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By Sandra L. Mesa-Espitia, Gretchen T. Lapidus

Gold present in arsenopyrite matrices is refractory and requires highly oxidative pretreatments in order to obtain acceptable degrees of extraction. However, these release many byproducts that are harmful to the environment. In the present work, a high-grade arsenopyritic ore was pretreated with different solutions, containing hydroxide ion, EDTA, oxalic, tartaric, or citric acids, to improve gold extractions in a posterior leaching step. The pretreatments were carried out at room temperature for 24 hours with a respective ligand concentration of 0.25 M. Once completed, the residue was leached in a thiosulfate solution to quantify the effect of the pretreatment on gold extraction. Only 29% of the gold content was leached, with very slow kinetics, in the untreated mineral. However, after pretreatment with tartaric or citric acid, the kinetics improved, although the percentage of gold extraction only reached 42-45%. The highest gold recovery, with very rapid kinetics, was found with the oxalic acid or the hydroxyl ion pretreatment (70 and 62%), respectively, but also corresponded to the most arsenic co-dissolution.

Jan 1, 2014

By David Deglon, Martin Harris, Mehdi Safari

"This study investigates the effect of energy/power input on the flotation of a platinum ore in a pilot-scale oscillating grid flotation cell. Oscillating grids generate near ideal hydrodynamic environments, characterised by turbulence which is relatively homogeneous and isotropic. Secondary rougher feed and primary cleaner tail streams were floated in a pilot-scale oscillating grid flotation cell at power inputs from 0 to 2.5 W/kg, using 0.50 and 1.50 mm bubbles. From this study one may conclude that the effect of energy/power input on the flotation rate is strongly dependent on the particle and bubble size. Flotation rates generally increase with increasing particle size and decreasing bubble size. Increasing energy input generally leads to an increase in the flotation rate for finer particles and an optimum flotation rate for intermediate & coarse particles. Optimum conditions for intermediate/coarse platinum ore particles are using small bubbles at low energy inputs, or large bubbles at higher energy inputs. These results suggest that higher energy inputs are generally beneficial for the flotation of platinum ores as these consist predominantly of finer particles (-75 µm) and most industrial flotation applications operate with larger bubbles (1.0-2.0 mm).INTRODUCTIONThere is a considerable body of experimental and theoretical evidence to suggest that energy/power input plays an important role in flotation kinetics, particularly in the finer particle sizes where flotation efficiency is poor (Deglon, 2005). A number of excellent studies into the effect of energy on flotation kinetics have been carried out in impeller stirred cells (Ahmed and Jameson, 1985; Deglon, 2002; Pyke et al., 2003; Newell and Grano, 2006). Investigations using this type of cell have a number of limitations. The impeller influences particle suspension, bubble break-up and agitation in the cell. In addition, turbulence is highly inhomogeneous and anisotropic, with power intensities near the impeller orders of magnitude higher than those found elsewhere in the cell (Deglon, 1998; Koh and Schwarz, 2003; Schubert, 1999, 2008). These limitations have resulted in the development of novel cells for the investigation of energy input."

Jan 1, 2016

By Huan-Qiang Zhang, Gang-Hai Huang, Yu-Yong Jiao, Fei Zheng, Zhang. Xiu-Li

An efficient and accurate three-dimensional (3-D) contact detection algorithm is of vital importance in large-scale computing of discontinuous deformation analysis. The contact detection algorithm takes up a large proportion of the whole calculation time because of the increasing calculation number in three-dimensional case. For block systems which consist of convex polyhedrons, the efficiency and accuracy of the contact detection algorithm is a great challenge. The presented contact detection algorithm in discontinuous deformation analysis (DDA) method is carried out in three phases: the global neighbour searching, the local contact type searching and the contact transferring. A contact detection algorithm for 3-D DDA is presented with some improvements on the three phases. A grid-based global neighbour searching algorithm is used to eliminate unnecessary neighbour blocks to the exact number. The local contact type searching includes two steps. In the first step, the common plane method is used to determine the contact type between convex polyhedrons. In the second step, the contact pairs detected by the common plane method are divided into four basic types. In the third phase, the four contact types are transferred into two basic contact types, vertex-to-face contact type and edge-to-edge contact type, which are managed in a uniform procedure. Three verification examples are calculated, the results show that the proposed algorithm based on the three contact detection phases is robust and efficient.

