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By E. B. Spice

"IntroductionExperience at Eldorado has been gained with a variety of mill feeds. That is, the actual mode of occurrence of the pitchblende varies to such an extent that gravity concentration has at times been decidedly unattractive and at others highly successful. Because of this, the type of ore necessary for economic recovery of pitchblende have become well known. Also, those types which do not lend themselves to gravity concentration have become familiar. In general, it may be said that when the pitchblende occurs free, to a large extent, from sulphides or arsenides of high specific gravity, and when the bulk of the pitchblende is localized rather than disseminated, excellent recoveries, high ratios of concentration, and good grades of concentrates , will result from proper gravity concentration. On the other hand, if the ore contains pitchblende intimately or otherwise mixed with large quantities of arsenides or sulphides, or if the pitchblende is finely disseminated, gravity concentration alone will yield high recoveries only at the expense of very low-grade concentrates and low ratios of concentration.According to Taggart, the ease with which gravity separation may be effected is determined by the value of the following ratio: []It is stated that when the ratio is above 1.75, gravity separation can be expected to be easy. Thus with pure U308 (S.G. over 9) and gangue consisting chiefly of siliceous material, the process can he expected to be entirely successful even when carried on at very fine sizes. Unfortunately, the term pitchblende covers a great diversity of material. Although some of the mineral occurs pure enough to have a specific gravity of about 7, the average is much lower than this and is probably well under 5. Some of the pitchblende particles have a specific gravity so low that gravity concentration fails completely. It may also be said that no degree of grinding will produce free pitchblende of sufficient density from such particles. This, then, represents the most important limitation to the application of gravity separation to pitchblende ores."

Jan 1, 1950

By Dillon. Patricia

Business Growth ?Coal ?Targeting 30 million tonnes by 2013 compared to 19 million tonnes produced in 2009 ?Expanding Energy Business unit (Oil Sands) ?Copper -Strong growth potential for existing operations and development projects ?New gold strategy recently launched ?New markets for zinc Need to retain existing and attract new employees to support growth Engaged Employee ?Has a positive attitude towards the organization and its values ?Is a person who is fully involved in, and enthusiastic about, his or her work Engaged employees are more likely to stay with the organization.

May 1, 2010

By A. Pranowo, G. R. F. Alvear F., N. Aslin, M. S. Moats

"The toxicity of arsenic is well known and documented; however, the presence of arsenic in copper electrorefining anodes and electrolytes is critically necessary to produce high-quality cathode. Arsenic as well as antimony and bismuth concentrations vary relative to their concentration in the anode copper received from the smelter. The behaviour and benefits of arsenic in copper electrorefining and the detrimental effects of antimony and bismuth on cathode quality and tankhouse performance are discussed. This will include the minimization and mitigation of problems associated with arsenic, antimony, and bismuth—including cathode contamination, floating slimes, scaling, and anode passivation.RÉSUMÉ La toxicité de l’arsenic est bien connue et documentée; toutefois, la présence d’arsenic dans les anodes de l’électroaffinage du cuivre et dans les électrolytes est d’une nécessité critique pour produire une cathode de grande qualité. Les concentrations en arsenic, ainsi qu’en antimoine et en bismuth varient selon leur concentration dans l’anode de cuivre reçue de la fonderie. Le comportement et les avantages de l’arsenic dans l’électroaffinage du cuivre et les effets indésirables de l’antimoine et du bismuth sur la qualité de la cathode et le rendement des cuves d’électrolyse sont discutés. On traite aussi de la minimisation et de l’atténuation des problèmes associés à l’arsenic, l’antimoine et le bismuth – incluant la contamination de la cathode, les schlamms flottants, l’entartage et la passivation de l’anode."

