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By A. S. Macfarlane

The introduction of new technology into mining operations is seen as a strategic necessity by many mining companies, in order to improve safety and to improve operational effectiveness. Many attempts have been made in recent years to introduce new technologies into mining operations in southern Africa. Amongst these are noteworthy successes, as well as some disappointing failures. Often, the reason for failure does not lie with the technology itself, but with the work system into which the technology is introduced. Such failures may come with a significant opportunity cost, and have a detrimental effect on future development, simply because the system has not been adequately engineered, and the risks have not been adequately assessed and managed. This paper examines the reasons for such failures, and proposes a methodology to be followed to ensure successful and sustainable implementation of new technologies, such as to reduce technical and financial risk to the company, and to energize the workforce into ensuring the initial objectives of the project are met. The paper also focuses on the application of appropriate technology, and the development of technological applications which are commensurate with the level of development of the work environment into which it is introduced. The paper therefore focuses on the application of risk management, change management, systems engineering and feasibility analysis as being key elements of a successful and holistic technology implementation programme.

Jan 1, 2001

By Philip J. Guerney, S. O’ Leary, André R. Laplante

"Concentration of dense mineral phases (s.g. greater than 7) for characterisation of individual particles and mineral grains by electron microscopy is a well established technique for the detection and characterisation of valuable mineral phases. This presentation describes the type of data that can be generated when both the concentration and characterisation steps are carried to higher levels than typical. The concentration step is the gravity recoverable gold (GRG) protocol that has been used for over 100 ore samples. This protocol yields three concentrates that represent three progressive degrees of grinding and liberation. Three ore samples were subjected to the GRG protocol and three size classes of each concentrate were characterised using the mineral liberation analyser (MLA), an automated, EDX-based tool. This presentation briefly presents GRG and MLA technology, and then focuses on the results obtained: photos, images and databank, the latter used to evaluate the extent of particle liberation and particle shape.INTRODUCTIONThe practice of gravity concentration prior to characterization of mineral samples using electron beam microscopy is solidly established. Typically, a dense liquid such as tetrabromoethane (density: 2.97 g/cm3) is used to reject the light phase, typically carbonates and silicates. The heavy phase, mostly sulphides, oxides and precious metals, is then mounted in a polymer matrix and examined using beam microscopy.Both the pre-concentration and the sample preparation/examination steps have seen significant advances over the past ten years, but are not without problems. A major issue of preconcentration is that most dense liquids used are toxic, tetrabromoethane being a prime example. More recently, a dense liquid with little or no toxicity (sodium polytungstate, distributed by Sometu Inc.) has become commercially available, but its use is limited to relatively low s.g. splits around 3 g/cm3. Dense liquids are viscous, and their use is limited to particles coarser than 37 µm, although centrifuge separation can probably lower this limit to around 10 µm. Magnetogravimetric separators can achieve much higher specific density cuts, but upgrading below 100 µm or in the presence of magnetic minerals remains a problem. The use of centrifuge separators such as the 3-in Knelson Concentrator (KC MD3) or the Falcon 4-in SB (SB4) is particularly attractive since these units can easily process large masses (by laboratory standards) and achieve a cut density well above those of dense liquids."

Jan 1, 2003

By E. V. Manlapig, David J. Spottiswood

In recent years great advances in the automatic control of flotation plants have been made, mainly due to the development of reliable sensing instruments to monitor process performance and the development of an adequate understanding of system responses to process disturbances. Some of the control strategies used in flotation plants which apply computer control are presented here. These schemes, which involve the control of collector; depressant, frother, and air and pulp level, are analyzed with respect to their control objectives, control variables, and the instrumentation involved. The knowledge gained in understanding these strategies may be applied in the dew and implementation of control system in other concentrators.

