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By Conny Postupack

To make money in mining coal you have to sell it for a lot more than it cost you to get it out of the ground. And yet, every year it cost us more and more to stay inbusiness, while the price we get for coal does not increase at the same rate.

Jan 1, 1990

By Michael G. Rulff, Tracy M. Holmes

"Vast amounts of time and money are spent fighting flow problems in plants that involve the handling or processing of industrial minerals. Because these types of projects tend to be capitalintensive, the right decisions, made at the design stage, can have a substantial positive effect on the economics of the project.Some of the problems related to solids flow in mineral processing plants include:•,Flow stoppages•,Uncontrolled flow•,Segregation of blended materials•,Build-up and dead material resulting in loss of live capacityUnfortunately few Universities in North America provide courses in the design or selection of bulk solids handling equipment, let alone the theory of bulk solids flow, with the result that engineers do not fully appreciate the effects of bulk solids handling on their process. The usual method of selecting “standard” equipment, all too often, leaves plant operators hammering on hoppers to promote flow, a technique that is not only usually ineffective but also unsafe and often causes damage to equipment. In short, too little consideration is given, at the design stage of projects, to the particular material and operating environment involved and how these will affect handling between process steps.This paper seeks to give a general understanding of bulk solids flow theory including flow patterns and flow property tests, and presents functional design guidelines to ensure reliable flow. As well, a case history will be presented. Our message is clear: To ensure uniform, reliable flow, a plant design must take into account the specific flow characteristics of the bulk solid to be handled or processed."

Jan 1, 2008

By M. D. Marshall

A survey showed that there were 24 bin-related fatalities in the 5 year period of 1975 to 1979 in the minerals industry. Only 4 victims wore safety belts and only 1 of these had a second person attending his lifeline, as mandated by Federal safety regulations. Not one victim observed the three main Federal safety regulations governing work in and around bins. A study was conducted on the force necessary to pull victims partially buried in sand and limestone. Recommendations are made on procedures and safety equipment that can minimize bin-related accidents. A Handbook, directed to the plant engineer responsible for bin design and safety, was also issued detailing bin designs and flow-aid accessories as a function of the flowability of the stored material to better maintain material flow from bins. A comprehensive table of the flowability of many materials produced in the minerals industry is presented and simple procedures given for determining the flowability of materials if not available.

Jan 1, 1984

Additional Attractive Force Between Alumina Particles Due to Low Solubility of Dicarboxylic Acids

Sep 13, 2010

By R. Falcon, P. den Hoed, A. Luckos, R. Erasmus, V. du Cann, D. Comins

Carbon as a reductant, additive or filler is an essential element in the processing of metallic ores and the manufacture of iron and steel in the metallurgical industry. In most cases, the element carbon is derived from coal and its carbon derivatives. The properties of carbon required for the different processes in each metallurgical sector vary significantly and, for this reason, matching the correct carbon product for each specific process has become an important if not vital function in all sectors of this industry. This selection process, however, has become increasingly difficult. In many cases, the substitution of new products, despite being similar in all relevant chemical specification characteristics to previous products, has resulted in different performance properties relative to that expected. Under these circumstances, the prediction of performance of unknown carbon products has become fraught with difficulties unprecedented in the past. In order to initiate an investigation into addressing these issues, a test case was selected for indepth study the results of which are reported in this paper. The case concerned the use of a specific carbon feed in a conventional submerged arc furnace which gave rise to an unprecedented amount of unreacted or only partially consumed residue trapped in the frozen slag on the refractory walls of the furnace. During the course of these investigations, different advanced analytical technologies were employed including, inter alia, Raman spectroscopy, surface dimensional tests, organic petrology and various thermal reactivity factors. All results have been integrated into a multidisciplinary assessment presented in summary in this paper. Based on the above, and previous experience, the concept of an all-embracing 3-D coal-carbon ?framework? is briefly introduced. This approach has succeeded in obtaining greater depth of knowledge and a better understanding of the issues at stake with specific reference to the organic composition, structure, texture, internal surface area and consequent reactivity of the carbon materials concerned. In consequence, it would now appear that various properties of relevance to the metallurgical industry may be predicted with greater precision than has hitherto fore been possible.

