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By Long Han, A. V. Kalinin, Xiujian Luo, Xiaobo Wang, Xiaoou Xia

"Inertia vibration crusher is a kind of vibration equipment which crushes ore by vibration. When the inertia vibration crusher works, ore between the two moving jaws is subjected to the high frequency contact force, which is produced by the two moving jaws with high frequency synchronous reciprocating motion. The synchronous motion of the two moving jaws depends on the self-synchronous feature of the inertia vibration crusher. To study the self-synchronous feature of the equipment, the dynamic model was established, in which relative parameters were taken into consideration. The kinematic coupling relations of the assemblies are discussed, and appropriate calculation method is chosen to solve the vibrating differential equation. Whether the two vibration exciter can realize synchronous operation depends on the ability of the vibration system's capture moment. Results show that though the two rotors’ motors and damping coefficients are different, and two jaws’ damping and stiffness coefficients are also different, as angular velocities of the two unbalanced rotors reach a certain value, the vibrating system can be stable. Their angular velocities tend to be equal, and the swings of the two moving jaws can be the same. The horizontal vibration and swing of the frame are large in a few seconds after starting the machine. When the system runs stably, the horizontal vibration and swing vanish, and the vertical vibration is stable. The study and its results can provide reference for the optimization design and parameter setting of inertia vibration crusher and related vibratory equipments.INTRODUCTIONMaterials can be easily broken by using the inertia force of the vibration exciter, which can effectively realize the selective crushing, reducing excessive combinations and the energy consumption, as introduced by Zhang in 2005. The initial micro crack between crystals in the material increases and new cracks can be manufactured because of the high frequency impact and the extrusion of the vibration crusher, so vibration crushing equipment can make it possible for any high strength brittle material to be broken theoretically. Inertia cone crusher and inertia vibration crusher have been successfully used in the treatment of metallurgical slag and construction waste, and it verifies the efficiency of vibration crushing."

Jan 1, 2016

By A. Supomo, H. Resendiz, C. Burbidge

"Freeport-McMoRan Inc. (FMI) commissioned the expansion of the Morenci Metcalf concentrator in 2014. The concentrator included many design and equipment innovations, including the first-of-its-kind Metso Hydraulic Roll Crusher (HRC), variable speed ball mills and variable speed crushers. In addition to the innovative design, FMI commissioned the Metso APC team to design a realistic process simulator and the plant APC. The process simulator was utilized to train operators before commissioning, which led to a smoother plant start up. The plant APC utilized the concept of dynamic constraint control, which controls the feed to the primary ball mills by “pulling” the tons from crushed rock storage bins, which then automatically are filled by the upstream HRC and secondary crushing circuits. The primary ball-mill control also adjusts the water addition to the cyclone clusters to avoid overload and achieve sufficient grind size. The constraints include in-circuit constraints for feeder capacity, screen-deck capacity, ball mill power, cyclone mass flow, pump capacity and pump motor capacity. The APC system was implemented shortly after the start of commissioning and immediately demonstrated increased throughput and an ability to highlight and quantify process constraints and bottlenecks. The following paper outlines the control strategy, discusses system implementation, results and challenges.INTRODUCTION The FMI Metcalf Concentrator is located in Morenci Arizona on the site of the old original Concentrator. The new Metcalf concentrator started operation in May of 2014. This plant was designed for an average of 63,500 tpd (70,000 stpd), increasing the total Morenci concentrator complex production to a nominal 113,400 tpd (125,000 stpd). The process flow diagram is shown below in Figure 1.The process consists of primary crushing feeding a coarse ore stockpile followed by secondary crushing operating in closed circuit with vibrating screen decks. The screen undersize feeds the first of its kind Metso hydraulic roll crusher (HRC) operating in a closed circuit with vibrating screens. The primary crusher is a Metso 60x110 gyratory crusher. Secondary crushers are Metso MP1250 Crushers with variable speed drives. Secondary crusher discharge is recycled to the dry screen feed bin and screened with oversize returning to secondary crushing and undersize feeding the Metso HRC3000. The product from the 3.0 meter X 2.0 meter roll crusher is wet screened with the undersize feeding the grinding circuit, which is comprised of two each 24-foot diameter by 40- foot-long variable speed ball mills running in parallel with each in closed circuit with a cyclone bank of 12 cyclones. The wet screen oversize is recycled to the HRC feed bin."