Jan 1, 2015

By Charles G. Kemsley

IN view of the truly remarkable development of special steels for special purposes, the mining industry has for years looked forward to a time when steel makers would come forward with a product which would be an improvement over the straight carbon steel which has always held the field for drilling rock. In order to avoid making changes in conventional shop practice, the industry has perhaps been too insistent upon obtaining a water hardening steel which could be handled in the blacksmith shop by long established methods. As early as 1932 or 1933, an oil-hardening tool-steel of the one per cent carbon, plus chrome, plus molybdenum type was applied to hollow drill steel. It was known as a hard as well as a tough steel, and one that, theoretically, should give a good account of itself as a rock drill, if properly heat-treated; and so it has proved in actual trials. There were numerous deterrents which retarded adoption of this steel. For several years there has been a constant improvement in the drilling qualities of the straight carbon steel, and, considering the higher unit price ? of the alloy, there has been considerable doubt in the minds of some mining? men as to what advantage there might be in the use of alloy over straight carbon for hollow drill steel. The alloy being an oil-hardening steel, its adoption meant having two kinds of steel in the mine, for a time, and that spelled trouble, unless some positive means of identification was adopted. The hardening and forging ranges of alloy steel being narrow also made necessary much closer control over these operations if poor results were to be avoided. These thoughts undoubtedly prevented its use becoming wide-spread, for, as a matter of actual record, less than fifteen per cent of all the hollow drill steel used in Canada today is alloy.

Jan 1, 1942

Sustainable Development SAFETY ?Safety is the most important element of sustainability. ?One bad experience or incident can mar a company?s reputation for a long, long time. ?News travels faster than ever ?Internet, blogs, texting, peer-to-peer communication, etc. and unfortunately sometimes the information is not always accurate. ?Rarely do we hear in the news about the mining companies or projects that are done safely ?we always hear about the exceptions. ?Safety is just like TQI / TQM ?the process of improving can never stop.

May 1, 2010

By H. Gharahbagheri, S. Shafiei Zadeh, H. Hassan Nejad

Waste Electrical and Electronic Equipment (WEEE) is one of the fastest growing types of solid waste in the world, and often contains precious metals, especially gold. Gold processing and recovery from secondary materials, especially WEEE, have been under investigation for more than a decade now; however, a comprehensive review that illuminates the future path is missing in the literature. The aim of this short paper is to discuss the recent advances in gold processing and recovery from secondary electronic materials and why it has not yet become practical. The role of pyrometallurgical and hydrometallurgical methods, as well as their advantages and disadvantages will be discussed; however, the focus will be on Biosorption and recent advances.

Jan 1, 2014

By M. Lahtinen, H. Takala, B. Saxén

Oxidic zinc fume dusts are formed in electric arc furnace (EAF), Waelz furnace operations, and also in the Top Submerged Lance (TSL) furnace of Outotec Ausmelt. These dusts are normally considered as secondary raw materials for zinc metal production, as they are mainly originated from steel scrap recycling or zinc plant residue processing. The latest development in zinc fuming is direct smelting of zinc concentrates in the Ausmelt TSL furnace and hydrometallurgical treatment of produced fume dust. This technology is for primary zinc production like roasting and concentrate direct leaching, as concentrates are directly treated. The various oxidic zinc raw materials differ in composition and content of impurities. Thus, they require different hydrometallurgical processes to produce pure zinc metal. In addition to zinc these dusts typically contain also lead, silver and indium, which can be recovered and can increase recovered metal value significantly. From the impurity point of view the most relevant elements in the fume dusts are iron, arsenic, fluoride, chloride and cadmium. This paper describes hydrometallurgical processes to treat Ausmelt TSL fume dusts to extract valuable metals at high recovery and also to control and separate various impurities efficiently.

