Search Documents

By Adriana Gómez

White dross is a result of the aluminum oxidation during its primary production and is mainly composed of metallic aluminum, Al2O3, with minor amounts of AlN and some other oxides. Because of the great variety of phases, the quantitative characterization is complicated. This work shows a quantitative method to determine the main phases of white aluminum drosses by means of X-ray diffraction (the Rietveld method). Nowadays the Rietveld method is maybe the most useful method for obtaining quantitative phases information in multicomponent mixtures, this method permits relatively quick quantitative phase analysis by fitting the calculated X-ray diffraction profile with the observed one. The analysis were done using powder with a grain size less than 45 µm; to obtain the suitable material size the aluminum dross was grounded by ten minutes, several times. The grounded material was screened, and the material smaller than 45 µm was taken to quantitative XRD analysis. Keywords: Rietveld Method, Characterization, Aluminum dross.

Jan 1, 2005

By Natalie J. Shackleton, Deryck de Vaux, Cyril T. O’Connor, Vratislav Malysiak

"The major losses of PGM and base metals in the beneficiation of platinum group deposits occur during the separation of gangue from the value minerals by selective flotation. A number of studies have shown that this negative impact on flotation is due to surface passivation, caused by various ions that may originate from the external water supply or, as is likely in the majority of cases, from the oxidation of the mineral surfaces and the grinding media. The objective of the study was to investigate the effect surface passivation and inadvertent activation have on flotation and how this can be managed so as to increase the separation of pentlandite and pyroxene. The aim was to minimise the percentage pyroxene reporting to the concentrate and simultaneously maximise the pentlandite recovery. The testwork incorporates the addition of an activator (copper sulphate), a complexing agent, such as DETA (diethylenetriamine) and a dispersant (polyphosphate) at pH 6 and pH 9 in an attempt to alleviate the surface passivation of pentlandite and inadvertent activation of pyroxene. Both synthetic minerals and plant ores were studied in order to determine the effect surface passivation and inadvertent activation have on mineral surface alteration and floatability. Zeta potential determinations, microflotation, ToF-SIMS (Time of Flight Secondary Ion Mass Spectrometry) analyses, laboratory batch flotation tests and continuous flotation testwork were used as tools to study the surface alteration and/or floatability.Zeta potential determinations and ToF-SIMS analyses showed that copper adsorption is non-selective. Both pentlandite and pyroxene become copper (II)-activated in the presence of copper sulphate and subsequently, in the presence of xanthate, adsorption of the collector will occur onto copper activated mineral surfaces. Zeta potential determinations also showed an alteration of the surface charge in the presence of polyphosphate, thereby inhibiting surface passivation of sulphides by slime coatings due to surface repulsion."

Jan 1, 2003

By W. Kint

More than 10 years ago, one of MECS?s current partners KVT developed the so called SULFOX process for cleaning waste gases containing sulfuric compounds. In this Wet Acid Process (WAP) compounds such as SO2 and H2S, CS2, COS are oxidized over catalyst bed(s) to SO3 and finally sulfuric acid is formed. The individual plants are designed according the feed gas concentrations and customers requirements to keep the investment and operating costs as low as possible. MECS strongly believes the technology we propose will meet all your expectations. Thanks to our vast experience in the construction of sulfuric acid plants (MECS built over 800 sulfuric acid plants worldwide) we were able to design you a very reliable installation. MECS is offering the metallurgical industry, besides our conventional acid plant technology (for strong SO2) and our DynaWave? scrubbing technology (for very low SO2), a SULFOX wet acid plant (for the mid range SO2 concentrations) including an optional upstream DynaWave gas cleaning plant if required. See the figure below. Besides providing advanced technology, MECS is the only company who designs and manufactures its own key critical equipment. We manufacture our own catalyst, mist eliminators, acid distributors and coolers. Because of our in-depth technology knowledge, we understand the critical aspects necessary for making optimum equipment designs. With this combined supply of technology and key critical equipment, we can make a single overall guarantee second to none other in the world.