Jan 1, 1981

By E. V. Redin

"The Bakal (South Ural, Russia) deposit of iron ore bearing iron carbonate (siderite) with the capacity of more than 1 billion tones belongs to the MMK. This ore cannot be fully processed via blast furnace technology because of high content of MgO. According to the investigations carried out in the USA and Japan in 1999-2004 the ITmk3 (Ironmaking Technology mark three) RHF technology is a breakthrough in Ironmaking. Four iron ore types (hematite, magnetite, high and low Al2O3/SiO2) were tested. Reduction, melting and slag removal can be achieved in just 10 min. The main objective of the investigation is to establish optimum operation conditions for the production of iron nuggets from iron carbonate bearing ore via the ITmk3 by means of the lab scale testing. Green pellets were processed via a lab tube (chamber) furnace to simulate RHF conditions. This preliminary test work provides valuable information which may be used for large-scale testing in a commercially sized RHF.IntroductionThe ITmk3 process upon which this paper focuses was developed by Kobe Steel in its research facilities in 1996 [1]. After pilot testing at Kobe Steel’s Kakogava Works in 1999-2004 the pilot demonstration plant was built and operations were successfully carried out by Mesabi Nugget joint venture in 2002-2004. Steel Dynamics has committed to building the commercial plant at the Mesabi Nugget site in Hoyt Lakes (Minnesota). Only 4 iron ore types (hematite, magnetite, high Al2O3/SiO2 and low Al2O3/SiO2), as well as 4 coal types with range of volatility, ash and fixed carbon were tested. Results were consistent with nugget characteristics confirming ITmk3’s flexibility with respect to raw material inputs. At the same time, no research in the field of nugget from iron carbonate bearing ore with high content of MgO has been done. Such kind of iron ore is restricted for charging into the blast furnace due to contamination of MgO. The reason for restriction is the limitation of load of MgO in the blast furnace. If a lot of MgO enters the blast furnace, slag becomes viscous. The viscous slag is obstacle for stable operation of the blast furnace."

Jan 1, 2012

By J. D. Brown

The electron optics, vacuum system, and sample stage assembly for the Bureau of Mines? electron probe X-ray spectrograph were purchased. Four scanning curved-crystal spectrometers, two reflection- and two transmission-type, were designed and constructed by the authors. The reflection spectrometers are placed in a vacuum chamber for measurement of long-wave-length X-radiation. Detection, pulse-amplitude discrimination, and recording circuits are provided for the simultaneous measurement of four X-ray spectral lines. Minimum spot size is approximately 2 microns in diameter at 30 kilovolts and a sample-to-ground current of 5 x 10-8 ampere. At this voltage and current the limit of detection with reflection spectrometers is less than 0.05 weight-percent for most elements. The limit of detection for elements determined by transmission-type spectrometers, evaluated at 35 kilovolts and 5 x 10-8 ampere, is approximately 0.1 weight--percent for all elements having excitation voltages below 20 kilovolts. In general, reflection spectrometers exhibited satisfactory but poorer resolution than the transmission type, resolution of the spectrometers being limited primarily by crystal imperfections, with greater mosaic structure being introduced by the grinding process for the reflection crystals. Several applications of the electron probe X-ray spectrograph are described. Analysis of a uranium-steel is discussed in detail to illustrate calculation of composition from measured X-ray intensities.

Jan 1, 1962

By D. J. Thorkelson

New data indicate Wernecke Breccia-associated iron oxide copper-gold (IOCG) deposits likely formed from moderate-temperature, high-salinity, non-magmatic brines. The breccias formed in an area underlain by a sedimentary sequence that locally contained evaporites (potential source of chloride and possibly sulfur) and was thick enough to produce elevated fluid temperatures. Metals (Fe, Cu, Co, U) were probably derived from host strata, transported as chloride complexes, and precipitated due to changes in fluid temperature and pressure during brecciation. These new data suggest that the spectrum of genetic models for IOCG deposits that typically invoke formation from magmatic or hybrid magmatic-non-magmatic fluids should be expanded to include those systems that formed in a non-magmatic environment. Modifications to the definition of IOCG systems are proposed that reflect the degree of involvement of magmatic and/or non-magmatic fluids and the nature of the mineralizing environment. A division into magmatic, non-magmatic, and hybrid magmatic-non-magmatic IOCG types is suggested. Typical magmatic end-member IOCG deposits include Lightning Creek and Eloise, Australia. Hybrid magmatic-nonmagmatic IOCG examples include Ernest Henry and Olympic Dam, Australia. The Wernecke Breccia and Redbank deposits are suggested as possible representatives of non-magmatic IOCG end members. Endmember magmatic IOCG deposits have similarities to some porphyry deposits, whereas non-magmatic IOCG end members share characteristic with some sediment-hosted Cu deposits, suggesting that the range of IOCG deposits may form a link between intrusive- and sediment-related deposits

