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By Jim Sundal

Primary steel manufacturers using electric arc furnaces generate one of the largest hazardous waste streams nationwide. The waste stream, known as electric arc furnace dust, is a listed hazardous waste with the designation K061. Oregon Steel Mills, Inc., (OSM) of Portland, Oregon, has implemented a process known as Glassificationn, which uses KO61 as an ingredient in an onsite recycling process. Because OSM was able to demonstrate that the Glassificationm recycling process beneficially uses all toxic constituents in the electric arc furnace dust and that the recycling process produces marketable products, the process is not subject to Resource Conservation and Recovery Act (RCRA) permit requirements. The marketable products manufactured using Glassificationn include roofing granules, ceramic glazes and colorants, abrasive blasting media and, more recently, synthetic slag fluidizers. The purpose of this paper is to identify the regulatory issues for recycling hazardous waste and demonstrate that OSM glass frit is effective as a slag fluidizer in primary steel manufacturing.

Jan 1, 1994

By Tom Paynter

In an underground mining environment, the primary method of firing a blast is using a combination of an electric detonator and a detonating cord to initiate the Nonelectric detonators. This method has been in use since the 1970’s. A firing line is used which can be subjected to damage and the need for constant testing and maintenance.

Jan 1, 2017

By Elliot Schwartz, Julian Szekely

"In this paper we describe an experiment that was recently performed on the IML-2 Space Shuttle mission in which the thermophysical properties of molten metals were measured using electromagnetic levitation. In the planning of these experiments calculations had to be performed to predict the levitation and stirring forces, heating rates, sample deformation, and internal flows within the sample. These predictive calculations were essential for both the planning of the experiments and for the re-planning of experimental runs during the actual Space Shuttle mission.Introduction""Materials Processing in the Computer Age"" involves the use of mathematical modeling to obtain a quantitative understanding of the phenomena that govern materials processing operations. Microgravity, or space shuttle experimentation represents a specific case in point here; the very high cost of the space shuttle flights, the very limited flight opportunities that are available, and the tight resources aboard a shuttle clearly mandate that these experiments be very precisely planned and that all possible opportunities for mathematical modeling be fully exploited.The purpose of this paper is to present the results of calculations performed for the planning of a space shuttle experiment involving electromagnetic levitation and wherever possible present a comparison of the computational predictions with both experimental measurements and asymptotic analyses. Finally we shall seek to discuss the practical implications of both the computational methodologies and the potential experimental findings."

Jan 1, 1994

By Behdeen Oraee, Amirhossein Bangian, Kazem Oraee

"Determination of the optimum design of chain pillars has a significant effect on the economics and safety of longwall operations. Most pillar design formulae are based on empirical methods and supplemented by local experience. They therefore lack versatility of application under different geotechnical conditions.In this paper, in order to illustrate the shortcomings of the above, a typical real coal pillar in Tabas coal mine has first been studied and the conventional formulae have been used to determine the optimum dimensions. The results show that a wide difference exists between the predicted and the real field data. The Oraee-Hosseini formula has then been applied to this mine in order to determine the optimum design. The results from this formula demonstrate a close fit between the theoretical VALUES (and those produced by laboratory tests and in practice. It is further demonstrated that the wide discrepancy between the results obtained from the two formulae is attributed to the dissimilarities between geotechnical conditions of Tabas and the original regions whose data were used to devise the empirical formulae.It is finally concluded that the application of numerical simulation methods and experimental equations together with engineering judgment used by the mining design engineer, will provide the most accurate design characteristics.INTRODUCTIONLongwall is an underground mining method which has a high rate of production capacity and mechanization ability. This mining method, which is appropriately applied for soft rock fiatlying bedded ore bodies, gradually became a widespread mining method amongst European coal mines at the beginning of the 19'h century. It was then applied in some of the U.S. coal mines with the development of self advancing support mechanisms in early 1960's (Oraee, 2001).Underground coal production around the world using Longwall mining method doubled during 1990s. The main reasons for this improvement were: the high level of mechanization, increased 10 safety, adequate design of panels, and well designed ventilation systems (Peng, 2006)."