Jan 1, 2009

By M. Barsky, A. Govorov, E. Barsky

A study was conducted to determine the structure and lifting capacity of a two-phase stream in a vertical pipe at different distances from the point of introduction of the material into the instrument. Stream velocity was set at 2.8, 4.0, 4.8, 5.6 and 6.25 m/sec to ensure separation regimes. It was found that the llifting capacity of the two-phase stream exceeded that of pure air by a factor of three or more, and that in a turbulent regime the velocity curve displayed marked deformation, becoming more rounded and tending towards a parabola. The following formula was obtained for entrainment of a given size fraction under turbulent, laminar and transitional particle flow regimes:

Jan 1, 2003

By E. Barsky

"The aim of separation is to obtain two products that are as distinct as possible from each other. It is currently believed that the most objective criteria for the quality of a separation are the Hancock criterion and the entropy criterion.1. Hancock criterion:- for yield of fine product"

Jan 1, 2003

By Brad E. Melanson

Because mine haul trucks consume considerable quantities of fuel, they are ideal candidates for the adoption of cleaner and cheaper fuels like natural gas. Impressive fuel cost savings will be realized in regions where liquefied natural gas (LNG) has cost advantage to diesel fuel, while also providing significant reductions of air contaminants and greenhouse gases. High Pressure Direct Injection (HPDI) of natural gas utilizes the diesel cycle combustion process and therefore retains the diesel engine?s high performance and efficiency characteristics. HPDI has been demonstrated in on-road Class 8 trucks since 2001 accumulating almost 10 million kilometres to date. The supply of LNG fuel will be an essential parallel aspect in the introduction of HPDI to mining. LNG can be transported to site as diesel is today, or may be produced on or near mine operations that have access to methane sources or pipelines.

May 1, 2006

By J. W. Paul

A study of mining methods and underground practices as they influence injury from falls of roof or coal reveals data as to the location in the mine where such injuries occur with the greatest frequency and as to some of the methods and practices which are in use for the prevention of injury. This paper, which presents statistics bearing on the frequency and place of occurrence of accidents and discusses regulations and practices which have resulted in a low-frequency rates from falls of roof and coal in a few representative mines, takes its information from mine-accident reports and from the results of studies conducted in a group of 80 mines in the bituminous coal fields of Western Pennsylvania, Ohio, and West Virginia. The statistics from this group of mines cover periods of one to four years but average 2 years and 7 months. During this time these mines produced over 110,400,000 tons of coal, equivalent to one-fifth of the annual production of all bituminous mines in the United States. The coal beds of the mines in the group studied are mostly flat, with local pitches of moderate degree. A number of mining plans are in use, each of which follows a general system of multiple entries, gross entries, and rooms. Room and pillar in panels either advancing, retreating, or half advance and half retreat, and the block system are employed. The methods of pillar extraction are by splitting, slabbing, pocket-and-stump, and open end. It is hoped that in presenting some of the details of the methods and practices at particular mines of this group which have commendable records in the prevention of injury some goad may accrue to many other bituminous mines which have similar natural conditions.

Jan 1, 1933

By A De, B Palmer, rade, P Stowasser, A Fanning

Mining and tunnelling share many commonalities (eg confined working environments, excavation equipment and processes), but of significance is an overarching commitment to provide safe work conditions and environments. This includes reducing exposure to hazardous airborne contaminants such as dust and fumes, in particular Respirable Crystalline Silica (RCS) and Diesel Particulate Matter (DPM), with methods that are environmentally sustainable. In mining, wet methods are common to suppress airborne contaminants, however these methods are reliant on water availability, can be less effective for respirable dust, can have implications for environmental water contamination and can increase maintenance on mining equipment. In contrast, the use of dust scrubbers that provide filtration of airborne contaminants are well established in the tunnelling industry and frequently used to provide spot extraction (dust control at the source) and act often as a complement to the main ventilation system. This paper sought to learn more about the advancements in tunnelling that could be readily applied to mining to improve health outcomes. The paper includes a review of literature and legislation related to health and sustainability and interviews with three respected, and experienced managers from the global tunnel construction industry. It is from these interviews that the focus of the paper turns to Sydney’s WestConnex underground tunnel network and the success of stage 3A M4-M5 construction link. The findings position dust scrubbers as integral to the overall project success as they enabled a Tunnel Production Line (TPL), where multiple stages of construction could take place simultaneously by controlling high volumes of dust at the source. The findings also suggest efficiencies of using mobile scrubbers, both track mounted and hydraulic stepping systems, to accompany road headers and other equipment throughout the excavation process. The findings have transferable applications to underground mining processes in which workers are exposed to high volumes of dust (eg drill and blast) or situations in which dust control at the source, mobility and flexibility offer value (eg room and pillar mining).