Jan 1, 2014

By K. V. Konigsmann

"The mill at Mattagami Lake Mines treats 3,850 tons per day. The mill feed is a heavy sulphide ore. It is composed ofPyrite & Pyrrhotite - 40%Marmatite - 17%Chalcopyrite - 2%Magnetite - 10%Talc and other Silicates - 31%The sulphides are intimately associated with each other and often finely disseminated throughout the siliceous gangue. An abundance of middling particles exist in the circuit and a delicate balance has to be maintained between concentrate grades and metal recoveries.The metal content of the mill feed fluctuates between 0.4 to 0.7% for copper and 6 to 13% for zinc.The flow sheet of the concentrator is shown in Figure 1.Eight sample streams have been selected for on-stream analysis, namely1. Copper Concentrate 2. Copper Cln Tailings 3. Copper Tailings 4. Zinc Concentrate5. Zinc Rgh Concentrate6. Zinc Cln Tailings7. Zinc Rgh Tailings8. Flotation TailingsThe mill feed is not being analysed. Only a very coarse sample could be obtained which would be difficult to pump, and the fluctuations in the copper content are too small in absolute terms to have much of a bearing on circuit operations."

Jan 1, 1969

By T. L. Lee, D. Y. Tan, J. Mi

Considerable progress has been made in studying the mechanism and effectiveness of using ultrasound waves to manipulate alloy solidification microstructure, However, uncertainties remain in both the underlying physics of how microstructure evolve under ultrasonic waves, and the best technological approach to control the final microstructure and properties. We used the ultrafast synchrotron X-ray phase contrast imaging facility housed at the Advanced Photon Source, Argonne National Laboratory, USA to study in-situ the highly transient and dynamic interactions between the liquid metal and ultrasonic waves/bubbles. The dynamics of ultrasonic bubbles in liquid metal and their interactions with the solidifying phases were captured in-situ for the first time. The experiments were complemented by the simulations of the acoustic pressure field, the pulsing of the bubbles and the associated forces acting onto the solidifying phases, providing more quantitative understanding for using ultrasound to control the growth of dendritic grains and to enhance grain multiplication effects for grain refinement.

Jan 1, 2014

By N. Katsikaros, R. Agius, B. Adaszynski

"With stricter limits globally being imposed on cyanide discharge levels in plant tailings, having a reliable and well designed cyanide detoxification circuit is critical for any operation. The INCO SO2/Air method is most commonly used for cyanide detoxification where sulfur dioxide and oxygen combine to oxidize cyanide to the much less toxic cyanate. This paper discusses the steps involved with the development, from laboratory through to design, of a robust cyanide detoxification circuit. The goal is to produce a cyanide detox circuit that reliably meets discharge target with the lowest operating and capital cost.Design begins in the laboratory where continuous tests simulate full scale operation of a detoxification circuit. Detailed design relies on several design parameters, based on theory and experience, to ensure the reactor can satisfy requirements of the cyanide destruction reaction. Selection of the correct reagents and their supply to the reactor is important to an operable process with minimal operator workload. The operability of the system relies on correct process control strategies to maintain optimal reagent addition and chemical conditions in the reactor. These design factors are critical to providing a robust plant that will consistently meet cyanide discharge levels, ensuring uninterrupted production and plant profitability."

Jan 1, 2014

By Esa Peuraniemi, Hanna-Leena Heikkilä

Boliden Harjavalta has been operating a copper flash smelter since 1949. Thus, in 2019, the smelter is celebrating its 70th anniversary of flash smelting. Slag formation is an integral part of the smelting process; currently the processing of slag is based on froth flotation at the slag concentrator. It provides high recovery of copper but restricts slag utilization; the final copper slag is deposited in a landfill. The Harjavalta smelter commissioned a new landfill area for final slag in May 2018. This paper describes the full project from permitting to commissioning of a new landfill area. The permitting process is described comprehensively, including environmental impact assessment together with the environmental and dam safety monitoring. During the environmental impact assessment, observations on rare animals protected on European level were made as well as archaeological findings. Successful completion of the permitting allowed the construction phase to start on time. After six years of intensive work, the new landfill was commissioned in May 2018. The new landfill area provides a sustainable way to store the smelter’s slag for decades to come. INTRODUCTION Slag processing Sulphide based concentrates have always formed the main raw material stream at Harjavalta’s copper smelter. During the smelting and converting steps, the iron included in the concentrate is oxidized and fluxed using a silica-based sand. Originally, the slag was processed by using an electric slag cleaning furnace after which the final slag was water granulated. Froth flotation has been utilized for slag treatment since 1966. In the beginning, the slag was cooled in open ditches. In 1984, controlled slow cooling of slag was licenced to enhance copper recovery at the flotation plant. Today, the slag from both the smelting and converting is tapped/skimmed to slag ladles and treated in the following steps: Slag ladle transportation from the smelter to the cooling area by slag hauler Slow cooling of slag in the ladle to allow mineral precipitation Unloading the slag by tilting the ladle; causing the slag to crush as it drops from the ladle Feeding the crushed slag (-500 mm) by wheel loader to a slag concentrator’s feed funnel followed by a conveyor belt transporting the slag to the concentrator plant Crushing and grinding using lump and pebble mills Froth flotation of the valuables Recycling the slag concentrate back to the smelter feed after dewatering Pumping the final copper slag to the landfill area.

