The Metso AG/SAG mills are utilized to grind run-of-mine rock or primary crusher is the world leading supplier of gearless AG/SAG mills operating globally. single stage crush, rock and pebble mill as operated at Mt Edon Gold Mine Pebble crushing impacts on. SAG mill operation. AG/PC circuits require good. Jump to Design Changes and Future Operating Strategies - Mill feed chute liner life continues to be a problem. The original chrome-moly liners lasted  ‎Ball Charge Motion inside a · ‎SAG Mill vs Ball Mill · ‎SAG Mill Operation.


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This means less unscheduled downtime and increase in production.

The reduced damage improves the mills availability and minimises the down sag mill operation. Test results also show a reduced energy consumption of up to six percent. Considering that mills are the largest power consumer in minerals processing, this is quite significant.

The special feeding of bulk material through a hopper leads to a material bed between the two rollers.


The bearing units of one roller can move linearly and are pressed against the material bed by springs or sag mill operation cylinders. In general they achieve to MPa.

Autogenous and Semiautogenous mills

The roller press has a certain similarity to roller crushers and roller presses for the compacting of powders, but purpose, construction and operation mode are different. Extreme pressure causes the particles inside of the compacted material bed to fracture sag mill operation finer particles and also causes microfracturing at the grain size level.


A similar type of intermediate crusher is the edge runner, which consists of a circular pan with two or more heavy wheels known as mullers rotating within it; material to be crushed is shoved underneath the wheels sag mill operation attached plow blades.

Buhrstone mill[ edit ] Table top hammer mill Another type of fine grinder commonly used is the buhrstone millwhich is similar to old-fashioned flour mills.

sag mill operation

Optimizing your SAG mill operation - International Mining

It can sag mill operation very difficult operationally to trade grind for throughput in an SAG circuit—once designed and constructed for a given circuit configuration, an SAG mill circuit has limited flexibility to deliver varying product sizes, sag mill operation a relatively fixed unit power input for a given ore type is typically required in the SAG mill.

This is particularly true for those SAG circuits designed with a coarse closing size. As a result, under-sizing an SAG mill has disastrous results on throughput— across the industry, there are numerous examples of the SAG mill emerging as the circuit bottleneck.

On the other hand, over-sizing an SAG circuit can be a poor utilization of capital or an opportunity for future expansion!

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  • SAG Mill Grinding Circuit Design

Traditionally, many engineers approached SAG circuit design as a division of the total power between the SAG circuit and ball-mill circuit, often at an arbitrary power split. If done without due consideration to ore characteristics, benchmarks against comparable operating circuits, and other aspects of detailed design including steady-state tests, simulation, and experiencean arbitrary power split between circuits ignores the critical decision sag mill operation determining the sag mill operation unit power in SAG milling.

As such, it exposes the circuit to risk in terms of failing to meet throughput targets if insufficient SAG power is installed.

Rather than design the SAG circuit with an arbitrary fraction of total circuit power, it is more useful to base the required SAG mill size on the product of the unit power requirement for the ore and the desired throughput.

Subsequently, the size of the secondary milling circuit is then sized based sag mill operation the amount of finish grinding for the SAG circuit product that is required. Restated, the designed SAG mill size and operating conditions typically control circuit sag mill operation, while the ball-mill circuit installed power controls the final grind size.

The effect of feed size is marked, with both larger and finer feed sizes having a significant effect on throughput.

Optimizing your SAG mill operation

With SAG mills, the response is typically that for coarser ores, throughput sag mill operation, and vice versa. However, for AG mills, there are number of case histories where mills failed to consistently meet throughput targets due to a lack of coarse media.

Compounding the challenge of feed size is the fact that for many ores, the overall coarseness of the primary crusher product is correlated to feed hardness.

Larger, more competent material consumes mill volume and limits throughput. A number of operations have implemented a secondary crushing circuit prior to the SAG circuit for further comminution of primary crusher product. Such a circuit can counteract the effects of harder ore.

Notably, harder ore often presents itself to the SAG circuit as coarser than softer ore—less comminution is produced in blasting and primary crushing, and therefore the impact on SAG throughput is compounded.

Occasionally, secondary crushing is included in the original design but is often added as an additional circuit to sag mill operation for harder ore either harder than planned or becoming harder as the deposit is developed or as a capital-efficient sag mill operation to boost throughput in an existing circuit.

Such a flowsheet is not without its drawbacks.


Not surprisingly, some of the advantages of SAG milling are reduced in terms of increased liner wear and increased maintenance costs.

Also, pre-crush can lead sag mill operation an increase sag mill operation mid-sized material, overloading of pebble circuits, and challenges in controlling recycle loads. In certain circuits, the loss of top-size material can lead to decreased throughput.

It is now widespread enough to be a standard circuit variant and is often considered as an option in trade-off studies.