Optimization of mill performance by using online ball and pulp measurements. It uses micro infinity i to grind or mill items into their crushed variants, like ores into dusts. Getting started denkbert november 30, 2015 june 12, 2017 applied energistics 2, feed the beast, mods this tutorial will show you how to set up a basic inventory management system with the applied energistics 2 mod. Maintaining the sag mill weight at the optimum value is critical for achieving maximum grind rate efficiency and mill production powell, m. The mill filling should be measured at a minimum of 3 points along the mill. Another very important point to consider is that the load distribution on ball mills fed by a sag mill is not equally distributed. Achieving sag mill design production at startup using. The mill will be driven by a gearless motor drive gmd which, at 28. Sufficient time is required to obtain all the important measurements correctly during the crash stop. Performance enhancment tools for grinding mills 105 by locating microphones near the mill on fixed positions and applying appropriate algorithms online to the microphone signals, impacts on mill liners can be isolated from mill noise, then classified and counted to provide a quantitative measure of their occurrence. Stated another way, money invested in a large sag mill is an investment that can produce handsome returns if extra production is needed or simply to give the mine the option to mill the hardest ores at design throughput rates. There are 12 short steps that will guide you throughout the tutorial. Grinding circuit design tools, including for sag millball mill circuits, and geometallurgy energy models are available to subscribers. Pdf conversion of the barrick granny smith grinding circuit to.
It can be applied to new or existing ag, sag and ball mills, powered by either ringgeared mill drives rmd or gearless mill drives gmd. Dramatic shortcomings of mill liner designs, especially of large sag mills. Opportunities for improved mill control based on the data from the online monitor are also discussed, as well as the implications in terms of mill processing and. A method of c alculating autogenous semiautogenous. In the platinum industry, by increasing the solid content in the slurry, the product becomes finer. The reduced damage improves the mills availability and minimises the downtime. Sag mill and how the vibration response and hence mill operating conditions vary as a function of time, including during mill equipment failures such as a broken discharge grate. A mill is a machine by which solid or hard materials are broken into smaller pieces by means of grinding, crushing or cutting. A method to determine the ball filling, in miduk copper. Fixed speed configurations the key issue to operate a mill in a fix speed mode is the starting. At a higher percentage solid than 73 to 74%, the product becomes coarser again.
Sag mill testing test procedures to characterize ore. In this case the mill is operated with the feed turned off until all of the ore has exited the mill. The sag mill product is then crushed to 100% passing 3. Feel free to compress, edit or modify your file further. The sag mill cube system graphic shown in figure 1 demonstrates that the system is fully integrated with the yokogawa cs 3000 dcs used at newcrest mining telfer operation and figure 2 next page. The thesis has provided improvements to the previous agsag mill discharge. Converting back to a twostage circuit required a few chute changes and was.
The new practice of applying full precrushing of sag mill feed to substantially increase throughput is challenged as. The sag mill design is based on outotecs proprietary grinding mill technology, developed over decades for maximum reliability and performance. This means that further energy can be saved if a mill speed below the rate speed is re. I am kind of following direwolfs lets play and he has survivalist generators powering a sag mill. This work addresses some current issues involving design and application of highpower drives employed in sag grind. Casaliminerals engineering 70 2015 156161 157 in fact the later can be modelled as a function of the others. Optimizing your sag mill operation international mining. Various kinds of mills are there with which different material processing takes place. This video was made for the sag conference, in which a company wanted to show a visual walkthrough of the sag mill, from the beginning of its processes to. Mil to pdf batch converter ultrafast image converter. Optimised design of isolated industrial power systems and. Two silos containing merensky and ug2 ore respectively feed the mill that operates at a fixed 75% of the critical speed.
However, frequency converter based drive systems provide benefits that improve the ball mill operation. Introduction this tutorial describes how to setup and analyze a sag semiautogenous grinding mill simulation. Royston principal, royston process technology pty ltd. When future tonnage is to be increased, the sag mill can feed downstream ball milling to boost capacity. For this load case, the model contains the concentric magnetic pull and stiffness for this operation mode, the maximum allowable initial mill eccentricity, stator assembly tolerances, the starting torque and the gravitational acceleration. Autogenous mills were introduced into the iron ore mining industry in the 1950s to eliminate. Computerbased modeling of charge motion in sag mills and on established.