Jan 1, 2016

By T. Ouellet, F. Chiesa, J. Carignan, D. Levasseur

Common practice for the preparation of permanent mold for aluminum casting is to coat the mold with a ceramic suspension to obtain a chemically stable interface with the aluminum melt. This practice serves two purposes: first, it helps the thermal regulation of the mold and second, it prolongs its life. The possibility of increasing the coating durability by applying it by thermal spray is appealing. Plasma spray of zirconium oxide based coatings was performed on H13 tool steel to study the coating’s thermal fatigue resistance. A unique dip test setup was used to characterize the thermal fatigue resistance of the coatings and of bare H13 steel. Observations of the failure mechanism bring an insight on the requirements of the coating to maximize its durability.

Jan 1, 2014

By N. K. Jaber

The "Pidgeon Process" for the extraction of magnesium from dolomite ore utilizing ferrosilicon as the reducing agent has been studied extensively by active metallurgists such Mr L,M, Pidgeon the father of this process, Most of the work sited so far has focused on heating the (FeSi/MgO,CaO) briquette mix under vacuum in stainless steel retorts by external fuel hydrocarbon heating, In this work Electrical Induction Heating was employed as the heating method whereby the briquette mix was placed in a steel crucible around which an Induction Heating copper coil was wound and placed inside in a stainless steel vacuum tank, It was observed that by virtue of the fast Induction Heating method utilized in the silicothermic extraction process higher reduction temperatures were reached in shorter periods of time due to fast heat transport into the ore charge mix, This facilitated shorter metal reduction times as compared to the conventional fuel heating methods.

Jan 1, 2006

By M. H. Colebrook

Nickel laterites contain about 70% of all continental or terrestrial nickel resources; therefore the recovery of nickel from lateritic ores has large economic significance. The processing of lateritic ores involves the preparation and movement of concentrated aqueous suspensions. However due to complex characteristics and non-Newtonian properties, ranging from shear-thinning to shear-thickening and from thixotropic to rheopectic, a basic understanding of the flow behaviour must be developed. This understanding will assist in the development of new plants and the operation of existing plants. The work in this paper involves the characterization of three ore types from the Vermelho ore deposit to categorize them as rheologically simple to complex. Rheological testing was also conducted on pure mineral samples that represent the main minerals in these samples. The results show that the rheological properties of the ore types can be related to the surface properties and physical characteristics of the main mineral constituents.

Jan 1, 2006

By J. E. Nesset, E. R. Bobicki, K. L. Bilaniuk

The introduction of froth flotation technology in Canada, and in particular, in British Columbia, began not long after it was successfully applied in the Broken Hill mining area of Australia which began around 1905. It proved to be a revolutionary and transformative technology that resulted in marginal operations in copper, lead and zinc becoming profitable in spectacular fashion. The paper presents the technology of both oil flotation and froth flotation in the context of the challenges of the time and its early application in British Columbia at the Le Roi No.2 mine (1903), the Britannia Copper mine (1912), and at the Allenby concentrator of the Copper Mountain mine (1918-19). New-found archival documents indicate the Britannia application to be the first production application of froth flotation for copper ore outside Australia, a claim that is currently made by the Braden mine (now El Teniente) in Chile. Flotation was initially an add-on process following gravity methods but was rapidly shown to be far superior method for the bulk and selective recovery of metal sulphides. Flotation proved particularly successful for the recovery of zinc sulphide (the so-called ‘zinc problem’) which was considered a contaminant at the time. The ‘copper problem’ related to the poor recovery of fine copper sulphide particles that were not amenable to gravity methods. The success of flotation led to changes in both the scale and methods of mining, concentration and smelting in a manner that allowed integrated mining companies to flourish. Many are still with us today. INTRODUCTION The advent of froth flotation in the early 20th century was truly a revolutionary technological development, not only for the mining and metallurgical industries, but arguably more so for business and society overall. The Canadian technology historian Jeremy Mouat stated (1996) “The development of flotation was the greatest single metallurgical improvement of the modern era...it is not overstating the case to claim that flotation was of central importance to the smooth functioning of the global economy”. It should, therefore, be a story of interest to us all. The aim of this paper is not to retell the full story, that has been well covered by others (Hoover, 1912; Rickard, 1916a; Hines & Vincent, 1961; Lynch et al., 2010) but rather to add some Canadian perspective and the key role played by companies and individuals in those early days, focusing on events in British Columbia’s copper industry. EARLY DEVELOPMENTS During the later half of the 19th century, a number of flotation-related patents were issued. These include the 1860 patent (Britain) granted to William Haynes for a process to separate sulphides from ground ore by mixing it with oil (1-10% wt) followed by a separation process in a water-filled vessel; the 1877 patent granted to Georg and Adolph Bessel (Germany) for a process involving the mixing of oil and graphite ore followed by boiling in water to produce a high grade graphite froth (>90% carbon); and the 1885 patent granted to Rebecca ‘Carrie’ Everson for the separation of sulphides by mixing sulphide ore with small quantities of oil, and adding water followed by sulphuric acid. These processes are more properly referred to as bulk oil flotation due to the relatively large quantity of hydrocarbon used.

