Grinding media is grinding feed plus 4-12% ball charge (ball dia100- 125 mm) High capacity (short retention time) Less sensitive to feed composition (critical size material) Semi-Autogenous Mill Note the size of the mill: Why does the diameter need to be so big? [image: (135-6-2)] SAG Mill Circuit Example — Gold Processing
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For SAG milling applications, the diameter of the balls, mill and throw action of the charge provide for a high impact environment - therefore a balance must be achieved between abrasion resistance and impact resistance in SAG balls to avoid excessive breakage
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The even wear allows for the new life potential of media rejected from ported SAG mills The rejects are totally recyclable since the media retains their integrity for ongoing deployment in a secondary mill Recycling to a ball mill as supplementary media or possibly as resale to other users provides additional value for our clients
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* Semi-autogenous (SAG) grinding is a grinding process carried out with small amount of ball charge (4-15%) unlike ball mills and with the help of bigger parts crumbling the smaller parts of ore * To achieve this type of grinding, SAG mills with large diameter and short length have been developed to take advantage of the kinetic energy of the .
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WiBM is the Bond ball mill work index, unitless CFnet is an empirical adjustment to a ball mill circuit [CFnet = 235 - 029 × ln(P80)] Morrell Mi model: Morrell (2008) published a two-parameter model based on two equations (3 & 4) to describe a variety of comminution devices, including single-stage SAG and AG mills The CEE
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Mill application featur Frozen charge protection – Detects frozen charge in the mill, minimizing equipment wear and liner replacements; Coupling supervision – Detects if a failure or slippage occurs in the couplings and stops the system in case, preventing major damag; Stand-still detection – Prevents the motors from re-starting if the mill is still rocking or moving ,
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The simulation results in the case of the ball mill are verified by comparing snapshots of charge motion Furthermore, it is shown that power draw of ball as well as SAG mills can be predicted .
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Chile equipped with one 40ft SAG Mill of 22 MW and two 26ft Ball Mills of 164 MW commissioned in 2011 In the light of increasing interest in that technology various further Gearless Mill Drives with FCS are presently being erected or are in fabrication phase Los Bronces suffered a Frozen Charge in their expansion plant Confluencia on 10th .
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autogenous (SAG) Mill via an utilized method Miduk copper concentrator is located in Kerman Province, Iran, and its size reduction stage includes one gyratory crusher which feeds one SAG mill (975 dia(m)*388 length(m)) following two parallel ,
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The SAG mill was designed to treat 2,065 t h −1 of ore at a ball charge of 8% volume, total filling of 25% volume, and an operating mill speed of 74% of critical The mill is fitted with 80 mm grates with total grate open area of 766 m 2 ( Hart et al, 2001 )
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The IntelliSenseio team was responsible for the following key tasks: reducing mill shutdowns through real-time predictions of ball charge and liner states, reducing the frequency of SAG mill overloads, and increasing the controllability of the grinding circuit
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Dec 01, 2002· The contribution of the work reported here is to present further examples of state estimation for SAG mills and novel models of the SAG mill discharge, SAG mill ball charge and shell protective lining State estimation of mill rock charge, ball charge (J b), water charge and thus total charge (J t) is demonstrated An assessment of structural .
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charge) Incompetent ore 5 Low ball charge SAG mill, high mill speed (4% ball charge, 90% Nc) A cross between AG and SAG for competent, abrasive or As typically operated in RSA 6 SAG mill (configurations 3, and 5 ) with recycle crusher Competent ores, better suited to coarse grind sizes as circulating loads can be high 7 SAG mills treating .
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An industrial ball mill operating in closed–circuit with hydrocyclones was studied by five sampling surveys The aim of the present study was to optimise ,
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Stresses, generated in the ball charge, increase, which may result in spalling of balls and blocking the grate discharge Optimization of mill performance by using online ball and pulp measurements by B Clermont* and B de Haas* Synopsis Ball mills are usually the largest consumers of energy within a mineral concentrator
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Oct 12, 2017· The ball charge of a SAG mill is about 29% to 30% By friction and influence of tumbling balls inside rotating cylinder grinds the raw material to the required fineness The internal machinery of ball mill grinds the raw material into the powder-like material, And if extreme fineness and refinery are required then rotation go on continue
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The grind-out condition cannot decline below the ball charge level of the SAG mill; if this happens, another warning message is displayed saying the SAG mill speed must be reduced to achieve the target power draw The model assumes all SAG mills are variable-speed; if a fixed-speed mill encounters this condition, it will completely grind out .
