If the critical size material, typically 2550 mm, is accumulated the mill energy efficiency will deteriorate, and the mill feed. While there is no generic control strategy for sag. Our union speaking on the silver carpet at the 26th annual screen actors guild awards 2020. Sag mill optimisation and increasing throughput at. Metallurgical contentball mill maintenance manualon mill installation and maintenanceball mill concrete foundationsgrinding mill foundationgroutingball mill sole plate am sure your ball mill is considered the finest possible grinding mill available. Photoanalysis is being used on sag mills worldwide to control the size of rock being crushed. A mill is a machine by which solid or hard materials are broken into smaller pieces by means of grinding, crushing or cutting. In sag mill operation, the grinding rate passes through a minimum at a critical size chapter 5, which represents material too large to be broken by the steel grinding media, but has a low selfbreakage rate. Understanding size effects of semiautogenous grinding sag mill operation as a pathway to solving feed disturbances case study using the mmg century sag mill, in proceedings th ausimm mill operators conference 2016, pp 3230 the australasian institute of mining and metallurgy. As such you will find it is designed and constructed according to heavy duty specifications. Please feel free to give your inquiry in the form below. Semiautogenous grinding sag mill liner design and development. Metso provides grinding mill parts for equipment previously sold under a variety of trade names and has oem parts to fit seamlessly with your existing mill and process.
Having oversize material entering the sag mill makes an operation less efficient, costing companies money in electrical and maintenance costs. There are many different types of mills and many types of materials processed in them. Today we will learn about difference between sag mill vs ball mill. A sag mill is usually a primary or first stage grinder. Ag or sag mills have been in use in comminution circuits since the 1950s and.
When a part fails, you need to make the right decision to get your plant up and running. Reline machines 16 it is a well recognised fact that global ore grades are declining while commodity demands continue to rise. The mill will be driven by a gearless motor drive gmd which, at 28. Rajamani4, professor metallurgical engineering 1barrick cortez gold mines star hc66 box 1250.
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. Introduction there are four main aspects of sag mill design that will be discussed in available in the sag mill and ball mill. Early sag mills had a diameter of about 32, later increasing to 34, 36, 38 and 40. 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. Because of segregation on the coarse feed stockpile, sagmill 2 receives a higher percentage of coarse material. Operating specifications were selected to achieve an optimum of capital and operating costs. Various kinds of mills are there with which different material processing takes place. So yes, there are situations where constant tonnage is appropriate. The extremely high throughput is facilitated by incorporating the use of outotecs patented turbo pulp lifter tpl technology. 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. Actual comminution circuits consist in most of the cases in coarse crushing, sag milling, pebble crushing and secondary ball milling. Achieving sag mill design production at startup using best. The laboratory benchscale sag mill reproduces operating conditions of a commercial sag mill. Pdf the new practice of applying full precrushing of sag mill feed to substantially increase.
One major issue was the operation of the sag mill caused vibration at an amplitude of up to 11 mm on the mill foundation and therefore it could not be operated at a production rate above 15,000 t. Typically a sag mill has a much larger diameter compared to its length. 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. 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. Grinding circuit design tools, including for sag millball mill circuits, and geometallurgy energy models are available to subscribers. The tendency of the charge to slip back along the rising side of the shell is reduced as charge level increases, until. Sag mill optimisation and increasing throughput at the phu kham coppergold operation a success story, in proceedings 14th ausimm mill operators conference 2018, pp 1128 the australasian institute of mining and metallurgy. Comminution simulation using discrete element method dem approach from single particle breakage to fullscale sag mill operation lawrence k. The optimal performance of agsag mills is the key to successful plant operation. Sag mill energy required according to this statement, is 2. This paper details the operation of the ultra fine grinding. This commutation is an essential part of many processes. Efficient operation even at higher mill speeds operatorfriendly smooth mill operation significantly improve wear life can be precisely designed to handle the given capacity can be easily retrofitted to existing mills. A minetomill study was conducted to improve the grinding circuit operation.
Metso has experience of over 8,000 grinding mills globally, including manufacturing and delivering the largest sag ag mills in the world. The final plan was to increase the ball charge in the sag and ball mill to 10% v v and 27% v v, respectively. The sag mill design is based on outotecs proprietary grinding mill technology, developed over decades for maximum reliability and performance. The results have seen a decrease in process variance with an associated increase in average circuit performance. The ability to mill a broad range of ore types in various circuit configurations, with reduced numbers of unit operations and a.
The operations comminution circuit, which comprises a semiautogenous sag mill and two ball mills, each with megawatts mw of installed power, was expected to be sag mill limited when. The phu kham operation has recently undergone a series of process improvements to treat the anticipated competent ores scheduled for 2017 and 2018. Four sets of sag mill operational data are graphed as histograms in figure 10. The total volume inside the mill is given by vm 4 d2 ml 1 2lc l l 1 dtdm 3 1 dtdm 8. In these circuits the sag mill is the largest energy consumer. Join thousands of sagaftra members from across the country sharing their union pride. It is required for predicting throughput in an existing mill. The plain vertical machines are characterized by a spindle located vertically, parallel to the column face, and mounted in. In the light of increasing interest in that technology various. Jun 19, 2015 a ball charge level has a significant effect on overall charge motion.
This paper describes the methodology by which the neural network model was implemented, the considerations. Quantitative estimations of these parameters can be found in 4, 5, 23. The desired throughput of the mill is multiplied by the specific energy to give the mill power requirement. Pdf the jkmrc has been studying and modelling industrial ag and sag mills. Recent new plant sag mill startups in canada have shown that. Yet the sag mill of newmonts yanacocha mine in peru is a.
