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SAG mills use a ball charge of 8 to 21%. The largest SAG mill is 42' (12.8m) in diameter, powered by a 28 MW (38,000 HP) motor. A SAG mill with a 44' (13.4m) diameter and a power of 35 MW (47,000 HP) has been designed. Attrition between grinding balls and ore particles causes grinding of finer particles.

3.5.2.2 Ball Mills. The ball mill accepts the SAG or AG mill product. Ball mills give a controlled final grind and produce flotation feed of a uniform size. Ball mills tumble iron or steel balls with the ore. The balls are initially 5–10 cm diameter but gradually wear away as grinding of the ore proceeds.

Precise control of SAG mill loading and flotation cell level is critical to ... interacting variables (such as rotation speed and ore feed rate on SAG mill weight). .... The effect of the feedforward variable is then simply added to ... A semi-autogenous grinding (SAG) mill is a rotating cylinder containing steel balls that is used as. Read More

I am a new in an iron ore plant were we are with magnetite ore using two Aerofall Mills but it's very hard for us to control the the mill feed rate, and we also have a problem with the Ball charge; we've tried different charges but it's still a problem; I would like to know if there's is any way to determine the optimal ball charge

An online calculator lets you calculate Top Ball Size of Grinding Media for your mill. Use this Equation & Method to properly grind your ore.

benchmark performance comparisons and are made with other power modelling techniques. Practical ... modern grinding circuits include a SAG mill, a ball mill and/or a combination thereof. The use of Bond ... MacPherson correlated Autogenous Work Index (AWi). A particle size analysis of the mill ore charge at

Depending on the mill size the SAG mills draws between 2 MW and 17 MW. The product from the SAG mill is further reduced in size using pebble crushers and ball mills. Hence, typical gold or copper ore requires between 2.0 and 7.5 kWh per ton of energy to reduce the particle size.

charge level and ball size were studied in the SAG mill circuit as well as ... Figure 3 illustrates the effect on ball mill cyclone performance due to the change from series to parallel cyclone ...

What is the effect of low ball % full on grinding efficiency?One of our clients is thinking of the future and has bought a ball mill that will be the right size someday, but is very large now.I know what happens to mill power from adjustments to % critical speed and % balls charge. What I don't know

charge motion. It is well known that ball milling efficiency varies during the lifetime of the shell liner. For instance, the mill performance could become worse or better by putting in a new shell liner. Data from pilot plant test work illustrates the influence of the shell lifting effect on .

In Grinding, selecting (calculate) the correct or optimum ball size that allows for the best and optimum/ideal or target grind size to be achieved by your ball mill is an important thing for a Mineral Processing Engineer AKA Metallurgist to do. Often, the ball used in ball mills is oversize "just in case". Well, this safety factor can cost you much in recovery and/or mill liner wear and tear.

• Mill lining knowledge centers in your region are backed by global support • Mill lining manufacturing in 14 factories globally The mill is at the heart of your production process. The yield of your grinding operation is highly dependent on the performance of your mill's lining. Select your mill .

Ball Charge and Grinding Efficiency Grinding & Classification . What is the effect of low ball % full on grinding efficiency? . With very low ball charge (less than 20 %) and low slurry density power draw will .. SAG Mill's effect is mainly crush the big ores and then use ball mill to grinding the small ores. Live Chat

Higher energy collisions cause liner damming and increased grind ball consumption. Mechanics Ball and ore particles follow Newton's laws of motion. 1. A mill speed approaching 80% of critical can optimize grinding action and reduce wear. ... DEM software simulated SAG charge motion, Conveyor-Dynamics ... describes the performance of ...

processing at an ore mill at Bougainville, New Guinea. Since then innovation has continued with the first GMD for a double-rotating ball mill in Carlin, Nevada, meeting a 160 °C heat challenge at the mill shell. GMDs have now been supplied for the world's largest autogenous (AG), semi-autogenous (SAG) and ball mills, fulfilling the highest power

Utah, SAG mill and a 11,200 kW gearless drive for the El Teniente, Chile, SAG mill. In a continued call for larger, even more powerful drives, Siemens kept pace. In 1996, Freeport ordered the first gearless drive for a 38-foot SAG mill located at the company's Grasberg plant in .

two correlations now allow mill performance to be predicted for a ... In SAG mills running with higher ball charges, the rock ... AG and SAG Mill Circuit Selection and Design by Simulation ...

For overflow ball mills, the charge should not exceed 45% of the mill volume . For grate discharge mills, the charge should occupy about 50% of the mill volume . Bond developed a relationship that can be used to determine the percent charge by volume as a function of the vertical height above the charge, He, and the radius of the mill, R, i.e.,

FLzenith breaks world record in Chile — FLzenith Discover Mining. May 1, 2011 ... The total power needed for the ore grinding in the primary SAG mill and the two secondary ball mills for the Esperanza Project was nearly...

process, which is choosing a SAG mill to accomplish the required specified design performance. At the test work stage, each ore hardness data point is a unique and discreet bit of information that represents the energy required to grind the ore represented by that sample at optimum SAG conditions.

The results in Table 6 show that there would be no adverse effect on the mill performance if the balls are replaced gradually by pebbles. As the pebble volume was increased, there was a progressive reduction in energy utilization, without affecting productivity, up to about 30% pebbles.

startling effect of ball scats removal on sag mill performance - Gekko. ratio of South African style SAG mills, Powell et.al, (2001). NAVACHAB ... The mill is operated at 90% of critical speed and with a volumetric load of 40%.

TECHNICAL NOTES 8 GRINDING R. P. King. 8-2 &ROOLVLRQ ... The effect of mill charge is primarily through the shifting of the center of gravity and the mass of the charge. As the ... steel balls in a ball mill, or large lumps of ore in an autogenous mill or a mixture in a semi-autogenous mill,

2 MODELLING THE SPECIFIC GRINDING ENERGY AND BALL-MILL SCALEUP Ball-mill scale up (Bond's Law)Data: zBond work index w i zFeed D f and product d size (both 80% cumulative passing) Result: The specific grinding energy w Mill power draw P = wT, where T the mill capacity Mill dimensions (from Tables or charts)
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