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By R. P. Taylor

"This paper covers the development of the property to its present production level of20,000 tonnes per day from the Valley Mine. It will also review the analysis of various case studies for the expansion of the project to its full potential, and discuss the impact of the recent structural change in the copper market on the development of a large low-grade deposit such as Valley.IntroductionIn 1964 Cominco participated, along with a number of other companies and individuals, in the formation of Valley Copper Mines Ltd. This company was formed in order to facilitate exploration on a large number of mineral claims held by these parties in British Columbia's Highland Valley, approximately 400 km northeast of Vancouver (Fig. I). Cominco 's ownership of Valley Copper was gradually increased over the years bot h through shares gained for exploration expenditures and through shares purchased on the open market. By the mid- 1970sCominco' s interest in Valley Copper exceeded 80%.ExplorationExploration from 1964 to 1969 led to the discovery of a massive porphyry copper depo sit now known as the Valley orebody. A claim boundary divided the deposit with 80% of it on Valley Copper claims and 20070 on claims held by Bethlehem Copper which was already mining adjacent copper orebodies. During the period when the Valley ore body was discovered, exploration by other companies resulted in the discovery of the large Lornex and Highrnont deposits nearby. The stage was now set for the Highland Valley to become an important copper-producing area (Fig. 2)."

Jan 1, 1986

The Coal Resources Survey commenced in 1974 as a search for Huntly Power Station coal, but soon developed into the most detailed regional coal search programme to be instituted in New Zealand. The program was initially conceived as geological in nature, but later included geotechnical, geohydrological, mining assessment, coal use, and environmental considerations in its investigations. The programme never undertook development work but has provided Government and the private sector with a sound basis for identifying development options. The discovery of large-scale coal resources in the Mokau, Waikato, and Taranaki regions and the lignite resources of Otago and Southland are a measure of the Survey's success. The directive by Government to phase out the NZCRS to a large extent coincides with the completion stage of the program. With most of the detailed regional study finished, it now remains to collate the data and publish summary reports at Coalfield and Coal Region level, in order to maximise the use and value of the data collected over the years.

Jan 1, 1987

By C. G. McLachlan

ONE phase of the treatment in sulphide flotation, covered generally in a review of pulp pretreat-ment by S. A. Falconer,' is the matter of grinding mills as conditioners, a subject on which further study could be advantageous. Flotation with few exceptions is preceded by grinding, and the grinding and flotation capacity required for the treatment of an ore is based generally on laboratory or pilot mill tests. The results of such tests, it then is assumed, will be duplicated in practice, and a flowsheet is prepared on that basis. This assumption may be too broad, because in several instances laboratory flotation tests made on massive sulphide copper ores could not be duplicated in plant operation without the introduction of an aeration step, either in closed circuit with the grind-inging mills, or between grinding and flotation.~' " The differences between laboratory and plant grinding practice are considerable, and may be summarized as follows: 1—In the laboratory a relatively fine charge is ground in a batch mill. In the plant, the feed, usually considerably coarser than the ore tested in the laboratory, enters the grinding mill continuously and more often than not, oversize material in the mill discharge is retained in the grinding circuit by a classifier until the required degree of reduction has been effected. 2—The rate of grinding in the laboratory is slower than in plant practice. 3—The percentage of volume occupied by the pulp in a laboratory mill rarely approaches that of a continuous overflow type mill. This does not apply if the comparison is made with grate type mills, but in that case an even wider discrepancy between the relative rates of laboratory and mill grinding almost invariably exists. The present trend in grinding is toward larger mills to reduce the number of operating units. This accentuates the foregoing differences. It is believed that the trend toward larger mills is sound, but that when large mills are used, metallurgists should check their flotation circuits carefully to determine whether laboratory tests are being reproduced in

Jan 1, 1952

By Débora Cardoso de Oliveira Silveira, Jean-Christophe Huber, Hamzeh Hamadeh, Kateryna Pastel, Guillaume Brosse

The dynamic behavior of oxygen gas flow, determined by the lance nozzle and blow pattern, is a key factor for determining jet efficiency in BOF Steelmaking. The present work compares the performances of Laval and parabolic nozzles with the aid of the Computational Fluid Dynamics (CFD). The Method of Characteristics (MOC) was applied to design a minimum length parabolic nozzle. The results show that the parabolic nozzle generates more uniform and stable jet, with 2% longer potential core and supersonic length and less shock waves. For the parabolic nozzle, the pressure nearby the nozzle wall is higher, which can protect this region from reverse flow of converter gases and offer longer life for the lance tip. Likewise, the flow rate variations would affect less this nozzle. In addition, the nozzle wear was investigated, and the parabolic nozzle has proven relatively less sensitivity to the presence of this deformity.

