Pdf ag and sag mill circuit selection and design by simulation. The mill filling should be measured at a minimum of 3 points along the mill. Gearless mill drive protection improvements and its. Each decision cycle the expert system calculates a change in the sag mill water set point. The synchronous machine is fed by a cycloconverter ccv. By combining with sag discharge and screening on the sag discharge screens, top size control to the ball mill circuit feed is maintained while still unloading the sag circuit mosher et al, 2006. Mechanical installation of a sag mill christof industries.
If p is less than 80% passing 70 microns, power consumption will be. By counting the number of lifters showing during a mill shutdown and comparing to the total number of lifters including those buried in the charge the fraction of the mill under the charge is determined. Whether youre talking about sag or a ball mill, space is. The engineering and process effects of choosing a motor. A method to determine the ball filling, in miduk copper. The results in sag mill line 2 are even more dramatic. The electric current of the motor is the main creator of.
Similar to the impeller design affecting pump capacity, the pulp lifter design affects the discharge capacity or mill throughput of ag and sag grinding mills. My alloy smelter or sag mill is not takeing any charge from. Another very important point to consider is that the load distribution on ball mills fed by a sag mill is not equally distributed. Modeling and evaluation of cycloconverterfed twostatorwinding. The liners are replaced as they wear and the lifting action has degraded. The test and study work showed that a single line 42 ft sag mill circuit gave the. Outotec grinding mills optimize grinding mill performance, efficiency, and availability to ensure you meet your plants operational targets. Request pdf modeling and evaluation of cycloconverterfed twostator winding sag mill drivepart i. The ore passes through a gyratory crusher where it is reduced to 8 inch diameter before being dumped on the pile. The rom sag mill circuita brief description the typical rom sag mill circuit is depicted in figure 1. It rotates, tumbling its contents violently, causing a breaking action. Continuous monitoring of mineral processes with special. Im trying to set up item automation and im running into an issue where i have an input for sag mill on the top face set to the pull setting and a retriever with what. The circuit is usually closed with either a screen or, more commonly, a cyclone for product size.
A sag mill is characterized by its large diameter and short length. Sep 10, 2012 what large 120,000 tpd grinding circuit in operation is. Ball mill is a secondary, and it is used after the sag mill. Sag mill liner development draws primarily on practical experience from sag milling operations supported by computerbased modeling of charge motion in sag mills and on established good design practice. Online monitoring of rheological effects in grinding mills using lifter deflection measurements. The word genesis comes from the first word in the hebrew bible, in the beginning. Karl gugel, digital control lab started its life in 1998 as an electronics consulting firm known as dicon labs. Specific energy consumption sec measured in kwht is a ratio of the mill drive power to the milling circuit output, without regard to circulating load. It too had an abb motor and it had operated longer than the collahuasi motor. A ball mill is a type of grinder used to grind, blend and sometimes for mixing of materials for use. These machines are typically electrically powered, but have been modified from a variety of powering systems over the years.
The gearless motor is fed by a cyclo converter, which is an extremely compact. Modifying the sag mill feed size distribution,secondary secondary crushing of sag mill feed has also been used by plant designers to minimise but the bond rod mill work index is high at 23 kwht. Sag mill crash stops after the project was approved baseline data collection was required in the form of sag mill crash stops. Difference between sag mill vs ball mill mech4study. Sag mills are currently the technology of choice in hard rock milling operations for reducing primarycrushed ore to ball mill feed. 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. Nowadays, the more successful plants are those that have adopted effective and efficient strategies to optimize their plant operation. Developments in sag mill design and operation over the last few years, sag mill manufacturing technology has advanced rapidly. Sep 10, 2014 the collahuasi motor was for a 40 ft sag mill. In the 2009 database, sag pinion energies to grind from f80 152 mm to t80 1.
During the early years, dicon lab was contacted by a leading cement. Outotec highperformance grinding mills use advanced simulation tools for the best possible process efficiency, mechanical reliability, and maintainability. Taking control of the mill feed r2 orway mineral consultants. You could do that by measuring the material flowrate qtonsh through the mill as well as the quantity mtons of material that. The worlds first 42foot diameter 28 mw gearless sag mill. The generators are still outputting correctly to cells. The cyclone overflow gravitated to the first leach tank via a trash screen. The enderio mod implements compact transportation for power, items, liquids and me network data, making it possible to run different types of conduits in a single block space. Dec 12, 2016 if p is less than 80% passing 70 microns, power consumption will be.
