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By C. Sensogut

The phenomenon of spontaneous combustion is one of the major hazards encountered in underground coal mines both from the safety aspects and on economic grounds. Every occurrence, however small, if not tackled effectively in the early stages can develop into open fire, or explosion of gas or coal dust. In terms of economy, even dealing with small incidents may be costly in terms of labour and materials, and in case of a sealing off of a district being necessitated, the loss of face equipment and sterilization of reserves is potentially great. Therefore, expense and effort in prevention and detection of such heating, together with a high state of readiness for dealing with likely event, is completely justified and may be considered as a sound investment. In order to achieve this investment, it may be worth to pinpoint the centre of the fire occurring due to autogenously heating which is supposed to be great assistance to inert it at a least cost and time. Therefore, it is the aim of this work to model the spontaneous combustion in the goaf.

Jan 1, 2002

By O Haavisto, N Khajehzadeh, L Koresaar

Online analysis of metal content can be used to optimise the grade and recovery of a flotation circuit. Compared to conventional laboratory analyses, the benefit of an online analyser is the speed of the measurement, therefore disturbances (eg changes in feed grade and decrease in recovery) can be reacted to in real time by an operator or automatic process control system. In some cases traditional X-ray fluorescence analysers can be applied to silica analysis in iron ore when the SiO2 grades are high enough and have a negative correlation with iron; however, generally a laser-induced breakdown spectroscopy (LIBS) analyser is more suitable for low Z elements.The Outotec Courier 8® analyser is a LIBS based analyser able to measure elements starting from lithium (Z = 3), thus being able to measure impurities; eg silica and aluminium directly in iron ore slurries. Besides online elemental analysis, the analyser can be combined with optical measurements for rapid continuous measurement of each sample line. Laboratory testing has also shown potential for mineralogical analysis using the combination of LIBS and reflectance spectroscopy.CITATION:Koresaar, L, Khajehzadeh, N, Haavisto, O and Timperi, J, 2017. Online elemental and mineral measurement of slurries in iron ore beneficiation, in Proceedings Iron Ore 2017, pp 561–566 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By James J. Kabat, James A. McDonald

Impregilo/SA Healy JV recently completed this Project using the first slurry shield TBM’s in the United States. The Project used two TBM’s to mine 18,000 feet in sands, gravels, and silty alluvial materials under the Willamette River and downtown Portland, Oregon. This paper discusses alignment and geological conditions, equipment selection and plant setup, and tunnel excavation means and methods, parameters, and results. Extensive hyperbaric operations were required and will also be discussed.

Jan 1, 2007

By Marwan M. Mohammed, Hani S. Mitri, Wilfrid Comeaul, Baoyao Tang

In many parts of the world, rockbursts have become a major problem of mining at depth. As orebodies are being mined deeper, rockburst phenomena have become familiar to deep hard rock mines. Rockbursts are generally characterised by sudden release of energy in a volume of highly stressed rock, which can cause local violent failure of the rock mass around the opening. One method of controlling these failures is to precondition the rock mass by detonating fully confined explosive charges at the appropriate locations. This method known as destress blasting, was first tried in the deep South African gold mines (Roux et al., 1957), and was widely used later in Canada, United States, France, Poland and Japan.

Jan 1, 1999

By Henri F. Letient

At the 25th Annual B.C. Mine Reclamation Symposium in September 2001, Huckleberry Mines Limited received the Jake MacDonald Reclamation Award for its exemplary mine waste management plan, conceived to prevent the onset of acid mine drainage and facilitate reclamation of the site. The mine is an excellent example of a total mine waste management plan, with all materials scheduled in detail for the life of the mine. The filling plan for the waste management facility takes into consideration the requirement for permanently flooding the potentially acid generating rock. From an acid generation point of view, the tailings fall in the zone of potentially acid generating material. To avoid long-term ARD concerns, it is planned to float pyrite out of the tailings towards the end of the mine life, thereby generating a non-acid generating tailings stream which will be used to cap the deposited mine waste. The pyrite-rich tailings will be discharged into the deeper portion of the impoundment. On closure, a permanent water cover will be maintained over the mine waste. Only beaches of non-acid generating tailings will remain exposed. Mining will be phased to also allow one of the pits to provide storage for potentially acid generating rock and to be flooded at the end of mine life.