Jan 1, 2019

By C. B. Mapes, E. C. Dowling Jr.

"To reduce concentrate dewatering and drying costs, the Concentrator Division at Phelps Dodge Morenci, Inc. investigated available filtration technologies. Numerous methods were explored, including: drum, disk, belt, pressure, hyperbaric, and ceramic media filtration. An economic evaluation of the individual filtration technologies indicated the advantages of ceramic media filtration for Morenci concentrates. This paper discusses the technological development culminating in the first full scale application of ceramic media disk filters in North America. Low moisture contents are obtained at high production rates and greatly reduced operating costs.INTRODUCTIONPhelps Dodge commissioned the Morenci Concentrator Filter Plant in 1942 with four 8'6"" Dorr-Oliver cloth disk filters. That year, the filter plant processed 265,537 tons of concentrate grading 20.5% Cu. The filter cake production averaged 9.3% moisture. In 1944, the Extension Filter Plant commenced operation with three additional 8'6"" Dorr-Oliver cloth disk filters. This coincided with the expansion of the concentrator. Production that year totaled 451,567 tons of concentrate grading 23.8% Cu. Moisture averaged 9.4%.Through the years additional filter units have been added in response to increased concentrate production. An Eimco drum filter was installed on the extension side and an additional Dorr-Oliver disk filter was installed on the original side in the 1950's. In 1961, two 8'6"" Peterson disk filters were installed, one on each side to replace two worn-out DorrOlivers. The installation of four 10xl2 foot Peterson drum filters was completed in 1974, coinciding with the Metcalf Concentrator startup. An Eimco belt filter was installed later.The greatest change to concentrate dewatering at Morenci occurred in 1963 with the addition of a 10x60 foot rotary gas fired dryer. The installation also included a number of conveyors to deliver filter cake from both plants to and from the dryers. Other ancillary systems included dust scrubbers and their slurry pumps. The commencement of drying was undertaken due to the rapid increase in cake moisture as a result of the LPF process and the recycling of acid plant scrubber dust slurry from the smelter. In 1972, a second dryer system was installed to increase capacity."

Jan 1, 1993

By Dirk Claessens

The term ?cost? is too small when describing the destructive power of safety incidents for mining companies. Breaches in employee or environmental safety are felt way beyond the bottom-line: human life can be taken; ecosystems tarnished; the ire of peoples, media and government inflamed; significant halting of production; and high levels of legal and financial challenges. According to a recent survey of Mining executivesi, ?ensuring workforce safety? was the most important issues identified above any other, with a plurality of 31 percent, reigning above capital projects, product efficiency, and equipment reliability. We accept that safety is a most paramount issue, yet for many reasons we keep approaching the problem the same way we have in the past. We need to stop doing the same things decade over decade and try something new. New innovations are significantly changing the fundamentals of how mining companies explore, excavate, produce, refine and distribute their valuable commodities. Technologies such as visualization, analytics, location awareness, and gaming simulation are making these enterprises smarter. Now, attention turns to an area we?ve long held as integral to our business: safety. By using the same breakthrough technologies that are changing our business, we can now boldly imagine ? and credibly strive for ? a world of zero incidents.

