Specific energy consumption models

Specific Energy Consumption Models

Specific Energy Consumption is the most common way of describing how much energy is used by grinding, and is the basis of the throughput estimations in SAGMILLING.COM. It is usually expressed as kWh/t (kilowatt-hours per tonne).

Models of this type assume a standard particle size distribution and use a single position on that particle size distribution to characterize the entire curve. The most common way to express this is the 80% passing size, which can be expressed as F80 (feed stream 80% passing size), P80 (product stream 80% passing size), or K80 (generic stream 80% passing size. Bond (1952)^[1] describes the rationale for using a single 80% passing size and indicative of the whole size range.

Models are arranged into classes, depending on the theory they are implementing. The models within a class usually almost entirely the same except that each implement a particular feature or default setting.

Bond Models

These models are based on the work of Bond^[1] and Rowland^[2]. They pre-date the wide adoption of SAG milling and can be considered "classical" models.

These models require either a sub-set or all three of Bond work index values: Low-energy impact crushing work index, rod mill work index and ball mill work index.

• Classical Rod mill - ball mill circuit
• Single stage ball milling

Bond/Barratt Models

These models require the three Bond work index values: Low-energy impact crushing work index, rod mill work index and ball mill work index.

• (Default) Optimized Bond/Barratt Model SABC (including phantom cyclone)
• (Default) Optimized Bond/Barratt Model SAB (including phantom cyclone)
• Raw Bond/Barratt Model (no phantom cyclone)

The Optimized model should be used in most situations. The Raw model is provided for situations with especially hard rock that is difficult to SAG mill – specifically situations where the crushing work index or rod mill work index is significantly greater than the ball mill work index.

Bond + Pilot Plant Models

warning - experimental model

This models requires an HPGR pilot plant test (bench-scale HPGR tests also work) plus the three Bond work index values: Low-energy impact crushing work index, rod mill work index and ball mill work index.

• HPGR and ball mill (using Bond and an HPGR pilot plant)

SMC Model

This model requires the two Mi results: SMC test giving Mia values, and ball mill work index details (P₈₀, F₈₀, etc.) giving Mib values.

• Model:Morrell SMC SAG SAB and SABC

SGI Model

This model requires: SAG Grindability Index (SGI or SPI™), and ball mill work index.

• Model:Amelunxen SGI SAB and SABC (similar to SPI™)