Jan 1, 2019

By P. J. Morgan, E. Wolmarans

The selection of the main mineralised zone (MMZ) concentrator milling circuit has followed a comprehensive route over the preceding 10 years. Many knowledgeable parties have contributed and assisted in developing the milling circuit according to the best available information. The final selection of the flow sheet was completed after DRA conducted a techno-economic study on four possible comminution circuits ranging from conventional crushing and ball milling to fully autogenous (AG) milling. The results from all the above mentioned work indicated that it is possible to treat the MMZ ore at the desired throughputs to the desired grind sizes in a fully autogenous grinding circuit. The flow sheet was designed to treat the main mineralised zone (MMZ) arising’s from both underground and open cast operations and incorporates a fully autogenous grinding (AG) circuit. Commissioning of the 375ktpm concentrator at Nkomati Nickel began in August 2009 with the first ore reporting to the mill on the 15th of September 2009.

Jan 1, 2012

By F. K. McKean

THE task of establishing a new corrosion testing laboratory is more difficult than it need be because there is very little information on the subject available in the literature. Many articles describing tests and results may be found, but a wide search will unearth only passing remarks on the different types of equipment that may be selected for accelerated corrosion tests. An article describing some of the apparatus needed in a corrosion laboratory should be of help to those interested in building a new unit or in making additions to an old one. In May of this year, the writer was given the assignment of equipping a laboratory for general corrosion testing, to form a part of the new Physical Metallurgy Research Laboratories of the Department of Mines and Resource~ at Ottawa. With the help of senior members of the staff, along with what could be gathered from other sources, a list of necessary equipment was compiled and a plan for arranging it in the rooms was decided upon. Where possible, the apparatus was constructed in the excellent machine shops at the disposal of this Department, while the rest was placed on order with the manufacturers.