Jan 1, 2010

By E. W. Shaw

The past year (1950) has been a big one for the oil industry in Canada, with new records being set in almost every phase of exploration and development activity. New highs were reached in acreage holdings, in geophysical activity, in wildcat drilling, and in field development and production. The only item that did not show a substantial increase over recent years was the amount of reserves added by new discoveries. This was not due to a decrease in the number of new discoveries, however, hut rather to the fact that most of the discoveries were made during the later months in the year and could not be fully evaluated by the year end. The foregoing remarks pertain mainly to activity in Western Canada. In Eastern Canada, operations continued on a modest scale. with exploration drilling down slightly from the previous year but with development drilling and production at about the same level. Returning to Western Canada, it is observed that the general exploration play was one of expansion and intensification. The issuing of new petroleum and natural gas regulations by the province of British Columbia precipitated a moderate entry of companies into the northeastern part of the Province.

Jan 1, 1951

By Bern Klein, Givemore Sakuhuni

Flotation is the dominant base metal extraction technique and it requires ore to be ground below the liberation size for effective recovery due to its dependence on mineral surface properties. For a poly-metallic ore, differential hardness of constituent minerals leads to over grinding of softer minerals before the harder minerals are fully liberated, which makes selection of a target grind size complex, and the complexity increases when treating leaner ores. Flotation recovery deteriorates above 100 and below 10 microns causing significant loses of valuable minerals in most flotation circuits. Although enhanced gravity concentration is known to be effective at recovering particles above 100 microns, which are difficult to hydro-dynamically transport, exploiting differential specific gravity for base metal separation was not an option in the past. This was partly due to the absence of high mass yield gravity techniques. The advent of continuous gravity concentrators with flexible mass yields, in the past two decades, has necessitated investigation of possible base metal applications. The Knelson CVD, one of the continuous discharge centrifugal concentrators, has an established application niche for sulphides associated with gold. However, its base metal applications have never been rigorously tested. Considering the dependence of flotation recovery on particle size, continuous discharge centrifugal concentration can be integrated in flotation circuits to capture flotation non-recoverable coarse particles. This paper explores how particle size, liberation and mineral hardness influence application of continuous centrifugal technology to regulate galena deportment in a polymetallic base metal plant. The results show that particle size affects galena recovery more than liberation. In view of these results, the CVD can be integrated in the primary grinding circuit to pre-concentrate the heavy sulphides at a coarser grind size with potential grinding energy savings.

Jan 1, 2014

By A. J. MacKellar

The economic viability of any project is generally assessed on an evaluation of the total capital constructed costs along with operating costs, owner's costs and market conditions. This paper will be directed to the role that Cost Engineering plays in the development of the capital costs and the cost control techniques applied thereto.

Jan 1, 1975

Visual computing opens the design process to a wider audience and allows rapid communication of mine plans to all stakeholders. The integration of software and hardware technologies that take advantage of a graphical environment will continue to improve both long-term and short-term mine design (Figure 1). A good design must be adaptive to respond to decision changes as the mine develops and more information becomes available. The constraints on mine design predicate careful analysis in order to operate the mine as efficiently and safely as possible.Continuous improvement in mining is assured by developing innovative technologies that target mine survey, drill and blast, modelling, short-term design and pit and stope optimisers. The design life of a mine has to be sufficiently long to ensure the mine is commercially successful, justifying the high start-up capital costs. Being able to execute a plan so that it honours the design realises the rewards of computerised mine planning and the long-term investment in data acquisition.

