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By J. F. McCoy

As mining develops into deeper and hotter regions, the safety and health of miners require that the workspace be cooled. Toward this end, this program has successfully developed a high performance, low maintenance spray cooler of 5000 cfm nominal capacity. Further, a series of four 25,000 cfm, nominal capacity, spray coolers has been built and mine tested with satisfactory results. The smaller coolers have been patented and become commercialized with 50 units currently in service. The concept has been developed independently overseas with an unknown number of units in operation.

Jan 1, 1984

By S. Banisi, M. Poorkani, M. Farzaneh, M. Askari

"At the Sarcheshmeh copper mine 40,000 t of ore per day with an average grade of 0.9 % Cu is ground to 70% passing 75 microns. Grinding is effected in 8 parallel lines of 8 x 5 m ball mills in a closed circuit with cyclones. The make-up balls are 80-mm forged alloy steel balls and the average ball consumption is 750 gh of ore ground. In order to optimize ball size distribution inside the mill, based on the previous investigation instead of using only 80 mm make-up balls a combination of 80 and 60 mm (75% to 25% by weight) ball charge was used in one of the mills. To evaluate the performance of three ball types namely forged alloy steel balls (A), ductile cast iron (C), high chromium cast iron (D) and also a combined (80 and 60 mm) charge of forged alloy steel balls (B), four identical parallel mills were charged accordingly. These four mills were sampled during a period of six months. The amount of material finer than 75 microns of cyclone overflows was selected as a criterion for the performance evaluation. It was observed that in a mill with the combined make-up balls the amount of fine produced was 4% higher than the other mills. The consumption of ball types A, C and D were 730, 710 and 534 g/t, respectively. The results of laboratory flotation tests showed that due to an improvement in the production of fines an increase of 1.4% in the overall copper recovery is obtainable. Due to the promising results, the new make-up ball regime was implemented in all mills in the plant.INTRODUCTIONThe Sarcheshmeh copper ore body which may rank as third or fourth largest in the world contains 1 billion tonnes averaging 0.90 % copper and 0.03 % molybdenum. It is located southeast of Iran and has been processing 40,000 t/d of ore since 1982. The mine produces 100,000 tonnes of copper and 2,200 tonnes of molybednite concentrate per year. After three stages of crushing, the ore with a F80 of 12.7 mm is fed to 8 parallel ball mills in closed circuit with cyclones to produce a product 70% finer than 75 microns. The concentrate of the first stage of flotation is reground and the tailing constitutes the main component of the plant final tailings. A concentrate with an average grade of 31% Cu is obtained after cleaning and re-cleaning stages. Total recovery of the plant varies between 83 and 87 % depending on the operating conditions and ore type."

Jan 1, 2002

By Hassan El-Shall, El-Sayed A. Abdel Aal

The major goal of this study is to decrease iron content in wet-process phosphoric acid. Reducing the amount of post-precipitated sludge in the acid is another important objective in this investigation. In order to achieve these goals, research efforts have focused on bench scale testing of an iron-chelating reagent to remove iron from phosphoric acid produced from South Florida high-iron and -magnesium phosphate concentrate, and plant testing using freshly produced concentrated acids for reducing the post- precipitated sludge. The data obtained in the above studies suggest that the addition point of the precipitating reagent is very important, as the precipitated iron compound has higher solubility at higher P2O5 concentrations. Up to 60% Fe2O3 removal efficiency is achieved depending on the amount of the reagent, concentration of acid used, and operating conditions. The addition of precipitating reagents to freshly concentrated phosphoric acid leads to a decrease of up to 84% in sludge volume percentage depending on acid type and clarification conditions. Decreasing the volume percentage of the sludge facilitates acid handling as well as decreases the adherent water- soluble P205 leading to lower total P2O losses.

