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By G. W. Healy, L. F. Sander

was investigated by reacting thin discs of calcium oxide with gas mixtures of CO2, CO, and Son. Its value was 19,300 * 300 cal independent of temperature in this range. No solid solubility of sulfur in calcium oxide was detected within the limits of the experimental method and it is estimated to be below 0.025 pct by weight. The importance of lime in desulfurization is well-established but complete information on the pure phase equilibrium: CaO + 1/2 s2 = CaS + +02 [11 is not yet available. The goal of this work was to evaluate solid solubility of CaS in CaO and to determine the free-energy change associated with Reaction [I] at temperatures of 1400" to 1650°C. The equilibrium constant for Reaction [1] can be written: It is convenient to rewrite Eq. [2] in the form: where A = {Ps /PqJ1'2 has been referred to' as the "sulfurizing power' of a gas mixture. In this work, thin discs of CaO were suspended in a vertical tube furnace and exposed to CO + CO2 + SOz gas mixtures having known values of A. The samples were then analyzed for sulfur. As expected, X-ray diffraction confirmed that CaS was the only sulfur-bearing phase formed at the relatively low oxygen pressures used. EXPERIMENTAL PROCEDURE Reagent-grade CaCO3 was pressed in a 3/8-in.-diam pill die and prefired in air to produce CaO discs weighing between 0.004 and 0.01 g. Several discs were used to provide a suitable weight for chemical analysis while maintaining a large surface area to react with gas mixtures. These were placed in a platinum mesh basket and suspended in the gas stream in the hot zone of a vertical tube furnace. Desired gas mixtures were prepared from cp grade CO and CO2 and anhydrous grade SO2. The method of soap bubble displacement was used to calibrate capillary flow meters. While this gave excellent results with CO and Con, some problems with bubble insta- bility and soap film "drag" arose with the use of SO2 at low flow rates. Hence, frequent sampling and analysis of gas mixtures was carried out to insure proper control of the ingoing SOZ. The furnace used for gas:solid equilibration was a vertical mullite tube externally wound with 60 pct Pt-40 pct Rh wire having a diameter of 0.028 in. An inner tube of $ in. ID served as the reaction chamber having Pyrex ground joints sealed to the mullite to provide gas-tight connections at top and bottom. A Pt-Pt 10 pct Rh thermocouple was inserted into a protection tube adjacent to the sample basket to measure sample temperature during a run. Constant-temperature control to 2C was observed at any desired set point within the range of this investigation. This was accomplished by a control thermocouple imbedded in the furnace windings which served to actuate an electronic controller wired for high-low operation. The sulfur analyses of the solid samples were carried out using a stoichiometric combustion technique based on the method of Fincham and Richardson. Some analyses were done using a modified evolution method3 but these were used primarily to check the results of the combustion method. The results were in good agreement but the combustion technique of-ferred an advantage in economy of time and material. CALCULATION OF GAS EQUILIBRIA Heating a given mixture of CO + CO + SO2 to high temperatures gives rise to a large number of product species. The details of calculating the partial pressures of these products of interaction and dissociation can be found in several references4,5 and need not be repeated here. The thermodynamic data selected for the major species in the gas mixtures are shown in Table I. Equilibrium constants from these reactions were combined with oxygen, carbon, and sulfur balances and a computer program written to facilitate the calculations. Some early difficulties in reproducing experimental results were finally traced to the effect of atmospheric pressure changes. No reference to consideration of this question had been found in the