Sep 26, 2011

By Samuel Nunoo

Gibraltar Mine is an open pit copper-molybdenum mine in central British Columbia. The stability and potential failure modes of pit walls in the Granite Pit are controlled by the orientations of joints and faults. The structural geology also has an impact on as-mined bench geometries. Geotechnical mapping and surveying were conducted using stereo photographs and photogrammetry software. Detailed digital terrain models were constructed to determine the pit wall geometry and the locations and orientations of larger structural features. The pit wall geometry is compared to conventional survey results and the mapped structures are compared to results from a nearby geotechnical borehole.

Aug 1, 2013

By G. R. Hart

The expected 1990 Clean Air legislation is providing electric utilities with a series of challenges and decisions as the utilities prepare strategies to comply with the resulting regulations. This paper addresses the strategy development of a coal-based utility --the legislation, the process used, the fuel issues, the options available, and the decisions to be made.

Jan 1, 1991

By S. R. Brown

A number of relatively recent factors associated with the design of new metallurgical processing plants have made the effective training of operators a requirement for a successful start-up. Some of these factors include large capital investment in a minimum of processing lines, highly complex process control systems, and stringent regulations on plant effluent, to name a few. More than ever, operating mistakes during the start-up phase can lead to substantial delays in achieving design production, as well as problems with government authorities if permit limits are exceeded. The only way to assure your return on plant investment is to ensure new plant operators have the knowledge to properly run the plant from the outset. A comprehensive set of operating manuals specifically targeted for plant operators and foreman, written by experienced operating personnel, is the only effective way to provide the necessary information for start-up-related training.

Jan 1, 1995

By S. K. Kawatra, T. C. Eisele

"Recent advances in microbiology have made the application of biotechnology to metallurgical processes possible. Hydrometallurgy stands to gain the cost from the use of microorganisms, as they are useful for both dissolution aids and for removing metals from solution. The development of genetic engineering techniques promises to greatly increase the importance of bioprocessing of metals and minerals by the year 2000.In this paper, the basic effects of microorganisms on metallurgical processes are reviewed, and the applications which are currently either in use or near being used are presented. Representative data collected at Michigan Technological University is also given.IntroductionMany hydrometallurgical operations exist which are thermodynamically possible, but which are industrially impractical due to slow kinetics, high reagent costs, or the need for a highly corrosive environment. However, recent discoveries in microbiology indicate that in many cases these difficulties can be reduced greatly by the action of bacteria and other microorganisms (1-8).A major advantage of using living organisms in hydrometallurgy is that once the culture is established the microorganisms produce their own reagents either from the material being processed or from low-cost nutrient supplements. They thus allow extremely complex chemical reactions to be carried out at reasonable cost. The major drawback of using microorganisms is their inability to tolerate extremely high temperatures, excessive concentrations of toxic metals, or very highly acidic, alkaline, or corrosive conditions. However, the complex reactions which bacteria make possible frequently eliminate the need for such extreme conditions. Also, in recent years a number of organisms have been isolated from such exotic environments as hot springs and deep-ocean vents which can tolerate temperatures higher than was previously thought possible for any organism, and can catalyze a number of metallurgically important reactions (8)."

Jan 1, 1988

By J. P. P. Silva

Sodium silicate (water glass) is a modifier reagent widely used in flotation with the function of a depressant or dispersant. The interaction between sodium silicate and mineral surfaces is still not well understood. This investigation aimed to illuminate the sodium silicate action mechanism as a depressant in the flotation of the minerals quartz and calcite. The experiments were done with high-purity mineral samples in the particle size range below 147 µm. The microflotation tests in a modified Hallimond tube showed that, in all systems tested, the efficiency of sodium silicate increased with the concentration. At concentrations above 1,500 g/t, almost total depression (96% for calcite and 97% for quartz) was achieved. The variation of sodium silicate modulus did not alter the quartz flotation performance in the presence of amine (150 g/t). The most efficient depression pH range was observed between 5 and 8. Above pH 10, the depressant action of sodium silicate was negligible. The infrared spectra obtained at pH 7 after silicate contact showed the presence of the groups OH and Si-OH, both suggesting that the adsorption of the neutral species Si(OH)4, as well as siloxane groups (Si-O-Si), attributed to adsorption of polymeric species. Sharing electron pairs is the proposed adsorption mechanism between Si(OH)4 and polymeric species and the surface sites (Si-O on quartz and Ca-O on calcite). At pH 11, the electrostatic repulsion prevents the species adsorption, impairing the sodium silicate action.