Apr 16, 2024

Bitumninous and semianthracite coal reserves underlie about 1,400 square miles of Arkansas, less than 2.7 percent of the state's total area. These deposits, located near the western border, contain an estimated 2.2 billion tons, of which about half are recoverable. This represents less than one-tenth of one percent of the national reserves. Most of the commercial coal is mined from thin beds that are at least 14 inches thick. In some locations, however, the coal beds can be as much as eight feet thick. Lignite was mined in southern Arkansas before the Civil War. Current estimates indicate that the reserves may be as high as 9 billion tons, which could be used in the state's coal-fired electric generating plants; however, these deposits are not being mined at present. Because many coal operations in Arkansas are small and the demand for coal is unsteady, the industry employs fewer than 25 miners on a daily basis. Arkansas gained primacy when its regulatory program was conditionally approved November 21,1980, subject to the correction of four minor program deficiencies. The regulatory program was fully approved January 22, 1982. Authority of the state to administer its Abandoned Mine Land Reclamation Program was granted upon approval of the Arkansas Reclamation Plan on May 2, 1983. Arkansas was the first state to assume responsibility for abandoned mine land emergency projects when its Reclamation Plan was approved.

Jan 1, 1992

By André van Wageningen

Long-term mine scheduling is one of the most difficult optimization problems. The problem is said to be NP-complete in that the best possible solution cannot be found any quicker than checking all possible permutations and combinations. Although a number of techniques have been used in the past, many include significant simplifications or fail to produce acceptable results within the required timeframe. Genetic Algorithms (GAs) are among the most promising optimisation techniques within operations research. They are based on natural selection and evolution of solutions to complex problems. They have been known to quickly converge within a few percent of the optimal solution by examining only a fraction of the solution search space. The GA itself contains very little problem specific information and as such, has been linked to a discrete-event simulation (DES). The DES feeds information regarding the feasibility and quality of the solutions back to the GA during the optimisation process. In this paper, GAs and DES are described and the coupling of the two methods is outlined. The GA coupled DES is then used to ?optimise? a problem and the results are discussed.

May 1, 2004

By Stanley C. Suboleski

1977 was the modern day low point for productivity in the coal industry. At that time, no one could have predicted that the industry was about to enter a productivity rise that would continue unabated through the 1980s. Thirteen years later, the cause of this phenomenon is still not well understood. While many government studies focused on the fall in productivity from 1969 to 1977, none have been undertaken to explain the rise. Some of the likely causes of the gain in productivity during this period will be discussed here. An attempt will also be made to quantify the value of some of the technical innovations that have taken place. The remainder of the gain is assumed to come from non-technical sources. The nature of these sources, although largely non-quantifiable, is also discussed. Since the number of mines that have adopted the technical innovations noted here is largely unknown, the actual contribu¬tion of technological changes to the overall productivity gain can only be estimated.

Jan 1, 1990

By M. Abdelkhalek, M. Hepworth, D. Tao, B. K. Parekh

Pre-combustion coal cleaning and post-combustion flue gas desulfurization (FGD) using lime or limestone are the primary methods employed to reduce sulfur dioxide (SO2) emission from coal combustion. These processes generate voluminous pyrite and gypsum solid wastes that are usually landfilled, occupying thousands of acres of land and creating serious land and water pollution problems due to the release of acids and toxic substances. An integrated process has been developed for the combined utilization of gypsum and pyrite wastes by converting them into useful products including lime, sulfur, and direct reduced iron (DRI). The process includes four major steps. The first step is to concentrate pyrite from coal preparation tailings using flotation or gravity separation. The second is the thermal decomposition of pyrite into pyrrhotite and sulfur. This is followed by the reduction of pyrrhotite with carbon in the presence of lime to produce iron and calcium sulfide. The fourth step involves the reaction of calcium sulfide with gypsum to produce lime. The chemical reactions involved in the process were studied using thermogravimetric analysis (TGA) and X-ray diffraction (XRD)techniques. Process variables studied included reaction temperature, time, reactant composition, and purity of reactants.

Jan 1, 2000

By Matt Leeming

Several of the underground mines in the UK require a significant number of cable bolts to be installed, remedially, to control worsening roadway conditions. Often the access is limited and the only power source is compressed air. Machines for this duty are generally designed to perform with 100 psi but regularly only half of this is available. This paper seeks to outline the difficulties this situation causes the Rock Bolting Engineer, highlight the technical requirements for a machine of this type to succeed and detail a solution offered by our engineers.