Mcken sgs keywords comminution, grindability, grinding, sag mill, ag mill, milling, hpgr, work index, pilot plant introduction the resistance of ore samples to breakage or hardness is measured. Choosing a sag mill to achieve design performance starkey. The behavior of the cycloconverter fed gearless drive under. Difference between sag mill vs ball mill mech4study. Improved relationships for discharge in sagag mills uq espace. The critical speed for a grinding mill is defined as the rotational speed where centrifugal forces equal gravitational forces at the mill shells inside surface. Like many, im sure, weve had trouble with pdf generation. Step 1 evaluate the effect of reducing rod mill feed size from 1.
Sag mills pdf sag mill liner development draws primarily on practical experience from sag. Each module at waterval concentrator wvalc employs a. Particle breakage will not take place during this simulation. This is shown because the simulation does not consider the closing of the mill brake and the stop of mill and motor. This commutation is an essential part of many processes. Abbs gearless mill drive system is the most powerful mill drive system in the market to power semiautogenous sag, ball and autogenous ag mills. Since the mill and its power unit are supplied as a module, the mill can be supplied, erected and commissioned very quickly without the need for highly skilled technicians. During normal operation, the mill operates in the speed.
Add steel to convert ag autogenous mill sag mill 911 metallurgist. Typical tests required to define a hardness variability function, are given below in figure 1. A method of c alculating autogenous semiautogenous grinding. Nowadays, the more successful plants are those that have adopted effective and efficient strategies to optimize their plant operation. It accepts energy in the form of redstone flux or minecraft joule, with an internal buffer of 100,000 rf and consumption of 20 rf per tick. The sag semiautogenous grinding mill is a machine designed to to grind smaller particles and break larger rocks. Certified under iso 9001 quality standard and iso 14001 environmental standard. Optimization and control of a primary sag mill using real. Figure 5 illustrates a trend taken from a sag mill running under expert system control using bearing pressure as. These equations are used by smcc pty ltd to estimate the specific energy of agsag mills under all normal operating conditions, eg ball load, mill speed, feed size and ore hardness and for all. Sag mill crash stops after the project was approved baseline data collection was required in the form of sag mill crash stops. Optimization of mill performance by using online ball and pulp measurements soon after a stop, a mill is a dangerous place to enter for the personnel tasked with taking measurements or. A conversion of ab and ta values to rod mill and ball mill work indices are.
For large mills requiring variable speed, the wound rotor motor and ser drive are economical for a total rating of approximately 2mw to 16mw. Berger lane salt lake city, utah 84107 2millwatch pty. In the past, when primary, secondary and tertiary crushers fed material directly to large ball mills, the energy efficiency of the concentrator was determined for the most part by the ball mill operation, whereas now the energy efficiency of a plant often rests largely on the sag mill operation. The test is operated in closed circuit and the time required to grind the material to a p 80 of 1. Grinding circuit design tools, including for sag mill ball mill circuits, and geometallurgy energy models are available to subscribers. In a crash stop the sag mill is operated under steadystate conditions and then stopped as if the power plug was pulled. To begin, drag and drop your doc or docx file in the word to pdf converter. Ringgeared mills operated with frequency converter much more than just variable speed english pdf article use of the latest technology to overcome the demands of mill operation english pdf article gearless mill drive animation english mp4 movie go gearless gearless mill drives english pdf brochure. Dec 19, 2014 advantages of ser drives for sag mills friday, december 19, 2014 for large mills requiring variable speed, the wound rotor motor and ser drive are economical for a total rating of approximately 2mw to 16mw. Modelling sag milling power and specific energy consumption. At this level, a drop in grinding efficiency occurs. Sag mill can operate at a reasonable efficiency if the final product is in the 75 m. The knowledgescape strategys ability to maintain smooth and stable operation of the mill was more apparent when contrasted to the dcs control on the difficult line. Evolution of liner design from current to future operations julius stieger1, process superintendent dave plummer2, process maintenance planner sanjeeva latchireddi3, chief process engineer raj k.
Put another way, the sag mill energy required according to this statement, is 2. Above 16mw, the gearless drive cycloconverter is typically used because gearboxes and pinion gears reach their present limit in size. This is the rotational speed where balls will not fall away from the mill s shell. Two 5000kw sixpole wrims with 11,000v stators a combining gear box driving the mill one 10,000kw liquid resistance starter rheostat. Figure 416 current waveforms on the supply side of sag mill cyclo converter 126 figure 417 full current harmonic spectra of sag mill cyclo converter 127 figure 418 average of one cycle current harmonic spectra of sag mill cyclo converter suitable for etap 127. Today we will learn about difference between sag mill vs ball mill.