May 1, 2002

Slime Flotation Using Ethoxylated Surfactants in Solutions of the Electrolytes

Sep 13, 2010

By R. D. Leitch

"INTRODUCTION The character of mine drainage from areas of low pyritic coal3 and from average pyritic coal4 has been investigated, and to complete the study it seemed desirable to select a number of mines situated in high pyritic are as to determine whether or not this variation determines the relative acidity of drainage from mines operating in these characteristic coal fields. Advantage has been taken of some worked on in 1918 by Henry Leighton 5, then Professor of Economic Geology, University of Pittsburgh. He visited and has reported certain areas of high pyritic coal which we also visited during this study. Many of the mines were found to be idle in 1930 and a few were caved shut, apparently for several years. However, samples of the outflow from all mines visited were collected if possible and analyzed, and some general information was gathered for each mine. The map (fig. 1) shows the location of these areas as given by Leighton.ACKNOWLEDGMENTSThe information and assistance obtained from officials and others at the mines visited during this study are gratefully acknowledged, as well as the original suggestion from Dr. Glenn V. Brown of the State Sanitary Water Board who called attention to the desirability of such a study.Thanks are also especially due the coal laboratory of the United States Bureau of Mines, under the direction of H. M. Cooper, for the analyses and determination of sulphur forms in the large number of solid samples necessary to the work reported,This study has been carried on under the direction of R. R. Sayers, chief, health and safety branch, and W. P. Yant, supervising engineer, Pittsburgh Experiment Station, of the U. S. Bureau of Mines."

Jan 1, 1932

By G. S. Hill

A large amount of the stereological error associated with liberation studies can he eliminated by assessing areas instead of linear intercepts. The presentation of a simple geometrical model as a stereological 'worst case' allows calculation of the worst possible grade/recovery curve for a given assemblage of areas. The true results are expected to lie in the window between this worst case and the hest possible case, represented by uncorrected data. The width of this window typically corresponds to an error margin of about 5% grade at a given recovery. An indication of where the data lies within the range of possible grade/recovery results may he obtained from a qualitative analysis of the locked section complexity. Assemblages consisting of texturally complex locked sections (ie. containing many mineral nuclei) are likely to exhibit minimal stereological bias and therefore will tend to lie close to the uncorrected side of the grade/recovery window.

Jan 11, 2011

By Kwong. Kyei-Sing

Gasification is a process that converts a carbon feedstock into synthesis gas (CO+H2). Slagging gasifiers operate at high temperature and pressure and in a corrosive-wear environment from the slag. Cr2O3-based refractory linings are used to protect the steel vessel that comprises the gasifier from the aggressive gasification environment. Increasing service life of the gasifier is one of the keys for wide spread development of this technology. In support of the goals, research on the gasifier atmosphere, the slag chemistry, the interaction of Cr2O3 refractory with different feedstock mixtures (e.g., coal and petcoke) were characterized by post mortem analysis of bricks from service in gasifiers and thermodynamics simulation of the environment. Examples demonstrating how thermodynamic calculations can explain the post mortem results and make predictions of material interactions will be given. Attention is placed on the possibility of Cr+6 in different feedstock mixtures and operating conditions.

Jan 1, 2010

By Robert L. Stroup

Let me open my remarks this morning by stating how we as legislators and as natives of the western coal-producing states feel about our role in becoming one of the major producers of coal-related energy and chemical products is similar to the groom at his shotgun wedding. We are apprehensive, to say the least, as to the ultimate outcome. We do not have complete freedom of choice. It will certainly change our quality of life. We are concerned about the increase in population, but are realistic enough to recognize that we are forced to go through with the marriage. Other alternatives could be worse than the bride. Also, we were aware that this could occur, but we did not plan on it being this sudden. Or, put another way, we have two groups advising us that our choices are cattle or coal, food or fuel, pollution and people or pure air, wheat or gas, clean water or prosperity, noise or solitude.

Jan 1, 1976

By Günther M. Volkmann

Continuous developments in tunneling require knowledge transfer between designers and suppliers to optimize the application of support systems. This collaboration allows the designer access to the latest research results, technical innovations, and support specific measurement techniques as well as the supplier?s experiences on recent projects. Project specific requirements determine the information that can be used to increase support system efficiency, advance rate, degree of safety, or decrease costs. This cooperative effort results in not only an unambiguous tender document, but also an optimized design with reduced risk that is coordinated with safe and high performance construction techniques. This paper will address the benefits of an early collaboration to both the design and the specifications in the tender document by using the A3 Hindhead project (UK) as an example.