Jan 1, 2007

By M. Bouchard, B. Cadieux et F. Goutier

Five phases of ice movement were r es pons ible f or glacial dispersion in t he study area. I ce fl ow directi on changed prog r es s ively from SE to SSW and then to the S. All observed glacial sed iments are associated with a south-southwest to south movement; t hey are grouped, on the basis of their texture, structure, morphology and composition, into four distinct lithofacies. A lithological study of the coarse-grained fraction (4-128 mm) of these lithofacies shows systematic compositional differences. These are: 1) variations in the proportions of local bed rock fragments; 2) variations in the horizontal displacement of the maximum abundance peak of a given lithology relative to its source area, and 3) variations in the length of dispersion trains associated with each lithofacies. Although dispersal trains can obviously be mapped without differentiating li thofacies, studies based on the consideration of lithofacies should give more reliable results than conventional methods.

Jan 1, 1984

By L. Voisin, K. Itagaki

In the reductive smelting of the copper concentrate like a blast furnace operation using coke as fuel and reductant or in processing the copper concentrate which contains coal in the bulk, a sulfur-deficient matte phase often coexists with an iron base alloy in the bottom of the smelting furnace. This alloy is generally called furnace residue or speiss when considerable amount of arsenic or antimony is contained in the alloy and in the extreme case of reducing condition the alloy is saturated with carbon. As a fundamental study to know the behavior of some precious metals such as silver, gold and platinum between the sulfur-deficient matte and the furnace residue or the speiss which are in equilibrium under reducing condition, the phase relations and distribution of precious elements in the Cu-Fe-S-As and Cu-Fe-S-Sb systems saturated with carbon were determined at 1473 K by a quenching method.

