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By Luino Jr. Dell'osso, Richard L. Every

The enormity of the methane-in-coal problem is discussed, with a brief summary of the state-of-the-art. Laboratory techniques and data on the desorption of methane from Pittsburgh seam coal are presented and discussed and include the effect of time, temperature and vacuum. Under laboratory conditions, it was possible to displace 90 per cent of the residual methane by flooding the coal samples with carbon dioxide. Carbon dioxide was found to be three times more effective than air and almost five times more effective than helium.

Jan 1, 1972

By K. Ohga, V. J. Hucka

The presence of methane gas in mines creates hazards of explosions, fire and suffocation. Under certain conditions the occurrence of methane also poses a danger of gas and coal outbursts. Consequently, prevention of gas and coal outbursts in coal mines requires a sound knowledge of methane gas occurrence in mine workings. However, the direct method of determining methane content of coals developed by the U.S. Bureau of Mines is time and labor consuming for measurement, a new transportable methane tester was developed for Japanese coal mines. The instrument automatically measures emission gas from coal samples in the underground and also records and stores the data. Back on the surface, the tester can be connected via a RS 232 port to a PC computer for methane content estimation. Details of this technique are described here. Results on methane content determined in Japanese and U.S. western coal seams are discussed, as well.

Jan 1, 1991

By Forrester P. I, Richardson W

Methane in coal mines is an ever present hazard resulting in loss of lives and serious economic consequences. For effective control of methane, ventilation alone may not be totally adequate in some situations. In order to deal with such cases, new methods for the control of methane are being researched. One such method based on biotechnology has been investigated in Canada in the past several years. This method involves bringing methane oxidizing micro- organisms into contact with coal to oxidize the methane released to non-flammable products.

Jan 1, 1988

By B. R. Mohal, S. Chander

"A new technique to determine wettability of powders is presented in this paper. In this technique the times for immersion of individual particles from air into liquids, defined as imbibition times, are measured. Through the measurements of imbibition times for a large number of particles, it is possible to determine homogeneity/heterogeneity of a powder sample with regard to its wetting behavior. Quartz particles give a very narrow distribution of imbibition times showing a homogeneous wetting surface whereas coal particles give a broad distribution indicative of the heterogeneous nature of its surface. The imbibition time measurement technique is considered to have certain advantages over other methods to determine wettability of powders in surfactant solutions. In this study we have also compared the imbibition times with the wetting rate mea¬surements obtained by a modified Walker test.INTRODUCTIONSeveral methods are available for determining wetting characteristics of sol¬ids. Each of the methods has been used in the past to obtain very valuable information for comparing wetting behavior of various solids in a given liquid or for comparing the wetting behavior of several liquids for a given solid. Each method measures a somewhat different aspect of wetting and therefore quantitative correlations between techniques have been difficult. A general approach is to use a method in which close similarity between the technique and the application (where results of wetting measurements are to be used) can be maintained. The objective of this investigation was to develop a method which could be used to determine the wetting characteristics of single particles in surfactant solutions. Wetting of individual particles is of importance in cap¬ture of dust particles by sprays of surfactant solutions.METHODS FOR DETERMINING WETTING — A BRIEF REVIEWThe various methods available for measuring wetting characteristics of solids include: contact angle, immersion/sink time, bubble pick-up, induction time, capillary rise, and displacement method measurements. Some of the methods are briefly reviewed in the paragraphs that follow."

Mar 1, 1989

By B. Dubreuil

Arsenical bearing deposits are posing an increasing challenge for the mining industry. In particular, mineral processing of arsenical sulfidic ores for base and precious metals recovery tend to produce problematic arsenical tailings. This arsenic being present as sulphide or oxide, tends to dissolve, contaminating surface and underground waters. To meet the environmental regulations, it is often required to stabilize the arsenic in a more insoluble form. Nichromet has developed a new patented technology using vitrification of the arsenic oxide in an economical way, giving a stable solid, well below the environmental regulations upon leaching. This technology involves oxidation of As (III) to As (V), by using a low cost natural oxidizer and transformation of the produced arsenic oxide into calcium arsenate, which is not volatile at the melting temperature of the glass. This technology would be advantageously applied on most cases around the world where sulphide concentrates are oxidized in a fluidized bed or smelted.

