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By O. D. Gonzalez, H. A. Wriedt

Alloys ranging from pure iron to pure nickel were saturated with nitrogen gas at 918°, 999°, and 1217°C and analyzed. The solubility of nitrogen at 1-atm pressure was obtained as a function of nickel content for the whole range of iron-nickel alloys and the temperature dependence of solubility is shown for the experimental alloy compositions. The heat of solution and the entropy of solution of nitrogen in the alloys as func-tiom of composition up to 41 pct Ni are given. 1 HE acquisition of more exact thermodynamic information for systems composed of iron with various alloying elements continues to interest ferrous metallurgists. The interstitial alloying elements, especially carbon, hydrogen, and nitrogen, comprise a field of particularly intense study. A recent investigation of carbon solubility in Fe-Ni alloys held at 1000°C in gases of fixed carbon activity showed an unpredicted minimum in the solubility near 72 pct Ni.1 The present investigation was undertaken to see if a similar anomaly in solubility existed for nitrogen in Fe-Ni alloys. The solubility of nitrogen in ? iron at known nitrogen activities has been measured several times.&apos;-&apos; Corresponding information for the solubility of nitrogen in solid Ni and Fe-Ni alloys is not available. Juza and sachsze9 reported that metallic nickel dissolved 0.07 pct N in equilibrium with Ni3N at 445°C. This result was regarded as dubious by Turkdogan and Ignatowicz10 who found less than 0.0004 pct N in nickel specimens equilibrated at 600°C with ammonia-hydrogen mixtures having fugacities of N2 gas up to 35,000 atm. Such fragmentary reports indicate only that nitrogen gas has a very much lower solubility in nickel than in iron. MATERIALS A purified iron from Battelle Memorial Institute was used for solubility measurements. This grade contained more than 99.95 pct Fe, the highest content of any measured individual impurity being 50 ppm for each of As, C, Cu, and Pb. The nickel and iron-nickel alloys, supplied by the International Nickel Co., contained 0.02 to 0.04 pct C, 0.17 to 0.19 pct Mn, 0.04 to 0.08 pct Si, < 0.01 pct P, <0.03 pct S, and <0.20 pct Co as principal impurities. The Fe-0.59 pct Mn alloy was of zone-melted quality, the highest concentration of any individual impurity being 15 ppm Al. The "prepurified" grade of nitrogen gas from Matheson Co. had a nominal nitrogen content of 99.996 pct. An "electrolytic" grade of hydrogen gas from National Cylinder Gas. CO. in which the principal impurity is water vapor was admixed with the nitrogen to prevent oxidation of these specimens. This grade was preferred to a purer grade because the presence of some oxygen helps in suppressing contamination of the specimens, for instance, by silicon from the porcelain furnace tube. EXPERIMENTAL PROCEDURE The specimens were equilibrated in vertical tube furnaces through which a 99 pct N2-1 pct H2 gas was passed at ambient pressure. For the 915", 918", and 999°C runs, a wound-resistance furnace was used, and for the 1217°C runs, a furnace with a tubular silicon carbide element was used. The temperature control system on both furnaces was similar: a Weston "Celectray" controller with a modulator, responding to the electromotive force of a thermocouple with its hot junction in the furnace, switched the furnace current between high and low settings. The temperature distributions in the working zones of the furnaces were determined with calibrated Pt/Pt-10 pct Rh thermocouples. The overall uncertainty in temperature was estimated to be ±3° at 915° to 999°C and ±5° at 1217°C . Consideration of the small temperature coefficients of the equilibria studied, together with the error limits in the method of analyzing for nitrogen, showed that further refinement in temperature uniformity would give no improvement in resultant accuracy. The reactive gas was generated by mixing together "prepurified" nitrogen and "electrolytic" hydrogen directly from cylinders commercially supplied. The flow rates of nitrogen and of hydrogen were fixed by setting with bleeders the pressure drops across the individual calibrated flow meters of constant resistance. For any given alloy, the solubility of nitrogen at 1-atm pressure (% N) was obtained from the analyzed nitrogen content of equilibrated specimens (% Na)according to Sieverts&apos; law, thus