Jan 1, 2007

By V. F. Zackay, W. A. Goering

ALLOYS of iron and aluminum up to 35 wt pct aluminum are single-phase solid solutions, and are of potentially wide applicability.1-3 In spite of early and continued interest1-4 little progress has been made until recently in the preparation and evaluation of sound alloys containing more than 6 wt pct aluminum. Vacuum-melting techniques for the production of ductile Fe-A1 alloys have been described recently.1-7 A. procedure for air melting these alloys is presented here. Low-carbon iron is induction melted without a slag in a rammed magnesia crucible. At the beginning of melt-down, aluminum pig (99.95 pct Al), charged in a clay-graphite bottom-pouring crucible is placed in a pot furnace at 1800°F. The primary deoxidation of the molten iron after melt-down is effected by the addition of 0.1 pct aluminum and 0.5 pct manganese. (Hilty and Crafts" have reported a significant increase in the deoxidation efficiency of the aluminum and manganese combination over that of the aluminum alone.) A more drastic deoxidation designed to reduce the oxyen content to the lowest possible level is accomplished by plunging metallic calcium to the bottom of the melt. This is done by wiring small cubes of the metal to a steel rod. A circular shield larger than the diameter of the crucible opening is attached to the rod so that any spa'ttering of the molten metal will not endanger the operator. Since the temperature of the molten metal is above the boiling point of calcium, the bath is vigclrously purged by calcium vapor. It is believed that the calcium-vapor treatment permits a homogeneous distribution of calcium in the melt. Owing to the vigor of the reaction the temperature of the molten metal should be kept below 2900°F prior to the calcium addition. A total of 0.05 pct calcium is added in two stages in this manner. The second calcium deoxidation is made just before charging the molten aluminum into the iron, in order that an excess of calcium be present for the remainder of the melt. The aluminum, which has been removed from the holding furnace, is then hydrogen degassed by bubbling chlorine through a quartz tube immersed in the molten aluminum. The hydrogen-chlorine reaction is an exothermic one preventing the solidification of the aluminum during the 5-min chlorination. Approximately 0.1 pct calcium, based on the amount of aluminum, is then added to the aluminum. A further excess of calcium is introduced into the melt in this manner. The oxide dross is removed, fluorspar is added to the molten iron, and the molten aluminum is poured through the fluorspar slag. The fluorspar should be dried thoroughly prior to its use, as any water present will react with the aluminum. Aluminum oxide formed during the pouring operation reacts with the fluorspar slag to form gaseous aluminum fluoride and calcium oxide. A forced-draft ventilating system is required for this operation as aluminum fluoride is toxic. As soon as the molten aluminum has been added, vigorous manual stirring of the melt is required because the slag-aluminum oxide reaction is highly exothermic and tends to take place near the top of the melt. The combination of high temperature and the slagging action of the fluorspar quickly erodes the crucible at the slag line if the aluminum is not stirred uniformly into the melt. It has been found that at least 4 min of manual stirring combined with induction stirring are necessary to ensure homogeneity. The power is shut off 1 min prior to pouring to allow metal and slag to separate. As much slag as possible is removed from the melt, which is then poured directly into cast-iron molds. A mold wash of aluminum oxide is used to prevent ingot sticking. For slab ingots which are to be rolled into sheet, a carbon-tetrachloride vapor atmosphere or a chlorinated-pitch mold wash is desirable, as the aluminum oxide formed in the pouring operation is subsequently removed by the chlorine in the presence of carbon." As in vacuum melting, a pouring temperature of about 2900°F is recommended. Adequate hot-topping is important as iron-aluminum ingots are subject to very deep piping. Ingots are removed from the molds and buried in vermiculite, where they are allowed to cool slowly to room temperature. The ingots are radiographed,

Jan 1, 1959

By T Suwa, S Ishida, J Xue, S Fuchida, H Shimada, Y Aoki, C Tokoro

Pyrite depression with prolonged pre-conditioning treatment in high salinity water has attracted much of researchers’ interest in recent years considering the increased utilisation of multiple stage flotation, closed water circuits, clay minerals, and sea water in flotation plants. In this study, the role of calcium (Ca)/magnesium (Mg) precipitates in stabilising the dissociative ferric hydroxy-xanthate (FHX), and its effect on modifying the balance of hydrophobic/hydrophilic species on the pyrite surface were primarily investigated. The total amount of extractable Fe-bearing species on pyrite concentrates and tailings after floatability test was quantitively determined using ethylenediaminetetraacetic acid (EDTA) extraction tests combined with inductively coupled plasma optical emission spectroscopy (ICP-OES). A more evident accumulation of extracted-Fe in pyrite concentrates rather than it in pyrite tailings was observed at both pH 9 and 10.5 when pyrite was pre-conditioned in Ca/Mg-bearing solutions for 360 min. Fourier transform infrared (FTIR) spectroscopy showed the main xanthate derivatives changed from di-xanthogen (1155 cm-1 ) to FHX (1167 cm-1 ) on the oxidised pyrite samples that were preconditioned in Ca/Mg-bearing solutions. Scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) suggested the preferential accumulation of FHX upon secondary Ca/Mg-bearing precipitates as reflected by the higher Fe/S ratio together with the decrease of O element herein after xanthate conditioning. Although the hydrophilic secondary Ca/Mg/Fe-bearing minerals on the pyrite surface generally deteriorate pyrite’s floatability, the upper section of these secondary hydrophilic aggregates is partially covered by FHX alongside with further multilayer-adsorbed di-xanthogen. The precipitated Ca/Mg-bearing precipitates promotes the immobilisation of dissociated FHX derived from the reaction among iron oxyhydroxides and xanthate anions upon the localised secondary Ca/Mg/Fe-bearing minerals via acid–base complexation. Therefore, this phenomenon alleviates the hydrophilic modification of secondary Ca/Mg/Fe-bearing minerals to pyrite considering the immobilised FHX upon localised precipitates shows a slight hydrophobicity, and meanwhile, the upper FHX benefits the multilayer adsorption of di-xanthogen via the interaction among their inner hydrophobic alkyl chains.

