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By Lynn B. Hales, Randy A. Ynchausti

Object-oriented technologies have been developed to more closely model the way we think about the world and our natural approach to solving problems. Higher levels of abstraction, generalization and classification are benefits of an object-oriented approach. Object-oriented programming, design, and expert systems are part of this technology which is shaping the future of real-time supervisory control. Goals of real-time supervisory control systems include: minimizing variations in process operations, improving efficiency, maximizing production, and implementing procedures for starting and stopping the process. Incorporating object-oriented technology in design, development and implementation of real-time supervisory control systems provides new opportunities for these tasks. This paper discusses some of the opportunities and challenges of implementing real- time supervisory control using an object-oriented expert system for a rougher flotation circuit

Jan 1, 1993

By L. D. Rickets

The principles on which an art is founded are usually few and necessarily basic in nature, but he who wishes to achieve the power to select his aides and give success to important undertakings that may be entrusted to him in the future must ordinarily undergo years of drudgery in order to gain the experience that will enable him to distinguish such fundamentals through the haze of reenforcing detail that clothes and tends to disguise them. This especially applies to those who would dream dreams that may come partly true. Professor Henry B. Cornwall of Princeton was a graduate of Freiberg with mining experience in Mexico. He was my friend and mentor during my college life. In 1883 I finished my postgraduate course and had two offers of work to consider. His advice is very clear in my mind today. It was essentially as follows: I know something of the mines of Mexico and have crossed through the mountains of the West. The West possesses a vast area of mountain and valley. California has long had its gold mines, the Comstock and Gilpin County followed and now comes the discovery of Leadville. I believe the West, will become a great mining country. You can choose now to teach here or go to the mountains. Were I in your place I would go West and identify myself with mining.

Jan 1, 1932

Jan 1, 1879

By P. T. Bissert, T. J. Lutz, J. A. Yonkey, G. T. Homce

"The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork. Relief pressures and flow characteristics were measured for three units: (1) a modified polyvinyl chloride check valve, (2) an off-the-shelf brass/cast-iron butterfly check valve and (3) a commercially available valve that was designed specifically for one manufacturer’s steel prefabricated RAs and had been adapted for use in one mine operator’s built-in-place RA. PRVs used in tent-style RAs were not investigated. The units were tested with different modifications and configurations in order to check compliance with Title 30 Code of Federal Regulations, or 30 CFR, regulations. The commercially available relief valve did not meet the 30 CFR relief pressure specification but may meet the manufacturer’s specification. Alternative valve designs were modified to meet the 30 CFR relief pressure specification, but all valve designs will need further design research to examine survivability in the event of a 103 kPa (15.0 psi) impulse overpressure during a disaster. BackgroundThe Mine Improvement and New Emergency Response Act of 2006, known as the Miner Act (U.S. Department of Labor, 2006), was enacted in the wake of three mine accidents involving explosions or fire that claimed 19 lives that year. Intended to help improve underground coal mine accident preparedness, the Miner Act includes provisions that target mine safety issues in areas such as emergency response planning; adoption of new technology; training and education; and mine safety standards enforcement. Section 13 of the Miner Act specifically directed the U.S. National Institute for Occupational Safety and Health (NIOSH) to provide for research into the effectiveness and viability of refuge alternatives (RAs) for underground coal mines, and the U.S. Department of Labor to act on the results of such research, as appropriate. These mandates culminated in the 2009 adoption of changes to the Title 30 Code of Federal Regulations, or 30 CFR, mining health and safety regulations (U.S. Department of Labor, 2008), requiring underground coal mines to supply mine emergency RAs and associated components so as to provide a life-sustaining environment for persons trapped underground. Such RAs can be either selfcontained mobile units or built-in-place facilities. The regulatory changes also include provisions establishing requirements for the approval of RAs and their components by the U.S. Mine Safety and Health Administration (MSHA), among which are numerous criteria for providing a safe breathable atmosphere under positive pressure within the RAs. One criterion for maintaining a safe RA atmosphere is the inclusion of an air pressure relief valve that will activate at a maximum of 1.25 kPa (specified as 0.18 psi, or approximately 5.0 in. H2O), or as specified by the RA manufacturer, above mine atmospheric pressure in the RA (U.S. Department of Labor, 2008)."