Jan 1, 1962

By Ahmad Hemami

A working code is developed to simulate the forces that are involved in the process of penetration of a bucket into bulk media during loading and excavation. The result of this work can be integrated with the simulation software that many manufacturers of heavy earthmoving machines introduce for training purposes. The simulator programs for machines such as backhoes, loaders, LHDs and the like, used for operator training, are usually only based on the kinematics of the machine. As a result, there is no indication of the effect of the medium when the cutting tool of such a machine touches the excavation material. This is like moving the machine in the air. Feeling the resistance force of medium to cutting by a bucket or blade during loading and excavation is more realistic, both mentally (by vision) and physically (feeling resistance in pedals and levers). The results from force simulation can be used by feedback in creating simulated resistance in these training gears, similar to what is done in flight simulators for aircrafts. In addition to serving for the above purpose, the results of this work can be used as a tool for examination and verification of the effect of a control policy for automation of loading and excavation of bulk media. So far no commercial product has been introduced that has such a capability, despite some extensive research on the subject.

Aug 1, 2013

By Arthur L. Bishop

INTRODUCTION Purpose The in-situ leach method for uranium extraction is a relatively new and innovative method of uranium mining. In 1975, the first commercial in-situ facility began operation in south Texas. Since that time numerous other operations have been initiated as either pilot or commercial ventures. Considerable literature has been published that deals primarily with generalities of the process or environmental concerns. Several federal agencies have published documents which do not reflect the true operating or environmental nature of the in-situ leach method of uranium extraction. From an environmental standpoint, this is also evident in the promulgation of rules and regulations. Hence, the purpose of this paper is to present experience with an environmental concern--non- production zone excursions--such that the industry and the regulatory agencies will gain greater insight devoid of preconceived ideas and misconceptions. General Process Description In south Texas, in-situ leach mining is utilized to extract uranium from permeable sandstone ore deposits 61 to 213 meters (200 to 700 feet) below the surface. Uranium is present as an insoluble uranium oxide. In the in-situ or solution mining technique, anoxidizing lixiviant is injected into the formation through injection wells. The solution reacts with the insol uble carbonate complex. This soluble uranium complex is produced at recovery wells, each containing a submersible pump. During production there is a constant sweeping of lixiviant through the formation from the injection wells to the recovery wells. Injection and recovery wells can be arranged in any of a number of geometric patterns dependent upon ore body configuration, aquifer permeability, and operator preference. Submersible pumps in the recovery wells pump the uranium rich pregnant solution to the initial processing facility. Monitor wells surrcsund the pattern area and are screened in appropriate stratigraphic horizons (production and non-production zones) to detect any lixiviant migration that may occur (Fig. 1).

Jan 1, 1980

By S. M. Matthews, D. J. Maconochie, L. G. Alexander, V. H. Tillmann

Case studies of the behaviour of large open stopes at the New Broken Hill Consolidated Mine, Broken Hill and the CSA Mine, Cobar, N.S.W. are considered. Deformations were measured by multipoint rod extensometers in sufficient detail to note the phases of rock behaviour, from intact through to rock-fall. In one case readings were obtained from a zone of stress failure in which two bumps, felt as ground tremors, occurred. In this case noise and stress were also monitored. Deformations were analysed in relation to previously measured in situ rock stress, and conclusions drawn about the degree of conformity to, and the areas of departure from, elastic model behaviour. Attempts to describe the growth of instability utilize reduction factors of the apparent modulus, a magnification factor for the apparent Poisson&apos;s ratio, and a correlation between progressive noise count and displacement. Monitoring itself is seen as an aid in determiing the final dimensions of stopes and pillars. One large stope, of intermediate dimension 80 m, was mined essentially without change of plan, whereas a change in mining plan was necessary in other stopes. Aspects of interest to mine planners, and areas where futher research is needed, are indicated.