Jan 1, 1969

By Louis H. Meece

The romance of the River lives on in the tales of Mark Twain; and many Americans still think of the Mississippi River in terms of the steamboats loaded with passengers, gamblers and cotton. Yet for many years, coal has been a major cargo on the American waterways. Currently, about 100 million tons a year of coal is handled in some part of its journey from mine to destination by barge. The bulk of this traffic has been on the Ohio River System and the Upper Mississippi River System in years past. Now we have a new entry. Over the past 10 years various movements of coal have developed down the Mississippi River to power plants at Memphis and along the Gulf Coast, and a small amount of metallurgical coal has moved down the Mississippi River for export to Japan since 1970. But in 1980 a brand new player came on the scene. 1980 was a momentous year for the American coal business. Historically, we have exported about 50 million tons a year of metallurgical coal to the world's steel mills. Just before and after World War I, we also had a fairly healthy export trade in steam coal; and again in the late forties, we supplied large amounts of coal to Europe until domestic production could recover from the ravages of World War II. But since the early fifties, the name of the export game has been metallurgical coal. Starting in the mid seventies, something began that was almost totally missed by the American coal industry; and that was the growth in the use of coal first in Europe and now in the Far East as a steam product and as an alternative to petroleum products. As these world coal markets began increasing, the U.S. at first was thought to be noncompetitive because ocean rates were still very low. For example, as recently as 1977, Australian coal could be moved all the way from Australia to the Gulf Coast for $12.50 per metric ton. Coal exporting countries were Poland, Australia and South Africa, except for the continuing exports of U.S. high quality metallurgical coal. But then came the second oil shock, and all of the sudden that $12.50 rate from Australia to the U.S. Gulf became $25.00. And then suddenly and almost unrecognized by the American industry, American coal was in fact competitive at overseas destinations because of the drastic change in trade patterns brought on by the doubling and tripling and quadrupling of bunker fuel prices for ships.

Jan 1, 1982

By Trevor Ellis

The following is extracted from a report by the author to the International Valuation Standards Committee (IVSC), with minor modifications for the purpose of publication. The author represented the IVSC at the annual session of the Ad Hoc Group of Experts on Harmonization of Fossil Energy and Mineral Resources Terminology. This is a body organized by the United Nations Economic Commission for Europe (UNECE). This second session, held in Geneva, Switzerland, achieved an important agreement for advancement toward uniform global standards for the classification of minerals and petroleum reserves and resources. Attendees discussed the possibility of enhancing the United Nations Framework Classification for Energy and Mineral Resources (UNFC) for implementation globally as the classification standard for use in financial reports under the International Financial Reporting Standards (IFRS). Presently, there are between 100 and 200 mineral and petroleum resource classification (or definition) systems throughout the world — a similar number to what there are countries.

Jan 1, 2006

By Peter Barker, Terry Jones

"The Kelsey Centrifugal Jig (KCJ) utilizes the application of centrifugal force (and the resultant enhanced gravitational field) to conventional jigging technology principles to successfully and efficiently process materials where the valuable constituent particulates are very fine and/or where there is a small specific gravity differential between these and the gangue minerals.The KCJ is applicable to a broad range of fine mineral recovery duties, with current installations in the mineral sands, tin, tantalum, gold and nickel industries. Other areas of application are being developed with mineral commodities including tungsten, base metals, iron ore, chromite and apatite/feldspar.Information on the principles of operation of the KCJ, typical performance figures in a number of application areas, comparison to centrifugal concentrators, key elements for a successful KCJ operation and recent developments with the KCJ are presented in this paper to demonstrate the capabilities of the KCJ.INTRODUCTIONAfter a number of years of development by inventor Chris Kelsey, the first commercial KCJ unit was installed at the Renison Bell tin mine in Tasmania, Australia, in 1992. The subsequent decade saw the installation of further KCJ units in applications including tin, tantalum and mineral sands.Development and improvement in KCJ hardware continued and culminated in the introduction of the high-capacity Model J1800 KCJ and standard features such as an automatic screen cleaning system. This opened up further markets and resulted in Model J1800 KCJ installations in the gold and nickel industries, as well as further KCJ installations in the mineral sands and tin industries. In recent years, work has continued on application of the KCJ to many other duties in industries including tungsten, base metals, iron ore, chromite, apatite/feldspar, etc."

Jan 1, 2007

By A. Duerksen

Surface coal mining in West Virginia has supplied energy to the eastern coast of the United States for over a century. The coal mining industry has been forced to adapt as societal demands regarding health, safety, and environmental impacts have changed with time. More recent pressure has called for another iteration of change: long-term post-mining sustainability. The research presented in this paper investigates one potential solution?or component of a solution?to improve mining sustainability in Appalachia: post-mining wind power. This paper intends to demonstrate and explain the feasibility of synergistic mine closure and wind development. Wind conditions at three reclaimed mine sites in West Virginia were monitored in order to develop representative case studies for post-mining wind power. This paper contains a summary of the literature consulted to plan the site assessments, the methodology employed to execute them, the analysis steps undertaken to derive conclusions, and a discussion of all findings. This research has found that significant cost savings can be yielded from synergistic mine closure and wind development, as compared to greenfield wind development. Though wind conditions themselves remain the primary driver for site feasibility, post-mining wind power is a practice with significant promise for improving project economics, contributing to renewable energy development, enhancing company-community relations, providing local employment opportunities, and exemplifying sustainable business practices in Appalachia.