Oct 1, 2016

By J. M. W. Mackenzie

Recent successful applications of emulsion flotation suggested that a detailed study of some of the physicochemical aspects of the process was warranted. The objective of the current research was to provide general information on the electrokinetic properties of emulsion drops of the type commonly used in oxide mineral flotation. Combinations of the parafin oil Nujol and several long-chain reagents in water were studied with respect to the effect of pH on the surface and zeta potentials. It war concluded that for emulsion drops in the presence of a long-chain reagent but in the absence of any other electrolyte which is adsorbed at the oil-water interface, the surface potential will be some two to four times the value of the zeta potential. During the last decade there has been a revival of interest in the so-called agglomeration, or emulsion flotation (in this paper the term emulsion flotation will be used), process. In this flotation technique, a neutral hydrocarbon oil, together with longcnain reagents, usually of a polar-nonpolar structure, are added to the pulp to function as collectors for specific minerals. The combination of oil and longchain reagent is either emulsified prior to addition to the pulp, or in the pulp itself, and the resulting collector species is an oil-in-water emulsion of a neutral hydrocarbon oil emulsified by polar-nonpolar long-chain reagents. Emulsion flotation has been used successfully in the treatment of ores containing iron, manganese,' and titanium oxides. 2 Two other major and long established applications of emulsion flotation are the flotation of coal and Florida phosphate ores. In recent years, emulsion flotation has been particularly successful in the treatment of ores containing oxide minerals which slime readily and, consequently, are difficult to treat by conventional flotation processes. The recent successful

Jan 1, 1970

By Gary D. Aho

The United States on a daily basis no consumes about 15MM barrels (2.38 x 106m3) of oil; 5MM (0.79 x 106 m3) of this is imported. This compares tai a daily consumption of 18MM (2.86 x 106 m3) in 1980 when we imported 8MM (1.27 x 106 m3). We are producing the 10MM barrels (1.59 x 106 m3 ) of conventional oil at home from what amounts to just 2% of our domestic energy reserves. Nearly 90% of our total domestic energy reserves occurs in solid forms such as coal, oil shale, and tar sands; this is more than enough to meet our needs for the next 100 years. Worldwide, oil shale is second only to coal as a potential source of energy and the U.S. has approximately one-half of the world oil shale reserves which average over 25 gallons per ton (10.43 x 10-2 L/kg). Since the United States has immense oil shale resources, including some of the richest in the world, and since oil shale produces a superior transportation fuel, it would seem logical that the U.S. would be prudently developing this domestic resource. Unfortunately, despite over 50 years of research and a number of false starts, there is not a commercial shale oil industry in place today. There are a number of recurring roadblocks which have hindered private industry's efforts to develop oil shale and we will look at some of these.

Jan 1, 1983

By Robert Craig, Earl L. Rau

Introduction Grinding circuits are used to reduce the particle size of ores to the size desired for beneficiation or to grind a concentrate to a size required for final marketing. Grinding and classification can be carried out using either wet or dry circuits. Most sulfide ores are ground in wet circuits using one or more stages of grinding to obtain the necessary mineral liberation to produce a final concentrate which will meet the desired criteria. Iron ores are ground in circuits applicable to the particular ore using either wet or dry grinding. Nonmetallic minerals frequently present different requirements. Barite is likely to be subjected to wet grinding before beneficiating the ore; the concentrate is dried and then dry ground to meet market particle size requirements. The one thing that most mill operators will agree to is that there is no such thing as the "best" configuration of equipment for grinding. The circuit which works well on one ore may be totally unsatisfactory for another ore body. The general trend in the industry is flow sheet simplication with fewer parallel circuits instead of multiple-line circuits using small mills. This change in philosophy has been brought about by the saving of both capital and operating costs that may be possible with larger equipment. Remember that comminution is basically a very inefficient process, and that the costs can range upwards to 50% of the total milling costs. It, therefore, behooves the mill operator to carefully design his grinding and classification circuits. He must ascertain the optimal economic particle size for beneficiation and then make certain he has achieved the best balance between capital and operating costs to achieve the desired mesh of grind. Equipment Grinding circuits consist of one or more pieces of equipment to grind the solids. Generally, these circuits include one or more grinding mills, classification equipment, and the necessary materials handling equipment such as pumps, pipelines, and conveyors. There are many different types of equipment available which are used to grind and classify ores and minerals. Following is a tabulation of most of the equipment used for wet and/or dry grinding.