Jan 1, 1981

By M. J. Langley

Zinc ores were first discovered in Tennessee in 1856 at Jefferson City where a deposit of oxidized ore became known as the Mossy Creek Mine. From that time until 1913 small scale attempts at prospecting and mining were made in various parts of the district. The actual systematic development of the zinc deposits dates from 1913 when the American Zinc Company started operations at Mascot. Six mines are in operation by three companies and a seventh mine is being developed by a fourth company. The total daily production from the field is 11,000 tons of crude ore, which grades from 3 to 6 per cent zinc. Most of the ore bodies are large and ramiform, resembling asyrmetrical networks in which the ore shoots form channel like branches with areas of non-comercia1 rock, called blank islands. Most of the orebodies are adapted to large scale mechanization.

Jan 1, 1962

By John A. Breslin

This publication provides an historical overview of research undertaken by the U.S. federal government over the last 100 years to improve the health and safety of our nation?s miners. Federal research efforts began with the establishment of the U.S. Bureau of Mines (USBM, or the Bureau) in 1910. They have continued over the past century, even after the Bureau?s closure in 1996. It is hoped that this publication will give the reader an appreciation for the work of mining health and safety researchers over the past century, and of the miners served by this research. Although not a comprehensive history, this report highlights the key organizational changes made within the Bureau and the federal government that affected mining safety and health research. Some mention is also made of Bureau research not directly related to mining health and safety. Note that the work classified as safety and health research has varied over the last century. For example, before 1970 the Bureau separated mining research and safety and health research. At that time, mining research included ground control and methane drainage because they had direct implications for mine safety. Explosives research was also reported separately from health and safety, even though permissible explosives research was obviously related to safety. Therefore, where budget figures from the Bureau are mentioned in this report, it is often not possible to separate safety and health research from other types of research. This history is generally chronological, with a few exceptions. Because of their prominence and direct links to Bureau research, most of the Public Health Service mining studies completed before 1970, when NIOSH was established, will be discussed in a single section, even though the work spanned many decades. Likewise, for convenience, the brief histories of the Bureau?s mining research centers are located in one section.

Feb 1, 2010

The comparatively low winter rainfall, exposure to heavy salt laden coastal winds, and the consequent high evaporation rate, are important considerations in the rehabilitation of the Maslins Beach Sand Pit. The deficit of rainfall over evaporation is assessed at 1085 mm per annum. Such a coastal environment complicates the establishment of plants. The endemic flora found on the Sand Pit environs is mainly low wind-planed shrubs and mat plants. The dunes near the coast support an association dominated by Atriplex cinerea, Spinifex hirsutus, Scirpus nodosus, and Olearia axillaris. The coastal cliffs carry a more diverse vegetation dominated by Beyeria lechenaultii and Eutaxia microphylla. Overburden is used to develop a new landscape to screen operations, batter final faces, and cover rubbish at the nearby Council dump. The early overburden dumps were built with little regard for stability, but the more recent practice of using scrapers has resulted in more stable dumps. The erosion problems created by poor compaction have been controlled by contour banks, diversion drains, bitumen lined run-off drains, and hay mulching.

Jan 1, 1976

The Yilgarn Block of Western Australia presents (figure 1) a number of problems for conventional diamond exploration based on heavy indicator mineral sampling. These problems are due to the geology and unique geomorphological development of the Yilgarn Block.Essentially the Yilgarn Block is a pene- plain developed on a craton composed of Archaean intrusive granitoid rocks with meta- morphosed greenstone; which, apart from regional uplift, has not been tectonically disturbed since planation by glaciation in the Permian. Therefore since the early Plesozoic the Yilgarn Block has been subjected to terres- trial weathering conditions. Bettany et al., (1984) identify two phases of particular importance in the development of the present landforms: 1. Periods of lateritization during the Tertiary which result in the ~lassi~al laterite profile (figure 2). Duricrust indurated : Fe and Al oxides Mottled zone : Clay and Fe oxides Saprolite or pallid zone : leached clay grading into fresh rock. 2. Subsequent periods of aridity and semi- aridity during which laterite development was truncated and reworking of laterite Occurred.