Aug 24, 2022

By R. Mohan Srivastava

"The goal of estimation is considered in the light of decision analysis. A simple example reveals the essential elements of decision-making in the face of uncertainty. A second example shows that these elements are also key features of many mining decisions. These two examples cause us to revive an old probabilistic notion that the goal of estimation should be to quantify what is unknown. The conditional probability distribution provides the complete statement of one's uncertainty. Once the conditional probability distribution has been established, one should retain as an estimate the value which minimizes some objective loss function. A third example shows how the ""best"" estimate depends on the chosen loss function. Current practice is almost exclusively based on the least squares method, which assumes a loss function which penalizes underestimation and overestimation equally. This is unfortunate not only because symmetry is an unrealistic assumption but also because mining offers a rare opportunity to state the loss function directly in terms of profitability. Both the theoretical framework and the practical tools exist to allow us to reconsider the conventional notion of the ""best"" estimate. IntroductionThis paper looks at estimation in the mining industry from the point-of-view of decision analysis. Virtually all decisions depend on estimates since few of the important parameters are ever known exactly. In this paper we will be referring mainly to the estimation of ore grades, though the approach discussed here is generally applicable to any decision in which relevant information is uncertain.In the first section we look at a very simple example of decision-making in the face of uncertainty. We will then tum to a mining example and see that the essential features of the simple example still pertain. From these two examples it will be clear that the decision analysis approach rests on two key concepts: the conditional probability distribution and the loss function. A third example demonstrates how different loss functions produce different ""best"" estimates from the same conditional probability distribution. In the final sections we willexamine the current practice of estimation in the mining industry. Though the tools for estimating the conditional probability distribution already exist, a change in the way we think about ""best"" estimates is needed. Very little attention is presently paid to the loss function even though it is readily available in many mining applications."

Jan 1, 1987

By Judy Che, Steven Ceccio, Gretar Tryggvason

"A detailed understanding of drop deformation and solidification is essential for quantitative predictions of geometry and properties of parts made by ballistic particle manufacturing processes. Axisymmetric results of towers built by the deposition of multiple drops are presented. In these computations, fluid flow, heat transfer, and phase change are fully coupled throughout the drop deformation and solidification process. The solution method is based on a single set of conservation equations written for all phases simultaneously. The phase boundaries are treated as imbedded interfaces by adding the appropriate source terms to the conservation equations. A parameter study demonstrates the effect of Weber number, Peclet number, and drop deposition frequency on the final shape of the structure. Numerical results show that most successful method of building uniform towers is when two conditions are met. First, each drop solidifies at the same time in the deformation cycle. Second, the cooling rate is slow enough to allow for good adhesion between drops. The ability to predict the final shape of deposited drops will greatly reduce the amount of experimentation necessary to select the desired set parameters for any artifact.IntroductionMaterial deposition techniques based on layering small molten metal drops holds the promise to build small, coherent three-dimensional structures. In this process, numerous 20-100 µm diameter drops are deposited onto a substrate with a low impact velocity (on the order of 5 mis). Both the momentum and trajectory of each drop are controlled precisely to build up complex parts. This material layering technique differs from processes such as spray forming and splat quenching which involve high impact velocities (on the order of 100 mis) and high frequency deposition with little control over individual drop placement. This process of layering small drops can produce parts with near net shape accuracy, while spray forming produces slabs of material which must then be worked to make a usable part. The ability to computationally predict final drop shape and cooling rate has the advantage of allowing the user to select parameters to produce parts with desired shape and mechanical properties. However, the development of such predictive methods requires a thorough understanding of both drop deformation and solidification"