Jan 1, 2002

By W. Petruk, M. J. Matos

An aplite ore from Guarda in northern Portugal, containing albite, microcline and quartz and muscovite gangue was studied to identify conditions for extracting the feldspar minerals. The large amounts of quantitative mineralogical data needed to evaluate grinding behaviour were provided by automated image analysis. The images were acquired on polished surfaces by measuring back-scattered electron signals produced with a microprobe. Minerals were identified from X-ray spectra and discriminated by grey level and element-characteristic X-rays. The quantities and size distributions of the minerals were determined by measuring thin sections of unbroken ore to predict the grind required to liberate the feldspars. The ore was then ground to -1.7 mm, polished sections were prepared from sieved fractions and the quantities of mineral species and apparent total liberation were determined by analysis. The predicted and measured liberations were compared and the grinding behaviour of the ore interpreted. In an appended correction, the correct version of Equation 1 is represented and Tables 3 and 6 are revised to consider all size fractions, including those coarser than 300 micrometres, in calculating the total liberation from King's fractional liberation

Jun 18, 1905

By T. A. Henrie

One objective of Project Gnome is to study the feasibility of a phase of the Plowshare program recovering thermal energy from an underground nuclear explosion. The test will be conducted in an underground salt deposit. It is anticipated that some of the energy thus released will be stored as thermal energy in molten salt. This report describes the pre-Gnome experiments conducted at the Federal Bureau of Mines Metallurgy Research Laboratory, Boulder City, Nev. The objectives of this study were to determine the problems involved in the recovery of thermal energy from molten salts to assist in planning the experimental program for the Gnome project.

Jan 1, 1961

By Grant Loveday, Vincent Dieudonné, Andrew Jonkers

Bateman Minerals & Metals supplies the APIC Technologies which include the under-bed air-pulsed APIC jig and related technologies such as the JigScan controller and advanced mathematical models of the jig process. Bateman have developed a methodology for predicting process performance for jigs from simplified testing and modelling, based on batch equipment matched to industrial designs. Batch tests conducted on laboratory scale air-pulsed jigs can process small batches of material, such as those obtained from drill core samples. The novelty comes from using an advanced jig process model, ASTRAD, to link the results of batch and continuous jigs. The batch jig presented as a novelty in this paper has been designed to be hydraulically equivalent to the full-scale APIC Jig, allowing the generation of equivalent pulse shapes and using JigScan controller. Lump and fine ferrous ore material have been separated in this unit and any feed >1mm can be tested and extracted. The global test procedure and further modelling focus on the stratification of material, with emphasis on key aspects such as pulse shape, feed characteristics and residence time. The splitting of rejects from concentrates is itself more difficult to reproduce in batch jigging, however the ASTRAD model includes a separation imperfection module, and the APIC Technologies have extraction systems adapted to each type of material. Air pulsed batch jigs are available in several locations and are relocatable. They have been used to treat samples from Australia, South Africa and India as part of studies into ore processing using jigs. Each test layer is available for various physical testing procedures (density and chemical analyses). Test-work is performed on a case by case basis, and analysed using an advanced model ?now available over the internet. Some fundamentals of air-pulsed jigging are recapped along with some of the features of APIC jigs. The process of designing a ?hydraulically equivalent? batch jig test is then described. Some results from jigging tests are presented plus the results of the ASTRAD advanced jig model, which was first developed at the JKMRC with ferrous ores and coal and is now being supported and further developed and utilised by Bateman.

