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By G. L. Zhu, Y. F. Wu, H. Nagaumi

A novel eutectic-type alloy Al12Si-HTC with high thermal conductivity has been developed by strict chemical composition control and heat treatment. The thermal conductivity of the alloy is about 30 % higher than that of current commercial Al12Si alloy. The Al12Si-HTC alloy has a silicon content of 10~12 wt.%, which provides excellent castability. Trace element strontium or calcium is added to modify eutectic silicon, and contents of transition elements such as copper, manganese are controlled in a low level. By appropriate heat treatment, thermal conductivity of the castings increases by 7.5 % and finally reaches 172 W/(m·K). It is found that eutectic silicon modification which makes average particle size finer than 2µm plays a dominant role in improving thermal conductivity, as well as further spheroidization of eutectic silicon and reduction of lattice defects in a-Al microstructure in subsequent heat treatment process. The alloy is successfully applied to produce a certain communication enclosure with complex finned structure by die casting process in industrial scale. The results of numerical simulation and thermal analysis experiments show that when manufactured by Al12Si-HTC alloy, the surface temperature of chips in the enclosure is reduced by 2.0~4.5 ? and the temperature distribution is more homogeneous compared with traditional Al12Si alloy.

Jan 1, 2015

By R. F. Favreau, L. C. Lang

"In modern blasting technology blasts are designed and analysed on an energy-mass-time relationship. The energy of the explosive is derived by computer analysis and the work potential of the available energy is expressed in numerical values. The mass involved in the blast is determined by the geometry of the blast and by the rock density. Time is also a relevant parameter, because time is required to complete the three basic stages of the breakage process.For successful application of the blasting parameters the basic mechanism of the breakage process must be understood.The physical-mechanical properties of the rock, local structural geology and the thermodynamic properties of the explosives can be brought together to create a computer model of a blast with which it is possible to predict separately the results of each parameter and to express the predicted degree of change in any parameter by actual numbers.A long-range project has started to create a ""bank"" of rock properties for as many Canadian and foreign mines as possible. A computer model has been successfully applied to predicting the effect of varying the ratio of spacing to burden at constant rock volume and significantly improved results are achieved, as the S/B ratio is increased up to about 2 to 2.5.High-speed photography has been applied to determine the time that has elapsed between zero time and the beginning of movement of the mass. The results assist in determining minimum and optimum delay time required for multiple-row blasting.The approach as described in the paper is now well proven and is clearly superior to previous methods based on powder factors and human assessment."

Jan 1, 1972

By E. C. Roper

THE Britannia Mining & Smelting Company, Limited, have been operating their property at Britannia Beach, B.C., continuously for nearly forty years and have mined over 33,000,000 tons of ore from orebodies within a belt of highly sheared rocks, five miles long by 2,000 feet wide. The property is in the Coast Range mountains, about twenty miles due north of Vancouver. The mountains rise abruptly from sea level to elevations of 4, 500 feet within a horizontal distance of 7,000 feet. The topography has enabled the orebodies to be developed by adit tunnels. The active mining levels are connected to the adits by incline and vertical service shafts. The main service adits are the 2200, 2700, and 4100 levels (see Figure 1). The mine surface shops, three bunk-houses, and over one hundred dwellings form the townsite camp at the portal of the 2200 level adit. A small camp of one bunk-house and a few dwellings is situated at the 2700 level portal. The beach surface shops and camp, adjacent to the 4100 level adit, service the mill, foundry, and other beach installations as well as the mining from the 4100 level. The ore mined from the various orebodies is delivered to the 4100 main haulage level through a system of rock raises and intermediate tramming levels and is hauled on the 4100 level to the mill.