Oct 1, 2019

By Thomas M. Barczak

With the development of the shield support, the primary requirement for successful ground control in longwall mining is to provide stable gate road and bleeder entries. Wood cribbing has been the dominant form of secondary support. However, the cost and limited availability of timber, along with the poor performance of softwood crib supports, has forced western U.S. mines to explore the utilization of other support systems. The recent success of cable bolts has engendered much interest from western operators. Several innovative freestanding support systems have been developed recently including: (1) "The Can"' support by Burrell Mining Products International, Inc., (2) Hercules and Link-N-Lock wood cribs and Propsetter by Strata Products (USA) Inc., (3) Variable Yielding Crib and Power Crib supports by Mountainland Support Systems, (4) the Confined Core Crib developed by Southern Utah Fuels Corporation; and (5) the MEGA prop by MBK Hydraulik. This paper assesses design considerations and compares the performance and application of these alternative secondary support systems.

Jan 1, 1996

By Ren G. Dong, Kristine M. Krajnak, Dan Welcome

Continual occupational exposure to vibrating hand tools can damage the neural, vascular and other soft tissues of the fingers. Rat tail models have been developed to investigate the biological responses of the tissues to vibration.1-2 However, the biodynamic response of the tail relative to that of the human fingers has not been characterized. The objective of this pilot study was to compare the transmissibilities of rat tails measured via a scanning laser vibrometer to those of human fingers gripping a handle. Methods In Part I of this experiment, four male Sprague Dawley rats (6 weeks old) were exposed to discrete 5g-rms sinusoids of 32, 63, 125, 160, 250, and 500 Hz. The rats were restrained in Broome-style restrainers with their tails constrained without compression to an exposure platform via elastic straps as shown in Figure 1. The platform was attached to a vertically vibrating shaker. The vibration was measured for the array of points shown in Figure 1 using a scanning laser vibrometer (Polytec) and the transmissibility calculated for each point on the tail relative to the reference points on the platform. In Part II, three male human subjects were exposed at the frequencies specified in Part I - with the addition of 1000 Hz - at a magnitude at the ANSI <0.5-hr limit up to 63 Hz, after which the acceleration was held constant at 5g-rms. The subjects gripped an instrumented handle at 20 N as shown in Figure 2. The transmissibility was calculated relative to the reference points on the handle. [ ]

Jan 6, 2006

By Jack Eloranta

"This paper compares energy requirements for blasting, crushing and grinding. By tracking electricalconsumption for various powder factors, a general trend has appeared. This study involved over 100million tons of ore and powder factors ranging from .5 lbs/L,T to .8 lb&T. Actual energy usage iscompared to predicted energy based on the Bond equation."

Jan 1, 1998

By Mike Adams

Comprehensive pilot testwork has been conducted on BHP Billiton&apos;s Ravensthorpe nickel laterite deposit over a fifteen-month period at Lakefield Oretest. Some 228 tonnes of ore were processed in a beneficiation pilot-plant comprising scrubbing, attrition scrubbing, screening and thickening over sixteen pilot runs with an average mass closure of 99.2%. This produced a suitable feed for hydrometallurgical piloting over seven runs covering 1,680 hours of operation. The integrated EPAL® (enhanced pressure acid leach) circuit comprised a limonite pressure acid leach front end discharging into a saprolite atmospheric leach circuit and subsequently to induced jarosite precipitation, counter-current decantation, iron removal, mixed hydroxide precipitation, and manganese removal. The pilot plant met its key objectives in demonstrating the flowsheet&apos;s technical viability, and generating raw data inputs for the project feasibility study. Rapid, intensive data capture, collation and reporting helped solve key flowsheet issues. The pilot plant also demonstrated its value as a risk management tool in the resolution of numerous engineering, metallurgical and materials selection issues at a manageable scale. A disciplined approach to experimental planning, operation and management was a significant contributor to the overall success of the campaign. Keywords: Ravensthorpe, Nickel, Piloting, Beneficiation, Pressure, Leach