Jan 1, 2007

By Angela Binder, Mareike Schubert, Yichen Jiang, Sandra Nowosad, Oliver Langefeld

GermanyINTRODUCTIONThe mining industry is currently characterized by various factors such as environmental impact, resource scarcity, social responsibility and geopolitical uncertainty. The production of minerals required to meet the demand for renewable energy is expected to increase by 500 % by 2050, particularly for critical minerals such as graphite, lithium and cobalt 1. Easily accessible deposits are often depleted, meaning that deeper and more complex deposits need to be developed. Furthermore, investors’ value systems have shifted towards more sustainable practices. Alternative approaches to solving this problem are therefore currently being developed, such as the Modular Mining Systems concept for scalable and adaptable mining projects 2. Many mining companies have also taken important steps to become more sustainable, implementing measures such as proactive closure strategies, restoration programs and the development of renewable energy projects. In the European Union, laws such as the Critical Raw Materials Act and the Net Zero Industry Act support the mining industry 3,4. They see it as important for the energy transition and promote more sustainable ways of working in the industry Particularly negative environmental impacts such as land degradation, scarcity of local water resources, water pollution and greenhouse gas emissions are ingrained in society’s memory. Despite these efforts, the public image has not yet changed. To change this perception, the industry must strive to better communicate its sustainable practices and the steps it is taking towards a more responsible and sustainable future, promote transparency and build trust.Digitalization, automation and electrification are driving the digital transformation in mining. However, their implementation can lead to higher capital expenditure, limiting their adoption across the industry. Furthermore, implementing new technologies can be a daunting task for any organization. Change management comes into play when introducing such disruptive technologies. It involves preparing an organization for change, potential resistance and establishing effective communication. This helps to ensure that the implementation is successful and the benefits of the new technology are maximized. Digital transformation requires well-trained, young mining, electrical, mechatronic and software engineers with a deep understanding of information systems. Unfortunately, the industry faces the enormous challenge of attracting this younger generation, who have little interest in the extraction of raw materials. The need for action is compounded by an aging active workforce heading into retirement and the forecast of increasing demand for critical minerals.In this challenging environment, the concept of Blue Mining with its constant further developments represents a promising approach. This implies a shift from a linear to a sustainably oriented circular economy. For the mining industry, this specifically means the introduction of innovative technologies, the increased recovery of materials from waste and the consistent questioning and application of circular principles along the entire life cycle of a mine. Such a change can not only reduce the environmental impact, but also contribute to economic resilience and increased social acceptance of mining.

Feb 1, 2025

By Robert W. Geehan

The Bureau of Mines developed, by core drilling, the property of Nevada Scheelite, Inc., from October 5, 1943, to February 24, 1944. Claims of the corporation are near Rawhide in the northern portion of Mineral County, Nev. The purpose of the work was to determine possible reserves in the lateral and vertical extensions of a tactite zone which was being mined for scheelite. Production from this zone to January 1, 1944, was said to be 64,500 tons, with a recovery of 50,618 units of tungsten trioxide. The development work was done by the Bureau of Mines in cooperation with the U. S. Geological Survey and comprised a study of the geology, mapping the areas, and exploring the deposit by diamond drilling, trenching and sampling. Eleven holes were drilled for a total footage of 2,365 feet of holes.

Jan 1, 1950

By E. Shelobolina, S. M. Pickering, J. E. Kogel

A long history of weathering and bacterial alteration processes have transformed Georgia’s Coastal Plain kaolins from dark organic muds to recrystallized white pigment-grade industrial clays. A sequence of six stages in development of these valuable mineral deposits is outlined over their Late Cretaceous and Tertiary deposition and alteration history. Anaerobic and aerobic iron oxidizing and iron-reducing bacteria are present in the Georgia kaolins. These bacteria may have had a major role in iron and organic matter removal during several of the alteration stages that occurred over the past 60+ million years. Iron was likely solubilized by both iron-reducing and iron-oxidizing bacteria, depending on availability of Fe(II), Fe(III), and NO3. Thus, over long periods bacterial activity slowly led to nearly complete groundwater removal of iron from the kaolin deposits. Further bacterial iron removal on an industrial process scale may eventually prove feasible. “Without the multitude of living reactions as channels for energy and electrons and without the enormous capability of life to transfer with and against chemical gradients, there would be practically no or at least a very reduced geochemical rock cycle on this planet.” (Krumbein and Dyer, 1985, p. 157)