Jan 1, 2019

By M. Bueno

Between 1993 and 2003, a series of AG and SAG mill pilot plant trials were conducted using Hardinge Ical pilot plant scale SAG mills on numerous ore samples and ranging across a wide variety of operating conditions. The data from these tests were used to evaluate the design of SAG and AG mill circuits for over a dozen projects, of which about half were eventually constructed and commissioned. The data were also used in the development of SAG mill modelling, scale-up and simulation procedures by several consultants who had access to part of the data set. Recently, we have had the opportunity to bring this data together and further analyse the consolidated dataset. This paper reports on the outcomes of this analysis that has identified the impacts of different AG/SAG circuit flowsheets and operating conditions on energy efficiency and operating cost.

Jan 1, 2012

By H. M. Woodrooffe

This paper deals with the laboratory facilities at the Mines Branch for carrying out research in the industrial minerals field, and also reviews current programs in ceramics and construction materials, in non-metallic minerals and in the milling of industrial minerals. It then discusses the application of these pro-grams to industrial problems.

Jan 1, 1967

By Chelto. D. Smith

With the pressure on mine and metallurgical managers to take accountability for responsible corporate governance in their operational area, it is no longer acceptable to rely on central departments in the organization to manage safety, health and environmental impacts of the company?s processes. Environmental impacts exist because of the production or mining process. Some of the inputs to the process are natural resources and some of the outputs of the process are the inputs to the environmental control equipment, plant and the environment itself. Environmental management therefore needs to be incorporated in production management to effectively control and reduce the impacts. Many aspects of environmental management are identical to production management and the systems to manage them will likewise be very similar. By examining key components of these two management systems a decision can be made whether environmental management and production management are structurally similar and can be integrated into a combined IT solution.

May 1, 2009

By T. W. Cavers

The Dwight-Lloyd sintering machine was the answer to the flue-dust problem of the copper blast-furnace smelter. Then came concentration by flotation, which threatened to eliminate the blast furnace from the smelting field altogether, and again the sintering process solved the problem. As is well known, the sintering process is dual in its function; it expels sulphur from the charge and it converts a powdery material into nodules or chunks that hold together. The charge is ignited on top just as it passes over the edge of the first suction box, and the oxygen of the air that is drawn downward through the charge breaks up the sulphide and oxidizes about fifty percent of the sulphur. The heat produced by this reaction in the upper stratum of the charge ignites that lying immediately below, and, when the pallett has travelled the full length of the machine, the tire has reached the graces and the fine concentrate has changed its characteristics by being partially fused and has become a more or less solid mass. When the Granby Company was smelting its ore as mined, one small D-L machine was adequate for the treatment of the flue dust, but as soon as the policy of smelting the concentrate was adopted, it became necessary to add two large machines to the sintering plant. The three sintering units, of which two are 42 in. by 396 in. and the other 42 in . by 264 in. in hearth area, have a combined capacity of from 370 to 450 tons (dry) of charge per day. The capacity varies directly as the hearth area. The sinter produced is about 88 per cent of the dry charge, or 325 to 400 tons per day. The sintered fines returned for resintering average between 30 and 35 per cent of the charge, but this is not as great a disadvantage as might appear, since the addition of hot fines improves the burning qualities of the mixture. From 50 to 54 per cent of the sulphur is eliminated in the sintering operation.