The converters output voltage consists of parts of the line voltage. A wet grinding ball mill in closed circuit is to be fed 100 tph of a material with a. Then define the behavior to be rigid or flexible, sticky or dry. Commissioning variable speed sag mill gearless drive. Liner design needs to respond to the process aspects of mill liner action that are critical to good sag mill performance, i. 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. A variant of this method is to direct pebblecrushing circuit product to the ball mill sump for secondary milling. Posted by matrix on 21st march 2007 sanjeev latchireddi, chief process engineer grinding americas, outokumpu technology, looks at the shift from ball mills to. Simine gearless mill drives digital asset management siemens. Download limit exceeded you have exceeded your daily download allowance. Typically operated in rsa on witwatersrand gold ore driefontein underground, kloof, jacobina 6 sag mill with recycle crusher 8 15% ball charge competent ores, better suited to coarse grind sizes. The sag mill is usually part of the primary stage in the grinding process. The sag mill product is then crushed to 100% passing 3. These equations are used by smcc pty ltd to estimate the specific energy of ag sag mills under all normal operating conditions, eg ball load, mill speed, feed size and ore hardness and for all.
My alloy smelter or sag mill is not takeing any charge. Generally, the discharge from ag sag mills consists of one or both of the following components. An updated data set for sag mill power model calibration this paper expands the sag mill survey database published by the author at procemin 20. Many grinding mill owners choose a variable speed drive. Firstly, the advent of ring motors has removed the constraint applied by the power that a single pinion gear was able to transmit. Particle breakage will not take place during this simulation. At the constant size of the cycle feed and discharge, sec is a prime characteristic of material grindability in a certain ore pretreatment. The performance of train 1 sag mill before the new manta cube. 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. Ball mill is used to grind the pieces of raw material into. 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. Sag mill feed is at its maximum and mill sound is high. Pieces of raw or fairly reduced materials are ground into smaller pieces for further processing or sorting.
The operation principle of softswitching dcac converter was analyzed and the. The discharge grates of the sag mill were identified as a key component in the sabc circuit, and their design is a crucial factor in the mill s performance 171819 20 21. A pendulum driven generator placed on the mill end produces the power to the transceiver, or. Semiautogenous grinding sag mill liner design and development. It can be seen from this set of operational data that the mill weight varies over a wide range and this is consistent with normal operator control of a sag mill. Sag mills are autogenous mills that also use grinding balls like a ball mill.
Sag mill breaks the raw material into pieces for the further grinding. Pdf optimisation of the cadia hill sag mill circuit. Comparative study of alnimo alloys obtained by mechanical alloying in different ball mills pdf. Each module at waterval concentrator wvalc employs a. Ball mill discharge combined with sag mill discharge to form the feed to the screen see figure 1. The ability to mill a broad range of ore types in various circuit configurations, with reduced numbers of unit operations and a. Just say what youd like to make, what you already have, it will do the rest, giving you a list of raw materials and instructions of which items to make in the proper order. In a crash stop the sag mill is operated under steadystate conditions and then stopped as if the power plug was pulled. Introduction this tutorial describes how to setup and analyze a sag semiautogenous grinding mill simulation. It shouldnt be that hard an economically appealing method for improving operations is available without the capital expense get more out of a mill by applying the advanced control capabilities in the existing plant control system by andrew thornton. Optimization and control of a primary sag mill using real.
Each of these performance parameters peaks at different filling values. The bounds of mill size have been pushed from two directions. It is similar in operation to a sag mill as described below but does not use steel balls in. Composed of a twelve pulse cycloconverter together with a synchronous ringmotor. Sufficient time is required to obtain all the important measurements correctly during the crash stop. The antamina 38 ft sag mill was also driven by an abb motor and the hanger plates had not failed on that machine after several years of. Jan 11, 2015 i dont know what has happened it was working a few days ago, and i havnot been on since. The sag grindability index sgi test, or alternatively the trademarked sag power index spi, is a sagspecific test involving a small batch sag mill that is charged with a two kilogram ore sample and. Modify a default shape, scan a real 3d object, or custom design your own shape and import it. Sag mill 4% ball charge, 90% nc a cross between ag and sag for average competency, abrasive ores. The function of the frequencyconverter, control system drive and lubrication systems are described.