Jan 1, 1982

By Wander. L. Vasconcelos, Virgínia. S. T. Ciminelli, Angela. M. F. Guimarães

"The present work was aimed at synthesizing nanostructured hybrid materials derived from the functionalization of smectite clays with ligands containing thiol (-SH) groups for application in cadmium adsorption processes. An in nature Brazilian bentonite was investigated. The modification route was based on the grafting reaction between hydroxyl groups present on clay surface and the hydrolyzable alkoxy group of the (3-mercaptopropyl)trimethoxysilane in dry toluene under reflux. The present work showed that the proposed modification route was effective for the grafting of the thiol groups in the clay structure. The thiol-functionalized bentonite samples showed average binding capacities 160% higher with respect to Cd2+ to those obtained with the ungrafted material. These results support a mechanism of adsorption involving primarily ion complexation by the thiol groups (specific) instead of cation exchange (unspecific). The proposed modification processes are suggested for the preparation of novel adsorbent materials with controlled selectivity and specificity and therefore with good potential for separation and pre-concentration purposes.IntroductionMany efforts have recently been devoted to the design and preparation of inorganic-organic nanomaterials because of their potential application in novel functional materials. The intercalation of organic species within the spaces between interlayers of inorganic layered crystals provides nanostructures consisting of alternating layers of inorganic and organic compound. The intercalation reactions occur by insertion of mobile guest species (neutral, molecules, or ions) into the accessible crystallographic-defined vacant sites located between the layers (interlayer spacing) of the layered host structure [1}.Silane coupling agents, used widely for the modification of silica surfaces, have also been employed more recently for modification of layered silicates [2,3,4,5]. Modification with organosilane involves grafting reactions by establishing covalent bonds between the reactive groups of the layer, normally hydroxyl groups, and silane molecules. These reactions can be restricted to the external surface (the basal spacing remains unchanged) or to the interlayer surface, in which case an interlayer expansion occurs. The resulting material can be defined as a hybrid material or, more specifically, functionalized inorganic layered material [1]."

Jan 1, 2008

By L. E. Shiffman

This paper describes the operation of two kerosine flotation plants in Alabama for cleaning —10 mesh bituminous coal. One plant treats washer sludge, the other raw coal. Data on capacity efficiency and capital and operating costs is given. Methods for increasing cell capacity are discussed. IN cleaning coal it has long been recognized that methods which give excellent results for the coarser sizes may give poor or even no cleaning for the finer sizes. Effective cleaning of the fines, therefore, is usually a separate and distinct problem. For many years the problem of fines was considered of relatively minor importance. Now there is growing interest in methods of cleaning the fine sizes of coal because: 1. There are more fines. Increasing mechanization and the adoption of full seam mining methods have resulted in the production of a greater percentage of smaller particles than were produced by hand loading methods. 2. The fines have deteriorated in quality. The same causes that have led to increased quantity have also operated to decrease quality through greater contamination with slate, rock, and other diluents. 3. The fines have become more valuable. When coal was comparatively cheap, loss of the finer sizes was tolerated but, with the rapid increase in the cost of mining coal, it has become imperative that the maximum amount of clean coal be recovered from the mixture of coal and rock delivered to the tipple. 4. In many cases, the fines have become a stream pollution problem. Increasing governmental activity and legislation to prevent stream pollution often have made it necessary to retain the fine material which formerly was permitted to escape with the washer effluent into flowing streams. The Sloss-Sheffield Steel and Iron Co. operates four coal mines, all within a 20-mile radius of Birmingham, Ala., with a total annual production of 1,-250,000 tons of washed coal. Three of these mines are in the Mary Lee seam and one in the Jefferson seam. Although some steam and domestic coals are produced, the major portion of the coal is used to make coke for blast furnace operation. Fine coal is desirable for coking, and all the coal so used by Sloss is crushed to 1/4 in. Therefore, there is no problem of an outlet for even the finest sizes of coal. Since the coal is used for metallurgical purposes, low ash is of greater importance than would be the case if it were used for steam generation or domestic heating. Based on present blast furnace practice at Sloss, it is calculated that each percentage of ash in the coal carries a penalty of $0.22 per ton of coal. Thus there is a considerable margin for operating costs in a fine coal cleaning method that will result in materially lowering the ash content of the cleaned coal. Development of Fine Coal Cleaning Problem In 1942 Sloss reopened its Bessie mine and constructed at this location a new preparation plant to clean 11/4 in. x 0 coal from the Mary Lee seam.