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ear for the mill and has the ability to accurately detect ball-to-liner impact occurrenc By quantifying the charge toe angle, or the media angle (β dynamic ), on each rotation, a precise control strategy based on the internal dynamics and volumetric loading of ,
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Apr 24, 2014· Conditions such as different blast designs, primary crusher setting, SAG mill grate design, SAG mill ball charge level, ball mill operating conditions, changes in classification with hydrocyclones, use and operation of recycle/pebble crushers were all considered and evaluated in the simulations
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Jun 19, 2015· % Steel Charge Loading in Mill = 113 – 126 H/ D Ball Mill Charge Volume Calculation Charge Volume of a Grinding Mill (Method 1) Charge Volume of a Grinding Mill (Method 2) Process Machinery Reference Manual by David Michaud May 13, 2021 June 19, 2015 Categories Tools of a Metallurgist Post navigation
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Even the SAG ball charge needs to be adjusted based on the size and hardness of ore it’s working on Too many grinding balls can prematurely wear out the grinding balls themselv Operating a mine mill requires balancing a dynamic set of tradeoffs
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and ball mills, have almost become obsolete in the move to higher milling rates required to process lower metal grad Grinding circuits with fully autogenous (AG) or semi-autogenous (SAG) mills, often combined with ball mills are now the standard to meet the high capacity requirement for processing ores with lower metal grad
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Since the early 1980s, we have been designing and manufacturing Semi Autogenous Mill (SAG Mill) and Autogenous Mill (AG Mill) under the Fuller-Traylor brand Semi-autogenous grinding uses a minimal ball charge in the range of 6-15% while autogenous grinding uses ore only SAG and AG Mills operate by lifting ore/grinding media and dropping it on .
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SAG mill SAG is an acronym for semi-autogenous grinding SAG mills are autogenous mills that also use grinding balls like a ball mill A SAG mill is usually a primary or first stage grinder SAG mills use a ball charge of 8 to 21% The largest SAG mill is 42' (128m) in diameter, powered by a 28 MW (38,000 HP) motor
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JKSimMet simulations were used to test various operating and design conditions to improve the comminution process Modifications to the SABC comminution circuit included an increase in the SAG mill ball charge from 8% to 10% v/v; an increase in the mill ball charge from, Expand
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Jun 24, 2018· Charge Motion inside a SAG Mill For proper design of SAG mills and other types of grinding mills, the operating conditions have to be defined ,
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• Mill type: SAG, FAG, Rod mill, primary ball mill, secondary ball mill, regrind, ,) • Ore feed size (F80 ,F100) and required product size (P80) determining the grinding mechanism to be favoured • Mill size (diameter, length) • Maximum ball top-up size • Mill rotational speed (rpm, variable or fixed speed, single or dual rotation)
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mill speed and shell liner/lifter simulations and, particularly, ball charge volume and ball top size, both of which are dependent upon the contingency applied to the transfer size in the SAG circuit product Iterations of these para-meters can be performed in some models (eg, DJB’s “Reduced Recovery” and “Millpower2000”) to determine
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SAG mills • Determination of your SAG mill’s power draw characteristics • SAG Mill Steel Charge Estimation tool provides an estimate of the percent steel in the charge of your SAG mill based on the power draw and the total charge volume • Ball impact energy chart to determine the impact energy of balls as a function of mill diameters
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Ball-limited circuits (where the T 80 hits the lower limit) will result in the charge level in the SAG mill dropping until its power draw matches the throughput limit dictated by the ball mill It is important to realize that once the SAG mill charge level drops below the ball charge, it can no longer empty and the mill power draw will be .
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