Jan 1, 2012

By T. Wang

A new generated NaNO3 ? NaNO2 ? KNO3 ternary thermal energy storage system which has low melting point as 124°C and high specific heat capacity was studied for the short and long?term thermal stability by using the Thermogravimetric Analyzer (TGA). Based on the actual working condition of molten salt in solar two, the simulated cyclic thermal stability measurement was also conducted. The ternary system demonstrates excellent short ? term thermal stability and thermal reliability after cyclic heating and cooling processes. However, in the long ? term as well as the simulated cyclic stability measurement, large amount of weight loss was observed. Moreover, the stepwise long ? term isothermal study reveals that below 440°C the weight change is minimal and this temperature is viewed as the upper limit temperature of thermal stability for this ternary system. To determine the lost phases at high temperature above the upper thermal stability limit, techniques such as XRD and SEM are used to compare the condition of the salt mixture before and after the long ? term thermal stability study. On the basis of the comparison, it can be concluded that the major weight loss was due to the decomposition of sodium nitrite.

Jan 1, 2012

By Raymond Mancha

The purpose of an accurate underground pressure survey is to obtain a pressure gradient along the circuit or circuits under investigation. The pressure gradient shows the rate of pressure drop between various observation points along a circuit. This determines excessive resistance regions and the economic feasibility of correcting such conditions by cleaning airways, driving additional airways, or modifying existing airways. A pressure gradient is useful for predicting the effect on other parts of the circuit when adjusting the air regulation on any one split or when planning a field airshaft or slope or a new drift to the outcrop. A single-compartment airshaft often produces disappointing results because it relievcs only a part of the circuit instead of the over-all mine pressure. It is valuable to know how the circuit pressure drop is distributed. The underground pressure survey is used also to determine the friction coefficient for various types of airway. High precision work is required to establish these vital data for predicting the characteristics of mine pressure volume when projecting new mine developments. Methods Regardless of the type of instrument used to conduct a circuit pressure survey, the work should preferably be performed at a time when the mine is idle, in order to avoid air-flow disturbances from moving trips and cages or from the opening or closing of trap doors. Preferably the survey should be made when the barometer is comparatively steady, to restrict variation in the air specific weight at observation stations while the circuit is traversed. The two most commonly used instruments for underground pressure surveys are: (I) the altimeter; (2) the inclined manometer with hose extensions. The altimeter is sufficiently accurate for determining the underground pressure gradient and is preferable to the nianometer for such work because of greater flexibility and shorter time required for the traverse. With the altimeter it is possible to select more widely separated observation stations than is practical with the manometer, with its restricted hose extension lengths. The altimeter also permits easier travel along haulage roads between airway observation stations, avoiding badly obstructed airways. The inclined manometer is more reliable than the altimeter for establishing friction coefficients in mine airways. Manometer readings are unaffected by differences in elevations between stations, which require corrections to altimeter data. The manometer provides direct reading without temperature correction, which may or may not be true with the altimeter, depending upon the make of instrument used. The elimination of correction factors combined with the instantaneous, simultaneous and

Jan 1, 1947

By Raymond Mancha

The purpose of an accurate underground pressure survey is to obtain a pressure gradient along the circuit or circuits under investigation. The pressure gradient shows the rate of pressure drop between various observation points along a circuit. This determines excessive resistance regions and the economic feasibility of correcting such conditions by cleaning airways, driving additional airways, or modifying existing airways. A pressure gradient is useful for predicting the effect on other parts of the circuit when adjusting the air regulation on any one split or when planning a field airshaft or slope or a new drift to the outcrop. A single-compartment airshaft often produces disappointing results because it relievcs only a part of the circuit instead of the over-all mine pressure. It is valuable to know how the circuit pressure drop is distributed. The underground pressure survey is used also to determine the friction coefficient for various types of airway. High precision work is required to establish these vital data for predicting the characteristics of mine pressure volume when projecting new mine developments. Methods Regardless of the type of instrument used to conduct a circuit pressure survey, the work should preferably be performed at a time when the mine is idle, in order to avoid air-flow disturbances from moving trips and cages or from the opening or closing of trap doors. Preferably the survey should be made when the barometer is comparatively steady, to restrict variation in the air specific weight at observation stations while the circuit is traversed. The two most commonly used instruments for underground pressure surveys are: (I) the altimeter; (2) the inclined manometer with hose extensions. The altimeter is sufficiently accurate for determining the underground pressure gradient and is preferable to the nianometer for such work because of greater flexibility and shorter time required for the traverse. With the altimeter it is possible to select more widely separated observation stations than is practical with the manometer, with its restricted hose extension lengths. The altimeter also permits easier travel along haulage roads between airway observation stations, avoiding badly obstructed airways. The inclined manometer is more reliable than the altimeter for establishing friction coefficients in mine airways. Manometer readings are unaffected by differences in elevations between stations, which require corrections to altimeter data. The manometer provides direct reading without temperature correction, which may or may not be true with the altimeter, depending upon the make of instrument used. The elimination of correction factors combined with the instantaneous, simultaneous and