Jan 1, 2004

By Carlos Fonseca, Gustavo Usero, Roberto Mentzingen Rolo, Gabriel Moreira, Octavio Rosa de Almeida Guimarães

Geological domain modeling is an important step in mineral resources evaluation. The procedure can be laborious and time-consuming, especially in multivariate settings. However, estimates are significantly improved when carefully limited by geological variables. This paper proposes a workflow for geological domain modeling suited for stratigraphic deposits. The workflow consists in automatically defining the domains by using clustering algorithms, generating the surfaces that represent the contacts by interpolation and subsequent triangulation, and simulating the surfaces. The proposed workflow produces consistent and realistic results and allows the user to test different domain configurations and assess volumetric uncertainty automatically and quickly.

Jun 25, 2023

By Belcher C. B

A simple gravimetric procedure was developed for the rapid determination of carbon dioxide in coal mine roadway dust samples and the result is used for the subsequent calculation of incombustible matter contentaccording to the requirements of the Queensland Coal Mining Act. The carbon dioxide is determined through loss of mass by a semi-enclosed apparatus, following room-temper.ature hydrochloric acid attack on the sample.With a sample containing 36 per cent carbon dioxide, the achieved standard deviation (ls) of 0&#183;3 per cent CO. is adequate for coal mine roadway dust analysis.This simple procedure enables relatively unskilled labour in mine laboratories, to analyze coal mine roadway dust samples in accordance with the Act. Some 50 analyses can be achieved per day compared with 8 by the Australian Standard Method for coal.

Jan 1, 1976

By Satyajit A. Vaidya

This paper presents a case-study in the design and construction of deep foundation element supported mats for two residential towers on an18,000-square-foot site in Brooklyn, New York. Based on site sub-surface conditions, conventional mat foundations bearing on medium dense sand, having an allowable bearing capacity of 3 tsf, were originally anticipated for the 16 and 25-story towers. However, when the tower shear walls were relocated to the edges of the mat foundations due to architectural revisions, the significantly increased mat edge contact stresses applied to the soil subgrade resulted in calculated settlements of a magnitude that would adversely impact the proposed structures and the neighboring/bordering lot-line building and rail transit subway structures. To address this issue, deep foundation element supported mats were designed for the towers. The design was performed as an iterative process involving structural SAFE and geotechnical Plaxis finite element computer analysis to develop a coordinated geo-structural model of the foundation system. Initial presumptive design values of 45 pci and 445 kips/inch were used for the modulus of subgrade reaction and minimum deep foundation element stiffness, respectively. The designed foundation system consisted of 40 and 60-inch-thick mat foundations for the 16 and 25 story towers, respectively. Initially, the deep foundation elements were designed as 50-foot-long, 14-inch-diameter elements installed to sustain a maximum individual compressive load of 250 tons. The final deep foundation element design was subsequently refined to consist of a 48-foot-long, drilled and grouted IBO Titan 103/51 element designed to sustain a maximum load of 167 tons. Subsequent field load tests on the deep foundation elements confirmed element stiffness ranging from 1,040 to 1,530 kips/inch, with measured mobilized side shear of about 29 psi. The mat foundation reinforcement was adjusted for the pile stiffness values determined in the field load tests, and the deep foundation supported mats were constructed. The two towers were subsequently constructed, and have performed successfully.

Jan 1, 2010

By Martin Mayers

FIVE-SIXTHS of all the coal that is mined in the United States is burned, without previous treatment other than screening, for the produc-tion of heat and power, so that its value is fixed by its suitability for this purpose. Nevertheless, the characteristics of individual coals that determine their fitness for use in particular pieces of combustion equip-ment are not yet well known. This condition is due not only to the small extent of our knowledge concerning coal itself, but also to our compara-tive ignorance of the nature of the combustion process. The following paper is an analysis of the combustion process as it occurs in industrial furnaces, based largely on the results of laboratory research on combus-tion rates. From this analysis it is possible to determine the characteris-tics of the fuel that limit the capacity of a given piece of combustion equipment. Limitations imposed by other factors than the attainable speed of combustion will not be considered, since they are subject to a different type of analysis involving the balancing of maintenance costs against fixed charges. In order to observe the relations among the various factors that affect the speed of combustion, representative particles of fuel will be followed through two types of furnaces. A pulverized-coal furnace will be con-sidered first, because the independence of the individual particles facili-tates the analysis of the effect of furnace conditions. The second example will be a grate-fired furnace in which ignition of the fuel takes place on the underfeed principle. This includes both underfeed and chain grate stokers,(8)? but does not include hand-fired furnaces and some overfeed stokers. The furnace will be considered to be large enough, the tempera-ture high enough, and enough air provided, to burn the fuel completely, without, for the moment, specifying these quantities more completely.

