Search Documents

By Kwang-suk You

This paper describes the characteristics of electric arc furnace slag (EAF slag) as an aggregate of concrete along with the chemical composition, leaching concentration of heavy metals, the soundness of EAF slag and compressive strength of mortar with 20% and 50% replacements of sand. The results showed that leaching of heavy metals and soundness of EAF slag satisfied Korean environmental limit and Korean Industrial Standard for aggregates. The compressive strength of mortar increased as the replacement ratio of EAF slag for sand increased.

Jan 1, 2006

By Nils Eivind Kamfjord, Halvard Tveit, Ingeborg Solheim

"Because of its negative environmental effect the attention towards NO emissions increases. This again leads to new demands from the authorities for better surveillance and control of emissions. Earlier and recent industrial measurements towards FeSi- and Si-metal furnaces reveal quite high NO-emission. The NO is believed to be produced in the combustion zone above the furnace surface, mainly as thermal NO.In order to expand the knowledge on NO-formation in silicon metal production, a pilot scale experiment in a 440 kVA silicon furnace has been carried out. The experimental set-up was designed with a view to be able to copy and manipulate the formation mechanisms for NO by controlling the flow of false air into the off-gas system.The resulting NO-values corresponding to the different air inlet to the furnace top, show significantly differences between the different air inlet geometries.IntroductionNOx is the common notion for the two gases nitric oxide (NO) and nitrogen dioxide (NO2). Since combustion of fuels, such as gasoline, diesel, bio diesel, propane, coal, and ethanol, forms NOx the dominating contributors to NOx emissions are the on-/offshore transportation industry and power generation based on fossil fuels [1]."

Jan 1, 2012

By Ralph Monaghan, Arthur Youmans

General principles of scintillation counter-type instruments for radioactivity logging are discussed and the various possible causes for instability are examined. It is shown how instrumentation problems are solved. Means are discussed for minimizing drift and instability due to "fatigue" of the photomultiplier tube and neutron activation of the crystals. INTRODUCTION Neutron and gamma-ray logs made with logging instruments employing scintillation counters are now routinely available from most of the logging service companies. The superior characteristics of scintillation counters by comparison with older types of detectors promises to bring about important improvements in quantitative interpretation of radioactivity logs. Moreover, new types of logs can be made with scintillation counters which are not possible with other detectors. But in spite of the obvious superiority of these counters with respect to efficiency, speed, and versatility, they suffer from a number of inherent difficulties and weak- nesses. Unless these inherent diffi-culties are fully recognized and satisfactorily overcome by sound engineering of the associated instrumentation, scintillation counter logs are particularly likely to exhibit drift and instability of sensitivity. This defect in logs when they are intended for quantitative interpretation is intolerable and more than outweighs any advantages over the older type of instrumentation when the latter is operating correctly. SCINTILLATION COUNTER OPERATION In general all radioactivity logging instruments consist of a detector sensitive to gamma radiation or to neutron radiation coming from the strata. This radioactivity is either due to naturally decaying radioactive elements in the rock, radioactivity induced in the rock by a neutron source in the instrument, or scattering by the rock of neutrons or gamma rays coming from a source in the instrument. In the scintillation counter the gamma radiation or neutron radiation reacts with the scintillation phosphor to produce light pulses. These light pulses are then converted to amplified electrical pulses by the multiplier phototube. Basically the problem of making a good scintillation counter logging instrument is to make the radiation sensitivity of the system as nearly constant as possible. The size of each scintillation counter pulse is dependent on the energy of the individual quantum of radiation being detected. In normal radiation logging, gamma rays of all energies, up to some maximum value, reach the detector. If a suitable scintillator is used, such as a sodium iodide crystal, each gamma ray produces a number of photons proportional to the energy absorbed by the crystal from the impinging radiation. The light flashes are detected by means of a photo-multiplier tube which contains not only a photo-sensitive cathode from which photoelectrons are collected, but also an amplifier, called an electron multiplier, built inside the photomultiplier tube; the electron multiplier usually has about 10 stages, having an over-all gain of perhaps 500,000. In an ordinary gamma-ray log one wishes to detect all gamma rays down to the lowest possible energy; therefore, one wishes only to reject the "noise" pulses which are invariably present due to thermal emission of electrons from the photo-cathode of the photomultiplier. In other radioactivity logs it may be desired to measure the radiation within a particular energy band, or above