Jan 1, 2006

By T. H. Yang, K. K. Lee, Z. Z. Liang, C. A. Tang, L. C. Li, Y. Tsui, L. G. Tham

Abstract: A series of numerical tests of hydraulic fracturing in heterogeneous rocks were performed to investigate the influence of pore pressure magnitude and gradient on initiation and propagation of tensile fractures. The numerical tests were run with a Rock Failure Process Analysis code, F-RFPA2D, incorporated with a Flow-Stress-Damage coupling model (FSD). To investigate the influence of pore pressure magnitude on fracture behaviour, “pinch-off” breaking tests, originally employed by Bridgeman to investigate the effective stress law for tensile fracture in a uniform pore pressure field, were numerically modelled. In another numerical test, a double-notched sample, with fluid pressure in one notch while keeping the other one open to the atmosphere, is numerically extended to investigate how the fluid flow direction or the pore pressure gradient will influence the fracture behaviour. The simulation results show that fracture is strongly influenced by both pore pressure magnitude and pore pressure gradient. Keywords: seepage mechanics; heterogeneous; pore pressure; numerical simulation; failure process ZUSAMMENFASSUNG: Um den Einfluss der Wasserdruckgroesse der Oeffnung und der Porisitaet auf den Bruchentstanden und Verbreiten der Tension von Gebirgen zu beurteilen, wurde viele nummerische Pruefungen auf den hydraulischen Bruch in dem Gebirgen aufgenommen. Diese Pruefungen wurden mittels der Analyse- Software F-RFPA2D und Flow-stress-Damage Coupling model ( FSD) durchgefuehrt. Um den Einfluess der Wasserdruckgroesse der Oeffnung auf den Bruch zu beurteilen, wurden auch Bruchpruefung und nummerische Analogexperimenten gemacht, und dadurch wurde die ganze Phase der Bruchentstanden und Verbreiten wiedergezeigt, und die Ergebnissen ergeben sich, dass die Wasserdruckgroesse der Oeffnung und der Porisitaet sehr viel auf den Bruchentstanden und Verbreiten der Tension von Gebirgen beeinfluessen. Schluesselwoerter: Durchlaessigkeit , ungeleichmaessig, Wasserdruck der Oeffnung, nummerische Analog, Zerstoerungspahse Résumé : Une série de simulations numériques a été ménée pour analyser l’influence de la grandeur de la pression de pore et du gradient sur la naissance et la propagation des fractures de tensions par le biais de la simulation numérique des fractures hydroliques dans des rochers hétérogènes . Le logiciel F-RFPA (Rock Failure Process Analysis code ) intégrant FSD ( Flow-Stress-Damage coupling model ) y a été employé. Les résultats des simultations montrent tout le processus de la naissance et de la propagation des fractures sous la pression de pore. Ces résultats nous ont permis de constater que la grandeur de la pression de pore et le gradient exercent une influence importante sur la naissance des fractures dans les rochers et sur leur mode de propagation . Mots de clé : le mécanisme de transfusion ; l’hétéogénéité ; la pression de pore ; la simultation numérique ; le processus destructif

Jan 1, 2003

By W. E. Webb

This report describes a method the Bureau of Mines devised for measuring the dielectric constant and loss tangent of low-loss minerals at microwave frequencies. Determina-tion of these properties makes it possible to predict the effects of using microwave heating in potential mineral processing applications. The method uses a test cell and radio-frequency (RF) impedance analyzer with automated data acquisition and analysis. In this initial phase of microwave heating research, the Bureau measured dielectric constants and loss tangents at frequencies between 100 MHz and 1 GHz. The objective was to establish a reliable data base for use in predicting the effects of microwave heating on minerals. Comparison with previously measured data showed the Bureau's measurement method to be accurate to within ± 3 pct. This report describes the method and discusses the preliminary results of the Bureau's investigations. Typical comparative data are included.

Jan 1, 1986

By Martin J. Gavin

[The theory of fractional "eduction" of oil from oil shale has been used by several inventors as the basis for the design of retorts for the production of oil f roan the oil shales of the United States. The term fractional "eduction" gives expression to the rather common belief that when an oil shale is he-test et produces light, low-boiling oils at to temperatures, and increasingly heavier, higher-boiling oils as the temperature of retorting rites. The theory evidently had its is origin in the fact that crude petroleum may be fractionally distilled, yielding light oils at low distillation temperatures, and heavier oils as the distillation temperature increases. Thus, gasoline is produced from petroleum at relatively log: temperatures, kerosene at a higher temperature, and heavier products such as gas-oil and lubricating distillates at still higher temepratures, The writers have examined several oil-shale retorts designed to take advantage of the belief that crude, and en some cases refined, gasoline can be recovered from the shale at low temperatures; kerosene at higher temperatures, and so on. Such retorts are usually designed to operate continuously, and. have several vapor-pipes lending from them at differing intervals and passing to separate condensers. Designers of such retorts expect that the distillate from the low-temperature parts of the retort will be gasoline, and that as the shale basses to zones of increasingly higher temperatures, the vapor lines leading from these zones will remove increasingly heavier products such as kerosene, gas-oil, etc.]

