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By D. M. Avant, S. M. Pickering

A variety of grades of very white muscovite mica are now being produced from sedimentary sands and clays in Central Georgia. The mica is naturally concentrated near the base of the lens-shaped kaolin deposits and also disseminated in associated quartz sands. The same weathering and bacterial alteration processes which have transformed the kaolins from dark organic muds to white pigment-grade industrial clays have also removed discoloring iron from the micas and developed unusually white muscovite. Further, chemical alteration has removed some potassium from the muscovite atomic structure, resulting in an easily delaminated mica which can be cleaved to unusually fine, high bulking, high aspect ratio products. The peculiar alteration history of these sedimentary micas enables production of some of the whitest, finest particle size, and thinnest aspect ratio muscovite mica products on the world market today. Raw mica feed is obtained from kaolin and sand processing by-products, and also from beneath the useful base of abandoned kaolin mines. The processed ultrafine and filler grade muscovite mica products are used for paint, plastics, cosmetics, mold release, thermal and electrical insulation, epoxy, and dry wall joint cement markets.

Jan 1, 2002

By J. Drelich

The highly-efficient and economically-feasible technology for bitumen recovery from US oil sands using a water extraction approach was developed at the end of the last century. This water-based bitumen extraction process has been optimized based on observations and analysis of microscopic mechanisms of bitumen release from oil sands and the bitumen transfer to a froth product as well as measurements of interfacial properties of bitumen. The wetting mechanisms that occur in the diluent-assisted water-based processing of US oil sands include bitumen film rupture and recession on sand grains and bitumen transfer to nucleated and injected gas bubbles. These mechanisms are reviewed in this contribution.

Jan 1, 2007

By M. G. Senyur

This study aims at investigating the structural characteristics of backfilling material. In this regard, spatial arrangement of solid particles and associated voids in a unit mass of coal mine refuse as backfilling material were tested. The materials were produced from coal mine refuse of Zonguldak Colliery, Turkey. The experimental procedures were developed to determine their void ratio (or its equivalent porosity), bulk density and the shape properties of constituent particles. The orientation fabric and the co-ordination number were the other two fabric elements determined. The filling materials were sieved and their particle size distributions were found. The results obtained by experiments were related to the particle size distribution parameters, namely, the coefficient of uniformity and the effective size. It was concluded that mean value of void ratio is correlated with coefficient of uniformity. The standard deviation of porosity as an index of fabric heterogeneity is clearly correlated to effective size. By an original experiment, the frequency distribution of coordination number was observed as binomial in uniformly graded materials. Also, the co-ordination numbers of test mixtures were calculated by the Marsal method and results obtained showed a good correlation between the minimum particle size and number of contacts per unit area.

Jan 1, 1998

By Bertrand Quiniou, Pierre Amadieu

Ion exchange technologies and processes are proven and established technologies widely used in numerous industries including hydrometallurgy for metal separation and recovery from metal bearing solutions. They have evolved through innovation which includes the development of countercurrent multistage (or multivessel) ion-exchange contactor systems with the benefit, for industrial operations, of greatly reduced footprints and ion-exchange media inventories, as compared to more traditional fixed bed contactor systems. Information on procedures for design and sizing of countercurrent multistage ion-exchange contactor systems is not readily available since it is most often proprietary know-how. The purpose of the present work is to develop a simple and innovative approach for the sizing and modeling of industrial countercurrent multistage ion-exchange contactor systems. The suggested approach builds upon published results and upon the following observation: in an industrial setting, knowledge of how component concentration or load on a contactor output streams vary with time t within a cycle duration (0 < t < T) is generally of little interest, only knowledge of time average of such concentration or load over a cycle duration T is sought for. The presented approach will be tested against current or past performances of industrial countercurrent multistage contactors of Orano Mining operations such as SNK‑3M moving packed bed contactors in Kazakhstan and NIMCIX fluidized bed contactors in Namibia.

Jan 1, 2020

By Frank A. Peters

This evaluation of the sulfurous acid process for the production of metallurgical-grade alumina is the first of a series concerning various known methods of extracting alumina from low-grade aluminous materials and was undertaken to permit comparison with other processes. In the process with which this Bureau of Mines report is concerned, calcined clay is leached under pressure with 20 percent sulfurous acid and then filtered to remove a siliceous residue. The aluminum sulfite remaining in the filtrate is precipitated as a monobasic sulfite which, together with iron sulfite, is then decomposed under pressure to form a crude alumina hydrate and iron oxide. This intermediate product is purified in a modified Bayer process to yield alumina suitable for electrolytic reduction to aluminum. A study estimate (16)3 is used for these evaluations. The capital cost, not including land, is estimated at $95,701,600 on a Marshall and Stevens index basis of 240.0 for a plant producing 1,000 tons a day of alumina or 350,000 tons a year. The annual operating cost for this size plant is estimated at $22,831,100 or $65.23 per ton of alumina using clay at $1 per ton. Depreciation and local taxes are included in the estimate, but profit and Federal taxes are not considered.