Jan 1, 1947

After more than 20 years dependence on bituminous coal as a primary fuel for generating electricity, the Pennsylvania Power and Light Company initiated a one-year study on the economics of building an electric generating station using anthracite as a fuel. The study will be completed in December 1976. If the feasibility study so indicates, PP&L will consider installing four 400,000 kilowatt generating units for scheduled commercial operation in 1985. Each unit would consume up to one million tons of anthracite annually. Anthracite generally is more difficult and expensive to extract than bituminous coal, but it has a significantly lower sulfur content than the bituminous coal currently being used by PP&L, thereby eliminating the costs of installing sulfur emission controls at generating stations. Moreover, significant reductions in transportation costs may be realized because the utility's operating territory is situated in the center of the anthracite region in northeastern Pennsylvania. These advantages may indicate that the use of anthracite is more economical than bituminous coal to PP&L. ASBESTOS -Asbestos production in the U.S. dropped again in 1975 until it was just two-thirds of that in 1973. This was in spite of the very strong demand caused by the Quebec strike. The 7-month strike of the asbestos miners in Thetford Mines, Quebec cut off 55 percent of the normal supply of U.S. consumers. Apparent domestic consumption was less than 75 percent of that in 1974. The wage settlement will probably result in a 20 percent increase in asbestos prices.

Jan 1, 1975

By J Kinal, P Steinier

A considerable volume of work exists in the literature examining the electrochemical interactions between grinding media and sulfide minerals. Broadly, most sulfide minerals are more noble than forged steel grinding media used during comminution, therefore a galvanic couple between the media and the sulfide mineral(s) exists, which increases the corrosion rate of the grinding media. The corrosion products of the grinding media, iron oxy-hydroxide species, invariably precipitate on to the surfaces of the sulfide minerals thereby affecting their floatability. This paper explores the science behind these corrosion reactions, and provides an explanation of their impact on the pulp chemistry of sulfide mineral slurries and subsequent flotation behaviour. A number of laboratory and plant case studies are used to illustrate the benefits of changing to a more inert grinding media.

Jan 1, 2005

By Yosep Han

Mechanically-induced chemical reactions between natural beach ilmenite (FeTiO3) and silicon (Si) have been examined by a combination of X-ray diffraction (XRD) and scanning electronic microscopy (SEM) analyses. The effect of various milling time on the phase transformation, crystallite size, and lattice strain of a beach sand ilmenite with silicon, and on their leaching behavior in hydrochloric acid (HCl) has been investigated. For mechanically activated FeTiO3, the crystallite size decreased and lattice strain increased monotonically with time of milling. However, the mechanochemically synthesized ilmenite with silicon showed a relatively smaller crystallite size and greater lattice strain compared with the mechanically activated ilmenite under the same milling condition. In accordance with the elapse of milling time, the intensity of both pure FeTiO3 and mechanically activated FeTiO3 gradually decreased. However, in case of the mechanochemically synthesized ilmenitereduction of FeTiO3 by silicon resulted in formation of rutile TiO2 at the milling time of 20 h and afterwards. Additional leaching experiments were carried out at an HCl/ilmenite (wt%) ratio of 20:1. The concentration of HCl was 3 M and the reaction temperature ranged from 70 to 90 oC. Mechanical activation was observed to significantly enhance the dissolution rates of both iron (Fe) and titanium (Ti) in HCl. Particularly, effects of both milling time and silicon addition on the dissolution rates of titanium and iron were significant, while those of temperature were relatively minor under the conditions investigated in this study. Keywords: mechanochemical treatment, natural beach ilmenite, silicon, leaching behavior