Jan 1, 1988

By W. D. Hall, M. Norris, J. R. Henke

Dewatering wells producing iron-rich water experience rapid declines in yield and drawdown due to the formation of ferric (Fe3+) hydroxide deposits in well screens, pump intakes and riser pipes. Precipitation is caused by a combination of dewatering-promoted iron oxidation and iron oxidizing bacteria. Physical and chemical well rehabilitation techniques, as well as alternative well-construction and well development techniques, were evaluated in this study. The addition of acid downhole feed systems to dewatering wells that are prone to iron encrustation can, in many cases, prolong their operational lives up to 500% that of unacidified wells.

Jan 1, 1992

By Stephen A. Gasiorowski, Frank J. Hrach, James D. Bittner

Separation Technologies, LLC (ST) has developed a processing system based on triboelectric charging and electrostatic separation that provides the mineral processing industry a means to beneficiate fine materials with an entirely dry technology. The environmentally friendly process can eliminate wet processing and required drying of the final material. The process requires little if any pre-treatment of the material other than grinding and operates at high capacity - up to 40 tonnes per hour by a compact machine. Energy consumption is low, approximately 1 kWh/tonne of material processed. Since the only potential emission of the process is dust, permitting is typically relatively easy. In contrast to the other available electrostatic separation processes that are typically limited to particles greater than 75 µm in size, the ST belt separator is ideally suited for separation of very fine (<1 µm) to moderately coarse (500 µm) materials with very high throughputs. The triboelectric particle charging is effective for a wide range of materials and only requires particle-particle contact. The small gap, high electric field, counter-current flow, vigorous particle-particle agitation and self-cleaning action of the belt on the electrodes are the critical features of the ST separator. The high efficiency multi-stage separation through charging / recharging and internal recycle results in far superior separations and is effective on fine materials that cannot be separated at all by the conventional electrostatic techniques. Since 1995, this triboelectric process has been extensively used for the beneficiation of coal fly ash with eighteen separators in place and over 100 machine-years of operation at locations in North America and Europe. The technology has been also successfully applied to the beneficiation of a variety of minerals including calcium carbonates, talc, and potash.

Jan 1, 2012

THE Copperton mill in reality was a sort of proving ground. It was. designed to serve three purposes: (1) to verify the accuracy of the mine sampling by actually treating substantial tonnages of ore, (2) to demonstrate on a reasonably large scale the percentage of the copper in the ore that could be recovered, and (3) to permit the testing of various kinds of machines and devices for crushing and concentrating the ore, so as to guide the engineers in designing the proposed 6000-ton milling plant at Garfield. As a matter of fact, it contained a lot of second-hand equipment sent by MacNeill and Penrose from the works of the United States Reduction &Refining Co. in Colorado; and it was by no means a model installation. Probably it would have been even less efficient, except for the skillful work of George O. Bradley and-Frank-G, Janney, both of whom had worked with Jackling at Mercur. Bradley was a mechanical engineer employed to design the plant. Later he directed the design of the concentrator at Garfield and remained as consulting mechanical engineer to the company until 1915. Janney, who afterwards became manager of mills, a position that he retained until his death in 1916, was a skilled mechanic at the Golden Gate mill at Mercur when Jackling built the plant in 1897. His flair was making machinery do what it was intended to do. He was not an ore-dressing engineer in a technical sense; but Jackling him- self was a specialist in this respect as well as in designing and construction and Janney&apos;s mechanical aptitude made him a particularly valuable man in the Utah organization. John McDonald, another of Jackling&apos;s Mercur associates, was the first mine superintendent. With practically all of the available funds earmarked for construction of the Copperton