Jan 1, 2008

By R. V. Tomkins

Introduction In the past fifteen years, bentonite production in the United States has increased very rapidly. From l50,000 tons in l934, it rose to 400,000 tons in l 942 and to a record 920,000 tons in 1948. Occurrences of bentonite ?in western Canada were described in the early part of the century by Ries and Keele (3), Ells (2), Spence (4). and other officer of the Dominion Department of Mines, and, in Saskatchewan, Professor W. G. Worcester (6), of the University of Saskatchewan has explored and carried out tests on deposits of the material at various times during the past thirty years. Nevertheless, Canadian developments have not kept pace with those in the United States. Exact figures for total Canadian production are not released, but it is probably under l0,000 tons annually. There are a great number of uses for bentonite, but in the United States three alone account for 90 per cent of the consumption. These are for drilling gel, foundry sand bond, and oil decolorizer. The tremendous oil exploration programme on the Canadian prairies has increased the possibility of an adequate domestic market for drilling gel. Therefore, in Saskatchewan, our efforts have been directed mainly to the production of a good drilling gel, with a minor part of the project devoted to activation of bentonites for oil decolorizing.

Jan 1, 1952

By L. M. Demers, R. E. Edelson, M. P. Rose, D. T. Superdock

The pulmonary alveolar macrophage is a major defensive cell which counteracts the invasive properties of bacteria and particles when these substances invade the pulmonary environment. Pulmonary exposure to coal dust particles is believed to activate these macrophages to release a host of d1emical mediators which can neutralize or contribute to the harmful effects of these dust particles. Our efforts have been concerned with assessing a specific family of mediator substances produced by the alveolar macrophage from arachidonic acid when these cells are in contact with activating substances such as coal dust. Metabolites of arachidonic acid produce a vast array of effects which can impact significantly on pulmonary function both with normal pulmonary events and with pathologic processes of the lung. Our studies demonstrate that isolated alveolar macrophages obtained from rats or guinea pigs cultured in vitro release appreciable amounts of the cyclooxygenase products prostaglandin E2 and thromboxane A2 and release significant amounts of the lipoxygenase products .5-HETE and LTB4. In the presence of l x 104 -1x10·7 g/ml of a coal dust suspension, alveolar macrophages from the rats and guinea pigs alters their pattern of arachidonic acid metabolite release. In the rat, exposure of alveolar macrophages in vitro to the higher concentrations of coal dust causes a significant reduction in PGE2, TXB2 and LTB4 in a 4 hour time course study. In contrast, macrophages from the guinea pig in response to coal dust had little change in TXB2 release, only a slight inhibition in PGE2 production and an initial stimulation in LTB.t release over the 4 hour time course. Cells from guinea pigs released considerably more TXB2 than the rat under these conditions while rat cells formed considerably more LTB4 than guinea pig alveolar macrophages. These findings support the following conclusions.

Mar 1, 1989

Many industries base their decisions on the assaying of tiny analytical sub-samples. The problem is that most of the time several sampling and sub-sampling stages are required before the laboratory provides its ultimate assays using advanced chemical and physical methods of analysis. As long as each sampling and sub-sampling stage is the object of due diligence using the theory of sampling it is likely that the integrity of the sought after information has not been altered and the generated database is still capable to fulfil its informative mission. Unfortunately, more often than not, unawareness of the basic properties of heterogeneous materials combined with the unawareness of stringent requirements listed in the theory of sampling, lead to the conclusion that massive discrepancies may be observed between the expensive outcome of along chain of sampling and analytical custody, and reality. There are no areas that are more vulnerable to such misfortune than sampling and assaying for trace amounts of constituents of interest in the environment, in high purity materials, in precious metals exploration, food chain, chemicals, and pharmaceutical products. Without the preventive suggestions of the theory of sampling serious difficulties may arise when making Gaussian approximations or even lognormal manipulations in the subsequent interpretations. A complementary understanding of Poisson processes injected in the theory of sampling may greatly help the practitioner understand structural sampling problems and prevent unfortunate mistakes from being repeated over and over until a crisis is reached. This paper presents an overview of the theoretical, practical and economic difficulties often vastly underestimated in the search for quantifying trace amounts of valuable or unwelcome components.

Jan 1, 2010

By D Beahm

Introduction The Energy Metals Corporation (EMC) holds numerous mineral properties in the northern portion of the Great Divide Basin including the JAB Property, one of several potential properties being planned for development as a satellite facility to the greater Antelope Uranium Project. A National Instrument 43-101 Technical Report has been completed for the JAB property. This report estimates total measured and indicated mineral resources on the property totaling 3,555,022 pounds U3O8 contained in 2,400,875 tons at an average grade of 0.073 % U3O8 at a .25 GT cutoff in accordance with CIM Standards on Mineral Resources and Reserves. The JAB Property is located in Sections 13, 14, 15, 16, 21, 22, and 23, Township 26 North, Range 94 West, approximately Latitude 42o 14’ North and Longitude 108o 00’ West (Figure 1, Location Map). This property consists of unpatented mining lode claims and Wyoming State mineral leases comprising approximately 2,100 acres.