Jan 1, 1924

By T. Sun, J. Kou, D. Tao

"The reduction behavior of low-grade lump hematite ore (100% 20-50 mm) has been evaluated by performing a series of coal-based direct reduction roasting tests followed by magnetic separation under different process conditions such as roasting time, temperature, reductant type and dosage, and grinding stage. To investigate mineralogical transformation and reduction characteristics of lump hematite ore, roasted ores and magnetic concentrates were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS) and polarizing microscope. The results have shown that a magnetic concentrate with a total iron (TFe) grade of 90.7% was produced at an iron recovery of 83.9% when lump hematite ore was reduced at 1,200° C for five hours using 35% lignite as a reductant followed by two stages of grinding, for 20 min and 30 min each, and low-intensity magnetic separation. The degree of reduction is closely related to the change in the internal structure of the roasted ore. Lignite with a higher fixed carbon content and lower ash generated roasted ore with a more highly porous structure, which provides better permeability of reducing gas. Magnetite, fayalite and wustite were the dominant intermediates of coal-based direct reduction of lump hematite ore. Parts of wustite reacted with SiO2 or Al2O3 in gangue and generated fayalite or hercynite. FeO in fayalite was replaced by CaO to produce wustite, which was finally reduced to metallic iron. However, Fe in fayalite and hercynite produced with low contents of CaO cannot be reduced into metallic iron. Introduction Low-grade hematite ore, characterized by low Fe content and high SiO2 content, cannot be treated by traditional mineral processing methods due to its nonmagnetic property and fine liberation size. The direct reduction (DR) roasting process has been studied and proven satisfactory in treating difficult-toprocess ores, such as low-grade nickel laterite oxide ore (O’Connor et al., 2006; Cao et al., 2010; Guo et al., 2011), high phosphorus oolitic hematite ore (Li et al., 2012; Yu et al., 2013), low-grade hematite ore (Wei et al., 2013;) and iron ore tailings (Li et al., 2010), which greatly expand the resources of usable iron ores (Srivastava and Kawatra, 2009). Therefore, the use of a DR process to treat low-grade hematite ore to produce direct reduced iron (DRI) is of great interest to many researchers of mineral processing and metallurgy (Weissberger et al., 1986)."

Jan 1, 2015

By Bingguo Liu, Daifu Huang, Jinhui Peng

"The conditions to prepare U3O8 by calcination from ammonium diuranate were optimized, and the response surface design method was applied to analyze the influence on the total uranium and U+4 of calcination temperature, calcination time and mass of sample. A quadratic equation model for the total uranium and U+4 of U3O8 was built and the effects of main factors and their corresponding relationships were obtained. The analysis of variance shows that calcination temperature and calcination time significantly affected the value of total uranium and U+4 of U3O8. The optimal calcination conditions were as follows: calcination temperature 931.83 K, calcination time 24.32 min and 43.89 g. Under these conditions the value of total uranium and U+4 of U3O8 was 84.78% and 28.02%, respectively. The validity of the model was confirmed experimentally and the results were satisfactory.IntroductionNuclear energy is clean, effective, and a sustainable from of energy. It plays an important role in overcoming the impending global energy crisis, and in reducing energy vulnerability. In addition, nuclear energy is a possible cheaper and cleaner source of energy compared to fossil fuels, with no not really, mining of uranium produces CO2 contribution to green house gases [1]. Uranium dioxide, one of the most important fuel pellets used as nuclear fuel in light water reactors, is manufactured by calcining ammonium diuranate to triuranium octaoxide, followed by its reduction to uranium dioxide using cracked ammonia at 700°C [2]. Earlier attempts to optimize the important calcination process through several common techniques have not yielded desirable results [3]. These techniques either rely on the classical one parameter at a time approach that ignores the combined interactions between physicochemical parameters, or are theoretical in nature. Furthermore, these techniques also require large number of experimental data to be generated [4]. In order to produce triuranium octaoxide in an optimized manner, which considers the interaction of different process parameters [5], there is a need to adopt a multivariate statistical technique."