Jan 1, 1958

By B. R. Zernich

Advances in tunneling technology, such as Earth Pressure Balance and Slurry Shield methods, have allowed the tunneling industry to construct tunnels in increasingly difficult ground conditions. In recent years, a number of civil projects including large diameter train tunnels, subway tunnels, water tunnels, sewer tunnels, and combined sewer tunnels have been successfully completed deep beneath the water table in soft ground conditions utilizing modern day Tunnel Boring Machines (TBM). With the increase in difficult ground conditions and higher water pressure comes the inherent need to utilize compressed air to gain access to the TBM?s cutterhead and cutting tools. This paper focuses on one such instance in Los Angeles, CA in which Traylor Brothers Inc. performed a cutterhead intervention by compressing the heading of an 11-foot diameter tunnel to approximately 3 bar gauge pressure. This paper focuses on the environmental controls used to manage ventilation, oxygen levels, temperature, and pressure, as well as discusses the problems associated with toxic gases and the increased risk of fire. The paper will also cover the physical science of the environment and the increased risks of performing basic job functions while in a compressed air heading.

Jan 1, 2009

By Charles E. Heinrichs

IN the last decade one of our oldest and largest non-metallic metallic mineral industries has been the subject of persistent technical research, the results of which are another example of the benefits following the systematic application of scientific principles. The consequent improvement in the technique of phosphate recovery represents the greatest material advance in the industry since the discovery of phosphate in Florida in 1881. Moreover, these successes have stimulated interest and development in numerous other nonmetallic industries. Strange as it may seem, and despite the fact that the phosphate deposits of Giles County, Tennessee, together with those of Polk and Hillsborough Counties, Florida, have yielded more than 50,000,000 long tons in the last twenty years, the mineralogy of phosphates has been given scarcely any space in our technical literature. For many years it was the general consensus that these so-called phosphate rocks represented a physical mixture composed principally of tri-calcium phosphate, together with smaller quantities of calcium carbonate, calcium fluoride, iron phosphate, aluminum phosphate and other less important constituents. More recent investigations, however, led to the conclusion that these phosphates really represent a complex mineral in which calcium, iron, aluminum, phosphorus pentoxide, carbon dioxide, and fluorine all form a definite part of the molecule. Colony, after a careful study, utilizing chemical, microscopic, and X-ray diffraction methods, reported that American phosphates consist principally of calcium-carbono-phosphate of the staffalite type.

Jan 1, 1933

By J. Piper

Markets and Production Beryllium (Be), an extremely light metal, is used in many specialty applications. It the lightest element in Group 2A of the periodic table, with a specific gravity of 1.85 gm/cc, and a high melting point of 12850C (Calvert, 2004). The functional properties of beryllium are stiffness, strength, dimensional stability, resistance to corrosion from acids, and electrical and thermal conductivity. The ability to reflect neutrons and transmit x-rays, makes beryllium irreplaceable in uses such as precision optical components, inertial guidance systems, and in nuclear reactors (Anon, 1993). Beryllium is used in Cu alloys to strengthen and reduce corrosion in copper wire, and in lightweight oxide ceramics that are used as heat sinks, and as electrical insulators. The market revenue of beryllium can be broken down into the seven major groups below, and are plotted on the pie chart in Figure 1 (Anon, 2005). 1.) Telecommunications & Computer 2.) Magnetic & Optical Data Storage 3.) Aerospace and Defense 4.) Automotive Electronics 5.) Industrial Components 6.) Appliance, and 7.) Other.