Jan 1, 2004

Jan 1, 1997

By Fookes R. A, Gardner K. J, Gravitis V. L, Watt J. S, Steffner E. J

Two radioisotope techniques suitable for the rapid laboratory determination of the ash content of coal have been tested ou unwashed coal samples from four Australian coal seams. In one techniqne, measurements of backscattered 238Pu L X-rays and iron K X-rays from finely ground coal samples have been combined to determine ash content in uuwashed coals to ±0.5 weight per ce111 ash (ls) for three seams and 0.9 weight per cent ash for the fourth.The second technique, which involves measurements of the transmission by the coal of narrow beams of 241Am 60 keV and 123Ba 356 keV ? rays, requires less sample preparat ion. The ash was determined to within the range of 0.8 to 2.6 weight per cent for the four seams (unwashed coal). For washed coals, errors are expected to be < ±0.5 weight per cent ash.

Jan 1, 1982

By Arpit Parikh

"Ground Water or Pore water pressure development in Sandy Soil formation is Critical situation in foundation analysis and design.Moreover it become severe while associated with higher liquefaction probability in river bank areas. It is difficult to find cost optimized solution for liquefaction mitigation under limited budget allocated for the project. Here in these research paper the attempt has been made to have clear picture of liquefaction by using various techniques and field tests. And its mitigation by suitable foundation type. In Bangladesh, On Bank of River Meghana, Power plant structures are proposed. The particular site is full of fine sand having partial silt throughout from EGL to 55 m depth. Hence in addition to Conventional Boring / Drilling operations, CPLT, SCPT, SCHT and PMT had been performed to arrive deterministic effect of liquefaction. By use of Geologismiki software and some excel based programs developed which indicates that Certainly liquefaction occurs under the event of earthquake. By Checking past records of Bangladesh we found, there are small magnitude earthquakes are inevitable and frequent. Hence fourth to overcome the bad effect of liquefaction, the deep pile foundation -Driven Pre Cast Solid Square Pile of 400 mm dia. had been suggested for various types of power plant structures. Which densify the soil and ground will improve in resisting liquefaction.1. INTRODUCTIONA Detailed Geotechnical/Foundation design Analysis had been done to arrive at optimum foundation design solution in highly probable liquefaction zone of Silty Fine Sand near Dhaka City of Bangladesh for proposed 750 MW Cyclic Power Plant. Hence about 24 no. of (Borehole) Boring and Drilling up to depth of 55 m from existing ground level has been carried out. Additionally, 09 nos. of Static Cone Penetration Test (SCPT), 02 Nos. of Dynamic Cone Penetration Test (DCPT), 02 Nos. of Pressure meter test (PMT), 02 nos. of Cyclic Plate load test (CPLT) of suitable capacity with 06 nos. of Seismic Cross Hole Test (SCHT) in boreholes had been carried out. The purpose of PMT and SCHT was to have clear idea about the Seismic behavior - knowhow of site. According to Basic principles of Soil Mechanics and foundation design, it is proved that PMT & SCHT are dynamic test. These tests stimulate field condition of occurrences of earthquake. In later stages of analysis, it is found that site have high probability of liquefaction through use of Geologismiki – Liquefaction Analysis Software. Author of these research paper also felt earthquake vibrations – strong aftershocks during site study where Epicenter of the earthquake was in Myanmar during month of august 2016."

Jan 1, 2017

By B. Asbury, M. Cigla, C. Balci

The Western Mining Resource Center (WMRC) at the Colorado School of Mines (CSM) received a grant from the National Institute for Occupational Safety and Health (NIOSH) to perform a study that will help reduce the amount of respirable dust generated from the cutting of coal. The study is based upon laboratory testing and field experience. This information is being used to develop a new cutterhead design in conjunction with Joy Mining Machinery. The new cutterhead design is being evaluated with existing computer models developed at CSM. The new continuous miner cutterhead will be tested at the Twenty Mile Coal Company’s Foidal Creek Mine. Baseline testing with the current cutterhead will also be performed. This paper presents laboratory test results, design methodology, and test results performed to date.