Jan 1, 1945

By Nicole Peter

When introducing digital training technology a practical approach helps address cultural concerns.  Solutions to help create acceptance are discussed.  Resistance to change may be deeply rooted in traditional mine training personnel.  Traditional training staff members may consider themselves less digitally-savvy and resist technological methods available to them. A transitional approach intended to help mitigate or resolve resistance is presented as a continuous improvement pathway toward full adoption.  This presentation contends every mine should welcome the benefit of a digitally connected critical enabler.  The adoption of a digitally savvy learning centre is often viewed a disrupter to existing practice.  Given a commitment-driven learning centre model, technology offers the opportunity to transition from a compliance-based training model to one of competence.  Learning and Development practitioners should welcome the latest advances in neuroscience, Bloom’s taxonomy of learning model, and principles which guide mine safety training as outlined by the Lowell Institute for Mineral Resources at the University of Arizona. By employing digital applications to include animation, game-based simulations and immersive Virtual Reality (VR) these technologies create a viable digitally-savvy learning centre. We will outline the ingredients of a digitally enabled, or VR, Learning Centre to offer some observed benefits, successes, and potential short-comings. Much excitement in the industry surrounds implementation of simulation and/or VR headset training.  Given fair consideration of these as a ‘fit-for-purpose’ solution we examine the paradigm shift required to create real results for on-the-job learning.  Interim steps may be needed to meet the cultural transformation.   Simpler forms of VR, in the form of 3D models and VR environments as displayed on a large interactive touch screen, can serve to bridge this challenge and address a group learning environment. Features of the interactive 3D technology and ease of adoption are presented.  Usage of the touch screen is similar to that of a smart phone. It may be implemented as an obvious transitional tool.  To help describe merits of the interactive touch screen the presentation points out these sample underground and surface mine training applications. There are 3-D simulations such as ventilation, emergency response, support installation, and mine cycle and activity scheduling programs. These applications offer the ability to conduct entry examinations, complete digital pre-use checklists, and perform planned task observations in the virtual world of work. The tool may be used to teach the flow of hydraulics and do fault-finding on machinery such as loaders and dump trucks. Learners may navigate in a virtual mining environment to identify hazards, detect and assess abnormal ground conditions, address poor design features, and alleviate traffic constraints. It is possible to use connected physical controls to navigate machinery in the virtual environment. We conclude the presentation with a “compare and contrast” approach to cite potential cultural benefits by adopting a transitional method. 

May 4, 2025

By A. Hutwalker, T. Plett

"Blast fumes are one of the major sources for NOx in underground mines. In 2016, the Occupational Exposure Limits for NOx in Germany were reduced by 90%. The task is to keep re-entry times after blasting at the present level and thereby ensure an economic operation of the mine. Measurements show that using ventilation solely is not sufficient. A new approach to reduce NOx from blast fumes is described. Laboratory experiments were performed and a reduction of NOx was observed. Measurements were conducted at an explosive factory’s testing facility and in an underground mine at blasting operations. INTRODUCTION Whether for production of ore or for drift development, the processes in an underground mine are always the same: 1) fracturing the rock, 2) loading the pile, 3) support the resulting cavity. The fracturing of the rock can be done mechanically, by cutting, for example by using continuous miners or tunnel boring machines, or by drilling and blasting. Drilling and blasting is more flexible than mechanical driving, as it can be used independently of the rock strength. Furthermore, this driving method allows a more flexible reaction to changes in geological and/or operational conditions. Thus, underground mining and blasting are almost inextricably linked with each other, and regardless of the size and level of technology of the mine, blasting is hardly avoidable. Depending on the mining method chosen and the existing framework conditions, such as the mechanical properties of the rock or the availability of machinery, blasting is an integral part of daily operations. Even in mines where blasting is not part of regular operations, it cannot be completely avoided. The blast fumes generated by the explosions are, in addition to diesel engine emissions, one of the two main sources of emissions of nitrous gases underground. Up to now, state of the art for dealing with blast fumes is ventilation. The fumes are diluted with fresh air and ventilated out of the mine. This treatment of blast fumes is more than sufficient with the former German Occupational Exposure Limits (OEL). The adaption of the OEL in Germany to the recommendations of the Committee on Occupational Exposure Limits (SCOEL), a committee of the European Commission, leads to big challenges for the mining industry in reducing the concentrations of these gases at the workplaces underground. On its meeting on May 2nd and 3rd 2016, the Committee on Hazardous Substances (Ausschuss für Gefahrstoffe, AGS), an advisory body of the German Federal Ministry of Labour and Social Affairs (BMAS), advised the BMAS to copy the OEL, as recommended by the SCOEL, to the Technical Rules for Hazardous Substances (TRGS 900). BMAS followed this advice, consequently the new OEL where published on November 4th 2016 and became part of the TRGS 900. Table 1 shows the former and new OEL for Germany. These new OEL became law after publishing, but two exceptions were made: For tunneling operations, they became law on October 31st 2017, for mining operations they will become law on October 31st 2021 (BAuA, 2004, 2016, 2017)."