Aug 1, 2013

By B. Dubreuil, J. -M. Lalancette, D. Lemieux

Arsenical bearing deposits are posing an increasing challenge for the mining industry. In particular, mineral processing of arsenical sulfidic ores for base and precious metals recovery tend to produce problematic arsenical tailings. This arsenic being present as sulphide or oxide, tends to dissolve, contaminating surface and underground waters. To meet the environmental regulations, it is often required to stabilize the arsenic in a more insoluble form. Dundee Sustainable Technologies has developed a new patented technology using vitrification of the arsenic oxide in an economical way, giving a stable solid, well below the environmental regulations upon leaching. This technology involves oxidation of As (III) to As (V), by using a low cost natural oxidizer and transformation of the produced arsenic oxide into calcium arsenate, which is not volatile at the melting temperature of the glass. This technology would be advantageously applied on most cases around the world where sulphide concentrates are oxidized in a fluidized bed or smelted.

Jan 1, 2014

By C. Abbruzzese, F. Vegliò, S. Ubaldini, R. Massidda

The aim of this paper was to study the influence of different water/organic solvent mixtures (isopropyl alcohol, ethanol and ethylene glycol) on the gold desorption process. The experimental work was carried out on laboratory scale, using activated coconut carbon with different temperatures and extraction times, without adding cyanide. Best results have been obtained in this order: isopropyl alcohol > ethylene glycol > ethanol. Starting from gold concentration of about 5 g Au per kg of carbon, best kinetics resulted in 97-100% of gold extraction, after 8 hours of desorption, at a temperature of 80ºC.

Jan 1, 2003

By C. Abbruzzese, F. Vegliò, S. Ubaldini, R. Massidda

"Gold solubilised during cyanidation can be recovered by precipitation (Merrill-Crow process) or by adsorption onto activated carbon, these being the techniques applied in industrial plants.Precious metals (Au, Ag) adsorbed onto activated carbon are extracted during a subsequent stage in aqueous phase, by various technologies, such as hot elution (70-80°C) or under pression desorption (100-130°), with hydro-alcoholic solutions.This stage is of great interest from an economic point of view, due to the high energy costs. Temperature represents the critical kinetic factor.The aim of this paper was to study the influence of different water/organic solvent mixtures (isopropyl alcohol, ethanol and ethylene glycol) on the desorption process.The experimental work was carried out on laboratory scale, using activated coconut carbon with different temperatures and extraction times, without adding cyanide.Best results have been obtained in this order: isopropyl alcohol > ethylene glycol > ethanol. Starting from gold concentration of about 5 g Au per kg of carbon, best kinetics resulted in 97-100% of gold extraction, after 8 hours of desorption, at a temperature of 80ºC."

Jan 1, 2003

By Hideki Yamamoto, Shigeno Matsumoto, Junji Shibata

"Some fundamental studies were carried out in order to produce composite powders comprising of two or three metal oxides ~y using liquid-liquid extraction and to develop the control technology of the particle size. The combination of samarium and cobalt was selected as the two component composite powders. Both stripping and crystallization occurred at the same time by emulsifying the organic phase loading the two metals extracted with Versatic Acid 10 and the aqueous solution containing oxalic acid. The effect of aqueous pH, oxalic acid concentration and agitation speed was examined on some properties such as crystallization percent, particle size and shape of each metal oxide powders obtained in this process. The analysis by using EDX showed that the two metal oxides were distributed uniformly.IntroductionComposite metal and metal oxide powders with high purity are indispensable as industrial materials in the fields of electrical engineering, electronics and metallurgy. It is difficult to mix metal powders or metal oxide powders uniformly for the production of alloy powders. If insoluble metal salts are allowed to collect as crystallization products in the crystallization-stripping process, the conventional melting and crushing process can be avoided. After mixing of the organic phase containing metals in fixed composition, fine metal and metal oxide powders of alloy composition are produced by using a crystallization-stripping method. Versatic Acid 10 and D2EHPA, both acidic extractants, were chosen in this experiment, and the metal oxide powders were produced by using oxalic acid as a crystallization reagent. Mixed metal oxalates containing samarium and cobalt were precipitated from the mixed organic phase containing these metals. Furthermore, the physical properties of the powders, such as particle size, shape and thermal decomposition, were measured in order to evaluate them for industrial purposes."

Jan 1, 2000

By Guy Deschênes

In spite of the wide use of lead compounds to enhance cyanidation of free milling sulphide-bearing gold ores, an industrial control method was only implemented four years ago. This study presents the results of the investigation that led to the development of the on-line control technology. Two free milling sulphide-bearing gold ores and high purity minerals were used to develop and test the concept. The first ore contains 2.8 g/t Au, 6.2% pyrrhotite, 2.1% pyrite 0.6 % arsenopyrite, 0.1% chalcopyrite and 0.1% organic carbon. The second ore contains 10.4 g/t Au, 3.2% pyrite, 0.8% pyrrhotite and 0.38% chalcopyrite. The first ore showed a much higher oxidation rate in the pre-leach than the second one and consumed seven times more cyanide. A relation between the formation of thiosulphate and thiocyanate and the additions of lead nitrate were quantified. The ?reducing power?, a titration with permanganate, predominantly determines the concentration of thiosulphate and thiocyanate in cyanide solution. The relation between the reducing power and the addition of lead nitrate at various concentrations of pyrrhotite and chalcopyrite in the ores was established, providing a monitor/control strategy for lead nitrate addition.