Jan 1, 1934

By W. Dan Hausel

"Hundreds of diamonds have been found in the United States. The majority of the discoveries occurred during the 19th century as a by-product of placer gold mining. Most of these early diamond finds have no known source, and in many cases are situated in areas unfavorable for diamond exploration based on current models that require kimberlite or lamproite to be emplaced in a stable Archean craton or Proterozoic craton margin.Diamonds have also been recovered in situ from lamproite at Murfreesburo, Arkansas, from kimberlite in the Lake Ellen region of Michigan, and in several kimberlites in the Colorado–Wyoming State Line district. Unverifed reports also suggest that diamonds may have been recovered from other related intrusions at a number of localities in the United States.IntroductionTo date, diamonds have been recovered in situ from kimberlite in the Colorado–Wyoming State Line district and from a kimberlite in Michigan. Additionally, diamonds have been recovered from lamproites in Arkansas. Diamonds have also been reported from kimberlite in Kansas, and from peridotite in New York and Maryland. However, these latter reports have not been verified."

Jan 1, 1995

By G. E. Wood

THE INSTABILITY of copper prices and their low levels since late 1974 are of great concern to both producers and, to a lesser degree, consumers of copper. The price levels portrayed by the "neutral long-term" price trend are assumed to have been enough to encourage sufficient investment to provide adequate world production capacity and yet not so high as to encourage development of excessive over capacity. The identification of the present level of this trend has taken on special importance for governments and for corporations active in the world copper industry. One approach to the possible determination of such a price is through the use of moving averages. In this way, the effects of relatively short-term price movements can be dampened, as can those related to business cycles. From such averaged price data, long-term trends can be sought over a selected time period. The choice of the past time period for which a price trend is sought may have a major effect on the result'. For example, in the period 1885-1973, the long-term price trend for copper in constant dollars showed a decline, whereas in the period 1919-1973 it was rising. For the purposes of discussion, an appropriate choice of period might be a relatively short and recent one so that the majority of the present cost factors would be present throughout. It should also be long enough to cover a number of full business cycles.

Jan 1, 1977

By L. E. Djingheuzian

"ForewordTHE FOLLOWING excerpt is taken from Fine Grinding Investigations at Lake Shore Mines (C.I.M., Trans., Vol. XLIII, 1940, p. 307):""MacCalman, who has carried out exhaustive testing on the accuracy of screen analysis, makes the following statement in his report, The Accuracy of Sieving Tests, Industrial Chemistry (London, England), Vol. XIV, p. 231:"" 'It will be shown that, as no specific relationship between the sieving value and the various dimensional features of the sieve is evident, though there is an apparent tendency for the sieving value to follow the average aperture size, it is apparently impossible to define the sieving value of a screen from dimensions alone, and the calibration of sieves for important tests on a specific material, whereby the sieving values of these sieves are related to that of an arbitrarily chosen master sieve by correction values, will be recommended."" 'It will be emphasized that these correction values are probably not applicable to other materials, or the same material of different size composition. Sieve users, for important tests or in cases of dispute, will be recommended to calibrate their sieves against a mutually acceptable standard with specified conditions of test, and to recalibrate at intervals' ""."

Jan 1, 1953

By A. Darragh

"Past Growth The Canadian coal industry has grown rapidly during the past two decades. Coal production increased over four-fold between 1965 and 1982; consumption almost doubled, imports remained relatively flat, exports soared and total demand increased nearly two and a half times. Coal production grew during this period at an average rate of 8.60/o, compounded annually; this remarkable performance is shown in Table 1 and Figure 1. The relationship between production and consumption is shown in Figure 1, where in 1981 the total Canadian production of coal for the first time exceeded total Canadian consumption. ln Figure 2, the relationship between imports from the United States and Canadian coal exports is shown; in_ 1981 again for the first time, exports offshore exceeded imports into Canada. The rapid growth in Canadian coal use between 1965 and 1982 followed a major decline after World War II, as the country moved rapidly to an oil based economy. Changes in consumption patterns between 1945 and 1982 are shown ~n Table 2. Railway consumption of coal was reduced to zero m the early 1960s. The industrial and domestic consumers market share fell from about 660/o in 1960 to 6.70/o in 1975; this share, however, appears to have stabilized in recent years and actual volumes can be expected to increase in the future. The steel industry's share of the coal market fell over the same period, but the volume in recent years has remained fairly constant at about seven megatonnes per year.Perhaps the most significant change in consumption is in the share of coal consumed in the generation of electricity; this has increased from 80/o in 1960 to over three quarters of the total Canadian coal consumed in 1982. This increase in thermal coal consumption has been supplied by indigenous coal, and was accompanied by a decreasing share for coal imported from the U.S.A. into central Canada. It is expected, because of the nuclear power commitment in Ontario, that this share will continue to decrease, although the total volume of coal imported may increase slowly over time. This will likely also have a dampening effect on future coal sales to Ontario from western Canada."