Jan 1, 1945

By Z. X. Cui, X. D. Ma, L. Contreras, X. Jiang

The bath smelting process is one of the key techniques applied in the current copper smelting production, which includes bottom-blown and side-blown furnaces differently from the direction of gas injection. Liquid matte and slag form the bath in the smelting furnace. To better understand the fluid dynamic of the bath and further optimise the operational efficiencies in the smelting furnace, physical simulation of the bath in the horizontal cylindrical reactor was investigated. The mixing behaviour and wave motion of the bath in the bottom-blown and side-blown furnaces have been studied systematically. The mixing time is reduced with increasing gas flowrate and height of the lower layer, while it increases significantly with increasing the height of the upper layer. The wave motion in the furnaces can be suppressed with the presence of the upper layer, but the bath with a lower density generates higher wave amplitude. Overall, in comparison to bottom-blown mixing, side-blown mixing shows better mixing efficiency and lower wave amplitude. In addition, the plume eye and splash phenomena occurred in the bottom-blown furnace have also been studied. INTRODUCTION The bath smelting process is one of the principal techniques used in the current copper making industry. The bath smelting techniques have some advantages of high smelting efficiencies, low capital costs, low energy consumptions and reduced dust generations. From the direction of gas injection, the bath smelting techniques can be classified into five general types: (1) top-submerged blown, e.g. Ausmelt and Isasmelt; (2) top-suspended blown, such as Mitsubishi smelting; (3) top direct-to-copper smelting, such as Outokumpu smelting; (4) submerged side-blown, such as Noranda and Teniente smelting; (5) bottom-blown, such as Dongying Fangyuan bottom-blown copper smelting furnace (Schlesinger et al., 2002; Zhao, Cui, & Wang, 2013; Perez-Tello et al., 2018). In many metallurgical processes involving bath smelting situations, the objectives of agitation are to accelerate the bath homogenization inside the bath which makes a significant contribution to process efficiency and product quality. Extensive mixing studies have been performed for ladle refining and tundish associated to steelmaking processes through water physical models. Mixing time is the parameter used to quantify the efficiency of mixing in the liquid bath and the first empirical equation predicting mixing time was proposed by Nakanishi, Fujii and Szekely (1975). Later on, more systematic studies have been carried out on ladle mixing and researchers realized that the geometry of the vessel could also have a significant impact on mixing (Khajaviand & Barati, 2010). However, the investigations using ladles which are vertical cylindrical vessels, cannot be directly used in the study of mixing behaviour in horizontal cylindrical reactors. Understanding the fluid dynamics inside horizontal cylindrical bath smelter is useful from the industrial perspective. Recently fluid dynamics of horizontal cylindrical smelter related to copper smelting have been studied by the authors’ group (Shui et al., 2015a, 2015b, 2018a; 2018b; Xu et al., 2018, 2019).

Jan 1, 2019

By Gonzalo Mato, Colin Godwin, G. Ditson

"The mid-Cretaceous Seagull batholith intruded Mississippian sedimentary and volcanic rocks and Jurassic(?) granitic and ultramafic rocks within the Omineca Crystalline Belt in the Yuk on Territory near the British Columbia boundary. Leucoerotic fluorine- and boron-rich granites of the batholith exhibit many textural variations from aplite to pegmatite, but are dominated by a coarse-grained seriate unit and a fine-grained porphyritic unit.Four distinctive tin vein occurrences within and near the batholith are described, the most interesting of which is the MC showing of quartz-calcite-chlorite-cassiterite veins in intensely fractured zones of sedimentary and volcanic rocks. Three other showings occur within the batholith:J) the EC showing of quartz-fluorite-cassiterite-sulphide veins with prominent muscovite-illite alteration;2) the DU showing of quartz-hematite-fluorite-sulphide- sulphide-cassiterite with considerable manganese staining and sericitic alteration; and3) the VAL showing of quartz-tourmaline-cassiterite-fluorite-arsenopyrite veins with little associated alteration.Most cassiterite occurrences are within easterly-trending, vertical structures and all occurrences are thought to represent parts of a single system. These mineralogical and physical variations are apparently related to the distance from the upper contact of the batholith.For the Seagull batholith, Rb-Sr isotopic data give a 100±1.4 Ma isochron age that is concordant with the K-Ar model age from biotite of 101±4 Ma. Initial Sr isotopic ratios for the batholith are high at 0.712, indicating an old, sialic crustal source for this pluton. This initial ratio is similar to values for granitic rocks associated with tungsten deposits in the Yukon Territory. The high initial ratio for Sr, the high Si02 content, the high s/I index, the presence of normative corundum. leucogranitic composition and associated lithophile-tungsten mineralization demonstrate that the Seagull batholith is probably an S-type granitic body. This factor is significant to regional exploration jar tin and tungsten in the Canadian Cordillera."

Jan 1, 1983

The cost benefits of controlling dilution of extracted ore have been very well understood by miners and mining professionals for many years. However, as we strive towards more mechanization, the dilution factor has been compromised in order to fit ?equipment? that is better suited to provide improved safety and productivity. Alternately, the drilling and ground support is accomplished by handheld drilling. In 2007, a short study, commissioned by CAMIRO (Canadian Mining Industry Research Organization) on the safety of hand held drilling vs. mechanized drilling, concluded that the risk of injury with handheld drills was seven times greater than with mechanized drills. Armed with this data, MEDATech Engineering proposed to the CAMIRO group to fund development of a ?MICRO Bolter?.