Jan 1, 1933

By Helmut Antrekowitsch

Nowadays nearly the half of the world zinc production is used for galvanizing. After their life span most of the galvanized products return as scrap to the steel mill During the steel process the zinc is collected in the flue dust It is astonishing to notice that between 40 and 50 % of the zinc produced is brought into the steel processing cycle by the coated scrap while only 3 to 5 % of the zinc production can be covered by the recycling of the zinc-bearing steel mill dusts. Responsible for this worse ratio is the fact that the established recycling technologies suffer from high energy consumption, low zinc yields, halogen problems and hardly any iron recovery. A development of new or an optimization of current recycling procedures for the dusts is unalterable because of increasing zinc amounts in these residues and the rising costs for the disposal. Different pyrometallurgical recycling technologies are tested in rotary kilns and vertical retorts at the Department of Nonferrous Metallurgy, University of Leoben, Austria. Various reducing agents from carbon monoxide to hydrogen and combinations are used. The results should make it possible to draw conclusions that allow an economical and ecological judgement of the different varieties. The goal is to support the affected industry to increase the low recycling rate and prevent a loss of high zinc values in the steel industry filter dusts.

Jan 1, 2003

By Joanna Bzówka

Nowadays, there are some new requirements for the supermarket floors. The floors are loaded by high point- and moving-loads. In spite of this fact, it is necessary to ensure the stiffness of the floor and the stiffness of its support. When pile foundations are designed in the case of weak soil, the piles are recommended under the foundations of the supermarket and also under the floor layers. The example of foundation of a typical supermarket located on long­standing municipal dumping ground is presented. Indirect foundation - CFA piles, 0.5 m in diameter and 4.5 to 20.0 m long, was de­signed. Fifteen trial loading tests were carried out.

Jan 1, 2006

By T. F. Dumm, L. G. Austin

"INTRODUCTIONGomez and Austin (1,2) have recently described calibration procedures for quantitative chemical analysis of particles by energy dispersive spectroscopy using particles mounted and polished in a resin matrix and scanned by an SEM under computer control. Their software is specifically designed for the analysis of Si, Al, Ca, Na, K, Fe and S in coal particles, and in this case the resin is loaded with iodine (3) to enable the exposed cross-section of an embedded coal particle to be differentiated from the matrix. However, the basic ideas of their procedures could be extended to any system of particles where it is desired to measure inorganic species in particles containing light elements such 0, C, H and N which are not directly detected. In these circumstances it is necessary to perform a quantitative determination of the measured components, so that the equivalent volume of light elements in the excited sample volume can be estimated by difference using ZAF and other corrections applied to the raw count intensities.Part of their procedure involves a new technique (2) for estimating background spectrum intensities; the intensity for a particular energy window is then subtracted from the total measured intensity for that window to enable the concentration of the corresponding element to be calculated. In addition, corrections for overlap of peak spectrums are applied. For example, Figure 1 shows some typical spectrums for known materials for the system they used, demonstrating a wide Gaussian spread about the theoretical peak energy. Since background spectrum and peak overlap corrections require a knowledge of the composition of the material, as does the application of the ZAF corrections, it is necessary to have an iterative solution of the equation sets, starting with estimates of the composition based on initial count rate corrected solely for dead time and detector efficiency."