Jan 1, 2007

By A. S. Richardson

THE recent installation of a high-pressure propeller type fan at the Moose shaft of the Anaconda Copper Mining Co. at Butte, Mont., is of interest on account of novelty of design and also because an appreciable saving was made over the cost of a reversible centrifugal fan such as is ordinarily used where a high pressure is required. The lower cost is due solely to the fact that by means of controls 'on the power supplied to the three-phase, alternating-current, induction. motor, directly connected to the propeller it is possible to reverse the direction of rotation of the propeller and thus reverse the direction of air flow. The extra air ducts and reversing doors required for this purpose with centrifugal fans are not necessary, and their elimination greatly reduces these construction charges, which form a great part of the total expense. The Badger State mine for which the Moose shaft is used as the main outlet air course is now being-developed to the 4100-ft. level. The old centrifugal fan, formerly used at the collar of the shaft, was installed 15 years ago at a time when most of the stoping was being done above the 2400-ft. level, and when the temperature of the rock was much lower than it is now on the bottom levels recently opened. The old fan, therefore, became inadequate to maintain desirable ventilation conditions, on account of the increase in resistance to air flow incident to the greater depth of the mine workings and because a much larger volume of air is required to offset the higher rock temperatures. Propeller, or disk, fans commonly used in the ventilation of mines are not suited to high-pressure work, but economies in the cost of their installation have long been recognized. In South Africa use has been made of a number of propellers placed in series along a common shaft, the number of propellers used being varied with requirements for meeting different conditions of mine resistance, but the mechanical efficiency is described as being low. In Butte, experimental work was done by the writer along similar lines under somewhat different conditions, but with poor results as to both pressure capacity and mechanical efficiency. Tests were also made of two different types of propeller fans of moderate size, which were said by the manufacturers to be suited to high-pressure mine ventilation.

Jan 1, 1932

By J Jackson, K Nguyen, A Nguyen, E Manlapig

"With the recent advancement in drill core imaging systems, a large volume of high resolution drill core images can now be rapidly collected and mineralogically classified. This paper introduces a novel semi-automated method for rapid prediction of process engineering parameters from this type of image. The aim is to allow for a rapid and low-cost assessment of the ore processing variability within a mineral deposit with a reduced amount of metallurgical test work. This method will see its application primarily in the project evaluation phase, where proper evaluation of the processing variability of the orebody normally requires a prolonged and costly metallurgical test work program. Applying this image-based texture analysis method on the mineralogical classified drill core images, the ores are classified according to their textures. For each engineering parameter, a small number of physical test work is required to produce a data set for training and testing of the predictive model. The paper also presents a case study in which this method has been applied to predict the A*b parameter used in mineral process plant design.CITATION:Nguyen, A, Jackson, J, Nguyen. K and Manlapig, E, 2016. A New Semi-automated Method to Rapidly Evaluate the Processing Variability of the Orebody, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 145–152 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By C. Opoku-Ware, M. Kukay, P. Conrad, F. Inkoom, R. Pal