Jan 1, 1999

By Frank Nicholson

Copper ore was first noticed in Ste. Genevieve County in 1563. The diswvery mas made by a German farmer named Simon Grass, who had occasion to make a road from his farm down the hill into the neighboring valley, and while so engaged noticed pieces of a green-colored mineral, some of which he collected. Not knowing the character of the ore he had found, and supposing it to be valua ble for its brilliant green color only, he carried a piece with him into the town of Ste. Genevieve and showed it around the various bar rooms as a curiosity. No special attention was paid to the matter until nine years later, when Mr. 0. D. Harris sent a specimen of the ore to Dr. Theodore Fay, of St. Louis, for analysis. This analysis, which was the first ever made of Ste. Genevieve copper ore, showed the specimen to contain : Copper,. .........17.75 per cent. Zinc,..........3.21 " Iron........... 24.50 " Sulphur ..........1.09 " Organic matter, silica, carbon, and oxygen,. .. 53.45 " 100.00 " From this analysis it is evident that the sample was taken from near the surface, and was probably recognized by its green color. The almost entire absence of sulphur proves it to be an oxidized form. There is on file, at the office of the Ste. Genevieve Copper Works, a paper* giving three arsays of the ore made in 1875 by Henry B.

Jan 1, 1882

By Guilherme Corrêa Soares

Deeper understanding about the strain hardening behavior of steels has become necessary due to its importance in industrial processes such as mechanical cold forming, rolling and drawing. In this work, the strain hardening behavior of AISI 304, non-grain oriented electrical (NGO) and dual phase steels was investigated. Tensile tests were performed and the strain hardening behavior of each steel was studied by the Hollomon’s equation. X-ray diffraction measurements and hardness tests were also carried out in order to characterize the specimens. Different work hardening stages were observed in each steel during the deformation process. The results obtained are discussed in terms of the relationship among the instantaneous strain hardening coefficient, hardness and eventual phase transformations. The instantaneous strain hardening coefficient of dual phase and NGO increases after the yield point, rapidly reaching its maximum and then steadily decreases until tensile strength is reached. In AISI 304’s case, the strain hardening coefficient keeps raising to high values in response to a large strain and then rapidly decreases before reaching the tensile strength. In comparison to the other steels, AISI 304 shows higher instantaneous strain hardening coefficient value, which persists even in large strains. This is a consequence of its strain hardening mechanism based on stress-induced martensite transformation.

Aug 16, 2017

By Robert Archer

IT is now well known that the structure of aluminum-silicon alloys can be refined in a rather remarkable manner, with consequent improvement of physical properties, by certain treatments applied to the molten metal shortly before casting. The differences between the treated and the untreated alloys are so marked that special terms are used to distinguish them, the untreated alloys being referred to as "normal" and the treated alloys as "modified." The first practical method of accomplishing this result was that of A. Pacz,1 which consists in treating the molten metal with a, salt flux of which the, active ingredient is sodium fluoride. The result can also be brought about, and in a more economical manner, by the addition of small quantities of metallic sodium (or potassium) to the molten alloy shortly before casting.2 The action of the Pacz flux evidently consists essentially in the production of free sodium by the reaction of sodium fluoride with aluminum. The changing of a normal alloy to a modified alloy is referred to as "modification' and any process for accomplishing this result is a "modifying" process. Modified aluminum-silicon alloys were introduced several years ago, and it has been demonstrated both in the laboratory and in commercial practice that it is no simple matter to produce castings having the maximum or nearly the maximum properties which under favorable circumstances can be obtained. The alloys are rather sensitive to small changes in chemical composition, and the modifying process must be carried out in a very particular manner to obtain the best results. Extensive experimental work has been carried out in the laboratories of the Aluminum Company of America with the object of determining the conditions that must be observed to make these alloys of the greatest possible