Jan 1, 1951

An optimized long-term mine planning determines the best order of material extraction, so that the Net Present Value (NPV) becomes maximum. In the case of oil sands surface mining, one of the key constraints in NPV maximization is the volume of tailings slurry that will be generated downstream. Specifications of tailings slurry are also important from environmental perspective. Moreover, most of the material that will be used for the reclamation of tailings ponds in later periods is generated in extraction and processing of oil sands. In this paper, an integrated optimization framework is proposed to maximize the NPV of the produced oil sands, with respect to tailings capacity constraints and reclamation material requirements. A mixed integer linear programming (MILP) model is developed to find the optimal solution for long-term mine planning problem. The proposed model is coded in Matlab and has been run using CPLEX for verification. The results for real-case oil sands dataset show that the optimal production schedule meets material requirements for reclamation, tailings volume is within tailings capacity range in all periods and the production schedule follows the predetermined horizontal direction.

Aug 1, 2013

The tragedy of the Moura No. 2 incident has lost much of its emotional mileage for those organisations that thrive on loss and suffering. However, for the families, workers, mine owners and operators in the Queensland underground coalfields, the challenge of delivering a positive outcome, though well underway, is in its infancy. The pressure created by interested parties is necessary for overcoming the inertia involved in change; but they cannot deliver the change. The responsibility ultimately resides at each individual minesite with the people who work there each day.

Jan 1, 1998

By B. J. Beaudry

The effect of various levels of purity of the rare earth fluorides and the calcium reductant used to prepare rare earth metals were determined. Metals which have low melting points such as La, Ce, Pr and Nd are not purified by distillation or sublimation. Impurities in the reactants remain as contaminants in these metals. Gd, Tb, Y and Lu which have slightly higher vapor pressures at their melting points than the first four metals are usually distilled to remove the Ta or W impurity introduced by the crucible and are purified slightly with respect to 0 and N by distillation. Rare earth metals that have high vapor pressures such as Sc, Dy, Ho and Er can be purified with respect to 0, N, C, as well as Ta or W by sublimation. The most volatile rare earth metals Sm, Eu, Tm and Yb are readily purified by sublimation and are usually prepared by a reduction-distillation process directly from the oxide. The importance of each step of the processes in determining the final purity of the individual rare earth metals is discussed.

Jan 1, 1989

By J. G. Pippenger

The Coteau Properties Company's Freedom Mine is a surface lignite mining operation utilizing large draglines, trucks and shovels, tractor-scrapers, and bulldozers to uncover a single coal seam. In 1989, a work order system was instituted to record data by equipment type, cost, productivity, and distance, and to provide historical information for planning the most efficient and economic use of each equipment type in the mining operation. This report explains how the work order system was initiated, what data is tracked, and how the data is utilized for equipment and project scheduling.

Jan 1, 1994

By Y. C. Lo

This paper presents the development of ultrasonic grinding technology for material and mineral processing. The principles underlying this new technology, as well as their implementation in two laboratory scale devices are described in detail. Ultrasonic grinding experiment results are discussed with respect to operating variables and the achieved product sizes. Special attention has been given to the electrical energy consumption of the grinder, and an attempt to compare its efficiency with tumbling mills has been made. A mechanical system capable of measuring the specific grinding energy is also described.