Jan 1, 1989

By C. Gatlin, N. E. Garner

Results of impulsive wedge penetration tests on two synthetic, plastically deforming rocks are presented. Basic data obtained were force-time, displacement-time, and force-displacement curves for the impacts, plus the crater geometry. Wedge geometry and blow frequency were varied over a considerable range. The synthetic rocks consisted of wax-sand mixtures; two waxes of diflerent ductilities were used to provide variable "rock" characteristics. Conventional triaxial tests showed that these synthetic rocks exhibited force-deformation curves and Mohr envelopes quite similar to real rocks, except that strengths were much lower. Measured forces from static penetration tests agreed closely with theoretical values; however, dynamic force values were much higher than the static. These latter disparities are attributed to the viscous nature of the waxes. Thus the utility of these or similar rock models must depend on the scaling of rock viscosity, which is as yet unknown for impulsive loadings at elevated stress states. It appears, however, that some macroscopic, static phenomena may be studied with wax-sand rock models. INTRODUCTION The resistance of solid materials to indentation or perforation by projectiles or other penetrators has been studied by workers in many areas. Despite these efforts no universally accepted laws or formulas are available for describing experimental observations. In the metals field the force-deformation behavior of impacting bodies is often analyzed by the Hertz law for elastic collisions, the Meyer law if plastic deformations occur, or some combination of both.&apos; The similarities of these expressions to empirical drilling formulas of the oil industry are apparent. Beginning with the basic contributions of Simon and co-workers at Battelle,&apos; a number of experimental papers concerning the reaction of rocks to vertical impact have appeared in the U. S. mining and petroleum literature.&apos;-&apos; Most published data have, to date, been obtained at atmospheric pressure, although some early high pressure information was reported by Payne and Chippendale.8 Maurer" has recently utilized available brittle impact data to develop a drilling rate equation based on the experimentally observed proportionality between crater volume and blow energy. His result agreed with earlier efforts by both Somerton, who used dimensional analysis, and Outmans, who used plasticity theory. It has long been known that rocks exhibit different modes of failure depending on the state of stress. The literature in this area is considerable; however, papers by Bredthauer, Handin and Hager,13 nd Robinson", are adequate to illustrate the point. Since rocks flow plastically at certain triaxial stress conditions, the mathematical theory of plasticity has been used to analyze the rock drilling problem. Cheatham&apos;" has altered the wedge identation solution of Randtl to rocks, and has developed useful equations for penetrator forces under a variety of conditions. Outmans" has utilized Hill&apos;s solution in a similar manner to develop a drilling rate equation. Both Cheatham and Outmans used the linear Mohr-Coulomb rule to relate rock strength and confining pressure. The actual stress at the hole bottom is not easily ascertained, although photoelastic studies by Galle and Wil-hoit," plus the analytical treatment of Cheatham and wilhoiti8 provide some insight. Consequently it is not clear to what extent the highly idealized rheological model of a perfectly plastic solid can be realistically applied to the rock drilling problem. This paper is the first report on a long range experimental study of crater formation in rocks at elevated stress states. The data presented here are from the first phase of the project. Data obtained from impulsive wedge impacts on two synthetic, plastically deforming rocks are presented. MODEL ROCKS Geologists have long been faced with modelling the behavior of the earth and, as a consequence, have studied scaling problems in some detail.&apos; In general, their main problem is handling the wide disparity between laboratory and geologic time. In our studies the time effects (blow velocity or rate of loading, blow duration, etc.) were essentiafly the same for both. model and prototype, as were were geometry and tooth penetration. Thus application of available scaling laws suggests that Similarity is obtained if the stress-strain curves of model and prototype are similar." For this reason Hubbert and Willis&apos;&apos;

By Dave Ecobichon, Éric Côté, Simon Nickson, Michel Leclerc

The feasibility assessment of a mineral deposit requires the construction of a geo mechanical model of rock mass properties, for the purpose of preliminary mine design. The Noranda Technology Centre has been involved in the development of geomechanical models for several mineral deposits at the feasibility stage. Each model is constructed through intact rock testing, geotechnical core logging, geotechnical mapping and rock mass classification. Rock mechanics principles are used to develop conceptual stope designs and propose possible mining sequences. This methodology is applicable to both new mining projects and to the development of new areas within anoperating mine. This paper explains how the geomechanical model is developed and reviews its application to several case studies.