Sep 1, 2012

By Wayne D. Goodfellow, William M. Luff, Steven J. Juras

Abstract-Brunswick No. 12 is a vent-proximal massive sulfide deposit that formed above a feeder pipe with associated hydrothermal alteration. Because of the replacement of bedded sulfides deposited above the hydrothermal vent, individual sulfide lenses show the following vertical and lateral zoning outward from the vent complex: massive pyrite-pyrrhotite-chalcopyrite core - interlayered pyrite-sphalerite-galena (Pb-Zn ore zone) - bedded pyrite. The feeder zone which underlies the Cu-rich core consists of an anastomosing network of pyrite-pyrrhotite-chalcopyrite­ quartz veins with variable and generally minor contents of ferroan carbonate, Fe-rich chlorite, sphalerite, galena and arsenopyrite. Hydrothermal alteration of felsic igneous rocks hosting and adjacent to the feeder pipe is represented by an inner zone (zone 1) characterized by sulfide stringers, Fe-rich chlorite, muscovite, quartz, and ferroan carbonate that formed at the expense of feldspars and what was probably glass; outer zones (Il and III) are represented by Mg-rich chlorite and muscovite formation, and the albitization and silicification of K-feldspar. Accompanying these alteration trends is a marked decrease of Na + Ca, and an increase in Fe + Mg + C03 in zone 1, and increases in Mg + Na in the outer zones. The classic zoning of metals within the sulfide lenses, the formation of a feeder pipe below the vent-proximal sulfide core, and the hydrothermal alteration of felsic volcanic rocks cut by the feeder pipe all support a vent-proximal origin for the Brunswick No. 12 deposit. Furthermore, restriction of sulfide stringer mineralization to the footwall sequence, the folding of the stringer zone by an F1 fold, and the difficulty of long distance mass transfer of metals from the sulfides into the host rocks all argue against a tectonic origin for the stringer zone. All of the evidence indicates that the feeder pipe formed during the ore forming hydrothermal event, but has been distorted and in some areas detached from the overlying massive sulfides during subsequent deformation.

Jan 1, 1992

By D. H. Lynch

Prompted by the need to conserve energy and reduce operating costs, Agrico Mining Company has made two significant improvements in the transportation of phosphate ore from the mine to the beneficiation plant. One improvement involves a change in a slurry pipeline system which substantially reduced pumping energy, and the other improvement is a major innovation for the phosphate mining industry which involves the transportation of the ore by railroad. This paper briefly describes these two projects.

Jan 1, 1981

By J. A. Berger, R. J. Towner

The pjPocesses of polygonization and subgrain growth were followed in slightly stretched 99.99 pct A1 single crystals heated for cumulative times at 400°, 500°, and 600°C. Changes in sub-grain size and boundary angle were determined from measurements on X-ray micrographs. CAHN1, 2 studied polygonization in stretched and heated aluminum single crystals of 99.99 pct A1 using various techniques, including etch pits, Laue patterns, and a slight restretching of heated specimens to reveal small changes in lattice orientation by the direction of new slip lines. He found that kink bands, which had well-defined boundaries lying in a plane perpendicular to the slip direction (at least in the early stages of deformation), formed during stretching. Also, he noted that bending occurred about the <211> axis lying in the (111) slip plane perpendicular to the <110> slip direction. His studies of polygonization were largely confined to the kink bands rather than to the weakly bent matrix regions between bands. The minimum temperature required to bring about polygonization was established at about 450 "C. Guinier and Tenevin used a focusing Laue X-ray diffraction technique to study polygonization in aluminum single-crystal specimens of 99.99 pct purity. Stretching the crystals 5 pct in tension caused a widening of the focused Laue spots. After heating for 4 hr at 450°C, their method revealed no change in the specimen. Above 450°C polygonization was detected and further annealing near 600°C led to subgrain growth. They concluded that the orientation of the crystal relative to the axis of deformation had no marked effect on polygonization. Gay and Honey-combe4 using an X-ray microbeam technique found that polygonization did not occur in a stretched aluminum crystal heated at 250oC, although some decrease in the yield strength occurred. When the temperature was raised to 475oC, the asterism became broken up as a result of polygonization. Honeycombe5 noted that reflections on X-ray mi-