Jan 1, 2006

By J. R. Dartez

The use of CCD (counter current decantat.io;1) thickeners, or; clarifiers, in the gold mining industry is quite common. Although there are a number of technologies in the industry which utilize these types of tanks, the fundamental requirement is to settle leach tailings and eventually separate gold and silver "values" from the "barren" (no values) solution. The thickener separation process varies depending upon the raw ores found in any specific mine. In mines where rudimentary, rocky ores are most common the settling process is fairly straight-forward and uncomplicated. But, for those mines with complex carbonaceous ores, usually identified by high silting, clay components, the ability to monitor and control the settled materials is quite laborious and costly. The task of monitoring and maintaining control of settled residue in clarifiers and thickeners, of any design, is difficult in any industry, but due to the added desire in the gold mining industry of leaching the values from the liquid slurry, the problem is multiplied. Other common activities taking place in the thickeners are exaggerated internal flow rates, settleable solids activity due to rake movement, and the settling activity generated by flocculents being added to the liquid medium. All of this action within the liquid column causes the continual monitoring of the interfaces within the tank close to impossible.

Jan 1, 1993

A New Technology of Applying SLon-2500 Magnetic Separator to Recover Iron Concentrate from Abandoned Tails

Sep 13, 2010

By X. W. Zhang

Mica plate is broadly used in electric industry, production of man-made mica paper plate is in-creasing. The problem coming with is that large quantities of leftover materials unable to be re-cycled are produced during cutting and molding of mica plate productions. The leftover materials are always abandoned as crabs, which not only pollute the environment but also waste our resources. The study intends to find a new measure to decompose and to reuse the mica plate leftover materials so as to create a new production process of mica plate, which is clean and does not produce crabs.

Jan 1, 2014

By G. F. Zhang

Yunnan mineral is a kind of containing Ta-Nb rare earth deposit, the most potential economic valuable element in it is Sc, and raw mineral has 17.0 g/t Sc. Take the character of Sc into account, the key problem in producing scandium chloride molten salt by adaptive technology is how to man-ufacturer anhydrous scandium chloride molten salt. During the course above, the key problem is that preventing Scandium chloride from being hy-drolyzed into ScOCl. The ScOCl content of molten salt not only affect purifying scandium but al-so do harm to the production of Mg-Al alloy. In order to restrain the creation of ScOCl, add ammo-nium chloride into molten salt. As long as ScOCl is created, it would be chloridized. Thus, during the course of dehydrating anhydrous chloride molten salt this method prevents scandium from hydrolyzing. Accordingly, the key phase of this producing course is eliminate ammonium chloride and the surplus crystal water, and the most crucial of it is restrain scandium chloride from being hydrolyzed into ScOCl. This research analyzed the theory that ammonium chloride is trend to be hydrolyzed into ammo-nium chloride, and propose the research scheme of restraining this process from creating ScOCl. The new process of restraining the generating of ScOCl and dehydration for crystal water rare earth chloride is adopted: Inert gas temperature increases rapidly to a certain degree to eliminate ammonium chloride and crystal water. The experimental research were done such as : the temperature of eliminating ammonium chloride and crystal water, amount of ammonium chloride, time, temperature growth speed, influence of inert gas flow toward to scandium percent hydrolysis, whereby, we conclude the optimal process condition in this period: Temperature: 400°C, proportion of oxidized scandium and ammonium chloride is 1:1.5(Proportion of oxidized scandium and additional salt is 1:5.4), time is 120minute, temperature growth speed is 10?/min inert gas flow is 5L/min.

Jan 1, 2014

By E. E. ELLIS

THE zinc deposits under development by the Universal Exploration Co., a subsidiary of the United States Steel Corporation, are close to Jefferson City, Tenn., a small town about 30 miles northeast of Knoxville, Tenn., and are served by the Southern Railway. The first zinc mining in this district was in the old Mossy Creek mine at the north edge of the town, opened for oxidized ores in 1871 and later worked for sulfide ores. An oxidized zinc ore deposit (carbonates and silicates) was opened near New Market in 1900 and worked through the war period by the G1'8sselli Chemical Co., producing around 25,000 tons of oxidized ore. In recent years a sulfide deposit has been found and developed but is not producing. About 1% miles south of this a small body of sulfide ore was developed by open cut, but the operation was unsuccessful. The Universal Exploration Co. entered the district in 1926 and, after extensive exploration, has been operating an oxidized ore-body since Janual:y, 1928, and has been developing a sulfide ore body since July, 1928.