Jan 1, 2011

By H. A. Pearse

NORMALLY, the Britannia ore mixture contains chalcopyrite and pyrite as the chief sulfide minerals, together with minor amounts of gold and silver and a low zinc content. Reduction is accomplished by jaw crushers underground, followed at the concentrating plant by Symons cone crushers, rolls, and ball mills. The standard flotation practice, evolved during several years of experimentation, provided for bulk flotation of the two sulfides, after primary grinding to only approximately 35 mesh, followed by regrinding of the bulk concentrate, with subsequent separation of the chalcopyrite and pyrite to make a marketable concentrate of each mineral. This so-called standard milling practice has previously been described in detail in U. S. Bureau of Mines Information Circular 6619. A modification will he discussed here. In the face of a constantly increasing world surplus of copper and a steadily falling price during 1930 and 1931, it was obviously undesirable to continue unprofitable production of large quantities of this metal. On the other hand, company officials were

Jan 1, 1934

By P. Forbes

Mining and metallurgical processing companies that have adopted the principles of good environmental management often find it difficult to carry out an environmental assessment that yields meaningful opportunities for improved performance. This topic was investigated by means of a case study of a South African Base Metal Refinery (BMR) producing primarily nickel. A process-based Life Cycle Assessment (LCA) was carried out on the refining process, with the environmental impacts related to the production of reagents and utilities forming part of the assessment. The lifecycle inventory (LCI) was based on plant operating data spanning 31 months of production, from which a baseline environmental profile could be generated and interpreted to indicate the main sources of potential environmental impacts. Consequently, opportunities for improved environmental performance could be identified from the LCA model, which expressly related potential environ-mental liability to specific sub-processes in the assessed industrial operation. The on-site steam plant was found to be the primary source of potential environmental impacts in most of the impact categories considered. In closing, the paper discusses some of the limitations encountered in use of the LCA method. Keywords: life cycle assessment; LCA; life cycle inventory; LCI; base metal refinery; improved environmental performance; environ-mental management systems; nickel refining.

Jan 1, 2000

By D. Kruse

Top-down constructed large-diameter (up to 90 m or 300 ft) shaft design and constructability issues present an interesting suite of challenges and opportunities highlighted in this paper. The study covers 2D and 3D finite element models used to analyze various failure modes, evaluate the shaft liner and internal structures' response to seismic loading, assist in segment design and assess final structural design tradeoffs. Efforts to achieve economic advantage over conventional heavy civil practices have prompted innovative solutions for ring and segment design, ring build assembly and annulus backfill grouting. Intended for soft ground conditions, relationships between soil parameters and structure design are also explored. Mining Engineering, 2011, Vol. 63, No. 9, pp. 81-88. Official publication of the Society for Mining, Metallurgy and Exploration, Inc.

Jan 1, 2011

By Clayton A. Landsidle

There has been little change in timbering methods in anthracite mines for 75 years, and technical information on strata control is almost wholly lacking. In order to assist the industry to establish technical data, the Bureau of Mines and a Northern field operator are cooperating in underground experiments, the first phase of which has been to investigate pneumatic packing. The four principal methods of packing in mining are hydraulic, pneumatic, mechanical, and hand. The hydraulic pa caring system is believed to have originated at Shenanodah, Pa., in 1864,4/ to prevent destruction of a church by surface subsidence after underground coal mining. This method was used again in 1884 to arrest an underground fire at Buck Ridge colliery, near Shamokin, Pa. In 1901 hydraulic packing was introduced to Europe in Upper Silesia, where it gained in popularity owing to the availability of large quantities of sand suitable for flushing .5/ Hydraulic packing has a number of disadvantages. Chief among these are the softening effect of large quantities of water on the mine floor conducive to heaving action; drainage and punning costs; and the inability to fill roof cavities completely in flat beds.