By D. Kruse, M. Sanaei

"3D finite element models of the Segmentally Lined Shaft (SLS) structure are simulated as means of numerical analyses of the system’s structural behavior. Top-down constructed rings, comprised of precast concrete segments, create a large diameter, relatively shallow underground space that can be utilized for various applications. To further investigate the effects of soil conditions and different loadings on the shaft structure, the FE model was run under various boundary conditions. Simulations include a) effects of various soil layers on the SLS, including a circumferential boundary of modified ground, b) effects of various soil layers on the SLS without any ground modification, c) Seismic analysis of the SLS with ground modification and d) Seismic analysis of the SLS without any ground modification. Comparing the analyses outcomes emphasizes the significance of the inclusion of the ground modification boundary in the structural performance of the SLS. INTRODUCTION TO SLS Underground structures are classically built rectangular in shape, which normally requires a two-step construction process beginning with installation of temporary shoring to support earth loads during the excavation, followed by the construction of the permanent structure. Attractive and practical alternatives are circular shafts referred to as segmentally lined shafts (SLS). The structure consists of a stacked series of rings formed from an assemblage of precast concrete segments. Top-down constructed systems of large diameter, relatively shallow SLS structures provide both temporary earth support during excavation and permanent structural support for many civil and building applications. The circular shafts sustain the lateral earth pressure mainly through hoop-stress mechanism, resulting in improved stability and structural efficiency. Cylindrical shell structures with large diameter to wall thickness ratios are prone to buckling under external pressure. In typical designs of small diameter shafts and tunnel linings with small diameter to wall thickness ratios, nonlinear buckling analysis (i.e., nonlinear geometric analysis) is usually not considered, since the buckling capacities for those structures are much higher than typical pressures encountered at their design depths. With an economically viable wall thickness, buckling becomes a critical issue, which should be addressed, for circular shafts with very large diameters. In the design and construction of the SLS, the stability of the structure can be improved by modifying the soil surrounding the circumference of the shaft to a limited thickness and to about 10 ft below the finished shaft structure. This thick wall of soil mixed with cement creates a composite integrated structure while serving additional purposes such as ground control and ground water seepage cutoff."

Jan 1, 2016

By W. Y. Gao

Diaojuntai Concentrator adopts a process of low intensity and high intensity magnetic separation and anionic reverse flotation, with all the concentrate from magnetic separation being treated by re-verse flotation to obtain a qualified final concentrate. The high reagent cost and energy consumption of the reverse flotation have led to a high concentrate cost. The test research on reducing the feed to the reverse flotation was therefore carried out. Based on the study of the properties of the ore sample, the concentrate of low intensity magnetic separation was screened at 0.076 mm and the undersize fraction was concentrated by concentrator with gravity and magnetic field. The results show that a qualified concentrate can be obtained at various rising current rate, pulsating current and power-on style, with the operation rate over 85%. The extraction of some part of qualified concentrate from the concentrate of low intensity magnetic separation by magnetic separation can reduce the feed to the reverse flotation by about 35% so as to reduce the production cost of concentrate.