Researchers at Montana Tech are investigating the potential for developing trees tolerable to degraded un-reclaimed mine site tailings and soils as a solution to re-establishing long-term tree growth on those sites. This project involves growing tree seedlings from seeds planted in the degraded mine tailings and soils in which they will eventually be planted. The outcome of the project is expected to lead to a successful solution for re-establishing tree growth in degraded tailings and soils in Butte, Montana with minimal post-planting human intervention. Work conducted on the project to date has shown successful growth of seedlings in degraded tailings and soils. INTRODUCTION In an effort to improve Butte Area One natural resources, this research project is working to help restore tree growth in the Butte Priority Soils Operable Unit Boundary (BPSOU) (Opoku-Ware, et al 2018). Research by Blicker, et al (2003) found that, the BPSOU, which is part of the Silver Bow Creek/Butte Area National Priorities List (Superfund) Site within and near Butte, Montana has multiple historic mining sites situated entirely within the urban setting of Butte. Mine wastes and mill tailings, accumulated from over 100 years of gold, silver, and especially copper mining are dispersed throughout Butte, posing health risks to human and environmental receptors. Stabilization of tailings sites is needed to control fugitive dust, prevent run-off of toxic material resulting in subsequent sediment deposition in streams, reducing the volume of water seepage through acidic and heavy metal contaminated material, and improving land productivity and aesthetic values (Watkin and Watkin, 1982). If successful, the project will help restore water quality and maintain stream flow in Silver Bow Creek where it flows through Butte Area One. Trees native to Butte are being grown to seedlings in a greenhouse located on Montana Tech’s campus which will be planted in degraded soils located within the BPSOU. Growing trees is expected to help restore vegetative ground cover within the watershed contributing to stream flow in Silver Bow Creek. The trees will prevent soil and tailings from eroding and being deposited in Silver Bow Creek where they could degrade water quality and choke stream flow. The project combines research with tree seedling growth to provide a resource for Butte that could produce thousands of tree seedlings each year adapted to the harsh climate, soil, and tailings conditions that exist in the BPSOU where they will grow. It is anticipated that the trees developed by the project will have the capability for long-term survival and growth because they will be germinated and grown into seedlings in the degraded soils and tailings collected from the BPSOU where they will be planted. Soils and tailings collected for the project have been evaluated to determine if they lack nutrients or contain substances potentially toxic to the long-term growth and survival of the trees. Toxic levels of metals, high concentrations of soluble salts, extremes in pH, nutrient deficiencies and imbalances, surface crusting, high bulk density, low infiltration rates, high surface temperatures, low cation exchange capacity, restricted microbial activity, low water retention, harsh climatic conditions and surface particle movement are some of the traits of mine tailings sites that restrict revegetation efforts (Barth, 1986).

Jan 1, 2019

By David M. Mchaina, Allan E. Hall, W. C. H. Kruining, Alan Coode, Stephen Hardcastle

This paper details an investigation into the feasibility of recirculating mine exhaust air in Saskatchewan potash mines. This project was initiated following a previous study at Ruttan Mine, Manitoba, which indicated that recirculation of exhaust air to reduce winter heating costs was feasible. The potash industry was selected for study because the mines use a minimum of blasting in their production methods and the exhaust temperature is significantly higher than that of most metal mines. These factors simplify the monitoring system required and have the potential for greater waste heat recovery. A series of measurements of underground mine pollutants was made at the main exhaust and intake shafts in order to determine the feasibility of introducing controlled recirculation of exhaust air. An experimental recirculation circuit was created by opening two existing doors situated between the return and intake shafts. During this recirculation trial, the air quality parameters at the intake, mixed intake and exhaust measuring stations were monitored. The results obtained from a questionnaire circulated to the regulatory agency and the major potash producers together with results obtained from underground field studies at Central Canada Potash (CCP) Division of Noranda Minerals indicated that controlled recirculation of mine exhaust air has potential application in these mines either to reduce heating costs and/ or to increase the face air quantities. A recirculation system is to be designed in conjunction with CCP and the Saskatchewan Ministry of Labour, Mine Safety Unit to attempt to implement a working recirculation system for CCP.

Jan 1, 1989

By Edwin G. Johnsen

Underground mining is relatively safe today, but no technique or equipment is completely fool proof and 100% reliable. The only sure way to prevent accidental death or injury to underground workers is to remove them completely from the hazardous environment. This alternate approach to underground work is now feasible. Tunnelling and mining systems can be built that could be remotely controlled by men operating consoles in a surface control room. This concept, called a teleminer, would use recently developed remote control technology to remove man from underground work but still give him the capability to remotely operate mining and excavating equipment as if he were actually in the working area. It is appropriate to present this concept in the session "Environmental Controls" because the rationale for environmental control in underground areas can be significantly modified if man is excluded from the underground operation. The development of teleminers cannot only reduce or eliminate most of the requirements for conventional environmental control, but it can also create new and powerful techniques for rapid tunnelling and excavation. TELEMINER CONCEPT The concept of remotely controlled mining machines is neither new nor untried.(1)(2) Conventional remotely controlled mining equipment employs the standard techniques of extending the controls of the equipment to a remote console. For example, the rotary cutters on a remotely controlled tunnelling machine are started or stopped by a human operator turning a switch on the remote control console.