Jan 1, 2002

By Shreyas Giridharan, Fursan Hamad, Sujith Gowda, Christian Moormann

"Pile installation in soil is a dynamic process which exhibits large deformation in the soil region. Experimental investigation of pile installation is both time and resource intensive. Numerical investigation can be a helpful tool for the analysis of the installation process. Furthermore, numerical analysis allows simulating various soils and loading conditions with ease. Finite Element Method (FEM) – a widely used framework for numerical simulations - fails to perform well for soil mechanics where large deformation and heavy material movement exists. In order to alleviate this shortcoming, Material Point Method (MPM), advancement to FEM has been used. In MPM, material points (particles) are used to represent the domain which carry the information and move over a fixed computational mesh where the governing equations are solved.In the present work, a variation of MPM, called CPDI (Convected Particle Domain Interpolation) is utilised which handles large deformation problems better than the classical MPM. Here, the material points are represented by a spatial domain which deforms according to the particle deformation. This eliminates stress oscillations while particles cross the grids. Implementation is validated and applied to pile installation in dry and saturated soil conditions. A 2D axisymmetric model is chosen, with penalty function method being used for evaluating contact between soil and pile. Sand is modelled via the hypoplastic constitutive description that takes into account large deformation, as well as small strain stiffness. From these simulations, various parameters like stress, void ratio and friction angle are studied.INTRODUCTIONOffshore piling is challenging in terms of testing and execution. Before the execution, predicting an efficient installation method requires study of various parameters, like soil conditions, type of loading, force requirement etc., and are the minimum parameters to be known beforehand. To obtain these parameters, testing a real scale prototype under different conditions is not feasible. Scaled model tests in lab can support in making certain decisions, but fail to replicate real behavior fully. Therefore, the need for a numerical simulation technique emerges, which can provide early predictions easily and accurately. This later can be extended to real scale tests, reducing the number of experimental investigation required.Simulation of displacement pile installation in sand involves large deformation due to penetration process, thereby making the application of FEM impossible, where large deformation causes heavy mesh distortions. Due to this, meshless methods are developed to treat large deformation in a better way. Among various meshless methods, Material Point Method (MPM) shows more applicability to geomechanical problems. This is mainly due to the ease of handling soil, structure and water in a unified manner."

Jan 1, 2017

By W. C. Lacy

Stratabound copper ore bodies in thick Proterozoic metamorphosed sedimentary and volcanic rocks at the Tong Kuang Yu Mine in southern Shanxi Province of China were considered as possibly being amenable to block cave mining. Initial evaluation of caving characteristics was based upon old calyx drilling records, limited underground mining experience and geological mapping, a few diamond drill holes and measurements in surface subsidence features. Classification and mapping distribution of rock quality types aided in mine design, prediction of fragment sizing and explosive requirements, cave assist and ground support requirements. Comparison is made between early feasibility predictions and actual mine experience.

Jan 1, 1989

As the question of zino recovery from lead blast furnace slags has lately become such an important subject with lead metallurgists, the following description of some of the work carried out in this oonnection by the Sulphide Corporation, at CockleCreek, should prove of interest to those concerned. Early in the life of the works it was realised by the metallurgical staff that a very wide field for investigation lay before them. At the head of these was the late Mr. F. H. Evans, and it was due to his work and suggestions that the question has grown from a mere hypothesis to a commercial undertaking, in so far as these works are concerned. A great deal of the early work was carried out in the form of small laboratory expe!iments, those giving the best results being ear-marked for subsequent trial on a larger scale. One of the main obstacles in the way of research was the lack of any data or information of similar work done in other...

Jan 1, 1920

"WELCOME/BIENVENUE TO THE COM 2014 IN BEAUTIFUL VANCOUVER!On behalf of the organizing committee, I would like to extend my thanks to you for participating in this year’s Conference of Metallurgists. Recent times have been extremely difficult for the resource sector, but it is crucial for our industry to maintain personal connections through good and bad times. These interactions include technical exchanges, and this is at the heart of MetSoc’s service to its members. The theme of this 53rd Conference of Metallurgists is Prosperity Through Process Advancements. There are thirteen symposia at this year’s conference mainly focused on processing from extractive fields, to materials and the environment. Supporting these topics are the plenary, poster session, and trade show plus opportunities for socializing at functions like the opening reception and the awards banquet.Many people have contributed to this conference, from the authors and presenters to the organizers and the generous sponsors. They are all gratefully acknowledged for their quality work over the last two years. A particular thank you to our student volunteers whom we hope will take advantage of their time at COM to network and to learn about this exciting industry.Again, thank you for being a part of this exciting conference of metallurgists. I hope it will be a memorable experience and that you are able to take advantage of all the conference and Vancouver have to offer."

