m (36 ft)
    • Diameter inside liners = 10.797 m (35.42 ft, 3.5 inch effective liner thickness)
    • Belly length inside liners (EGL) = 4.417 m (14.5 ft)
    • Centre-line length = 6.920 m

Table 4 presents results of several SAG surveys at different speed and load conditions. The survey measured motor input power. Drives are assumed to have an efficiency of 0.96 and pinion efficiency of 0.985, so the model shell power draw is converted to motor input power by dividing by 0.9456. 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
Ball load,
%v/v
Total load,
%v/v
Pulp %solids,
w/w
Morrell SAG Model,
kW at input / shell
Loveday/Baratt Model,
kW at input / shell
Survey 1 9,255 72.5 13 21.6 65.9 9,268 / 8,764 10,372 / 9,808
Survey 2 10,374 77 13 25.2 63.3 10,481 / 9,911 11,238 / 10,636
Survey 3 8,395 75 15 16.1 70 9,193 / 8,693 10,818 / 10,230
Survey 4 8,299 78 11.5 13.5 60 7,766 / 7,344 can't do
Survey 5 10,976 80 11.5 22.2 60 9,877 / 9,340 10,322 / 9,760
Survey 6 8,616 74 11.5 13.6 63 7,394 / 6,992 can't do
Survey 7 11,684 82 14 20 75 10,782 / 10,195 11,037 / 10,437
Survey 8 11,610 78 13 28.6 75 11,415 / 10,794 11,125 / 10,520
Survey 9 11,571 78 13 25.8 75 10,990 / 10,392 11,668 / 11,033
Survey 10 9,408 80 12 19 75 9,655 / 9,130 10,309 / 9,749
  • The overall average difference between the Morrell model motor input predictions and the measurements are -3.4%, and range from -15.3% to +9.1%.
  • The overall average difference between the Loveday/Barratt model motor input predictions and the measurements are +4.8%, and range from -6.1% to +25.2%.

The SAG mill belly length reported can be achieved with a 16.5 degree head angle and 2.47 m trunnion diameter.

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, 3.0 inch effective liner thickness)
    • Belly length inside liners (EGL) = 7.60 m (25 ft)
    • Centre-line length = 8.76 m
    • Top ball size = 80 mm

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 68.3 38.7 72.0 3,933 / 3,776 3,592 / 3,345

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.

Historic & Other Interesting Benchmarking

  1. Myers, J.F., Michaelson, S.D., Bond, F.C., Rod Milling—Plant and Laboratory Data, Technical Publication No. 2175, American Institute of Mining and Metallurgical Engineers, 1947. [1]