Jan 1, 1997

By D. S. Choi

Underground production of coal by longwall methods has increased significantly in the last few years and will very likely continue to: increase. There are several reasons for this. First, as mining moves into seams having greater overburden, roof exposure must be reduced since support will become' increasingly expensive. Secondly, the growing demand for coal has forced the coal industry to seek alternative, more productive, coal mining methods. In addition, the longwall method greatly simplifies the underground ventilation network. This paper addresses itself to the design of longwall development headings, particularly to those of the United States where multiple development headings are required by law. The most burdensome problem encountered in many longwall mining installations is deterioration of the tailgate due to the combined effect from, the active longwall gob and the old gob made by mining the previous panel.1 Portions of the tailgate entry are sometimes closed to such a degree that extensive repair work is necessary to keep the entry in usable condition. The purpose of this paper is to present the result of a study in progress which combines field measurements with numerical model analysis to reduce the cost of maintaining tailgate entries in longwall mining systems.

Jan 1, 1975

By W. van Antwerpen, J. Guzek, A. Lane

Strategy is about making choices. Mining companies choose to do certain things and not to do other things. Mining is a long-term business, and the choices made typically have large investments attached to them, long payback periods, and significant socio-economic consequences. In today’s uncertain world, it is important to make the right choices. The mining industry in South Africa finds itself in a difficult situation. Operating conditions are tough, the socio-political environment is complex, and financial performance is under pressure. The choices made by all the stakeholders in this industry in the short term will shape the future of the industry. This paper characterizes some of the big, difficult decisions faced by the mining industry in the South African context, and discusses how these decisions could be approached in a fact-based and robust way.

Jan 1, 2015

DR. PeRsifor Frazer, Philadelphia, Pa. (communication to the Secretary):* Mr. Campbell's very interesting contribution, after complimentary mention, finally decides against the acceptance of the classification proposed by me in a paper bearing the same title and read at the Wilkes-Barre meeting, May, 1877.2 That paper was written primarily for the Second Geological

Jan 1, 1906

By Brad McBain

Agenda ? Accurassay Laboratories and Automation ? History and experience ? Features and benefits of automation in the lab ? Tata Steel Minerals Canada (TSMC) Iron Ore Laboratory ? State-of-the art systems and design ? The integration of fusion systems and XRF units ? Meeting deliverables: quality, reliability, safety

Aug 1, 2013

By S. Gaydardzhiev

Laboratory batch tests having preliminary and orientation character aiming at improvement of the molybdenum flotation at Ellatzite copper processing plant in Bulgaria have been conducted. The following technological parameters have been screened to study their influence on the grade and recovery of copper and molybdenum during the rougher flotation stage: flotation pulp density, pH, addition of secondary collector and replacement of MIBC by pine oil as a frother. The results have shown that slightly better grade/recovery figures could be obtained for both copper and molybdenum at lower flotation pulp densities. The addition of kerosene has improved the recovery of molybdenum however, on the expense of that of copper. The effects from pH variation and the replacement of MIBC by pine oil as a frother have been almost negligible.

Sep 1, 2012

By C. Steyn, J. D. le Roux

A dynamic model is used to represent the single-stage closed grinding mill circuit at Mogalakwena North Concentrator. The circuit consists of a ball mill closed by a hydrocyclone. The circuit is modelled according to a semi-mechanistic non-linear dynamic model available in literature. An algebraic routine is used to fit model parameters to steady-state process data. Preliminary validation results against dynamic data indicate that the model is capable of capturing the main dynamic trends of the plant. Since classical system identification techniques proved insufficient to produce accurate models; the non-linear model can be used as a reliable source for model-predictive controller design. Keywords: Grinding, modelling, process control, parameter estimation