Jan 1, 1985

By J. Kramer, T. Hartmann

In the Hydrometallurgical processes, the presence of the so-called “crud” is a constant challenge in solvent extraction. Crud is a stable emulsion which forms along the interface between the aqueous and organic phase. The spread is influenced by the following parameters: first, wind blows the dust and impurities into the open sedimentation tanks. Second, the undissolved solids such as sand transported in the PLS causing problems in conjunction with incorrect agitator design. The crud fraction can decisively impact the efficiency of the hydrometallurgical extraction because the phase interface can constitute a large fraction and the sedimentation tanks cannot react flexibly to it. In the downstream process of the seriesconnected sedimentation tanks, they are thus all contaminated with crud. At the same time, the necessary mass transport is significantly impeded at the phase boundary between organic phase and aqueous phase due to the crud formation. The transfer of the organic phase into the electrolysis cell can result in a “burnout” of the cathode. The carry-over of this electrolyte into the extraction can cause problems with the pH regulation. The carry-over of the organic components into the raffinate also leads to contamination of the leaching circuit. The continuous treatment of the crud with a 3-phase decanter centrifuge is extremely effective in combating this problem. This technology splits all three phases from each other and they are consequently continuously separated. All subsequent process steps exhibit a stable, uniform effectiveness. The main advantage for the customer is that fluctuations in the process are eliminated and the organic phase can be recirculated back to the extraction. The recycling of the solvent alone justifies the investment in less than 6 months as examples from South Africa and Chile show. To operate solvent recovery in daily operation fully automated online at the optimum limit, the decanter centrifuge is equipped with a concentration-dependent pond adjustment called DControl®. By this means, we can guarantee our customers the maximum possible solvent recovery and minimise the solvent costs in this process step. This system is presented in detail in this paper.

Jan 1, 2012

By Peter Hayes, Evgueni Jak, Taufiq Hidayat, David Grimsey, Denis Shishin

"An integrated nickel flash smelter is operated with Peirce-Smith converters at the Kalgoorlie Nickel Smelter. To improve the partitioning of arsenic between slag waste and matte product, an option to modify the slag–matte chemistry by addition of CaO was analysed. A combination of plant sample analysis, high-temperature laboratory experiments and thermodynamic modeling was carried out to evaluate the process options. The high-temperature experiments involved the re-equilibration of industrial matte-slag samples at 1225 °C and P(SO2) = 0.12 atm, rapid quenching in water, and direct measurement of phase compositions using electron probe X-ray microanalysis (EPMA) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LAICPMS). A private thermodynamic database for nickel sulfide smelting and converting was used together with the FactSage thermochemical software package to assist in the analysis of the distribution of elements between slag and matte as a function of CaO addition. The thermodynamic predictions combined with experimental data obtained in this study can be used to characterise the effect of CaO fluxing on the slag–matte thermochemistry during the nickel sulfide converting.INTRODUCTION At the Kalgoorlie Nickel Smelter (KNS), nickel sulfide concentrate is processed in an Outotec-type flash furnace to produce nickel matte containing +47 wt% Ni. Separation of nickel matte and waste slag from the flash smelting is enhanced through settling in the electric arc -heated zone attached to the flash furnace. The flash furnace matte is further processed in a Peirce-Smith converter to produce Ni-rich matte containing +66 wt% Ni (Crundwell, Moats, Ramachandran, Robinson, & Davenport, 2011). Iron silicate-based slag is used in the converting process at KNS. Most of the arsenic is contained in the final matte and very little of the arsenic partitions into the slag. Previous work by Font et al (Font, Hino, & Itagaki, 2003) shows that the distribution ratio of arsenic between calcium ferrite slag and nickel-matte (LAsslag/matte) is significantly higher than that between iron silicate slag and nickel-matte, where LAsslag/matte = (wt pct As in slag)/{wt pct As in matte} (1)"

