EF3 – Diameter Efficiency Factor – using the base mill diameter of 2.44 meters (8’) inside liners, the diameter efficiency factor can be calculated from the followings:
Table 2 gives a tabulation of the EF3 factors for some of the more common mill diameters in both the imperial and metric measuring systems.
TABLE 2: DIAMETER EFFICIENCY MULTIPLIER
Mill Diameter Inside Shell
Mill Diameter Inside Liners
Diameter Efficiency Multiplier
Feet
Meters
Feet
Meters
_______________
3.0
3.281
4.0
5.0
6.0
6.562
7.0
8.0
8.5
9.0
9.5
9.843
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.124
0.914
1.0
1.22
1.52
1.83
2.0
2.13
2.44
2.59
2.74
2.90
3.0
3.05
3.20
3.35
3.51
3.66
3.81
3.96
4.00
2.6
2.88
3.6
4.6
5.6
5.96
6.5
7.5
8.0
8.5
9.0
9.34
9.5
10.0
10.5
11.0
11.5
12.0
12.5
12.62
0.79
0.88
1.10
1.40
1.71
1.82
1.98
2.29
2.44
2.59
2.74
2.85
2.90
3.05
3.20
3.35
3.51
3.66
3.81
3.85
1.25
1.23
1.17
1.12
1.075
1.06
1.042
1.014
1.000 Base
0.992
0.977
0.970
0.966
0.956
0.958
0.939
0.931
0.923
0.914
0.914
Should be noted that mills where the diameter inside liners is larger than 3.81 meters (12.5’) that the diameter efficiency factor does not change and remains 0.914.