Jan 1, 2019

By Rejean Gagnon, Fernand Rochefort

"Haulage costs, in most operations, represent a large portion of total cost. Quebec Cartier Mining Company came to the conclusion t hat an electric trolley assist providing more horsepower than available from dieselgenerator sets presented the best oppor tunity for improvement. Accordingly, a testing and development program was carried out which resulted in the design, installat ion and application of a practical system. This paper describes the development of the system, the equipment used as well as the actual operation. A projection is also made to indicate further improvement in productivity. A comparison is made of truck operating data before and after activation of the trolley assist system in order to determine its economic impact."

Jan 1, 1972

By L. Bratek, K. Jaworek, M. Czaplicka

Methods for arsenic compound removal from aqueous solutions include processes such as: coagulation, adsorption, membrane techniques, electrochemical and biotechnology techniques. Advanced oxidation using both UV radiation and strong oxidizing agents such as ozone and hydrogen peroxide may also decompose these compounds. It is known that effluents from metallurgical processes contain inorganic arsenic compounds in addition to the organic compounds such as: dimethylarsinic acid and phenylarsonic acid. This paper presents the conditions that lead to the formation of deposits containing mainly arsenic, such as pH, the wavelength of the radiation and the type of oxidant, for this type of effluent.

Jan 1, 2014

By G. McIsaac

"This paper discusses the formulation of a linear program with the objective of maximizing the cash flow of the long-term plan of an underground operation. A mine is split into eleven independent ore zones, each characterized by its reserves, required development, and mining method. Based on practical considerations, maximum rates are set for each zone’s development and production capacity. For the total mine plan, a minimum daily production rate is set along with a minimum feed grade to the mill. A maximum daily development capacity is set based on the equipment and labour available. Proven and probable ore is mined preferentially over possible ore in the early years of the plan. Also, the fixed cost of operating the mine is taken into consideration whenever mining activities take place.Once the linear program is solved, it can be critically reviewed, and unrealistic results can be identified. Some resource allocations constraints can then be changed in certain sectors, and new results can be analyzed. “Whatif” scenarios can also be examined, such as determining the impact of hiring a contractor to develop a given sector, or dropping an ore zone completely from the plan."

Jan 1, 2005

By G. McIsaac

This paper discusses the formulation of a linear program with the objective of maximizing the cash flow of the long-term plan of an underground operation. A mine is split into eleven independent ore zones, each characterized by its reserves, required development, and mining method. Based on practical considerations, maximum rates are set for each zone?s development and production capacity. For the total mine plan, a minimum daily production rate is set along with a minimum feed grade to the mill. A maximum daily development capacity is set based on the equipment and labour available. Proven and probable ore is mined preferentially over possible ore in the early years of the plan. Also, the fixed cost of operating the mine is taken into consideration whenever mining activities take place. Once the linear program is solved, it can be critically reviewed, and unrealistic results can be identified. Some resource allocations constraints can then be changed in certain sectors, and new results can be analyzed. ?Whatif? scenarios can also be examined, such as determining the impact of hiring a contractor to develop a given sector, or dropping an ore zone completely from the plan.

Sep 1, 2005

By A. Eltringham

Operations downstream of mining and beneficiation are still being subjected to increasing scrutiny as highly capitalized projects have been either slow to achieve their targets or have actually failed to do so. Leaching and smelting projects have fundamentally high calls on capital and technology as reaction rates are increased and the capture and disposal of unwanted products are subjected to greater restrictions. Separating value from waste inherently becomes riskier as the purification of the desired product imposes greater demands on the process to produce benign wastes. When we superimpose on the chemistry of the project severe predictions of throughput rates, that bring in facets of manufacturing, we are introducing complexities that the records show are not handled well. This paper discusses some of the more common challenges that operators face and what methods are available and are likely to be successful in preventing the loss of value as projects are brought on-stream. This thinking needs to start much earlier and at greater intensity than our industry has normally chosen to employ.

Jan 1, 2011

By D. A. Temple, G. O. John

Until recently, the approach to the problem of treating complex ores bas been to produce, insofar as is possible, mono-metal concentrates which are treated in traditional zinc, lead and copper smelting circuits, with the residues and by-products from some of these circuits being retreated for the recovery of contained values either by a separate residue treatment process or along with the primary feed to the appropriate circuit. The continued development of the Imperial Smelting Process, with its ability to treat poly-metal concentrates, calls for a re-examination of the traditional approach to this problem, and this the paper attempts to do. A survey of recent progress in the technical development of the process is made and a summary of current operational performance is included.

