5
Equation (5), then computing the corrected work index
using Equation (6).
Levin B Value as a Laboratory QA Check
Levin B values should normally be in the range of 15 mWh/
rev to 25 mWh/rev, and are known to vary with test P80
and with ore hardness. Plotting the Levin B versus ball mill
work index of a particular test against a database of such
values is a quick quality control check on the results of a
laboratory program. Figure 4 shows an example data set
(bold points) plotted against a background of a larger data-
base where the QA check is “satisfied” – the bold points
generally fit the trend observed in the larger database.
Table 3. Calibration sample laboratory data
Test P100, µm 150 212 300
Metric BM work index 15.5 16.1 17
Measured P80, µm 114 170 243
Measured F80, µm 2342 2342 2342
Measured grams/rev 1.47 1.75 2.02
Feed %passing CSS 10.2% 13.0% 15.9%
Bond E, kWh/t 11.31 9.02 7.39
Morrell exponent P80 –0.295 –0.295 –0.295
Morrell exponent F
80 –0.297 –0.297 –0.297
Measured Morrell Mib 19.1 17.8 17.1
Levin B, mWh/rev 18.5 18.2 17.8
Morrell E, kWh/t 11.3 8.6 6.7
100 120 140 160 180 200 220 240 260
6
7
8
9
10
11
12
E_Morrell =296.38 x^-0.69
R² =1.00
E_Bond =162.22 x^-0.56
R² =1.00
E, Bond Power (E, Bond) E, Morrell Power (E, Morrell)
Test product P80 size, μm
Figure 3. Signature plots for Bond &Morrell models
Figure 4. Levin B versus ball mill work index (bold points) as a quality-control check versus a larger
database
Specfcenergyconsumpton,kWht
Equation (5), then computing the corrected work index
using Equation (6).
Levin B Value as a Laboratory QA Check
Levin B values should normally be in the range of 15 mWh/
rev to 25 mWh/rev, and are known to vary with test P80
and with ore hardness. Plotting the Levin B versus ball mill
work index of a particular test against a database of such
values is a quick quality control check on the results of a
laboratory program. Figure 4 shows an example data set
(bold points) plotted against a background of a larger data-
base where the QA check is “satisfied” – the bold points
generally fit the trend observed in the larger database.
Table 3. Calibration sample laboratory data
Test P100, µm 150 212 300
Metric BM work index 15.5 16.1 17
Measured P80, µm 114 170 243
Measured F80, µm 2342 2342 2342
Measured grams/rev 1.47 1.75 2.02
Feed %passing CSS 10.2% 13.0% 15.9%
Bond E, kWh/t 11.31 9.02 7.39
Morrell exponent P80 –0.295 –0.295 –0.295
Morrell exponent F
80 –0.297 –0.297 –0.297
Measured Morrell Mib 19.1 17.8 17.1
Levin B, mWh/rev 18.5 18.2 17.8
Morrell E, kWh/t 11.3 8.6 6.7
100 120 140 160 180 200 220 240 260
6
7
8
9
10
11
12
E_Morrell =296.38 x^-0.69
R² =1.00
E_Bond =162.22 x^-0.56
R² =1.00
E, Bond Power (E, Bond) E, Morrell Power (E, Morrell)
Test product P80 size, μm
Figure 3. Signature plots for Bond &Morrell models
Figure 4. Levin B versus ball mill work index (bold points) as a quality-control check versus a larger
database
Specfcenergyconsumpton,kWht