Jan 1, 2014

By D Craw

Bulk ore tailings from the Macraes gold mine gold extraction process are stored in a large (ca 0.6 km2, 80 m deep) mixed tailings impoundment whose pH is maintained near 8 by natural rock neutralizing capacity. The mixed tailings will be stored in this impoundment in perpetuity after mining ceases. Confidence in the long term environmental stability of these tailings can be gained from examination of mineralogically and chemically similar geological situations in the immediate vicinity. A sequence, typically about 5 m thick, of sands and gravels derived from the Macraes mineralized zone 12 000 to 28 000 years ago contains rounded detrital sulphide mineral grains which are unoxidized despite close proximity to the surface and occasional incursion of oxygenated waters. Saturating water pH is currently 7-8. Sands with 0.2 to 0.8 wt % organic carbon host sulphate-reducing bacteria (SRB), and localized cementation by authigenic framboidal pyrite has occurred. Comparison of the 28 000 year-old sediments with the modem tailings suggests that similar chemistry will prevail, possibly with deposition of authigenic pyrite in the tailings, in the long term. As long as the present slightly anoxic and circumneutral pH environmental conditions are maintained in the mixed tailings dam, sulphide decomposition and acidification are unlikely. These sediments provide a plausible geological analogue for long-term benign storage of the mixed tailings impoundment.

Jan 1, 2000

By René Lefebvre

Numerical simulations of the physicochemical processes related to acid rock drainage (ARD) in the Sugar Shack South rock pile of the Questa Mine were performed with the TOUGH AMD simulator. The objectives were to 1) identify the main processes responsible for observed present-day conditions, 2) provide an estimate of gas phase humidity transfer, and 3) give a preliminary indication of the potential impact of closure involving the installation of an alluvial soil cover. Modeling results indicated that the mine rock geometry (thin layers placed along steep mountain slopes) favors the onset of strong thermal air convection. Simulations also indicate that resloping the piles would not significantly reduce convection and oxidation. For simulation purposes, a potential cover with the permeability range of a local alluvium was investigated and found to be of questionable effectiveness since its permeability can exceed the value of 3x10-13 m2 required to prevent thermal air convection and reduce ARD.

Nov 1, 2002

By J. Bakken, M. Th. Jonsson, G. Sævarsdottir

A typical three-phase submerged-arc furnace for production of silicon metal and ferrosilicon has arc currents ~100 kA, phase voltages ~100 V and total furnace power ~10 - 60 MW. The arcs burn in gas filled cavities or "craters", where the main atomic components of the plasma mixture are silicon, oxygen and carbon. Two quite different simulation models for high-current AC arcs have been developed: the simple Channel Arc Model (CAM), and the more sophisticated Magneto-Fluid-Dynamic Model (MFD). These models have been described extensively and results reported at INFACON-8 and INFACON-9, respectively. The coupling between the arcs and the AC power source is described by a complete three-phase Electric Circuit Model. Recent numerical modelling studies of industrial AC arcs show that the boundary conditions at the cathode and anode are critical for the simulation results. A novel Cathode/Anode Sub-Model for high-current AC arcs that treats both cathode and anode indicates a completely different cathode behaviour than previously assumed. A cathode spot which serves a high-current electric arc is shown to be dominated by the energy impact from the arc. This leads to lower cathode fall voltage than obtained from previously developed models. The anode fall voltage is negative, as the main function of the potential barrier is to repel plasma electrons. The cathode spot is diffuse in the sense that the arc in fact contracts away from the cathode. Simulation results are compared to measurements on both industrial furnaces and smaller scale pilot furnaces. An important conclusion, supported by our arc studies, is that the arc length in silicon metal and ferrosilicon furnaces does not exceed 15 cm and the arc may burn anywhere on the electrode, not necessarily beneath the electrode tip.

Jan 1, 2004

By Wilton Johnson

The Bureau of Mines study indicates that land utilized by the mining industry for mineral extraction and processing from 1930 through 1980 amounted to 5.7 million acres, or 0.25 percent of the land mass in the United States. Land reclaimed by the industry during the same period was 2.7 million acres, or 47 percent of the land utilized. Land use by the mining industry includes surface land used for excavation or mining, for waste from underground mining, and for wastes from milling or processing operations. Data on land use for disposal of overburden waste from surface coal mines and on areas affected by subsidence associated with underground mining are included for the period 1930-71 only. The 10 leading States in total land used for mining over the 51-year period were, in decreasing order, Pennsylvania, Kentucky, Ohio, Illinois, West Virginia, Florida, Indiana, California, Alabama, and Missouri. Seven mineral commodities accounting for 92 percent of land use are, in decreasing order, bituminous coal, sand and gravel, stone, phosphate rock, clay, copper, and iron ore, all predominately surface mined. Bituminous coal production was responsible for nearly half of the total area utilized. Reclamation of mined lands and waste disposal sites over the reporting period was largely on lands utilized in mining bituminous coal; 75 percent of the land used for bituminous coal production was reclaimed.