Jan 1, 1991

By B. B. Tati

The project report is based on vacation work done by the writer at the Khutala Colliery during December/January 2009?2010. The purpose of this report is to explain and describe the design process in a multi-seam mine design for coal extraction at the Khutala Colliery. The multi-seam design will focus on the No. 2 and No. 4 seams as these are the seams that are currently being mined by underground methods at Khutala Colliery. The seam thicknesses and the parting thickness between the seams provide suitable conditions for designing a multi-seam mine design. An investigation into the pillar design aspects is carried out followed by a numerical modelling analysis of various scenarios. This analysis validates the first principles approach provided by multi-seam design guidelines. The design results from the analysis of the selected pillar design indicate sufficient parting for primitive conditions between seams, thus illuminating the need for superimposing in-panel pillars. This multi-seam mine design confirms the potential for the extraction of coal in a new panel. The design indicates that significant amounts of power station coal are present and suitable for extraction by room and pillar mining methods. The panel block indicates 401 625 tonnes of ROM coal. This block has a life of panel that will be mined just over a 4-month period. This 4-month period is assumed to mined at a production rate of 48 000 tonnes per month. The total capital cost required for the new panel is R48 281 127.05. Keywords Multi-seam mining, panel design, ventilation flow, superimposition.

Jan 1, 2011

By K. V. Godfrey

With the increasing need to exercise better control over mill circuits has come a requirement to develop rapid, accurate means of measuring circuit parameters. One of the most important parameters is the assay of the material in the circuit (or about to be introduced to the circuit). To date, most on-stream analysis has been performed using X-ray fluorescence equipment. Neutron activation offers an alternative method in certain circumstances, and one which has several interesting advantages. Recognizing the need for a simple, safe neutron activation unit suitable for on-stream analysis in the mineral industries, Atomic Energy of Canada Limited has designed, built and tested the SHERLOCK system. One prototype (SHERLOCK I) is located in Ottawa and is now used primarily in research. A second prototype (SHERLOCK III) is located in Vancouver at the laboratories of B.C. Research. This unit is being used for some development research and for evaluating the unit in specific applications. Most of the work completed to date has been aimed at proving the technique and in developing some of the parameters needed to design systems for a milling plant. Funding for the work has been through research grants and through sponsor¬ship by interested companies.

Jan 1, 1971

By Eric L. Christiansen

A dynamic simulation model for the iron blast furnace has been developed which predicts flow rates, compositions, and temperatures of the top gas, slag, and hot metal exit streams as a function of time from specification of the time-dependent tuyere inputs and raw material charges. As a matter of convenience, a previously developed steady- state model is employed to fix furnace-dependent parameters. It also provides initial conditions for the internal states of the furnace for subsequent dynamic solution of the simultaneous differential equations which describe the local rates of chemical reaction, heat transfer, and mass transfer in the stack, bosh, combustion zone, and hearth of the furnace. The dynamic model was tested by a demonstration of its ability to relax to steady-state representations of the time-averaged data from two separate industrial blast furnaces and of its ability to follow eight days of time-dependent operating data for one of them. Simulated responses to step changes in tuyere input and burden variables have been shown to be of the correct magnitude and duration. Although complex functions of many variables, a proper description of these responses is needed for the development of optimization and control strategies . The model correctly predicts the non-minimum-phase type dynamic response observed in real furnaces in which the output variables proceed through local minima or maxima, often including inverse responses (i.e., opposite signs from their final steady-state values ) .