High fidelity simulation of sag milling is a technique, which uses dem, cfd and. The performance of tumbling mills is sensitive to the volumetric mill filling which influences grinding media wear rates, throughput, power draw, and product grind size from the circuit. Because of segregation on the coarse feed stockpile, sag mill 2 receives a higher percentage of coarse material. I dont know what has happened it was working a few days ago, and i havnot been on since. Evolution of liner design from current to future operations julius stieger1, process superintendent dave plummer2, process maintenance planner sanjeeva. The sag test reproduces commercial sag mill grinding conditions on 4. Because of segregation on the coarse feed stockpile, sagmill 2 receives a higher percentage of coarse material. Sag mill optimization using model predictive control. Autogenous and semiautogenous mills wet grinding plants. Miduk copper concentrator is located in kerman province, iran, and its size reduction stage includes one gyratory crusher which feeds one sag mill 9.
In order to continuously optimize mill operation, it is vital to. I expect that this type of drive would be the most common large mill variable speed mill drive in the worlds minerals. Refining cupellation parkes process bottomblown oxygen converter poling isakidd process. The results in sagmill line 2 are even more dramatic. Crafting guide gives stepbystep instructions for making anything in minecraft or its many mods. The mill is lined with wear resistant steel liners which are fitted with lifters to assist with raising the load. The circuit is closed with a 600 m aperture classification screen with. Two silos containing merensky and ug2 ore respectively feed the. Rocky dems highperformance computing hpc abilities can simulate a large number of realsized and realshaped particles faster and with less memory usage. A positive set point change will be applied if all of the following conditions are true. A method of c alculating autogenous semiautogenous. What large 120,000 tpd grinding circuit in operation is. Ag and sag mill circuit selection and design by simulation.
A wet grinding ball mill in closed circuit is to be fed 100 tph of a material with a work. Put another way, the sag mill energy required according to this statement, is 2. The sag semiautogenous grinding mill is a machine designed to to grind smaller particles and break larger rocks. Ball milling pdf crusher mills, cone crusher, jaw crushers. Mechanical installation of a 28 x 15,5 sag mill including lubrication and cooling system, mill wear liner as well as commissioning assistance and surveying after trail run. Abbs gearless mill drive system is the most powerful mill drive system in the market to power semiautogenous sag, ball and autogenous ag mills. How does a sag mill work crusher mills, cone crusher, jaw. Typical tests required to define a hardness variability function, are given below in figure 1. Similarly, the sossego motor for the 38 ft sag mill had not failed. The wet grinding plant for gold ore consists of an sag mill and a ball mill.
Mt rawdon 2003 addition of a secondary crushing circuit. Pdf the new practice of applying full precrushing of sag mill feed to substantially increase throughput is challenged as retrogressive and. Ag and sag mills are now the primary unit operation for the majority of large grinding circuits, and form the basis for a variety of circuit configurations. Semiautogenous grinding mills can be optimized for maximum ore throughput or maximum grinding energy efficiency. It uses micro infinity i to grind or mill items into their crushed variants, like ores into dusts.
Estimates the charge volume of a grinding mill based on the number of exposed lifters. The antamina 38 ft sag mill was also driven by an abb motor and the hanger plates had not failed on that machine after several years of operation. Rocky dem the most powerful particle simulation software. Supplying resources, processing machines and power generation of redstone flux to automate the production of diverse and interesting items, such as armor, tools, lighting.
A sag mill is usually a primary or first stage grinder. Grinding circuit design tools, including for sag mill ball mill circuits, and geometallurgy energy models are available to subscribers. In recent years, the trend has been towards largersized sag mills with diameters of 10. Pdf a silverleadzinc mine in queensland, australia was originally designed to treat 1. Optimization of the design of sag mill internals using high fidelity. Sag mill liner development draws primarily on practical experience from sag milling operations supported by computerbased modeling of charge motion in sag mills and on established good design. Sag mill feed is conveyed from the coarse ore stockpile. A method of c alculating autogenous semiautogenous grinding. Two silos containing merensky and ug2 ore respectively feed the mill that operates at a fixed 75% of the critical speed. Whether youre talking about sag or a ball mill, space is a delicate issue, especially in the. Morrell and others published ag and sag mill circuit. Optimizing your sag mill operation international mining. 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. There are 12 short steps that will guide you throughout the tutorial.
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