Jan 1, 1961

By Leopoldo Gutierrez

Eight oil sand ores with the bitumen content ranging between 3.6 and 15 wt.% and the fines content (-44 micrometers size fraction) between 9 and 69 vol.% were subjected to the standard alkali extraction test used to measure the degree of oxidation of metallurgical coals. The results showed that there is a strong correlation between the absorbance of extracted solutions at a wavelength of 520 nm and the ratio of the fines content to the bitumen content. The latter factor is directly relevant to assessing the extractability of bitumen from oil sand ores. Bitumen extraction tests showed that the bitumen recovery decreased from 90 % to 30 % when the absorbance at 520 nm increased from 0.23 to 0.64. A comparison of the UV/visible spectra of solutions obtained from the alkali extraction tests with solutions of Aldrich Humic Acids suggest that low bitumen/high fines oil sand ores release substantial amounts of organic matter very similar, if not identical, to humic acids. In contrast, high-bitumen and low-fines ores do not release as much of the organic matter, and UV spectra of these leached substances are quite different from those of humic acids. Overall, the results show that chemical composition of bitumen in the tested ores varies greatly with ore type and oxidation, and that the alkali extraction test is a promising technique to quickly assess the extractability of bitumen from a given ore type.

Sep 1, 2012

Planning for the Macraes Extension project highlighted the need for additional tailings storage availability. The possible solution of developing new tailings impoundments in Northern Gully, in tum, led to concerns being expressed by the regUlatory authority over the assimilative capacity of Deepdell Creek. Philosophical differences over the appropriateness of applying a seepage model used to set standards in consents for the original project resulted in the company re-evaluating the whole monitoring system associated with tailings disposal and seepage control. Re-evaluation indicated problems arising from the existing in-stream water quality monitoring in respect of protection of the aquatic ecological system and verifiability of results. A new monitoring system was designed relocating the compliance monitoring point out of the stream and into the gully containing the tailings impoundments giving greater certainty of monitoring results to all parties and providing improved protection for the aquatic ecology of Deepdell Creek.

Jan 1, 1993

By S. Pastor, S. Hahn

"As the concept of autonomous haulage systems (AHS) moves from proto-types to production-ready applications, the operating performance of the haul road will become ‘mission critical’ to the overall success of autonomy in mining. Deterioration in road performance will require remediation, human intervention and significant, albeit temporary, changes to operating procedures, to accommodate road maintenance. With autonomous trucks comes the opportunity to reduce road formation and operating width, and therefore generating potentially significantly reductions in stripping ratios and improvements to mine economics, but only if the design of the road, and it’s associated deterioration rate, is predictable and manageable, based both on the materials used to construct the road and the maintenance interventions to be carried out on the road. This paper presents the assessment of a digital photogrammetric approach to the characterization of a mine haul road surfacing, or wearing course material. Design and maintenance parameters for these roads are currently determined from physical particle size distribution (PSD) assessments of ‘in-road’ material. However, this approach does not accommodate the need, nor leverage the benefits from, AHS. The digital imaging approach is assessed in this paper, using two standard digital analysis software tools, together with in-service mine haul road wearing course samples and images which are assessed to determine the applicability and reliability of the approach to deliver a real-time assessment of haul road surfacing conditions and thus to identify the road maintenance interventions required to address deterioration. INTRODUCTION Enhancements in mine road design, construction and management for the past 20 or more years has largely been focused on short-term tactical needs. These improvements have not been matched by advances in the fundamental technologies that underpin mine road design and management, and although the quality of mine roads have probably increased, many of fundamental and longer-term issues have yet to be addressed. With AHS’s evolving from prototype to production applications, any decision to implement these systems in a mine requires a thorough evaluation of impacts, not only operational improvements, but the inter-connectivity of this autonomy technology to other organizational processes. In developing an understanding, the full interactions that may affect autonomous truck behaviour due to changes in various sub-systems or external environments, haul road conditions and operating performance is a key consideration. This is as true in autonomous as well as in conventional mine truck-based hauling systems where the mine haul road network is a critical and vital component of the production process."