Jan 1, 2014

By Wi11iam I. Rau

In the recent past, there have been numerous projections of the capital requirements for additional mine and processing capacities required to meet projected non-Communist World demand for minerals during the next 15 years. A consensus judgment would place this currently at $14 billion per year, with the largest expenditures required for increases in aluminum and copper production. Until the early 1960's, internally-generated funds were used to finance nearly all of the large mining companies' capital requirements. Since that time, however, the enormous rise in capital costs per ton of capacity, accompanied by a relative stagnation in the financial condition of many of the major mining companies, have caused the industry to begin to rely on external sources for financing expansion, most notably, project financing from commercial banks and institutional lenders. Seven years ago, it was estimated that, in the five-year period 1972-1976,75% of the total capital requirements of $10 billion per year would come from internally-generated funds, with the balance to be provided by external sources. l There is little doubt that, in the coming decade, the percentage provided by external sources will increase. There should be little difficulty in attracting the necessary investment within the U.S., particularly in view of the expected continuation of companies in diverse industries seeking mineral investment opportunities. The more serious question lies in the availability of internal and external sources of funds for the expansion of mine and smelting capacity in the developing countries. Recently, R. F. Mikesell projected an average annual investment of $4.7 billion (in 1977 prices) over the 1977-1990 period would be required from foreign sources to expand metal producing capacity in developing countries. Mikesell concluded that external financing of mining projects in the developing world has averaged less than $1 billion per year over the past five years, thereby requiring more than a quadru1ling of this financing over the next decade.

Jan 1, 1978

By Larry A. Morris

The environmental impacts of industrial activities have become very serious concerns of the public over the past few decades. Not surprisingly, governments have responded with legislation and regulations to force industry to operate in a more environmentally responsible manner and, more recently, have prompted industry to initiate voluntary measures in response to specific environmental issues. The concept of Product Stewardship has evolved as a system or vehicle for the industrial sector to demonstrate an active concern about the environmental impact of their products, services and processes.

Jan 1, 1996

By M. Tardif, F. L. -Lavoie, M. Ruel

"In mineral processing, it is often very difficult to reliably measure several key operation variables. The harsh environment and high temperature encountered in pyrometallurgy processes lead to some difficulties when selecting the instruments, valves and actuators. If an important variable cannot be measured or manipulated adequately, controlling it can really become a big challenge. Sometimes, it is simply impossible to find the perfect equipment for the task. To help overcome these difficulties, a different approach is required. This approach will not correct the inherent problems related to the instruments and valves, but will cope with these problems. This article will demonstrate how modern process control techniques can be used to solve complex problems while remaining easy to implement. In this article we will described how soft sensors and multivariable fuzzy logic control were implemented at Koniambo Nickel to stabilize the furnace feed and allow for safe and reliable operation of an 80 MW DC arc furnace.INTRODUCTION Process Overview The process plant at Koniambo Nickel SAS is located in the North Province of New Caledonia, 310 km north of Noumea. The nickel-bearing ore is mined in the nearby Koniambo massif. After being screened and crushed, the ore is transported to the processing plant using a 12 km conveyor. After stacking in two blending piles, the ore, containing 2.3% nickel, is fed to the processing plant where it will go through the NST process (Nickel Smelting Technology) before being sent to refining and shotting. This article will focus on the improvement to control of the NST processes. The first steps of this process consist of milling the ore and removing all moisture through calcining (Figure 1)."

Jan 1, 2017

By A. I. A. Salama, M. W. Mikhail

"A comprehensive software package has been developed at the Western Research Centre to meet many of the coal preparation requirements in the Canadian coal industry. This package performs three main functions: (1) data handling and manipulation; (2) data analysis, including the generation of washability data, performance evaluation and prediction, density and size modelling, evaluation of density and size partition characteristics, and attrition curves; and (3) graphics output.The software described in this paper is potentially a valuable tool for coal preparation plant engineers and operators for evaluating process performance and adjusting plant density separator cutpoints. Moreover, the analytical laboratory technician could find this package very useful in manipulating and presenting laboratory results."

Jan 1, 1997

By W. S. Fyfe

The future environment of our planet, with the concept of sustainable development, has moved to centre stage of all future plans for development. This global view is new. It presents great opportunities and challenges for the Earth Sciences. We have the tools to describe our environment on all scales - planetary to molecular levels. We must respond to this great demand by world society.

Jan 1, 1990