Step 1: Mill overload power •Determine a set of operating conditions that reflects the maximum “overloaded” condition that the mill should be able to handle: –SAG mills: 20% v/v ball charge, 30% v/v filling and 78% critical speed with worn liners –Ball mills: 36%
The SAG mill was also designed with a high maximum ball charge (18%) so that sufficient media was provided when 9 treating incompetent ore. At the proposed ball charge levels, the use of extremely high mill speeds would not have been possible without damage to the mill lining
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The development of the controller incorporates transfer function relationships and the description of the SAG mill variables of powerdraw, weight, rock charge and ball charge as integrating variables
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helps understand charge motion in SAG mills for the given liner designs and lifters, ball size and rock properties, and mill operating conditions. Based on the success of the 2-D model of the SAG mill, the 3-D model in DEM was developed. These types of models could help study charge motion, power draw, liners wear, and energy draft
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Chile equipped with one 40ft SAG Mill of 22 MW and two 26ft Ball Mills of 16.4 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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balls on the rocks (SAG mill) or by interaction between rocks on the one side and mill shell and toe of the grinding charge on the other side (FAG mills). The trajectories of grinding media and rocks promote size reduction by im-pacts. This grinding mechanism is required in SAG and FAG mill
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Grinding (AG), Semi-Autogenous Grinding (SAG), rod, and ball mill circuits operating within the normal range of appli-cation. This guideline does not directly address analysis of crushing plants and fine grinding circuits, but it is a useful reference for such endeavors. Applying power-based analysis techniques requires suf
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For the SAG mill, optimization involves finding the operating conditions that would maximize the fresh feed tonnage to satisfy the demand of the ball mill. The same theoretical considerations used for conventional ball milling systems are also applicable to SAG systems, providing it is recognized
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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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mills: the mill diameter, effective grinding length, charge filling, and so on. The operating power draw of the mill and, consequently, the motor torque consumed will vary during mill operation as the operating parameters vary. The SAG mill power draw model of Austin (using the cali-bration by Doll, 2013) is used to predict the process power
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vi. “Design…shall include a ball charge of a least 3%...greater than the maximum operating (sic) ball charge…, but not less than 18% of the total volume.” This states that AG mills are designed at 18% ball safety, mills operating at maximum 12% balls get 6% ball safety, while operations at maximum 18% get 3% ball
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PJV is running the SAG mills at approximately a 12% ball charge and the ball milling circuit is The purpose of the “Mine-to-Mill” project was to determine the impact of not often constrained. blasting on SAG mill feed size distribution and hence mill throughput
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Jan 01, 2015 For example, for an 36′ 17′ SAG Mill, with a power consumption of 11.7 MW, operating at 73% solids, 13.5% balls charge and at 76% of the critical speed, with 50% of the feed in the size class −6″ +1″; it could be possible to increment in 2% the balls charge (to 15.5%), reducing the % −6″ +1″ to 34.8%, with no changes in the
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The development of the controller incorporates transfer function relationships and the description of the SAG mill variables of powerdraw, weight, rock charge and ball charge as integrating variables
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The motion of an individual ball in the charge is ... methods which provide valuable information about the dynamic conditions inside the mill. Some of the terms that are often used to describe the motion of the media in a tumbling mill are shown in ... LG A mill power equation for SAG mills. Minerals and Metallurgical Processing. Feb 1990 pp57-62
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variation is between 1.2– 3.7% which is lower than mill ball filling percentage, according to the designed conditions (15%). In addition, acquired load samplings result for mill ball filling was 1.3%. Keywords: Miduk Copper oncentrator, SAG Mill, Ball Filling Percentage Introduction Semi-autogenous (SAG) mills are
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The standard method for sizing secondary ball mills (usually the overflow type) in AG/SAG circuits follows published mill supplier information with aspect ratios in the range 1:1.5 to 1:2.0, depending upon product sizing and pulp flow, i.e., the highest expected circulating loads (Morrell, 2001). The applied net power, calculated from testwork
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SAG mill balls experience both significant abrasive and impact wear due to their large (75 – 100 mm) diameters. Ball mill balls experience a greater number of impacts, but at lower magnitude than SAG mill balls, due to the smaller ball size, and smaller mill diameter. Feeds are typically highly abrasive
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IV-126 Figure 1 The mill interior and details of the discharge grate Figure 2 Ball scats IV-127 Evidence of Excess Scats Mill charge When inspecting the mill charge during the crash stop at the end of
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Jun 06, 2016 This refers to high-aspect AG/SAG mills. Ball Charge Motion inside a SAG Mill. With a higher density mill charge. SAG mills have a higher installed power density for a given plant footprint relative to AC mills. With the combination of finer grind and a lower installed power density (based on the lower density of the mill charge), a typical AG
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Grinding (AG), Semi-Autogenous Grinding (SAG), rod, and ball mill circuits operating within the normal range of appli-cation. This guideline does not directly address analysis of crushing plants and fine grinding circuits, but it is a useful reference for such endeavors. Applying power-based analysis techniques requires suf
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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. Predicting the composition of the SAG mill charge is a difficult task since a number of significant phenomena associated with the charge motion must be taken into consideration
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