Jan 1, 1934

By T. J. Woods

Tars paper deals with the origin, definition and prevention of scabs an semifinished rolled-steel product. Mold coatings, which are considered essential in scab prevention, were found to be effective only in relation to the ingot surface of semikilled and killed steels and not necessary for the rolled product. That is to say, the scabs on ingots caused by having been cast in uncoated molds are eliminated in the soaking and rolling operations, therefore are not present on the rolled product. This fact, which is contrary to the average opinion, was established after extensive and thorough experiments had proved the ordinary conception of the origin of scabs to be incorrect. This subject may be of little or no concern to steel plants producing small ingots for the manufacture of small billets and bars, except as it may be of interest in showing why their surface troubles with scabs do not exist on the product of heats with normal pouring practice. But to the producer of large ingots to be rolled into slabs for large plates used in shipbuilding, it is a very important subject. DEFINITION OF A SCAB The generally accepted opinion is that the individual scabs present on rolled products (as shown by Fig. I) are considered to have been individual splashes on the ingot surface. This opinion was found to be incorrect. Experiments showed that there were no individual scabs on the product that had appeared as individuals on the ingot surface. The single scabs seen are either pieces of a shell that is present near the bottom of all top-cast ingots, or a veneer that may be present on any part of an ingot improperly poured, as when the stream strikes the mold wall. This definition is based on a detailed study of scabs and their characteristics in which the following have been found true: Location.- On the product of heats poured without trouble, scabs, if present, are always on the product that corresponds to the bottom end of the ingot, and usually occur in clusters, This is true whether molds are coated or not. Shape.-There is no regularity as to shape, size or thickness. It is sometimes possible to separate a few pieces and place them together, like pieces of a jigsaw puzzle, indicating that at one time they had been united as one piece. If individual splashes were the origin of scabs, the foregoing would not be true. Instead, the splashes, which occur throughout the pouring of the ingots, would be present uniformly over the entire product and there would be considerable similarity in the shape and thickness of the scabs. EXPERIMENTAL WORK Our experimental work was conducted on 200-ton heats of semikilled plate steel tapped into an oval ladle 15 ft. high. All ingots were top-cast direct into 24 by 54 by 82-in. molds, straight-sided, set on fat stools. Two separate studies were made about one year apart, each study extending

Jan 1, 1943

By C. R. Fahnestock

One of the major problems for us in the earthmoving industry is the analysis of materials under the ground surface. Countless engineering and construction jobs would be simplified if there were an inexpensive and fast way to obtain information on problems such as: Depth and solidith of bedrock? Nature of the materials between bedrock and the surface? Adequate foundation for bridges and drainage structures? Location of supplies of materials to be used in construction? Investigation of tunnel sites? Characteristics of swampy areas and investigation of existing and potential slide areas? These questions are of paramount interest to highway contractors as they bid jobs and plan, equipment spreads to handle them at optimum efficiency. Such information also is invaluable to engineers in the design and construction of bridges, buildings, railroads, canals, and tunnels.