Jan 1, 1929

By W Y. Guo, L X. Chen, D X. Zhang

To obtain the rock type-I crack propagation process accurately, a novel fixture is used to make the prefabricated crack of rock propagation along the predetermined direction. In this study, the crack propagation process of rock is monitored with the digital image correlation method (DICM), and a mechanical model of crack directional propagation was established. The results show that the simple crack directional propagation device can effectively realise the stable propagation of type-I crack along the predetermined direction, the crack initiation angle is less than 10°, and the deviation between the peak strength of crack propagation calculated by a simplified mechanical model and the tensile strength of Brazilian splitting is 22.76 per cent and 7.53 per cent, respectively. According to the deformation field evolution law, crack propagation can be divided into three stages: microcrack development, main crack propagation, and main crack propagation. As for the rock type-I crack initiation and propagation mechanism, before reaching the peak strength, the prefabricated crack tip is subjected to maximum tensile stress; the elastic energy increases rapidly, and the dissipation energy increases slowly; after the peak strength, elastic energy exceeds its energy storage limit and released rapidly, and most of the input energy is converted into dissipation energy, which makes the crack propagation rapidly. The crack directional propagation device will be further optimised and improved, and it is expected to provide a new method for the study of crack propagation mechanism, rock failure precursor information and crack arrest principle, etc. It will also provide theoretical references for the optimisation of coal strata directional blasting, fracturing, fracture arrest, and other related technologies in geotechnical engineering.

Nov 29, 2022

By K Nguyen

The advances in computerised processors and digital microscopic imaging have enabled more studies that attempt to quantify textural information from rock images. However, a texture classification system designed for geometallurgy has always been challenging, as it combines general image analysis techniques and specific texture classifications in terms of the size, shape and orientation of mineral particles. In this paper, a novel texture analysis technique using grey level radial shell association (GLRSA) and spectral angle mapper (SAM) to discriminate between different geological images is outlined. The technique can be applied in routine analysis and characterisation of mineralogical and textural attributes which may correlate with variability in mineral processing behaviours. Using this texture analysis technique, a set of small texture reference images, a texturelet reference library, has been identified from a suite of drill core images. Rock types are classified according to the proportion of each texturelet type recognised. The library is site specific.CITATION:Nguyen, K, 2013. A new texture analysis technique for geometallurgy, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 187-190 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By Fred C. Bond, Jen-Tung Wang

Comminution energy is principally energy of deformation before break-age, which appears as heat. An empirical equation is presented which covers the entire comminution range. The new strain-energy theory considers comminution from the known principles of mechanics and the reduction ratio. Energy requirements according to the different theories are compared.

Jan 8, 1950

By Fred C., Fred C. Bond

Comminution energy is principally energy of deformation before breakage, which appears as heat. An empirical equation is presented which covers the entire comminution range. The new strain-energy theory considers comminution from the known principles of mechanics and the reduction ratio. Energy requirements according to the different theories are compared.

Jan 1, 1950

By H. M. Chance

Discussion of the paper of H. M. Chance, Bi-Monthly Bulletin, No. 23, September, 190S, pp. 791-808. CHARLES CATLETT, Staunton,Va. (communication to the Secretary *):-Mr. Chance's suggestions that the brown hematite ores of the Potsdam formation are due to the alteration in place of iron sulphide, and that their extension may reasonably be expected to contain valuable deposits of unaltered sulphide, are interesting; but the facts marshaled by him are too limited to justify more than the hope that they may serve as a commercial source of sulphur. It is true that these deposits have been the source of large amounts of iron-ore; and it. is common, as stated by him, for the mining operations to extend to a shallow depth only; but this is largely due to the fact that the surface-material represents an accumulation from the breaking down and collection of the ore which formerly reached a much higher level. With, increasing depth comes a decreasing thickness of valuable material. This is especially appreciated by a glance at Mr. Chance's drawings. This is the reason why so many disappointments have resulted when these ores have been followed to greater depths. Even if the ore is largely derived from oxidation in place, it is impossible to ignore the great number of concretionary forms, as well as those showing the evidence of secondary solution and deposition now taking place, such, for instance, as the part replacements of fragments of quartzite derived from the underlying beds. Concretionary form does not necessarily mean long transportation, and may be a variation of material in place; but commonly it is an evidence of collection, and tends to imply that more or less concentration has taken place. This fact would also argue against an equally extensive develop¬-

Nov 1, 1908