Jan 1, 2017

By S. Balideh

A good understanding of the behavior of broken rock helps to make more informed decisions regarding slope stability and waste dump issues in mines. The cohesion coefficient of rock has little influence on the strength of broken rock; therefore, a criterion based on friction and cohesion of intact materials does not provide an accurate analysis for the strength of broken rock. This paper illustrates the effective strength of broken rock through a brief literature review about failure of intact rock and rock masses. The complete stress- strain curve and some important points of residual strength of rock are summarized in this paper.

Jun 1, 2012

By Navid Bahrani

The grain-based model (GBM) has resolved the difficulty of matching both the directtension (sc) and unconfined-compressive (st strengths of typical brittle rock by providing a synthetic material that mimics deformable, breakable polygonal grains cemented along their adjoining sides with deformable, breakable interfaces modeled as smooth-joint contacts. In this paper, a GBM utilizing a parallel-bonded base material is calibrated to match both st and sc of Lac du Bonnet granite and then used to simulate a Brazilian test. The Brazilian strength (sB) is slightly overestimated and the failure mode includes ductile post-peak response that is not representative of what occurs in laboratory Brazilian tests. By reducing the grain tensile strength, grain failure occurs during the Brazilian test and a more realistic failure mode that includes brittle post-peak response is obtained. However, the unconfinedcompressive strength of the modified material is too low. Sensitivity analysis on the grain and grainboundary strength properties demonstrates that the grain tensile strength controls the sB/sc ratio. Because the grain strength is controlled by the parallel-bond properties and the lowest achievable st/sc ratio in a parallel-bonded material is ~0.25, it is concluded thatsc, st and sB for a typical brittle rock cannot be matched with a GBM that utilizes a parallel-bonded base material.

Jun 1, 2012

"ALTHOUGH Canadian metallurgists have long been active in research, the scope of the work was somewhat limited until the be-ginning -of World War II. The rapid industrial development of Canada during the past ten years has been accompanied by .a similar upsurge in research. However, the wide geographical distribution of the research centres has made it difficult for the individual research workers to meet together and to exchange ideas or even to learn what projects .are being investigated or the nature and extent of the facilities available for work of this kind.The purpose of the present symposium is to assemble data relating to projects under investigation and the facilities employed at the various metallurgical research laboratories in Canada, thus providing some measure of correlation so that workers in different locations may learn what kind of work •is being .done at other points throughout the country.In reporting the symposium it has not been possible to reproduce the papers in full, but excerpts have been selected that give the essentia1 data."

Jan 1, 1952

By Veerendra Singh, Y. Rama Murthy, Sunil Kumar Tripathy, Nikkam Suresh

"High intensity dry magnetic separation is commonly employed to separate different para-magnetic minerals including mineral sand. Separation in these separators is majorly influenced by the combined effect of gravity, centrifugal and magnetic forces on a particle. These separators are included in the process flow-sheets either for pre-concentration purposes or for the beneficiation of paramagnetic minerals. Separation in these separators is majorly influenced by the difference in the magnetic susceptibility of the associated minerals, particle size and shape along with the process variables of the machine. Particle size is one of the major parameter that plays an important role and decides its probability of selectivity under the magnetic field. However, effect of particle size on the performance of these separators are not well understood which is evident from the literature.In the present investigation, an effort is made to bring out the effect of particle size on particle separation in an induced roll magnetic separator while treating ilmenite fines. Effects of operating parameters, such as; magnetic field intensity, roll speed, feed rate and splitter position have been studied and their influence on particle size has been analysed in terms of yield (wt.%) to magnetic product, particle size distribution characteristics in terms of D50 and D80 size, skewness, kurtosis. Also, the particle size distribution of each test was fitted in Rosin-Rammler equation. The test results were analysed statistically to understand and quantify the influence of each variable on particle separation. It is found that, rotor speed of the separator had maximum influence on yield to the magnetic product whereas splitter position had major influence on D50 and D80 (µm) size of the product."