Jan 1, 1971

By K. C. Lahiri, H. P. Das, G. G. Sarkar

"The petrographic components of any particular rank of coal often show some distinct physical and chemical characteristics. Therefore, their pro-portionate distribution in a coal greatly influences the technological behaviour of the coal.In any size or gravity separation of a coal, the petrographic constituents become segregated to different degrees in some preferred size or specific gravity range. Therefore, a knowledge of the petrographic nature of the washed and/or screened fractions is often considered essential in selecting the most efficient method for coal preparation and in exploring the proper evenues for its utilization.A graphical method is described in this paper to indicate the mineral-matter content and the petrographic components of the washed fractions of a coal at different ash levels of separation in the form of a new washability diagram. This diagram can be conveniently used to assess or predict the petrographic composition of clean coal or sinks corresponding to any desired ash level in the cleans. With the help of this diagram, it is also possible to locate the yield level of cleans at which maximum enrichment of vitrinites and exinites occurs with the least amount of mineral-matter content."

Jan 1, 1971

By Robert M. Hopkins, Craig C. Monahan

A corrosion survey was performed on ten selected H-piles which support a reinforced concrete wharf located at Trepassey, Newfoundland. Approximately 900 thickness measurements were taken at twelve different locations in each off our zones on the steel piles: the splash (atmospheric) zone, the intertidal zone, the low tide zone and the submerged zone. Results show that over the 2o-year life of the wharf, corrosion has been most severe in the splash, low tide and submerged zones with average corrosion rates for the flanges of 6.95, 9.45 and 6.86 mils per year (mpy}, respectively, and average corrosion rates for the webs of 5.13, 4.12 and 3.45 mpy, respectively. Minimal attack was found in the intertidal zone where the average corrosion rate was only 1.66 mpy on the flanges and 1.37 mpy on the webs. Such a pattern of attack is frequently observed f or steel piles partly submerged in seawater. The abnormally low corrosion rate associated with the intertidal zone is generally explained as being due to cathodic protection induced by the high corrosion rate in the adjacent low tide zone. Analysis of the corrosion data obtained for the Trepassey wharf would suggest that this explanation might be incorrect. An alternate hypothesis has been brought forward which better accounts for the extremely low corrosion rate observed in the intertidal zones of these piles.

Jan 1, 1990

By Peter R. Drummond

THE paper consists of four sections: (1) a discussion of early work; (2) presentation of the results of a chemical investigation of Falcon-bridge nickel-copper blast-furnace matte; (3) application of the results of this investigation to mattes in general; and ( 4) a summary of conclusions. All general discussion will be confined to the fundamental system of ferrous-cuprous sulphides (FeS-Cu2S). Nickel-, lead-, and zinc-bearing mattes will be treated as minor varieties of the parent system. DISCUSSION OF EARLY INVESTIGATIONS Matte investigations may be divided into three classes: first, those treating the sulphides as alloys-theoretical studies of the system FeS-Cu2S, such as those of Hofman (ll)t or Carpenter and Hayward (2); second, chemical research on mattes made under smelter conditions, such as that carried out by Hawley (3) or Avetision ( 4); third, combinations of the . above, such as the investigations of Gibb and Philp (5) or Fulton and Goodner (6). Much research in the first of these classes, including determinations of . freezing points and of data for structure-composition diagrams of the system FeS-Cu2S, was carried out in the period 1890-1910. LeChatelier and Ziegler (1, 13) proved that FeS, when heated alone above its melting point, dissociated in part, and Friedrich ( quoted by Fulton, 6) showed the same for Cu2S. The reactions may be expressed by the following equations: [xFeS yFe + yS (volatilized)+ (x -y)FeS xCu2S )'Cu+ yS ( vohtilized) + (x -)')Cu,S ] Sulphur is lost by volatilization, leaving a melt of metallic iron plus ferrous sulphide in the one case, and of metallic copper plus cuprous sulphide in the other. If the mixed sulphides are heated far above their melting points, there results either an iron-rich matte containing Fe-FeS-Cu2S or a copper-rich matte containing FeS-Cu2S3-Cu, depending on the relative amounts of each sulphide in the mixture.