May 1, 2009

By R. Lovat, J. A. Hunter

"The design, development, and verification of the Lovat 7.6metre diameter full-face tunnel-boring machine is reviewed. Programmatic and technical challenges are outlined with a review of the specifications and the design to meet these requirements. Subsystem designs are presented for the waste material removal, ventilation, cutter head, structural support, advance technique, water removal, and interfaces with the Donkin-Morien Mine. The techniques used to verify that the design meets the requirements is by testing in the Lovat factory and in the field. Certification of the machine for use in a methane environment is discussed.IntroductionStudies have concluded that the average annual worldwide tunnel construction is 500 kilometres at an estimated average co st of $3,400 U.S . per linear metre. The total market value of the tunnelling industry is estimated as approximately $1.7 billion U.S. per annum. Of this, the current market for tunnelboring machine excavation is approximately $270 million U.S. per annum worldwide with a further potential of $250 million if more contractors are convinced that Tunnel-Boring Machines (TBM) are more suitable than conventional techniques. The worldwide civil tunnelling market has the potential to double each year in the next 5 to 15 years. Growth has been identified in the energy and mineral resources sectors of the economies of many nations and a significant volume of machine tunnelling studies and trials are presently underway for the extraction of coal, uranium , heavy oil or oil sand fuels, metallic and non-metallic industrial minerals and base metal or rare earth ores. Further tunnel projects for regional transportation, waterpower, irrigation , high density urban transportation, storm water sewers and water supply purposes are continually being implemented with new concepts like military security facilities and underground storage schemes being considered.Lo vat Tunnel Equipment of Rexdale, Ontario, the only Canadian manufacturer of TBMs was incorporated in 1973 to manufacture so ft ground tunnel-boring machines to satisfy this growing market demand. Lovat has produced an average of 5 machines per annum during the period 1972 - 1982 and has established an international reputation for competitive costs, quality of construction, after-sales service, and reliability. As of June 1982 Lovat TBM's have been used to tunnel over 240 km in projects throughout the world."

Jan 1, 1984

By J. Mizera, J. Zdunek, K. J. Kurzydlowski, A. Dobkowska

This work concerns comparison of corrosion resistance of the aircraft aluminum alloy composed of Al - 2.3%Li - 0.1% Zr. The alloy was hot rolled (HR) from 13 mm to a thickness of 4 mm (e = 2.4) and 1 mm (e = 5.2). Corrosion resistance was investigated by Potentiodynamic Polarization Test. The investigation relied on exposure samples in two different corroding medium: 0.5 M NaCl solution and 0.01 M Na2SO4 solution with added 0.01% of Cl- at room temperature. Furthermore, the microstructure was analyzed using the optical microscope with polarized beam. The hardness was measured on lengthwise profile. It was stated that alloy after the largest deformation (equivalent total strain e = 5.2) is characterized by the best mechanical properties and the best corrosion resistance. The alloys in initial state and after deformation to 4 mm (e = 2.4) are characterized by worse corrosion resistance. It is associated with microstructure and density of dislocation in analyzing material.