Sag mill optimization using model predictive control. It is a grate discharge mill with an inside diameter of 10363 mm 34 feet and a. The breakage rate function shape of the sag mill is largely governed by the mill load particle size distribution and mill speed. My previous fix for windows 64bit installs was to replace the sage pdf printer with the one provided by intuit. The feed in the mill contains fractions of ore that serves as the grinding media. Because of segregation on the coarse feed stockpile, sagmill 2 receives a higher percentage of coarse material. In reality, the mill continues turning in case of a mains power outage due to its inertia until the brake applies or it moves. Process flow and control infrastructure each module at waterval concentrator wvalc employs a. This can translate to literally millions more tonnes of ore milled. Mill drive example an example of slip power recovery is the wound rotor motor shown below, one of two for powering a new 10,000 kw sag mill in australia as shown in figure 3.
The energy storage capacity and processing speed can be increased by adding one of 3 tier of capacitor into. Overview on the grinding mills and their dual pinion mill drives abstract this paper will first give a short overview of the copper mountain project in british columbia, which just has started commercial operation earlier this year. However, sag mill weight is difficult to control as the dynamic response changes as the mill approaches maximum capacity. After sag mill, a trommel screen produces two over and under size materials which the oversize part is circulated into sag mill and undersize reports to hydrocyclone for further process. The sag test reproduces commercial sag mill grinding conditions on 4. Posted by matrix on 21st march 2007 sanjeev latchireddi, chief process engineer grinding americas, outokumpu technology, looks at the shift from ball mills to sag mills. Uniquely, the sag mill can use grinding balls made from various materials to increase energy efficiency resulting in.
Metallurgical contentball charge motion inside a sag millsag mill operationsemi autogenous design factorssag mill operation exampleprocess plant descriptionsag mill design and specification operating problems since commissioningdesign changes and future operating strategies ag and sag mills are now the primary unit operation for the majority of large grinding circuits, and form the basis for a. Additionally a small excitation converter is required to supply the poles excitation via the slip rings to the rotor of the gearless motor. Mines wa 36ft sag mill the number of outer head liners was reduced from 36 to 18. Developments in sag mill design and operation over the last few years, sag mill manufacturing technology has advanced rapidly. A squirrelcage motor or a synchronous motor started direct on line without any help of a frequency converter normally cannot produce sufficient starting torque. Outside of traditional hard rock mines, these mills offer an attractive, economic alternative. Pdf the jkmrc has been studying and modelling industrial ag and sag mills for over 40 years, but the ability to simulate the effects of blending hard. W steyn, k keet, w breytenbach control engineer, anglo american platinum, control and instrumentation department, johannesburg. The perfect converter to transform png, jpg or gif images with the best svg resolution.
Power consumption is influenced by load respectively torque and mill speed. The millminder audio signal converter listens to the sound levels generated by the impact inside the grinding mill and provides the operator with an output signal that allows automatic material feed control to the mill. Pictures of the insides of an ag mill and a sag mill which have been crash stopped are shown in figures 5 and 6 respectively. If the sag mill is not intended to be the ratelimiting step in a process plant, then it is best to adjust the sag load and power to hold a constant tonnage to satisfy another constraint elsewhere. The bounds of mill size have been pushed from two directions. Semiautogenous grinding sag mill liner design and development d. If d sag mill itself and not on the test work program. Accurate measurements of the ball filling can only be made after the mill is ground out. Design and dynamic behavior of large ring motors for grinding. Sag mill is an investment that can produce handsome returns if extra production is needed or simply to give the mine the option to mill the hardest ores at design throughput rates. Current issues on highpower cycloconverter fed gearless.
Rajamani4, professor metallurgical engineering 1barrick cortez gold mines star hc66 box 1250. Too fast, too empty, full mill left to right after the polar plot is checked to determine if a mill is operating at too high an rpm, the fill levels are monitored. Single stage sag mills are very beneficial in reducing capex for plants with a staged throughput approach. The results in sagmill line 2 are even more dramatic. The copper mountain sag mill is 10363 mm 34 feet in diameter and 6096 mm 20 feet long. The conversion to pdf should take place right away. Our steel forged grinding balls in the diameter range of 3. Firstly, the advent of ring motors has removed the constraint applied by the power that a.
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