The new measurement technique is demonstrated by surveying the load of a large SAG mill following a crash stop and a subsequent grind-out. The SAG mill in this example has an internal diameter of 11.93 m; a belly length inside liners of 6.09 m; cone angles of 15 degrees and a trunnion diameter of 2.80 m.
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A Semi-autogenous (SAG) Mill utilizes steel balls in addition to the natural grinding media. T he addition of balls (typically 6 to 12 percent by mill volume o f 100 mm diameter or 125 mm diameter ...
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towards larger-sized SAG mills with diameters of 10.4 m (34 ft) and above, with the largest being 12.2 m (40 ft) in diameter and drawing 20 to 22 MW (Jones, 2006). Mill liners …
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It would be unreasonable to dismiss the viewpoint of a mill designer on the design of ring motors just because the mill structure is relatively much simpler than the motor. So, let us look at the design validation of mills. Svalbonas [2] presents strain gauge measurements from a mill in a paper dated 1979.
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In the present invention a method, apparatus and computer program are presented, with which the amount of balls among ore material contained in a grinding mill is estimated as a percentage by volume of the total volume of the mill. Preferably, the invention relates to semi-autogenous mills. In the invention, an expanded Kalman filter is used to estimate …
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A total of 120 t of Cristalino ore was prepared and sent to CIMM, where it was crushed and screened prior to grinding tests. The processing equipment included a 1.83 m (8′) diameter by 0.61 m (2′) length AG/SAG mill equipped with a 20 kW motor, a cone crusher, a 0.91 m (3′) diameter by 1.22 m (4′) length ball mill equipped with a 15 kW ...
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It is possible to design and operate Cadia is undertaking a plant optimization study with the SAG mills of 40 ft (12.2 m) diameter (and likely larger) objective of economically increasing plant capacity. with designs based on currently available large mill power There are a number of changes to the grinding circuit data.
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The SAG grindability index test. Peter Amelunxen a,, Patricio Berrios b, Esteban Rodriguez b a AME Ltda, Cerros de Camacho 440, Dep F-17, Santiago de Surco, Lima, Peru b Aminpro Chile SpA, Cerro San Cristobal 95111, Quilicura, Santiago, Chile a r t i c l e i n f o Article history: Received 13 June 2013 Accepted 31 August 2013 Available online 5 …
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Due to the large volume of the SAG mill, in ord er to facilitate the simulation and calc ulation, the SAG mill is simplified to a ring column model of ∅ 5250 × 500 mm, which is one t enth of ...
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Our team of product engineers continually improves SAG/AG Mill designs in order to provide the most robust, safe, and efficient grinding mills available. Key design features: Robust head castings and shell fabrications …
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In large mills it has been found that the use of the conical end plate construction produces a more efficient use of material, with a controlled and predictable stress and deflection pattern due to Its …
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Mill Power required at pinionshaft = (240 x 16.5 x 1.025) ÷ 0.746 = 5440 Hp Speed reducer efficiency: 98% 5440 Hp ÷ 0.98 = 5550 HP (required minimum motor …
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and asymmetric conveyor off-takes to the 2 sag mills (12% balls) that the stockpile feeds. The F80s of each stream are almost identical. However, the finer feed size distribution consistently results in 50% higher throughput than the coarser one. 1 10 100 100 1000 10000 100000 size (microns) cum%pass SAG 1 feed SAG 2 feed
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AG mills (or SAG mills with low ball charges) are often used in single-stage grinding applications. Based on their higher throughput and coarser grind relative to AG mills, it is more common for SAG mills to he …
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The mill reportedly rotates at 70% of critical velocity (Verret et al., 2011), or 54 rpm (Gonzalez, 2000).There is controversy surrounding the mill rotational speed. The calculation of mill critical velocity (V c) is derived from the balance of gravitational force and the centrifugal force acting on a ball, and is given by Eq.(1), after Austin and Concha …
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The following recommendations are proposed to improve the test method: 1.The test should be conducted for a fixed grinding time of 120 min, regardless of the time required to reach 80% passing ...
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hemisphere. It employs the world's largest SAG mill, 40 ft diameter and two 22 ft ball mills in the grinding circuit. In that project, the owners considered it necessary to assess the dynamic response of the foundations for the SAG and ball mills due to vibration problems experienced in other installations. Numerical models of the foundations
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The authors analyze the influence of the semi-autogenous (SAG) mill parameters on the mill grinding efficiency, energy consumption and the tangential …
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A simplified grinding flow sheet, generic in the sense that represents all circuits considered in this work, is presented in Fig. 1. Also shown are the main SAG mill variables included in this study. All others were discarded due to its low availability or because the requirements of the models developed in this work. The lever arm is
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Dramatic shortcomings of mill liner designs, especially of large semiautogenous grinding (SAG) mills-such as rapid failure, mill shell damage arising from the charge impacting directly on the ...