Jan 1, 2015

By K. R. Barnard, K. D. Marte, T. V. Gamarano

"The first commercial scale application of CSIRO’s direct solvent extraction (DSX) technology has been in operation at the Boleo project in Mexico since December, 2015. In this application, DSX is a synergistic solvent extraction system consisting of the extractants LIX 63 and Versatic 10 for recovery of cobalt and zinc from a solution background of manganese, magnesium, and calcium. Key operating parameters such as metal extraction, phase disengagement and extractant stability are summarized and discussed in this paper.INTRODUCTION Commissioning of the Boleo processing plant, located on Mexico’s Baja peninsula, began with the copper circuit starting in late 2014, with first copper cathode production achieved in January, 2015. The cobalt and zinc circuits began commissioning in December, 2015 with first zinc sulphate monohydrate (ZSM) and cobalt cathode production achieved in February and April, 2016 respectively. The Boleo project flow sheet and development has been described in detail in previous publications (Dreisinger, et al. 2005; Dreisinger, Baxter, & Molnar, 2006; Dreisinger, et al. 2008; Dreisinger, et al. 2009) and is summarized schematically in Figure 1. Boleo is a mixed oxide/sulphide Cu-Co-Zn-Mn high clay deposit that is processed in a whole ore, atmospheric, oxidative and reductive, sulphuric acid/seawater leach. Copper is recovered as cathode by conventional solvent extraction and electrowinning. Cobalt and zinc are recovered, from a solution background of manganese, magnesium, and calcium, by CSIRO’s synergistic solvent extraction technology Direct Solvent Extraction (DSX). Cobalt and zinc are bulk stripped from the DSX circuit and then further purified by phosphinic acid solvent extraction to produce zinc sulphate monohydrate granules via spray dried granulation and cobalt cathode rounds via divided cell electrowinning."

Jan 1, 2017

By Ross G. Bertinshaw

"The Line Creek Mine of Crows Nest Resources started mining coal in the fall of 1981. There are seven mineable seams with thicknesses ranging from 1.5 to 13 metres and with dips varying from 0 degrees to 60 degrees. This, together with internal partings and the very friable nature of the coal, creates a number of mining problems.The coal is divided into zones depending on the dip of the seam. Each zone requires a different mining technique to ensure optimum recovery and low dilution while still keeping fines to a minimum.Line Creek employs a combination of hydraulic front shovels and backhoes to mine its coal without blasting or use of dozers. This has been very successful in reducing the proportion of fine coal hauled to the plant, thus improving quality control and reducing costs in coal processing.There have been a number of other benefits from the use of excavators instead of more conventional methods. These include better selectivity, good cleanup, reduction in traffic at the face and lower cost.IntroductionThe Line Creek Mine is situated approximately 25 km north of Sparwood in southeastern British Columbia (Fig. I). Preproduction stripping began in J98J with the first coal shipments made in 1982. In 1983 the mine produced 2.1 million tonnes of raw coal.Similar to other East Kootenay coals, the seams at Line Creek are characterized by their friability, producing a large proportion of fine coal during mining. In an attempt to reduce these fines Crows Nest Resources has instituted the use of hydraulic excavators to mine and load the coal.Hydraulic excavators offer other substantial advantages over front-end loaders and dozers, which has been the conventional system in other mines in the area."

Jan 1, 1985

By Raymond D. Potts

"Minntac is a taconite mining, concentrating and pelletizing operation located near the town of Mountain Iron, Minnesota, U.S.A. It is totally owned and operated by USX Corporation and represents its largest source of domestic iron units. Minntac began producing fluxed pellets in 1988 and has produced both acid and fluxed pellets since then. This paper compares the acid and fluxed pellets produced at Minntac. It reviews modifications that have been made to the plant flowsheet and discusses areas recognized for improvement since the beginning of fluxed pellet production. It also comments briefly on the performance of Minntac fluxed pellets in USX blast furnaces and the future of fluxed pellets at Minntac.IntroductionMinntac was built in three steps with each step designed to produce 6 million long tons of acid pellets per year. The actual production has varied though. Figure I shows the production by year at Mirmtac. Step I began production in 1967, Step 2 in 1972 and Step 3 in 1978. Mirmtac produced 16.5 million tons in 1979 but only 3.5 million tons in 1982 when the facility was shut down for six months because of the lack of demand for pellets. Since the initial start up, Mirmtac has produced over 200 million long tons of pellets. Until 1987, all the pellets produced were ""acid"" pellets. In 1987, equipment to produce ""fluxed"" pellets was installed and tested. In 1988, full scale production of fluxed pellets began."