Jan 1, 2002

By J. Lazareck

"XPotential Products Inc. has developed technologies to convert auto shredder residues and other forms of plastic waste into useful products such as posts suitable for retaining walls and parking curbs. The technology is competitive provided low-cost plastic waste is available, and could have applications throughout the world. The paper describes the technology used and illustrates the various processing steps. Development of the TechnologyPresently, state-of-the-art auto shredding yields approximately 75% ferrous and non-ferrous metals and approximately 25% by weight of auto shredder residue (ASR). Advances in metal shredding and non-ferrous metal separation technologies turned XPotential Products Inc.’s attention to ASR as a potential revenue source, or at least a means to markedly reduce the cost of disposal. This abundance of nuisance ASR was, in the company’s view, a potential resource as derelict autos and white goods were similarly perceived 40 years ago. As owners of General Scrap & Car Shredder Ltd. in western Canada, XPotential faced significant disposal costs for four shredders. This journey began over 10 years ago and took many twists and turns until a final course of action was chosen. The recovery of the metallic portion of vehicles and white goods has reached technological maturity and attempts to add value are now achievable only in very small increments."

Jan 1, 2004

One of the most important parameters in mine ventilation planning is the friction factor (K). Accurate values of friction factors are critical especially when carrying out mine ventilation simulations. No computer simulation of a mine ventilation network is meaningful if the airway resistances are not accurately estimated (when planning a new mine) or measured (for an existing mine). However, in the first case not many reliable values of friction factors exist in the international literature. This paper presents the results of a research project carried out in the province of Quebec where ventilation friction factors were measured in all underground metal mines. These friction factors are statistically analyzed and tabulated. A friction factor database was created that also includes the friction factors measured in the past by other people. This database can help the mine engineer to accurately estimate ventilation friction factors according to the specific conditions. This database offers several values of friction factors typical for hard rock mine conditions typical of modern underground metal mines.

Jan 1, 2009

By Tony Szwilski

Indonesia has enormous mineral resources. Its population of more than 180 million people inhabit most of the more than 13,000 islands. The country is becoming a significant economic power in Southeast Asia. Indonesia is the largest Muslim country in the world. Java, its largest island, is the most densely populated area. The country's diversity is its strength. However, as only an estimated 16 million inhabitants speak bahasa Indonesia as the first language, communication problems endure. Although burdened with large debts, Indonesia has been able to service the debts better than most developing nations. This has given it high credibility and, with increasing frequency, creditor nations compete to provide Indonesia loans with the most the most favorable financial terms. Recent rising prices of petroleum crude has further improved Indonesia's economic status. It maintains a policy of stable oil prices that it promotes in OPEC, of which it is an influential member. As a result, Indonesia is becoming increasingly attractive to foreign investors. The South East Consortium for International Development (SECID) is made up of 34 universities in the southeastern US and Indonesian partners Lembaga Afiliasi Penelitian dan Industri (LAPI) of the Institute of Technology in Bandung, West Java. SECID bid successfully against international competition to develop new academic programs and campus for the Sriwijaya University UNSRI) in Palembang, South Sumara. Funding for the project was provided by the government of Indonesia through a loan from the Asian Development Bank (ADB). There are 47 public universities

Jan 1, 1991

By G. Onal, E. Gock, H. Dincer

"During the conventional chromite dissolution process; chromite ore concentrates were ground to at least <90 µm using the ball mill and after adding Na2CO3 and leaning material (instead of CaCO3 also residues from the leaching process) at a ratio of e.g. 1:0.75:1.2, depending on the specific formulation, follows the digestion e.g. in a rotary kiln, heated in countercurrent. The reaction time is 3 to 8 h. The calcine is comminuted and leached with water or a thin chromate solution. Depending on the type of ore used, the yield is 75-85 %. The disadvantage of the above-described process is that it is impossible, using current technology, to achieve a complete digestion of the chromite ores and that the chromium-containing residues have to be disposed of as special waste, involving a large financial effort.The subject of this study was the investigation of the effect of vibratory milling on chromite dissolution. The impact stress in the vibratory mill causes the mechanical activation of chromite, which is characterised by lattice defects. The degree of mechanical activation can be quantified by measuring the relative X-ray diffraction intensities at the parent lattice planes of chromite. Each relative X-ray diffraction ratio correlates with a certain degree of digestion. As opposed to vibratory milling, a complete digestion of chromite using a ball mill is impossible, even at extremely long grinding times.In this investigation a chromite concentrate from Pulpinar/Kayseri with content of 44 % Cr2O3 and the Eccentric Vibratory Mill was used. In order to verify the effect of the vibrating grinding on chromite dissolution, reaction kinetic investigations on digestion and leaching were carried out."

Jan 1, 2003