Jan 1, 1961

"Ground control research in underground coal mines has been ongoing for over 50 years. One of the most problematic issues in underground coal mines is roof failures associated with weak shale. This paper will present a historical narrative on the research the National Institute for Occupational Safety and Health has conducted in relation to rock mechanics and shale. This paper begins by first discussing how shale is classified in relation to coal mining. Characterizing and planning for weak roof sequences is an important step in developing an engineering solution to prevent roof failures. Next, the failure mechanics associated with the weak characteristics of shale will be discussed. Understanding these failure mechanics also aids in applying the correct engineering solutions. The various solutions that have been implemented in the underground coal mining industry to control the different modes of failure will be summarized. Finally, a discussion on current and future research relating to rock mechanics and shale is presented. The overall goal of the paper is to share the collective ground control experience of controlling roof structures dominated by shale rock in underground coal mining.INTRODUCTIONThe National Institute for Occupational Safety and Health’s (NIOSH) Office of Mine Safety and Health Research (OMSHR), formerly the United States Bureau of Mines, has been conducting research on ground control safety for over 50 years. The overall objective of the research is to reduce underground mining injuries and fatalities by characterizing roof conditions, improving roof support performance and application, and optimizing pillar design and mine layout. Underground mining has one of the highest fatal injury rates of any industry in the United States—more than five times the national average compared to other industries (CDC, 2012). Roof fall injuries can be severe, resulting in lacerations, bone fractures, amputations, and death. Non-injury roof falls can also be problematic, resulting in lost production, delays, blockage of primary escape routes, disruption to ventilation, and hazardous rehabilitation conditions.Coal mining is increasingly subject to more adverse geological conditions. Weak roof can be found in all coal mining regions in the United States, but there are a few geographically isolated areas with higher roof fall rates contributed to by particularly poor roof conditions, as represented in Figure 1. This figure shows that when non-injury roof fall rates are normalized to production, the Illinois Basin and Central/Northern Appalachia regions have the highest rates. These isolated regions have inherently weak roof even before mining has occurred, and this roof is easily damaged during the mining process. The weak roof in these regions consists primarily of shale. Shale can be troublesome in underground coal mining because it can appear massive but easily splits along bedding planes and is often moisture-sensitive."

Jan 1, 2015

By K. -H. Lux, Z. Hou

ABSTRACT: It is well known in underground mining and waste disposal that the development of excavation damaged zones (EDZ), and thus, hydraulic pathways, is closely related to the excess in the corresponding damage boundary (= long-term strength) of the rock mass and the resulting damage. By integrating short-term and long-term strength, dilatancy, damage and healing into the newly extended Hou/Lux constitutive model for rock salt, it is possible to treat the tertiary creep, to identify the EDZ around underground facilities and to predict the time-dependent development of the EDZ in rock salt. Under in-situ conditions, the EDZ of a 37-year-old drift at the Sondershausen salt mine and the EDZ around a drift dam in rock salt are numerically examined. The numerical analysis gives satisfactory results. RÉSUMÉ: Dans les exploitations minières et le stockage souterrain des déchets, le développement des zones endommagées et fracturées (EDZ – excavation damaged zone), créant des chemins préférentiels pour écoulement, est étroitement lié au contexte géotechnique et à la méthode d’excavation. En intégrant la résistance court et long terme, la dilatance, l’endommagement et le colmatage, le nouveau modèle rhéologique Hou/Lux pour le sel gemme est capable de traiter le fluage tertiaire, d’évaluer l’extension de l’EDZ et de prédire l’évolution de EDZ dans temps autour des ouvrages creusés dans le sel gemme. L’EDZ d’une galerie datée de 37 ans dans la mine de sel de Sondershausen et les EDZ autour de barrage des galeries dans un sel gemme ont été modélisées. Les résultats numériques fournissent des résultats satisfaisants. ZUSAMENFASSUNG: Bekanntlich ist die Entstehung von Auflockerungszonen und damit hydraulischen Wegsamkeiten in der unmittelbaren Umgebung um bergmännische Hohlräume mit der Überschreitung der entsprechenden Schädigungsgrenze eng verbunden. Unter Berücksichtigung der Bruchfestigkeit, Schädigungsgrenze, Dilatanz, Schädigung und Verheilung kann das Stoffmodell Hou/Lux das Verhalten des tertiären Kriechens beschreiben, die Auflockerungszone im Salzgebirge ermitteln und ihre zeitabhängige Ausdehnung vorausberechnen. Mit diesem Stoffmodell werden die Auflockerungszonen einer 37jährigen Strecke in der Salzgrube Sondershausen und die Auflockerungszonen um ein exemplarisches Abdichtungsbauwerk im Salzgebirge numerisch untersucht. Dabei werden zufriedenstellende Berechnungsergebnisse erzielt.