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The Granny Smith grinding circuit with a SAG mill aspect ratio of 2.3 (D=8.53 m, L=3.66 m) operated successfully as a SSSAG mill (Dance and Radford, 2015) between 2008 and 2010.
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Art MacPherson was a pioneer in the introduction of AG and SAG mills to industry. Through strength of character and a keen perception of improving grinding economics he was able to convince corporate directors to purchase large and larger SAG mills, matching industry's need to process lower grade ores at higher tonnage.
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A grinding mill model based on discrete element method (DEM) simulations is being developed at Outotec Oyj (Finland) to be used in mill design optimization. The model can be used for many purposes; one example is the selection of the lining and the size of the mill to meet the requirements of the clients. To validate the accuracy of the DEM ...
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SAG mills are the largest tumbling mills used for primary grinding in mineral processing, using a coarse feed (typically up to 250 mm diameter rock) coming from a crushing stage of the grinding circuit [8]. One of the largest SAG mills (12 m diameter), has a variable speed gearless mill drive (GMD) with a capability of 28 MW for refining copper ...
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INTRODUCTION. Pilot-scale testwork based on a 6' x 2' mill is arguably still the. most reliable method for predicting full scale autogenous (AG) and semi-autogenous (SAG) grinding mill behaviour when treating. a given ore. However, the cost of a detailed pilot-mill programme. both in terms of providing sufficient sample material as well as the.
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Semi-Autogenous Grinding (SAG) Mill. Wet or dry; Higher capacity than A-G mill grinding; Primary, coarse grinding (up to 400 mm feed size) Grinding media is grinding feed plus 4-12% ball charge (ball dia.100- 125 mm) High capacity (short retention time) Less sensitive to feed composition (critical size material) Semi-Autogenous Mill
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Based on experience, mill-liner designs have moved toward more open-shell lifter spacing, increased pulp lifter volumetric capacity, and a grate design to facilitate maximizing both pebble-crushing circuit utilization and SAG mill capacity. As a guideline, mill throughput is maximized with shell lifters between ratios of 2.5:1 and 5.0:1.
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the trend in large SAG mills has been to use wide-spaced shell lifters with large lifter face angles, primarily to reduce packing and ball/liner damage, and to use larger, hence fewer, mill liner parts to reduce downtime at liner change-outs. Key words: Comminution, Grinding, SAG mill, Mill liners Paper number MMP-07-002.
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Abstract and Figures. The author has developed a simple and sound approach to determine the preliminary SSSAG mill aspect ratio before conducting population balance model simulations.
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By this summer, a grinding mill that is bigger around than a Boeing 747 will turn chunks of copper ore into gravel-sized bits for smelting and refining. The largest ring gear ...
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Table 1 – SAG Mill Operating Data Data Description Unit Design Data Grinding circuit configuration SABC SAG mill circuit No. of mills # 1 SAG mill motor power installed kW 28,000 Motor type Gearless Mill manufacture FL SAG mill dimensions diameter length 40 ft (12,192 m) 26 ft (7,924 m) Mill direction Bi-directional
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The Premier horizontal grinding mills are engineered to "excel and create vast possibilities" for customers and applications. Earlier this week, Outotec was awarded what it says was a major contract for the delivery of sustainable crushing, screening and grinding technologies to a greenfield iron ore project in South America.
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mills. SAG mills of over 40-foot diameter have been constructed. Like the ball mill, the AG/SAG mill will have a critical rotation speed above which grinding ceases. Mill motor types There are three common motor types that drive the grinding mills described above: – Gearless motors. These variable-speed motors range up to 30 MW and have the
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combines state-of-the-art control technology with rigid machine construction, ball screws, and linear guide ways to provide the ultimate in cutter grinding capabilities. With grinding head power up to 10-hp and spindle speeds up to 6000rpm, the rigid spindle allows up to (4) 4" dia grinding wheels to be mounted at once to provide maxi-
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A typical SAG-HPGR-Ball mill circuit suggested by Patzelt et al. [6] is shown in Figure 9.6, where the pebbles from the SAG mill are crushed in the high-pressure grinding rolls. It is a general observation that SAG mills are helpful for grinding where wide variations in the grindability of ores are experienced.
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The power draw of the SAG mill has room for significant improvement. As ball filling in the SAG mill is quite low, additional grinding media would likely increase the processing capacity of the SAG mill; however, the capacity of the ball mill, with installed power for the required product size of 170 µm, has reached its limit.
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