Jan 1, 1996

By A. Liem, R. L. Johnson, C. Sturgess, E. Kuzub

New challenges in mineral processing arise as high-grade ores become less available and the mining industry is forced to exploit lower grade ores. One of the challenges in beneficiating lower grade ores is the liberation of mineral particles while maintaining control over material management. Lower grade ores need fine grinding to free valuable minerals, but finely divided particles can cause severe problems, such as dustiness and flowability, in subsequent stages of material management. There are at least two approaches that can be taken to resolve this dilemma, both of which relate to particle size enlargement. First, the application of a dust suppressant can be used to control that aspect of material management. The optimal choice of dust suppressant agent depends on effectiveness and cost, both of which can be strongly influenced by the selection of application method. Second, agglomeration combining small particles into larger units-can reduce dust and improve the flow characteristics of the material at the same time. There are several mechanisms that can be employed to agglomerate mineral materials. Although agglomeration adds a new processing step, it is often cost effective. This paper describes these two approaches and their respective challenges, as they relate to a mined ore. We report on modified or newly developed procedures for characterizing mineral ores with respect to material management. On the same material, we use agglomeration processing to capture fines within larger particles and show how dustiness and other aspects of material handling are affected. We conclude by discussing their specific application in accordance with the mineral properties and processing needs.

Jan 1, 2004

By J. M. Bugbee

THE engineer and the conservationist agree that effective water drive is the desirable reservoir production mechanism. Water drive may result either from the expansion of edge water, the reservoir water bordering an oil pool, or from the artesian flow of edge water from the outcrop. Thus, the extent of the reservoir has an important bearing upon both the rate and the ultimate quantity of water influx to an oil pool. Lens-type reservoirs are generally recognizable, but the complete structure of the more important domal types, having possible limitations from crestal and synclinal faulting, is not well understood. The delineation from cores, electrical logs and exploitation phenomena of the crestal portions of reservoirs is increasingly exact. This paper suggests that inference from these factual pictures, combined with the scattered well and geophysical data of the synclines and with consideration of the dynamics of structural formation, may be applied to solving the complete geologic structure. Since faulting on the domes and in the synclines may effectively seal and thus limit the size of a reservoir and bar additional water influx, consideration of geologic structure and its possible effects is essential to complete analysis and prediction of reservoir performance.

Jan 1, 1942

By O. Güven

In recent years, there is an increasing demand on manganese consumption which stems from the important role of manganese in carbon steel production. And the growing need for manganese ores makes the beneficiation of low-grade manganese ores more economical. In this study, the characterization and beneficiation studies were carried out to propose a flow sheet for typical low-grade Turkish manganese ores. For this aim, different gravity separation methods were applied. According to the mineralogical analysis, the major mineral phases are pyrolusite (MnO2) and psilomelane (MnO2) while the major gangue mineral is radiolarite. Gravity separation tests were accomplished by using jigs, shaking table, MGS (Multi Gravity Separator) and in order to obtain products with high Mn ratio, high intensity magnetic separation was also performed. As a result, different combinations of flow sheets were utilized and a concentrate assaying 56.5% Mn with 85 % recovery was obtained.

Sep 1, 2012

By David White

ATTENTION has been given to the sources and supply of the raw vegetal matter and. the conditions of its submission to the process of sedimentation. An original and most valuable review has been made of the more important or significant chemical compounds originally contained in the organic debris, and of the biochemical changes-undergone by the latter during deposition. Consideration also has been given to the factors controlling the selective biochemical decomposition, in whole or in part, of :this debris, and the deposition, as, sediments, of the undecomposed plant structures and compounds, together with more or less of the so-called "ulmic," or "humic," organic decomposition products in colloidal solution.1 BIOCHEMICAL CHANGES END IN PEAT FORMATION The biochemical process terminates in the peat stage of coal formation, and with the cessation of this process organic sedimentation is completed. All subsequent changes result from geological causes and conditions. The deposits are in the form of peats of different types, organic muds, oozes, etc. They are essentially uncompressed and are wholly unconsolidated, and their water content is great, amounting to over 85 per cent. near the surface of the deposit. Many of the chemical compounds remain as in the once living organisms; others are biochemically broken down and new ones formed.

Jan 2, 1925