Template:BarrattEsagEquation

Barratt SAG Specific Energy Equation

This is a basic equation of the family of Bond/Barratt calculations. It describes specific energy requirement of a SAG (or Autogenous) mill Esag as a function of feed size F₈₀, transfer size T₈₀ and the work index values at three different sizes:

Wi_C: the Bond low-energy impact crushing work index, covers 20 mm to 100 mm size range.
Wi_RM: the Bond rod mill work index, covers 2 mm to 10 mm size range.
Wi_BM: the Bond ball mill work index, less than 2 mm size range.

There are a series of calibration parameters that correspond to the size ranges listed above. It is useful to think of this model as a hypothetical 3-stage crushing — rod mill — ball mill circuit with a calibration adjustment (1.25) for SAG milling.

P_C is the hypothetical tertiary crusher product size (default=18850 µm)
P_R is the hypothetical rod mill product size (default=2100 µm)

Three Rowland Efficiency Factor adjustments are required:

EF₄^RM is the oversize feed factor for rod milling, and is a function of the hypothetical crusher product size or the larger of work index for crushing and work index for rod milling.
EF₄^BM is the oversize feed factor for ball milling, and is a function of the hypothetical rod mill product size and the work index for rod milling.

$< / n o i n c l u d e > E | E_{S A G} = [W i C | W i_{C} \times (\frac{10}{\sqrt{P c | P_{C}}} - \frac{10}{\sqrt{F 80 | F_{80}}}) + W i R M | W i_{R M} \times (\frac{10}{\sqrt{P r | P_{R}}} - \frac{10}{\sqrt{P c | P_{C}}}) \times E F_{4}^{R M} + W i B M | W i_{B M} \times (\frac{10}{\sqrt{110}} - \frac{10}{\sqrt{P r | P_{R}}}) \times E F_{4}^{B M}]$ $\times 1.25 - W i B M | W i_{B M} \times (\frac{10}{\sqrt{110}} - \frac{10}{\sqrt{T 80 | T_{80}}}) < n o i n c l u d e >$

See list of pages that use this formula:

Template:BarrattEsagEquation

Barratt SAG Specific Energy Equation

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