Jan 1, 1940

By Dawei Yu, Kinnor Chattopadhyay

In the nickel industry, molten slags produced from a Pierce-Smith converter contain significant amounts of valuable metals in the forms of oxides and physically entrained matte droplets. A slag cleaning step, which takes places in an electrical slag-cleaning furnace, is therefore required to recover the valuable metals as a common practice. Utilization of a waste material from aluminum industry (i.e. spent potlining) as a flux to improve the slag cleaning in terms of both the metal recovery and the operation efficiency was studied by simulation with FactSage program. Results show that the addition of SPL could substantially reduce the slag viscosity due to its fluoride values, thus accelerating the settling of matte droplets. The carbon value in the SPL could also help increase the metal recovery by reducing the valuable metal oxides followed by settling.

Jan 1, 2015

By Viraj Parekh, Kinnor Chattopadhyay, Sina Mostaghel, Xiao Zhang

Electric arc furnace steelmaking is a dominant approach in North America and controlling EAF emissions is a key issue today because of stringent permit limits imposed by various regulatory bodies. In the present study, an attempt has been made to mathematically model EAF emissions, and use the models as a predictive tool for fine tuning the process. CFD modelling has been used to model various fume release scenarios, and optimize the exhaust conditions for maximum capture. Thermodynamic calculations have been used to analyze various chemical reactions which lead to the emissions of hazardous air pollutants with special emphasis on Zinc, Lead and Manganese.

Jan 1, 2015

By M. B. Shongwe, R. K. K. Mbaya, C. K. Thubakgale, P. Mendonidis

"A low-grade nickel-bearing ore was pre-concentrated on a SB40 laboratory model Falcon Concentrator. Three size fractions, -212+125, -125+75 and -75 µm were tested with the intent to upgrade the nickel content by reducing their content of fine silica, which becomes amorphous during leaching. Separation of silica from nickel-bearing magnesium silicate minerals; hornblende, clinochlore and talc, was more efficient in the finer particle sizes, -125+75 and -75 µm, and at high G-forces. For these two size fractions, nickel was upgraded from 0.06 to 0.07%, with a reduction in silica content from 52.12 to 50.71%. Leaching of feed samples prior to pre-concentration resulted in the formation of amorphous silica, indicative of the presence of fine silica in the samples. Leaching of nickel from the -125+75 µm fraction increased with increasing G-force and feed pulp percent solids, while that of -75 µm was not influenced. The optimum nickel recovery was 15.68% to the Falcon underflow, using the feed size fraction of -75 µm, 30 G and a feed pulp solids content of 10% solids, after 120 minutes of treatment.INTRODUCTION A low-grade South African nickel-bearing ore with about 0.06% Ni was previously studied for atmospheric pressure acid leaching using sulphuric acid. The study was motivated by the continuing search for methods to treat of low-grade ores, which appear to be an increasingly important source of valuable metals as a result of a declining production from rich sulphide ores. Nickel is a base metal that is used as an alloy in steelmaking and chemical industries because of its resistance to corrosion (Haudet et al., 2015). Nickel laterite ores with grades lower than 1.50% Ni are considered to be complex ores, accounting for 70% of the global nickel reserves (MacCarthy et al., 2016). Their complex nature may be attributed to the indefinite mineralogy of these ores, in which nickel may occur in more than one mineral host. In some cases, nickel may be finely disseminated in the ore. The grade of such an ore and complex mineralogy do not justify the application of pyrometallurgical methods for extraction of nickel (Zhu et al., 2012). This suggests that there is a need for less expensive alternative methods of extraction. This study investigates the application of centrifugal gravity concentration, using the Falcon concentrator, followed by leaching to determine the effect of pre-concentration of the ore prior to extraction by atmospheric pressure leaching with sulphuric acid."

Jan 1, 2017

By R. J. Munday

Although uranium deposits in northern Saskatchewan are clustered around the Athabasca basin, basement lithostructure determines their distribution. Basal Wollaston Group pelites are invariably graphitic and carry uraninite in felsic segregations and biotitic pegmatite. Where these intersect the Athabasca Formation, remobilized uranium concentrated as pitchblende. Uranium is also concentrated in silicified and hematized sandstone where the Athabasca Formation overlies post-orogenic faults. Presumably, pregnant solutions associated with the fault were stripped of their metals as they emerged into the contrasting physico-chemical environment of the sandstone basin. Both these types of mineralization correlate with a Grenvillian (-1,000 m.y.) heating event and associated diabase intrusions. However, the rich pitchblende veins at Uranium City appear to predate the Athabasca Formation, but display spatial correlation with the Martin Formation. They are tentatively associated with a syn- to post-D3 retrograde metamorphic event which thoroughly leached crystalline basement and generated uraniferous fluids which escaped, and precipitated metals, into fractures associated with faults that define the grabens in which the Martin Formation was deposited. Remobilization events allowed some of this uranium to move upward into fractures within Martin sediments.