Jan 1, 2007

By John. A. Lombardi

Membrane technology for mining applications has gone beyond producing high-quality water from well- and sea-water by pushing forward with process water treatments to recover and concentrate metals, reagents and clean, discharge-quality waters. Therefore, the main objective of this work is is presenting state-of-the-art process alternatives using membrane technology to face four treatment issues common in the copper, gold and in general all the mining industry regarding process waters and streams that offer treatment challenges to the metallurgical and process engineers.

Sep 14, 2009

By M. J. Allan

"The paper describes the author's experiences in the startup of autogenous and semiautogenous grinding circuits gained over the last twenty years on both large and small grinding circuits. Typical phases in commissioning from construction to startup with ore are covered. The paper also describes experiences with material handling systems, slurry pumping, vibrating screens, trommel screens and pebbles crushing systems. INTRODUCTIONThe commissioning of any new mineral processing plant is an important and exciting milestone in any project. It is at this point in time that the efforts of developers, design engineers, equipment suppliers and operators culminate in a finished product. The successful completion of any project requires that the plant achieve design throughput as quickly as possible. The success of any startup can generally be anticipated by the amount of careful planning which takes place before equipment is operated. The first part of this paper describes the steps in going from construction through to introduction of ore. The organization and planning of startup activities is also covered.The second part of this paper describes some typical problem areas and past experiences in the startup of semi-autogenous grinding circuits. Semi-autogenous grinding circuits present some special challenges in the startup phase. The description of some of these problems and experiences will hopefully provide other operators with suggestions on how to avoid (or at least prepare for) these problems."

Jan 1, 1992

By Rimas Pakalnis, Tom Brady, Lewis Martin

A major focus of ground control research presently being conducted by the Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) is to incorporate weak rock masses (such as are associated with operations in the Carlin Trend in Nevada) into existing design relationships. The original database that led to most of the empirical design relationships presently employed in hard-rock mining was derived from fair-to-good-quality rock. In this study, the relationship between weak rock quality and opening design (nonentry/entry methods) is being investigated. The common factor in all mines is a weak back or wall. This work attempts to provide tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment.

By A. Ahmed, A. Fathy, M. Eissa, K. El-Fawakhry, A. El-Mohammady

Silicomanganese is widely used as a complex reducer and an alloying addition in the production of various grades of steel due to its economic and metallurgical advantages. It is also used as a semi-product in the manufacture of medium- and low-carbon ferromanganese and metallic manganese. Manganese-rich slag, resulting from high carbon ferromanganese production, has the advantages of high manganese content, high Mn/Fe ratio, low excess oxygen, low phosphorus content, low fine content and low cost. Such slag seems to be very attractive to use as raw materials for the production of silicomanganese alloys. In the present study, experimental heats were designed and carried out to optimise the factors affecting the production process of silicomanganese using manganese rich slag in the charge. The results of pilot plant experimental heats showed that the optimum metallic yield and recoveries of manganese and silicon are obtained with initial slag basicity,(CaO + MgO) / (Al2O3), equals 1.8 by using dolomite as fluxing material and charging quartzite and fluorspar in percentage of 25% and 4% of the blend, respectively. The results showed also that an amount of 30% of coke in excess of the stoichiometric amount should be added. These result are relative for the specific high Al2O3 ores used.

Jan 1, 2004

By Thomas P. Mucho, Dennis R. Dolinar, Anthony T. Iannacchione

The Chestnut Ridge Anticline is a prominent structure in southwestern Pennsylvania, USA. This structure has brought two economically valuable limestone formations to the surface, where they are easily accessible to room-and-pillar mining. Nine active crushed stone quarries, an underground research facility, and one industrial facility currently operate along the linear trend that represents the axis of the anticline. The National Institute for Occupational Safety and Health (NIOSH) has identified significant variation in levels of horizontal stress within relatively short distances at shallow overburdens along the anticline. At one quarry, the horizontal stress is high enough to shear strata with a modulus of approximately 77 Gpa. Conversely, zones of extension were observed in parts of another quarry, indicating very low horizontal stress conditions. This study found that high levels of horizontal stress are to be expected in this very stiff rock formation and that local geologic and topographic structures are capable of altering the magnitude and possibly the orientation of the horizontal stress field.