Jan 1, 2003

By David M. Mchaina, Michel Grenier, Stephen G. Hardcastle

An airborne dust survey was conducted at the Arthur W. White mine of Dickenson Mines Limited by CANMET/MRL and Dickenson Mines Limited Staff in April 1990 for the purpose of evaluating environmental conditions underground and in the surface mining plants. The survey was designed to measure respirable silica, total arsenic and lead concentrations at several workplaces. In addition, settled dust and rock samples were collected from workplaces and analysed for total arsenic content. More importantly, arsenic exposure data were needed to evaluate the impact of Ontario Regulation 176/86 as amended by Ontario Regulation 23/87. A total of 165 area and personal air filter samples were collected during the study. Of these, 85, 67 and 13 samples were for arsenic, silica and lead respectively. Sampling aid analyses were performed according to the Ontario Ministry of Labour Regulations. More than 90% of the workplaces sampled for respirable silica, total arsenic and lead were below the Ontario Ministry of Labour Regulations; and 10% of the workplaces sampled for arsenic shaved concentrations above the Threshold Limit value (TLV) proposed in the Ontario Regulation 176/86 as amended by Ontario Regulation 23/87. These results were used to identify occupations and/or workplaces where more sampling and control measures were required respirable silica, total arsenic and lead. This paper describes the results of the dust sampling program conducted at Dickenson Mines Limited.

Jan 1, 1991

The proximity of the Town of Kalgoorlie to the Mount Charlotte mine necessitates that charge weight per delay be limited in order to keep surface vibration levels within acceptable limits and to reduce damage to underground workings. The mining system requires that large mass blasts must be used to recover pillars and therefore a large number of separate delays are needed. Until recently all blasting has been done electrically, fired from mains, but with the introduction of large diameter blastholes (165mm diameter) this firing system was inadequate. Various firing systems were considered, but after extensive trials a non-electric sequential firing system was chosen. This system fulfilled all criteria of blast design, was relatively straight forward in charging technique and had a very simple primary initiation system. Although initially designed for large mass blasts, the non-electric firing system is now used for all large hole blasting and in a simpler form for small (57mn diameter) holes.

Jan 1, 1982

By Karim Ramji

The extractive sector today faces growing social, legal and political risks (SLPs) from so many different stakeholders including national and local governments, name and shame groups, civil society and environmental groups, and the ?Occupy? movement. Beyond these stakeholders, there are the indigenous peoples who have growing legal, social, political and economic influence which can often determine the outcome of the Project. The development curve in the extractive sector from initial exploration to mine start-up has become longer, steeper and more risky and expensive as these SLPs have grown in scope and complexity. Even if a project is permitted or starts commercial production, its ongoing development and operations are also facing these SLPs. The continuous assessment of these SLPs and the strategy to mitigate for them has now become critical for every project in the extractive sector. A project will only be successful if it is able to obtain the legal permits to operate, then withstand any judicial reviews, and then also to be able to gain and maintain the Social License to Operate (SLO). Stakeholder identification, management and engagement are key risk-mitigation tools. This paper focuses on the growing influence that indigenous peoples are now enjoying and the impacts on the extractive sector. Indigenous peoples are a unique stakeholder group because their legal rights and interests to lands and resources, their aboriginal title and rights, are gaining more recognition. When indigenous peoples form alliances with other stakeholders, this simply adds to their growing momentum and leverage, and this can become a daunting challenge for the extractive sector. More due diligence is required by companies to understand and assess the challenges posed by operating in areas claimed by indigenous peoples. There is a real need for mining companies to develop an effective indigenous engagement strategy to address these challenges in order to successfully convert risks into opportunities. Early identification and engagement with the indigenous peoples is required and the goal should be to conclude an Impact Benefits Agreement (IBA) with the affected indigenous peoples. The real objective must be to develop a real and transparent relationship between the company and the indigenous peoples so as to gain and maintain the SLO.

Aug 1, 2013

By Fábio Lucas da Silva

Com a queda brusca nos preços das commodities, os termos redução de custos e maior produtividade tornaram-se assuntos constantemente abordados no cotidiano das empresas, pois esses fatores representam questão de sobrevivência das organizações. Para tal, a busca por melhorar continuamente o processo produtivo em prol de garantir espaço no mercado é uma realidade e necessidade, com isto é importante que as empresas conheçam detalhadamente os seus processos e tenham maturidade para tomar decisões baseadas em dados e fatos. Assim, este trabalho tem como objetivo aplicar a metodologia Seis Sigma para investigar quais são as variáveis que mais influenciam no processo de flotação reversa de minério de ferro reduzindo o consumo do reagente coletor amina uma empresa de mineração na cidade de Itabira MG.

Oct 30, 2017