Jan 2, 1926

By Edgar E. Vidal, Keith Smith, James A. Yurko

Beryllium, like many other reactive metals, is extracted from a halide (generally BeF2) using magnesiothermic reduction, also known as the Kroll process. The beryllium is produced in a molten state, which when solidified resemble "pebbles". Although beryllium is used in limited quantities compared to other metals (< 100 Mt/annual), it is a critical material for the nuclear, defense/aerospace, and large science markets because of its unique nuclear and mechanical properties. Beryllium processing has unique environmental, health, and safety concerns which must be handled appropriately in the 21st century from a worker and environmental safety perspective, and must be designed with this first in mind. In 2011, Materion began operations of its new Kroll plant – informally known as the “Pebbles Plant” - in Elmore, Ohio. The plant was majority funded by a U.S. Department of Defense Production Act (DPA) Title III grant, which is a unique government/industry partnership program to, "create assured, affordable, and commercially viable production capabilities and capacities for items essential for national defense." After a twelve year hiatus from primary beryllium production, Materion has reentered its extraction business and has relearned how to make pebbles. The purpose of this presentation is to give an overview on beryllium extraction and discuss some of the unique aspects of building and operating a safe beryllium facility during the production scale-up phase.

Jan 1, 2015

E. T. Dumble, Houston, Texas (communication to the Sec-retary?):—In addition to the list of publications mentioned by Mr. Schorr and those by Prof. Hofman, I call attention to the following references:— Sludi sulle Lignite, by Capacci. Turin (1890). (An excellent work.) Report of Brown Coal Industry in Germany. J. Cosmo New-berry. Department of Mines, Victoria (1892).

Jan 1, 1905

By E. Morgan Massey

Located in virgin coal acreage near Gilbert, W. Va., Massey Coal Mining Co.&apos;s Ben Creek No. 2 mine afforded the company&apos;s engineers the opportunity of designing and laying out the entire mining operation from the mine faces to the railroading loading site. However, the topography of this region posed difficult problems in haulage of coal for, in this extremely rugged terrain the uppermost coal seams lay in the mountain-top ridges, approximately 1400 ft above the valley floor. The decision for mining equipment naturally leaned to the new high-capacity continuous miners where seam conditions permitted: otherwise, to the new super-high capacity conventional cutting and loading machines. Since the coal seams lay in ridges and points of considerable outcropping, the decision was to keep the transportation on the surface and mine the coal with multiple entries into the outcrop. This way, the major problems of underground haulage, drainage, and ventilation are eliminated, and the opportunity to take advantage of a-c underground power becomes a much simpler proposition.

Jan 10, 1960

By J. L. Cupp, R. C. Ford, B. R. Romig

The Climax Molybdenum Mine, located near Leadville, Colorado, is the site of a lengthy mining history spanning more than 80 years. In the 1960’s, extraction of molybdenum from oxide ore located adjacent to the massive molybdenite sulfide deposit resulted in the construction of an earthen core dam to impound fine-grained oxide tailing in the Eagle River Valley. Through recognized value of water storage and reclamation opportunities, a tailing removal project was initiated in 1993 to convert the impoundment facilities to a post-mining beneficial land use of developed water resources. An evaluation of the effect residual materials and lake dynamics would have on in-stream water quality was performed. Eagle Park Reservoir stands as a model for future reclamation efforts that involve water delivery to highly sensitive receiving waters. This paper provides a case study on project development, the evolution of water quality assessment, and the regulatory framework that contributed to this project’s success.

Jan 1, 1999

By D. E. Karvelas

Argonne National Laboratory is conducting research to develop a cost-effective and environmentally acceptable process for the separation of high-value plastics from discarded household appliances. The process under development has separated individual high purity (greater than 99.5%) acrylonitrile-butadiene-styrene (ABS) and high-impact polystyrene (HIPS) from corruningled plastics generated by appliance-shredding and metal-recovery operations. The process consists of size-reduction steps for the commingled plastics, followed by a series of gravity- separation techniques to separate plastic materials of different densities. Individual plastics of similar densities, such as ABS and HIPS, are further separated by using a chemical solution. By controlling the surface tension, the density, and the temperature of the chemical solution, we are able to selectively float/separate plastics that have different surface energies. This separation technique has proven to be highly effective in recovering high-purity plastics materials from discarded household appliances. A conceptual design of a continuous process to recover high-value plastics from discarded appliances is also discussed. In addition to plastics separation research, Argonne National Laboratory is conducting research to develop cost-effective techniques for improving the mechanical properties of plastics recovered from appliances.

Jan 1, 1996