Aug 1, 2013

By Chun-Sheng Liao, Chun-Hua Yan, Sheng Wu, Fu-Xiang Cheng

"INTRODUCTIONChina is providing more than 90% of the rare earth products consumed in the whole world. Acidic extractants are commonly used in the extraction separation of rare earths. Saponification of the acidic extractants by basic substances is usually necessary for the purpose of increasing and stabilizing their extraction capacity, and meanwhile inorganic acids are required for both scrubbing and stripping. Thus acids and bases are the main consumed chemicals, and the resulting salts are the main pollutants generated by rare earth separation processes. Currently, due to increasing environmental concerns in China, rare earth solvent extraction separation techniques are being developed to reduce both consumption and emission of chemicals, which is driving the developments on both theories and processes for solvent extraction separations.In the 1970s Prof. Xu et al. developed the Theory of Countercurrent Extraction (Xu, Li, & Yian, 1985). In recent years, the development of novel processes for rare earth separation has moved beyond the earlier theory. One rare earth separation process, the so-called hyperlink process, has been developed in the past decade and proven in industrial practice to dramatically reduce both the consumption and emission of chemicals during multi-component solvent extraction separations, and therefore is now widely used in the Chinese rare earth separation industry (Liao, Wu, Cheng, Wang, Liu, Zhang, & Yan, 2013). The present article will give a brief review of the development of the theory of the hyperlink processes, and the hyperlink separation flowsheets for typical rare earth mines in China designed using the theory.HYPERLINK PROCESSES (LIAO et al., 2013)A flowsheet of multiple-component separation consists of a couple of separation units. The units of a conventional flowsheet separately consume chemicals for saponification and scrubbing and discharge wastewater with resulting salts. In contrast, the separation units in a hyperlink process are hyperlinked and thereby the chemical demands of the whole flowsheet are decreased. For a feed containing t components of A1, A2, …, and At, it has been proved in theory that the separation mode of (AtAt-1…A2)/(At-1At-2…A1) is preferred in a single separation unit. The hyperlinking between separation units can have two forms. The link between two units locating at a same separation level, such as between (A4A3)/(A3A2) and (A3A2)/(A2A1), is known as horizontal hyperlinking. The link between two units located on different levels, such as between (A4A3A2)/(A3A2A1) and (A3A2)/(A2A1), is known as vertical hyperlinking. Both the hyperlinking forms have been proven to save chemical usage and consequently to lower the pollution emissions in industrial practices as well as in theory."

Jan 1, 2016

By Eugene Larochelle

The serpentine of the Eastern Townships of Quebec is more or less seamed and impregnated with chrysotile asbestos, of which we note two types: the cross-fibre and the disseminated fibre. The cross-fibre type always appears in fibres or crystals arranged parallel to one another, and disposed at right angles to the walls of the matrix serpentine. The length of fibre of these veins, which run in every conceivable direction, even crossing ?one another, varies from microscopie dimensions to three and sometimes four and even five inches. It is the principal form of asbestos found in the serpentine of Thetford Mines, Black Lake, Coleraine, and Asbestos. The disseminated-fibre type, which is the main product of the serpentine of Broughton township, in which ate located the mines at East Broughton, does not form veins, but occurs in the serpentine without any definite arrangement. There is a difference in the toughness and hardness of the rock of the two types, the Broughton serpentine being softer than that at Thetford. The disseminated-fibre section of the serpentine belt is probably more regular in its content than is the cross-fibre section. Nevertheless, it contains no 'crude,' which is the most valuable of asbestos, and the fibre is usually shorter than the cross-fibre average.

Jan 1, 1928

By William Petruk, Donald Leroux, Michael Cooper

"Brunswick's primary flotation circuit (CuPb) produces a low grade concentrate containing considerable amounts of undesirable sphalerite and pyrite. To determine the cause of the poor selectivity, a series of Quantitative Mineralogical Analyses (QMA) were performed on several CuPb circuit streams. It was observed that significant fractions of sphalerite and pyrite reporting to the concentrate was liberated, meaning that their depression was not complete. The study highlighted the need for some R&D efforts to be spent in sulphide flotation fundamentals.IntroductionThe viability of many mining projects strongly depends on the performance of their concentrators. More than ever, competitive grade concentrate and high metal recoveries are criteria of paramount economic importance. The selectivity of solid/solid separation processes used in concentrators must be maintained at high levels or continuously improved.Flotation is the solid/solid separation process used by most base metal producers. In spite of its low operating cost, flotation remains a very complex process. To make it selective, precise reagent dosages and electrochemical conditions must be maintained. The difficulty in controlling flotation lies in the numerous heterogeneous reactions that can take place between the different solid, liquid and gaseous phases involved. This complex chemistry makes flotation selectivity difficult to understand and, therefore, to improve from a theoretical point of view.Brunswick Mining and Smelting, near Bathurst N.B., operates a 10500 tpd concentrator which produces four concentrates through five stages of sequential flotation (Figure I). Various reagents are added at key process stages while the ore undergoes different electrochemical conditions. Although the selectivity is important at all stages, the performance of the very first separation, the CuPb circuit, is the most critical. It is here where mineral misplacement to the wrong stream has the greatest economic consequences."

