4
This ratio indicates the impact conditions in the mill, low
ratio is typically 0.4, a safe ratio ~0.65 and a very high
ratio 0.85 in some SAG mills. In this case, the mill speed
must be adjusted to avoid balls and liners breakage, grates
pegging, etc.
GRINDING PRINCIPLES
In 2006, Powell and Mainza introduced the power curves
to the grinding industry (Power, 2006). They serve as a
valuable tool for understanding the importance of mill fill-
ing in achieving optimal grinding efficiency under varying
conditions. The most common use of power curves is in
surveys where the process is in a steady state and a single
data point is collected. However, this approach has several
challenges when we are searching to obtain the real-time
optimum operating point in the grinding process as it
has numerous continuously changing variables and vary-
ing mill internal &surrounding circuit conditions. i.e.,
changes in ore density, hardness and size, ball charge, mil
speed, wearing liners and grinding balls, slurry density, dis-
charge blockages, etc.
Figure 4. Advanced analytics measurements (AAM) with respect to traditional power curves
This ratio indicates the impact conditions in the mill, low
ratio is typically 0.4, a safe ratio ~0.65 and a very high
ratio 0.85 in some SAG mills. In this case, the mill speed
must be adjusted to avoid balls and liners breakage, grates
pegging, etc.
GRINDING PRINCIPLES
In 2006, Powell and Mainza introduced the power curves
to the grinding industry (Power, 2006). They serve as a
valuable tool for understanding the importance of mill fill-
ing in achieving optimal grinding efficiency under varying
conditions. The most common use of power curves is in
surveys where the process is in a steady state and a single
data point is collected. However, this approach has several
challenges when we are searching to obtain the real-time
optimum operating point in the grinding process as it
has numerous continuously changing variables and vary-
ing mill internal &surrounding circuit conditions. i.e.,
changes in ore density, hardness and size, ball charge, mil
speed, wearing liners and grinding balls, slurry density, dis-
charge blockages, etc.
Figure 4. Advanced analytics measurements (AAM) with respect to traditional power curves