Jan 1, 1981

By Christopher C. Jobes, Alan G. Mayton, Timothy J. Matty, Joseph P. DuCarme

Mining injury statistics show that a significant number of back, neck, and head injuries are linked to exposure from vehicle vibration. Use of a suspension seat is a common way to isolate the vehicle operator from the adverse effects of vibration exposure. Thus, researchers at the National Institute for Occupational Safety and Health1 – Pittsburgh Research Laboratory (NIOSH – PRL) performed laboratory studies on four passive and two semi-active seat suspension designs. These are typical of seat suspensions commonly found on large off-road heavy surface mining, construction and agricultural vehicles as either replacement or original equipment manufacturer (OEM) systems. One included a pneumatic (air bladder) spring mechanism. The fifth and sixth suspensions were a NIOSH magnetorheological (MR) semi-active damper design based on the pneumatic (air bladder) and one of the coil spring suspensions above. These suspensions were modified with a commercially available MR damper substituted for the OEM damper. These six seat suspension systems were tested and analyzed, for vertical vibration only, using the ISO 5007 Standard [1]. This paper describes the laboratory vibration tests using a MTS® shaker table and discusses the results obtained for the different suspension designs and highlights the rheonetic technology studied. Implications of the seat suspension designs relative to their capabilities for isolating vehicle operators from vibration exposure are discussed. Results for suspensions 1 through 3 showed frequencies of isolation from 2.1 to 3.0 Hz using the 40-kg (88-lb) mass and from 1.65 Hz to 1.8 Hz using the 80-kg (176-lb) mass. Suspension #4, in tests with only the 80-kg (176-lb) mass, showed an isolation frequency of 3.7 Hz. With the MR damper added to seat suspension #4, the peak transmissibility was lowered from 1.3 to 0.95 and showed a corresponding downward shift in frequency from 2.25 Hz to 1.4 Hz. In fact, the results for suspension #5 (the MR damper added to seat suspension #4), using test #3 conditions of the programmed control algorithm, showed isolation (attenuation of transmitted vibration) throughout the test frequency range from 1.0 to 6.0 Hz.

By Inn-Joon Park

Major problems associated predicting soil-structure interaction behavior are based on the fact that soil is neither homogeneous nor elastic and soil properties are spatially variable. There also exist significant coupling problems between the behavior of the structure and geologic media. When designing foundation or other geotechnical structures, the load transfer between the soil and structure takes place at the contact surface. This surface is called the interface. The behaviors of interface play an important role in the load-deformation response of soil-structure interaction systems. The purpose of this study is to develop improved model for simulation of saturated sand-steel pile interface behavior based on a general concept, called the disturbed state concept (DSC), which can characterize the behavior of saturated soils under dynamic loads. In this study, the Disturbed State Concept (DSC) constitutive model is calibrated and modified for steel pile-saturated sand interface and interaction by using the continuous hardening model for relative intact (Rl) state and the critical state model for the fully adjusted (FA) part in the saturated sand material. The general formulation for implementation has been developed. Then, the DSC model with modification for interface and saturated sand is implemented in finite element program based on the generalized Biot's theory. The interface tests under one-way monotonic and two-way cyclic loading and cyclic triaxial tests are executed for defining the parameters for interface and surrounding soils. Based on these parameters, steel pile-saturated sand interface and interaction are numerically simulated using the finite element program modified in this study. The DSC predictions show improved agreement with the observed results from laboratory test.

Jan 1, 2002

By Walter Ensinger

Working safely means working cost-effectively. Every "dangerous occurrence" and - even more so - every industrial accident causes disruptions in the planned course of construction. Besides moral and legal obligations, economic aspects are therefore also factors motivating increased efforts towards optimal prevention: improvements in work safety and protection of health are wise investments! Ever since its earliest days, the European Federation of Foundation Contractors (EFFC) has made this subject one of its key objectives and therefore set up a Safety + Environmental Working Group, in which experts from the member organisations exchange national experience and develop proposals for "best practices". The paper presents current developments and results from the work of the S+E WG with particular reference to the project "Ideas for Safety Improvement".

Jan 1, 2006