Jan 1, 1996

By D. R. Schmitt, N. Ong, R. S. Kofman

Shales and mudstones comprise about 75% of all the sedimentary rocks. In, particular, organic rich shales are considered as a petroleum source rock and more recently with the advent of hydraulic fracturing technology to be a reservoir in their own right. In this sense, the aforesaid motivates our work with laboratory measurements of elastic properties of these geologic materials, which are known to be anisotropic. As such, assuming Vertical Transverse Isotropy (VTI) symmetry, the dynamic and static moduli of a series of cores from various geological formations in Alberta, Canada are simultaneously investigated as a function of confining pressure using the ultrasonic pulse transmission method and strain gages. Dynamic moduli were obtained from ultrasonic P- and S-wave velocities measured on a prism cut with faces perpendicular, parallel and oblique to the assumed vertical axis of symmetry. Static moduli were calculated from strain-stress curves obtained along the directions perpendicular and parallel to the assumed axis of symmetry as well. Velocity measurements show that samples are highly anisotropic, but that the pressure-dependent behaviour of the wave speeds differs. VP(90°) and VSH(90°) both with layer parallel propagation and polarizations change little with pressure while VP(0°) and VS(0°) (both with layer perpendicular propagation) display significant nonlinear responses particularly at pressures < 25 MPa. These characters transfer to the derived full set of elastic constants. In order to effect a proper comparison of the dynamic and static moduli, we convert the dynamic elastic constanst to linear compressibilities pependicular (Kdyn1) and parallel (Kdyn3) which are directly comparable to the static tangent compressibiities obtained by differentiation of the observed strains. Both sets highlight the anisotorpic nature of the material but most interestingly Kdyn1 _ Ksta1 but Kdyn3 > Ksta3 by nearly 40% for one of the samples. The other samples measured respond similarly suggesting that conceptually the structure of such materials could be considered to be constructed of alternating stiff or compliant layers. This finding has implications in the response of the formation to stress particularly during hydraulic fracturing and the interpreation of acoustic logs in providing appropriate measures of elastic properties for engineering purposes.

Jan 1, 2015

By C. R. Whittemore

PROGRESSIVE industrial organizations have recognized the importance of maintaining an adequate reference library of volumes covering all phases of their particular branch of industry, but it has been the experience of the writer that few engineers know how to use to the best advantage this store of extremely -valuable information which has been accumulated for their service. Nor does the average engineer appreciate the fact that it is only through the current technical literature that he can keep abreast of the rapidly developing fields of engineering. The present-day ramifications of the engineering field are of such wide scope that the human mind is not capable of storing away more than a small fraction of the information available on any particular topie; yet, from time ? to time, such information would prove invaluable. An engineer can know intimately only a small part of his own branch of engineering; but he cannot afford to neglect to take the fullest possible advantage of all that is already known in his own particular field. Technical information may be obtained by one or more of the following methods: (1) by enquiring of the individual who knows; (2) by performing the experimental investigations necessary to ascertain the facts; (3) by consulting the technical literature, where a record may be found of the work of others. This last method is the one we wish to examine. Our main consideration is the question of how to use the library, but first it is necessary to give some attention to the kind of enquiries one takes to the library, and to the nature of the sources of information available.

Jan 1, 1938

By Norm Clegg

The Plant Engineering and Maintenance Association of Canada PEMAC is a national, not-for-profit industry association for plant and facility maintenance, engineering and physical asset management in all industry sectors in Canada. Our mission is to provide professional development for our members and the profession in Canada

Feb 1, 2008

By D. Royston

In SAG mills fed with a variety of ore types, hard packing between the shell lifters can come and go depending on rock type and rock size distribution and the presence of a binder. Packing can appear in all sizes of SAG mills, and can be tenacious. High ball impact forces (depending on ball size) in larger mills may compact and encourage packing. Packing can have a negative impact on milling performance and a change in shell liner design may be required to remove it. However shell liner design changes need to be managed with care to ensure liner reliability. In smaller mills control of packing can extend shell plate wear-life and may help to maintain milling performance in fixed-speed mills through the liner wear-cycle.

Jan 1, 2012