Jan 1, 2015

By Huijun Shao, Qiang Liu, Zhengming Yi

The increase of the proportion of high Al2O3 content iron ore fine in iron and steel enterprises has brought about a series of problems such as the increase of the viscosity of blast furnace slag and the difficulty of the separation of slag and iron. In order to solve this problem, the effect of increasing MgO content on the technical and economic index, the cold strength, and metallurgical properties of high basicity and high-alumina sinter was studied through sinter pot test. Nova400NanoSEM field emission scanning electron microscope was used to analyze sinter microstructure. The experimental results show that when the MgO content fraction in the sinter with high basicity and high aluminum increases from 1.72 to 2.49%, the vertical sintering speed decreases by 4.38mm/min, the utilization coefficient decreases by 0.51t/(m2 h), and the low-temperature reduction degradation index increases by 6.7%. When MgO content in sinter is 2.11%, drum index and reducibility index are the highest, reaching 61.93% and 86.39% respectively. Mg2+ is mainly solid dissolved in the magnetite lattice and replaces Fe2+, up to 3.64%. The generated magnesie-containing magnetite inhibits the phase transition from Fe3O4 to Fe2O3 oxidation process in the sinter cooling process, which reduces the generation of secondary hematite and is conducive to improving the low-temperature reduction degradation performance of sinter.

Jul 4, 2021

By Qiang Wang, Jiaqiang Yu, Chunhui Fan, Yong Wang, Changyu Jin, Jun Bai, Yu Lu

Accurate ore blending necessitates an in-depth understanding of movement trajectories of fragments and the spatial evolution of the displacement field in the bench during blasting, Accurate ore blending is currently one of the most complex challenges faced by mining engineers. In light of this problem, a systematic study was conducted in this paper using neural network and numerical simulation based on field monitoring data. A nonlinear mapping relationship was established between the mechanical parameters of rock mass and the displacements of the monitoring points. The measured displacements of monitoring points under blasting were input into the neural network, which used back-calculation to derive the mechanical properties of the rock mass. These parameters were then applied in a forward calculation to analyze the movement trajectory of the monitoring points. The results showed that the calculated displacements were in good agreement with the monitoring results during the. The average relative errors in the horizontal and vertical displacements were 4.12% and 15.2%, respectively. Furthermore, the muckpile profile was in an inverted recumbent “S” shape after bench blasting, which was consistent with the actual shape of the muckpile. This verified the rationality and accuracy of the method proposed in this study. Finally, the movement trajectories of particles in the bench and the spatial evolution law of the displacement field during bench blasting were determined based on the calculation results, offering theoretical support and fundamental information for accurate ore blending.

Dec 16, 2023

By W. C. Lilliendahl, H. W. Highriter

The method developed and used in this laboratory for the production of metallic uranium of such purity that it is ductile and can be cold-worked to fine wire or thin sheet by rolling has already been described1. It consists, briefly, in the electrolysis of potassium uranous fluoride (KUF5) in a molten bath composed of equal parts of sodium and calcium chlorides. The bath is contained in a graphite crucible, electrically heated to about 775° C., the crucible serving as the anode for electrolysis. The uranium deposits in finely divided form mixed with salts upon a molybdenum cathode suspended axially in the crucible. Upon completion of the electrolysis the cathode is removed and cooled, the deposit broken and leached to remove salts. The metal powder is washed with water and dilute acetic acid and dried in vacuo to reduce oxidation. Suitable amounts are then prcssed into pellets and heated in vacuo by high-frequency induction, using a thoria crucible. The uranium melts and flows away from the pellet, leaving a shell, which is largely oxide. In general, this method produced a satisfactory metal, although at times tile uranium was not ductile. The investigations recorded here were made to find the cause of this embrittlement. It was known that the metal generally contained carbon, derived from disintegration of the graphitc crucible in which electrolysis is conducted, in amounts dependent upon the thoroughness of washing the metal powder. Accordingly, analyses of several samples, both ductile and brittle, were made by combustion and absorption of CO² in Ascarite, using air instead of oxygen to reduce the temperaturc and rate of oxidation. Several of these metals were made with special precautions to reduce carbon content. The results show no relationship between ductility and carbon content in the range investigated (Table 1). Microscopic examination of ductile and brittle metals disclosed the presence in the latter of an intergranular constituent, harder than the matrix and less easily oxidizable, which was absent from the ductile material. Rough estimates of the volume of the hard constituent

Jan 1, 1935