Jan 1, 1984

By Yelloji M. K. Rao, P. Somasundaran

Reagents of biological origin are becoming more and more important in the field of metallurgy, especially in the areas of mineral processing and hydrometallurgy. The advantage of lower operating cost over physical and chemical processes and the capacity to operate with low grade ores make the microbial processes further attractive. In this paper, the role of microbes directly as a reagent and microbially produced reagents or secreted metabolites in mineral processing and hydrometallurgy will be discussed. Adhesion of microbes to surfaces is known to alter the hydrophobicity of minerals. Applications include surface modification to impart hydrophobicity or hydrophilicity on sulfide or non-sulfide minerals and dissolution of precious metals. Microbes can also perform the role of flocculating agents. Biosorption of toxic and heavy metal ions by microbes are finding application in treating tailing ponds. Mechanisms associated with the use for microbially produced reagents are discussed along with some recent results.

Jan 1, 1994

By K. Krishnapisharody, G. A. Irons

"The modeling of gas-liquid plumes in steelmaking ladles has been the subject of many investigations. In most studies, the “modified” Froude number, based on the momentum of the injected gas, has been employed to characterize two-phase plumes. This approach has several shortcomings and is critically reviewed in the present work. Based on an extensive review of previous work and theoretical considerations, it is demonstrated that the injected momentum and consequently, the modified Froude number has no significance to gas blowing operations in Ladle Metallurgy. Instead, an approach based on the “plume” Froude number, previously shown by the authors as the proper form for Froude similarity, is extended as a simpler alternative.IntroductionGas injection is central to most Ladle Metallurgy operations. During ladle processing, the steel melt is usually stirred by an inert gas like Argon through porous plug(s) fitted in the bottom of the ladle or a lance inserted deep into the melt. The purging serves several purposes viz., homogenizing the melt, flotation of inclusions, enhancing the rates both of refining reactions and dissolution of alloying elements and promoting inter-phase interactions in the ladle.The topic of gas injection into liquid baths has been the subject of several investigations in the past. A great deal of this work, both experimental and computational, was devoted to describing the structure and properties of two-phase plumes as reviewed recently [1]. Generally, the ascending two-phase mixture is sub-divided into three distinct regions [2]: the jet core, transition and the bubble plume, respectively. The jet region, where the momentum of the injected gas is transferred to the bulk liquid, is also called the ‘momentum region’. In a similar manner, the plume is called the ‘buoyancy region’ where the motion of liquid is caused by the buoyancy force exerted by the bubbles. The proper characterization of these regions is important for the analysis and modeling of stirring operations in Ladle Metallurgy. Although many mathematical correlations exist for this purpose, some issues of theoretical and practical interest to the modeling of gas-liquid plumes need further attention."

Jan 1, 2012

By Vince Luongo

"INTRODUCTIONThe West Side Combined Sewer Overflow (CSO) Tunnel Project is located in Portland, Oregon and is part of the Willamette River CSO Control Project. The purpose of the West Side CSO Project is to reduce the frequency and volume of combined sewage overflows from the drainage areas on the west side of the Willamette River using the West Side CSO tunnel as a combined storage and conveyance facility. The sewage is then directed to the Pump Station on Swan Island, which is located on the east side of the Willamette River. From here the combined sewage is pumped through force mains that discharge into the existing Peninsular and Portsmouth tunnels.The West Side CSO tunnel has an inside diameter of 14-feet (4.27m) and is approximately 18,150-feet (5,532m) long. The tunnel slopes at a constant down gradient of 0.0018 from south to north over the entire length of its alignment.The tunnel passes beneath six existing bridges; Hawthorne Bridge, Morrison Bridge, Burnside Bridge, Steel Bridge, Broadway Bridge and Fremont Bridge. The general tunnel alignment follows beneath the Naito Parkway starting at Clay Street Shaft and connecting three other shafts on the west side of the Willamette River, Ankeny Shaft, Upshur Shaft and Nicolai Shaft. It then passes below the Willamette River and on to Swan Island to connect with the Confluent Shaft, which will combine flows from the West Side CSO and East Side CSO (not part of this contract) and then continues to the Pump Station Shaft.The Nicolai Shaft is the primary mining shaft from which two TBM’s were launched to construct the West Side CSO tunnel. The first TBM started mining south and terminated at the Clay Street Shaft. The second TBM started mining north below the Willamette River and terminated at the Swan Island Pump Station Shaft."

Jan 1, 2006