Jan 1, 2016

By Barry J. Morash

The over-all slope angle of between 55 and 60 degrees at the Adams Mine necessitates control blasting on the final pit walls. The control blasting techniques used are pre-shearing and buffer blasting. Pre-shearing with 2'I2-inch holes on 5-foot centers is used in areas where jointing and rock type are not conducive to smooth stable walls. Buffer blasting with 12'/4-inch holes is used in areas where the rock is competent. Control blasting adds to the operating costs, but can result in substantial savings in increased slope angle and reduced stripping.

Jan 1, 1978

By G. V. Poropat

Roughness of a discontinuity may be an important factor influencing shear strength of the discontinuity. Traditionally, determining the roughness of a discontinuity surface and providing a numerical measure of the roughness has required considerable effort or specialised equipment. The development of new 3D imaging tools that are easy to use has provided effective fast and accurate means of creating 3D surface models from which roughness measurements can be readily obtained. These new techniques are versatile enabling a user to measure roughness along any desired profile and at any resolution up to the limit of the spatial subtense of a measurement on the discontinuity surface. This paper primarily reviews extensions to the use of 3D imaging that enable the measurement of roughness. Additionally we provide some examples of the measurements and examine some of the issues associated with extracting measures from the spatial data that will support estimation of shear strength.

May 1, 2009

By Shigeomi Nishigaki

This paper presents quantitative indexes to evaluate operator?s bearing, difficulty in a task, and machine operability when an operator remotely controls a backhoe, and reports the use cases. The quantitative indexes would give her/him the opportunity to reflect on her/his works, and enable us to gain in-depth insight into the teleoperation, and furthermore give us with promising hints to improve it.

Aug 1, 2013

By A. Vervoort

The concepts of geostatistics are commonly difficult to understand for students, even for those with a strong mathematical background. A main problem is certainly the link between the variation of the parameter value in space or time, and the calculated experimental semivariogram as a function of the interdistance, but over the entire area. Another problem is to differentiate between directional and omnidirectional semivariograms and the way they have to be interpreted. Furthermore first time users of geostatistics often do not want to struggle through different books with the whole geostatistical background before using it. Too often this leads to using geostatistics as a black box with all the risks linked to it. That is the main reason that we developed some interactive tools based on the free public domain software R. We aim by developing three different modules to assist individual first time users, but also regular students and teachers to get a feeling of the importance of the various aspects in conducting a good geostatistical study. The modules show directly e.g. the impact of deleting, moving or adding data points, of changing parameters of the semivariogram model and of the geometrical parameters during kriging. The first module allows making the link between the variation of the parameter values in one direction and the calculated experimental semivariogram, and this for different given datasets. The second module covers two dimensional datasets and apart from calculating the semivariogram values, models can be fitted to the calculated data. A distinction can be made between omni-directional and directional semivariograms, including the effect of the tolerance on the angle and lag-distance. The third module focuses on ordinary kriging of point values in two dimensions. The aim of the interactive tools developed is limited to educational purposes only, i.e. to visualize some basic concepts for different pre-selected types of spatial variation. They do not intend to do a geostatistical study on a certain dataset (for this purpose there exists already a broad spectrum of good software packages). The original intention of developing the three modules was aimed at users with no or a limited amount of geostatistical experience. However, these modules seem also very useful to remain critical for experienced users. One should never forget that in a real application one does not have a complete view of the phenomenon studied. The geostatistical interactive modules can be accessed through: www.bwk.kuleuven.be/geostatistics . We compiled a manual to facilitate the use of the modules and to guide the user we formulated several questions to be solved for each module.

Aug 1, 2013