Jan 1, 1979

By D. B. Dreisinger, M. Rasouli

"Developing technology to address the environmental hazards associated with selenium in mine-impacted waters has been a serious challenge. Ion exchange (IX) has been identified as a potential treatment technology. This paper begins with a review on selenium adsorption with commercially-available basic anionic exchangers (BAS). It then looks at the use of resins for selenium removal via modification with the addition of -O, -N, or -S-containing chelating ligands and chelating polymeric ion exchangers pre-loaded with immobilized metal cations. The synthesis of chelating exchangers requires a final product with a highly stable metal in the ligand-metal complex. The nature, oxidation state, size, and affinity of the metal for the target oxyanions and the size, degree of protonation and space configuration of the oxyanion are among critical factors affecting the oxyanion uptake. There is a limited number of studies on the critical parameters affecting the selenium affinity for chelating exchangers. Such a study could fill in the gaps of our understanding of selenium-metal-chelating ligand interactions and assist in developing a new ion exchanger. In addition to commercial IX resins, layered double hydroxide materials (LDH) have received attention for oxyanion removal from waste water. The adsorption capacity of the LDHs are affected by the crystallinity of LDH, the nature of metal components, the ratio of metals, charge and type of anion, and the space between the layers. In particular, the Friedel phase (FP), a member of the LDH family, showed high adsorption capacity for selenate removal from synthetic solution. A study is currently underway at the University of British Columbia to investigate the effect of different synthesis methods and aging on the suitability of FP for selenium removal from mine waste water."

Jan 1, 2017

By A. P. Yovanovic, P. Bonadia, M. N. Moraes, C. F. Matos

"The magnesite flotation operation of Magnesita Refractories, in Brumado – Brazil, has four parallel ball mills working in closed circuit with hydrocyclones to grind the ore for the reverse flotation of silicates in mechanical cells. The modification proposed here opens the circuit for three of the ball mills so that their products are collected together to feed a high frequency screen. The oversize of the screen feeds the fourth ball mill in closed circuit for secondary comminution. The product reports to dewatering and flotation. The undersize undergoes desliming and subsequent flotation operation. According to pilot tests performed, the modification on the magnesite flotation operation will promote a 20% increase in the productivity, 8.5% increase in mass recovery and a 26% reduction in water consumption. The gains are due to the fact that the silicates in the feed are concentrated in the smaller particles (<100µm) with over grinding in the existing closed comminution circuit, making it impossible to take advantage of this natural selectivity. The combination of open circuit, more selective milling, and the high frequency screen, ensures high efficiency particle size classification. This renders the process more effective, both to the screen undersize with its high contents of silicates and fines, and to the screen oversize, which is almost without fines and has a higher magnesite grade. This situation allows for the setting of specific parameters for the flotation of both the primary milling undersize and the secondary milling product.INTRODUCTIONMagnesita Refractories, with its operations site in Brumado, is the largest producer of high purity dead burned magnesia (DBM) in Latin America. The magnesite ore is extracted from an open pit mine, named Pomba, after which it is crushed and handpicked. Due to the presence of disseminated silicate the ore has to be ground and concentrated by means of reverse flotation, before feeding the high temperature kilns for sintering and conversion to DBM.The magnesite flotation unit has an impact crusher to reduce the size of the feeding ore, which is transported to the mills by conveyor belts. The milling operation is composed of four ball mills in closed circuit with hydrocyclones. The closed circuit generates a high circulating load with excess fines, which is detrimental to the selectivity of the desliming and flotation operations, reducing both mass andmetallurgical recovery.In the current scenario, the capacity of the flotation plant is insufficient to meet the demand of the DBM kilns, forcing the operation to work with high purity ores in order to attain the highest possible mass recovery in the concentration process. This is not an ideal situation as it requires the mining site to work with higher stripping ratios.The objective of this work was to improve the magnesite flotation unity to increase its productivity. After a detailed analysis, the milling was identified as the limiting process, which made the authors to focus on this operation."

Jan 1, 2016