Jan 1, 2020

By A. Makinen

There is an increasing trend between increasing consumption of water and the production of metal concentrate. Along with this trend we see that ore grades are declining and getting more complex to concentrate around the world. This will not only complicate processing but also generate new requirements for the management of water and waste streams on mining sites. The mining industry is a large user of water and its water consumption is growing rapidly. The processing of lower quality ores requires greater volumes of water. For these reasons, the need for efficient use of water and water management at mine sites is becoming more urgent. The perception of water in the mining industry has changed from thinking about it only in terms of "water treatment" to actually seeing it as a valuable resource, a resource that needs proper management. This resource management needs to involve various aspects, such as optimizing water usage of the entire mine or concentrator site, minimizing fresh water usage, minimizing or eliminating waste generated in water treatment and implementing practices for water reuse and water recycling. This paper presents trends and new developments relating to waste and water management in the mining industry.

Jan 1, 2015

By J. Sadaki, G. Dodbiba, S. Murakami, T. Fujita, S. Matsuo, H. Ono, K. Okaya

Printed circuit boards (PCBs) from discarded personal computer (PC) and household appliances were crushed by mechanical crushing or water explosion to remove mounted parts. More parts were stripped from PCB for PC composed of epoxy resin than from PCB for household appliance composed of phenol resin. In an attempt to raise the copper grade of PCB by removing other components, a carbonization treatment was investigated. The crushed PCB without surface-mounted parts was carbonized under a nitrogen atmosphere at 1073K. After screening, the char was classified by size into oversized pieces, undersized pieces and powder. The copper foil and glass fiber pieces were liberated and collected in undersized fraction. The copper foil was liberated easily from glass fiber by stamping treatment. On the other hand, tantalum capacitors were collected from mounted parts. The tantalum-sintered bodies were separated from molded resins by heat treatment at 723 to 773K in air atmosphere and screening of 0.5mm. Silica was removed and 70% of tantalum grade was obtained after more than 823K heating and separation.

Jan 1, 2011

By Filippo Maria Leoni, Alessandro Bertero, Gianluca Pianezze

"As part of the Southeast Louisiana (SELA) drainage program, designed by the U.S. Army Corps of Engineers (USACE) to reduce flood damages in the City of New Orleans and surrounding parishes through the construction of new pumping stations and better drainage canals, the SELA-22 project entailed the installation of a concrete covered canal along Jefferson Ave. and Prytania Street, in a highly urbanized portion of Uptown New Orleans, LA. The scope of the required soil improvement was to replace the soil between two parallel lines of sheet piles with a soil-cement mass to eliminate underseepage and provide structural support for the concrete culvert. The USACE selected the jet grouting (Jet Grout) technology for the construction of the bottom plug. The bottom plug is between 18 and 21.5 ft thick with a maximum depth of approximately 40 ft, for a total length of approximately one mile. The treated soil comprised soft clays and silts with occasional presence of sands. Project specifications required 100% area coverage, a 28-days unconfined compressive strength of 100 psi and hydraulic conductivity of 1x10-6 cm/s, to be verified by testing specimens from cored samples. The specialty geotechnical contractor proposed to accomplish the task utilizing their proprietary and innovative elliptical bi-fluid Jet Grout technology, and elected to perform a pre-construction bench scale laboratory mixing program to determine the most suitable grout mix features (i.e. binder type and proportions, binder content, etc.) to be applied in the subsequent field test and production stages. This paper will summarize and compare the results obtained from the different pre-construction and construction stages; interpretations of the data will be provided, along with general considerations regarding the effectiveness and significance of bench scale testing for jet grouting applications.INTRODUCTIONIn general, the effectiveness of the construction parameters in any ground improvement work depends largely on the physical and mechanical properties of the soil to be treated. Therefore, well designed laboratory and field test programs, aimed to disclose the interaction between the site-specific soils and the mixing parameters, are essential to achieve the desired end product."

Jan 1, 2016