Jan 1, 1991

By E. Faria

"The Santa Rita mine is located in north eastern part of Bahia in Brazil and is owned and operated by Mirabela Mineração do Brasil Ltda. Typical SABC circuit was designed as the preferred option for the 4.0 mtpa (500tph) to produce a P80 of 125um for flotation. Although the SAG was originally designed to operate with conventional radial pulp lifters, later it was fitted with Outotec’s Turbo Pulp Lifters – TPL (Latchireddi, 2005). The milling circuit commenced commissioning on the 24th of October 2009 and the milling circuit achieved the nameplate capacity within days. with small and relatively simple measures to rectify. Since commissioning, the SAG mill has been working in fully autogenous grinding (FAG) mode with no balls (in contrast to the estimated 10% ball charge) and has been consistently treated up to 650tph.This paper examines the comminution design process, the operating philosophies, start-up experiences, post commissioning optimization and future development works. An evaluation of mill performance relative to the design criteria for the project life to date is also included."

Jan 1, 2012

By M. Saghaeian, R. Hejazi, Sheikhzadeh. V., A. Abazarpoor

"The morphology of iron ore concentrate particles is known to influence several properties of iron ore pellets, including drop number, compression strength, and reduction properties. This study aimed to determine why grinding methods and particle morphology influence green pellet properties. Particle morphology can be directly related to the grinding method: ball mill (BM) or high pressure grinding roll (HPGR). In this research, two iron ore concentrates, namely Gol-e-gohar and Ardakan, were ground by a BM and HPGR to produce a suitable Blaine value for pelletizing (nearly 1,900 cm2/g). Morphological features of particles were subsequently investigated by sieving and cyclone sizing for particle size distribution, the Brunauer-Emmett-Teller (BET) and Blaine methods for specific surface area (SSA) and scanning electron microscopy (SEM) for the evaluation of shape descriptors. It was concluded that HPGR resulted in generating a greater proportion of fine particles compared to ball milling. The BET results showed that the SSA of HPGR pellet feed was higher than that from the BM due to a greater proportion of cracks, indents and bulges and the creation of new fracture surfaces. SEM images processed by ImageJ software indicated that particles ground by the BM tended to be more rounded and less elongated than HPGR particles because of the breakage model of each method. To show the effect of morphology on the green pellet quality, green pelletizing was performed in a pilot pelletizing disc. The HPGR pellet feed had a higher drop number in comparison to the BM pellet feed, due to the angular and rough shape of the particles.INTRODUCTIONThe demand for fine or ultra-fine particles as feed material for ceramics, composite materials, and mineral processing is on the rise (Kotake, Kuboki, Kiya, & Kanda, 2011). The final concentrate of iron ore processing plants (filter cake) has a size range roughly between 0 and 300 µm, depending on the liberation of Fe containing particles (Meyer, 1980). In general, to produce a suitable pellet feed of appropriate quality, Blaine numbers of 1800–2000 cm2/g should be achieved (Van der meer, 2015)."

Jan 1, 2016

By Garston Blackwell

Abstract - During geostatistical estimation of block grades, the kriging process produces a measure of error, the kriging variance or the kriging standard deviation. Estimation of the block error depends on the semi-variogram model for a deposit, which reflects fundamental characteristics of a deposit such as (1) nugget effect, (2) range of influence of grades, (3) different local spreads of data as a function of average grade (proportional effect), (4) nested structures, and (5) underlying anisotropies in the data; this model may be affected by sampling or assaying limitations, however. Because the kriging error incorporates so many features of both the deposit and data to be used for estimation, it may offer a substantial improvement on block classification over traditional procedures such as data density. Practice indicates that the relative kriging standard deviation (RKSD) is particularly useful for block classification in measured, indicated and inferred categories. Plots of RKSD in plan and section also can be used to demonstrate where extra drilling and sampling would be most advantageous for upgrading the class of some blocks. Moreover, the use of grade and RKSD filters can show where material near cut-off grade is poorly defined, indicating sampling target areas to improve block classification in the vicinity of the ore-waste boundary.

Jan 1, 1998