Jan 1, 1953

By A. E. M. Warner, A. Vahed, P. J. Mackey

"Since early 2015, the price of nickel has dropped from the region of US$6/pound to current levels of around US$4.60/pound (March 2017), reflecting several market factors, but principally due to lower demand from China. Under such conditions, nickel companies have been under pressure to contain operating costs. In addition, labor and energy costs will continue to rise, while nickel ore grades will likely continue to drop. All major companies now accept the need for climate change action and consequently efforts are being made towards lowering carbon-based emissions. Nevertheless, meeting these challenges can also contribute to higher operating costs without parallel innovative developments - which at the same time, under current conditions, major companies are tending to curtail. In this paper, several productivity improvement opportunities to reduce unit operating costs at nickel sulphide and nickel laterite plants are reviewed. Opportunities include: (a) process technology and energy-type selection, production capability, optimization of process intensity and implementation of newer technologies; (b) improved productivity, equipment availability including maintenance best practice; (c) energy savings and recovery opportunities and use of energy surveys and, (d) process modeling and improved scheduling. Such improvements along with an uptick seen in nickel demand going forward should better position the world nickel industry.INTRODUCTION Nickel is an essential metal to modern society, primarily through its use as an important ingredient in stainless steel. Thus, stainless steel finds vital applications in food preparation facilities, as well as important uses in transportation and industrial applications. Canada has always played an important role in nickel production and nickel metallurgy. In the 1940s and 1950s, Canada supplied over 90% of the world’s nickel. However, this proportion has declined considerably to around 10% of the world nickel supply today. Still, Canada remains an important nickel supplier and contributor to nickel extractive technology. Due to the importance of nickel to society, nickel demand is expected to continually rise. On the other hand, nickel companies have been under pressure to contain production costs amid languishing nickel prices. While demand projections show nickel growth, there are uncertainties in actual levels of future market growth. Ore grades are dropping, while labour and energy costs, which are key cost contributors are rising, hence efforts to lower production costs will generally require innovative approaches."

Jan 1, 2017

By Alvin Kaufman

Following the gold discoveries of the late 1800's much was written regarding the vast mineral resources of Alaska, and much interest was aroused, and yet over the years little has been done to exploit those resources. Between 1906 and 1935 the Kennecott copper mines of the Copper River region were the keystone of the mineral economy (fig, 1). After the depletion of the Kennecott ore reserves and aided by the statutory rise in the price of gold, the yellow metal became the major mineral commodity. In recent years it has shared the honors with coal and sand and gravel. Although this trend should indicate the development of a stable, diversified mineral industry, yet the trend of production is downward. This report results from a study by the Federal Bureau of Mines to delineate the problems and to forecast the growth of the mineral industries in Alaska. The need for such a blueprint for the future was enhanced by the population explosion in the United States and the consequent eventual need for additional living space, as well as the current interest in new areas, and the necessity to develop reserves of strategic minerals.

Jan 1, 1961

By G. L. Oldright

The data in this paper were collected at the Trail smelter of the Consolidated Mining & Smelting Co. of Canada, Limited, through the courtesy of S. G. Blaylock, vice president and general manager; James Buchanan, smelter superintendent; George Murray, assistant smelter superintendent; and the staff members given in Paper XI, Report of Investigations 3243. INTRODUCTION This paper is the thirteenth of the series on Smelting in the Lead Blast Furnace, and the third of the series on Handling Zinciferous Charges. Tyro other papers have been written on the Rate of Descent of the Stock Column, and Formation of Accretions. These are Reports of Investigations 2963 and 3094, for the Tooele plant and the Bunker Hill plant, respectively.

Jan 1, 1934

By G. B. Harris, C. W. White

Cyanide has been used for the recovery of gold since the mid 1800s, but several jurisdictions have already banned its use, and environmental pressures are increasing to finding an alternative. Gold also forms chloride complexes similar to those of cyanide, but the use of chloride has never achieved widespread acceptance. This paper describes a chloride-based flowsheet, wherein the key unit process is the recovery and recycle of chloride ion. It is shown that the chloride-based flowsheet is competitive economically with the conventional cyanide-based flowsheets, and that it has a number of other advantages, particularly environmentally.

Jan 1, 2011

By Ronald Ticona, Anaani Huaman, Andrea Lucero

Mine-to-mill optimization begins with a clear understanding and ongoing assessment of blasting, crushing, and grinding operations. Modification of blasting practices to optimize feed size can increase a mine’s throughput. However, this is only an initial step. To optimize the entire process and fully utilize downstream equipment, fragmentation must be measured at critical points along the size reduction circuit

Jan 1, 2019