A mill is a device that breaks solid materials into smaller pieces by grinding, crushing, or cutting. A ball mill is a type of, a rock tumbler functions on the same principle ball mills are also, it is suitable for both batch and continuous operation, get price. Comminution simulation using discrete element method dem. 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.
The operating principle of the ball mill primo pizza. Sagaftra members are the faces and voices that entertain and inform america and the world. A method of c alculating autogenous semiautogenous. The material grinding occurs during impact falling grinding balls and abrasion the particles between the balls. Grinding mills used in the mining industries are the most energyintensive. Sag mills are autogenous mills that also use grinding balls like a ball mill. Frozen charge detection and automatic loosening with.
In this case, mill speed is the primary manipulated variable used to control mill load. Schematic diagram of agsag mill process mechanisms after. The grinding mill will be installed during 2014 at first quantums kansanshi copper mine. Optimizing performance of sabc comminution circuit of the. As of 2010, in the world mining industry, about 200 large mills of full or partial sag were in operation, including about 100 of them working in the iron ore industry, 30 in copper, while others. The results in sagmill line 2 are even more dramatic.
Chandramohan, r, braun, r, lane, g, hollis, k, le, j and baas, d, 2018. Sagaftra members united in solidarity for fair union contracts. Typical tests required to define a hardness variability function, are given below in figure 1. Such comminution is an important unit operation in many processes. Even though the device worked well it could not withstand the impacts in the plant scale mill. In this training module, well cover the workings of a semiautogenous grinding mill, or sag mill, thats designed to be the first stage of a grinding circuit. Flsmidth, usa design sag mill production when you need it most. Grinding mills for mining and minerals processing metso. The sag mill model in the jksimmet software has not been shown to accurately reproduce the performance of a single stage mill for greenfield design. 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. The speed of rotation of the mill determines three basic types of operation modes. Mineral processing design and operations sciencedirect. The designs of autogenous and semiautogenous sag grindings mills are described followed by the description of their methods of operation in grinding circuits involving crushers and ball mills.
The histogram shown here paves the way for sag mill signature. Methods of estimating sag mill volumes, mill charges, feed size and power consumptions and optimum speeds of rotation during operation are described. This allows mines to reduce downtime in operations by reducing scheduled liner wear inspections and unnecessary changes. Sag mill 4% ball charge, 90% nc a cross between ag and sag for average competency, abrasive ores. Gearless mill drives machinery risk solutions practice 2009 matt dugalic p.
They are available for arbor mounting, or with an integral shank with or without a pilot. The grinding circuit optimization application is the first technology to accurately predict critical sag mill performance variables. With the development of the kx3 cnc key to both is the use of precision ball just cant be done effectively on a manual mill. Nowadays, the more successful plants are those that have adopted effective and. The operating principle of the ball mill consists of following steps. Sag mills operation data abstract comminution, particularly milling, is on average the largest consumer of energy in mining. Backfill specialists acquisition 11 vpf technology 12 product news.
In a continuously operating ball mill, feed material fed through the central hole one of the caps into the drum and moves therealong, being exposed by grinding media. The igb was tested in the sag mill at cortez gold mines operations. Herbst svedala optimization services september, 2001 abstract. Pdf evolution of sag mill process control at the xstrata. Difference between sag mill vs ball mill mech4study. This type of helical cutter is particularly useful for milling elongated slots and for light cuts on soft metal. Because sag mills rely both on the ore itself as grinding media to varying.
Jan 08, 2016 in this training module, well cover the workings of a semiautogenous grinding mill, or sag mill, thats designed to be the first stage of a grinding circuit. Understanding the effects of liner wear on sag mill performance conference paper pdf available september 2015 with 1,495 reads how we measure reads. In other words, a sag mill would exhibit a specific force histogram under a set of operating conditions. Terms used in sag mill design and operation to begin, it is necessary to understand the terms used when discussing sag mill testing, design and operation. Each type is characterized by a specific trajectory of motion of the charge in the mill and a different impact of the milling bodies on the ground material. The design of a ball mill can vary significantly depending on the size, the equipment used to load the starting material feeders, and the system for. Your mill is at the heart of your production process.
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. The sag mill is 26 diameter x 123 egl and powered by 4,500 hp motor driven by a variable speed lci drive that can control the mill speed from 36% to 80% of critical speed depending on ore type and operational demands. How does a sag mill work crusher mills, cone crusher. An expert system applied to the control of mineral process unit operations is, by its nature, the site best. Improving autogenoussemiautogenous grinding performance and.
Our experts welcome the opportunity to assist you with circuit and circuit control design as well as startup, operation, and optimization of your mill. Frozen charge detection and automatic loosening with gearless. Companies are using this technology to determine the size of particles being processed in the sag mill. In the case of the large sag mill referred to in fig. Pdf understanding the effects of liner wear on sag mill. Every mining operation has a unique grinding process. A control strategy recently implemented on a large variablespeed sag mill at mmgs century zinc operation in australia is shown in the chart found on pg. The telfer train 1 sag mill operational data was collected for a six week prior to the installation of the manta cube. Ultra fine grinding a practical alternative to oxidative. Optimizing performance of sabc comminution circuit of the wushan porphyry copper minea practical approach. It then correlates this data to give an accurate picture of conditions inside the mill. Metal slitting saw milling cutter the metal slitting saw milling cutter is essentially a very.
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