Jan 1, 1962

By K. Prajapati, P. Hes

Transmission of vibration to the operator from percussive vibrating tools is increasingly of concern in industrial and mining applications. Prolonged exposure to high levels of vibration transmitted via the hand causes disorders known as hand-arm vibration syndrome (HAVS). The vascular component of HAVS is called vibration white finger (VWF) and has a debilitating effect on the hand. Vibration at frequencies below 1250 Hz, a tight hand-grip force and cold environments are reported to increase the likelihood of developing VWF. A vibration damping handle design with patents pending that addresses some of the causes of VWF has been developed and retrofits onto jackleg pneumatic rock drills. The handle is decoupled from the drill while maintaining jackleg twist-grip controls on the hand-grip using a combination of sealed self adjusting hydraulic pistons and compliant materials in series, and a new air control valve. The ergonomics of the hand-grip was also modified by the addition of a polyurethane sleeve with a diameter of 50 mm. The new hand-grip reduces direct cold metal contact and minimizes grip force. Measurement of vibration as the quantity acceleration was made in accordance with international standard ISO 5349. Overall vibration damping in all axes of 50% to 63% was attained at frequencies below 1250 Hz. The dimensions of the damping handle are comparable and its weight is only 100 g heavier than a standard handle.

Jan 1, 2001

By D. A. Bruce

To check the feasibility and the quality of a very deep diaphragm wall, a tern of adjacent panels has been constructed, up to a depth of 100 m, in the Milan sandy gravelly soil by means of a hydraulically driven milling machine with reverse circulation of mud. The results of the monitoring carried out in order to evaluate the panel geometry and the quality of both joints and concrete are described. The use of instrumentation based on different physical principles allowed the cross checking of measurements as well as the evaluation of the accuracy and sensitivity of each single procedure to be performed. The trial field was successfully carried out and the feasibility of a diaphragm wall of such a depth was demonstrated and corroborated by a reasonable level of quality control.

Jan 1, 1989

By L. G. Austin

"This paper is based on the development of the Maza-Austin technique for characterizing thousands of coal particles by approximate analysis of the major inorganic constituents Ca, Al, Si, K, Na, Fe and S in each particle. The technique has sufficient sensitivity to work on small volumes, is fast enough to handle large number of particles within a reasonable period of time, and consists of scanning electron microscopy combined with energy dispersive x-ray spectrometry (SEK-EDS). A computerized SEK-EDS system that allows the automated analysis of hundreds of coal particles per hour' is described. The analysis is based on the location and tracing of coal particles embedded in a polished specimen, the selection of sampling points on the traced particles, the collection of an x-ray spectrum from each sampled point for a defined period of time, and the processing of the x-ray intensity to calculate point composition using ZAF corrections. Procedures for correcting for dead time, background, detector efficiency and spectrum overlap are described. These corrections are essential if reasonably accurate analyses are to be obtained from unknown complex mixtures of the elements in a coal or fly ash particle. Examples are given. INTRODUCTION Coal is a complex mixture of organic and inorganic materials. The inorganic fraction is referred to as mineral matter (Gluskoter, 1978) but can occur in three modes: (i) an observable mineral species; (ii) as cations held by ion exchange to carboxylic groups; and (iii) in chelate complexes. The mineral matter content normally represents a significant proportion of a coal, with an average value of about 15% for US coals (Gluskoter, 1975). The standard methods of analysis of the mineral matter in coals are performed on a sample selected to represent the whole coal as closely as possible, and give the overall inorganic composition in the coal. Such analyses are of limited use for solving problems originating from the behavior of individual coal particles, whose compositions vary widely from the average value. This is particularly true in pulverized coal combustion, where the current methods of predicting the slagging and ·fouling potential of a coal are based on the bulk ash composition, but the fly ash particles which create the deposits originate from coal particles with large differences in mineral compo1ition. Some examples can be found where, in a comparison between two coals, the one with the smaller slagging potential according to the mean ash composition was the one that behaved worst in the furnace (Moza et al., 1980; Koza and Austin, 1983). The u1e of gravity fractionation to assess the slagging potential of pulverized coals has shown that conventional ASTM analysis is not sensitive to differences in the distribution of mineral matter when comparing coals (Borio and Narciso, 1979). Bryer (1979) concluded that coals should be examined for fouling and slagging potential by analyzing gravimetric and size-fractionated coal, preferably pulverized· and ground to the size expected at the mill outlet."

Jan 1, 1989

By Raymond W. Henn

The 32nd annual short course ?Grouting Fundamentals and Current Practice? was held at the Colorado School of Mines, June 13-17, 2011. The field demonstration portion of the course was conducted June 16 at Baski Inc.?s yard in Denver, CO. The full-scale field demonstration presents many types of drilling and grouting equipment in operation as well as numerous grouting methods per-formed under various field conditions. As part of the field demonstration, the class was shown the proportioning, mixing, testing and injection of various cement grout mixes into sand columns under controlled and recorded conditions. These sand column demonstrations have been conducted under controlled and measured conditions each year since 1999 as part of the short course. The sand column demonstrations were conducted prior to 1999, but with less quality control and minimal record keeping of the proportioning, mixing, testing, injection pressures and the final permeation results.

Jan 1, 2011

By Anderson Ayres Bittencourt

O monitoramento de sistemas e ativos de automação sempre existiu de forma rudimentar e descentralizada. A análise desses dados tanto quanto sua obtenção é um desafio para as empresas atuais. Foi a partir deste princípio que nosso projeto foi desenvolvido.Este trabalho tem como objetivo demonstrar a solução de Monitoramento online e preditivo implementada na ArcelorMittal Aços Planos da América do Sul, onde desde o início de sua implementação pudemos capturar benefícios operacionais, melhoria dos processos, otimização, eliminação e/ou diminuição de indisponibilidade de plantas, entre diversos outros retornos que serão apresentados.

Oct 30, 2017

By Peter J. Nicholson

The methods of reinforcement to be discussed in this paper are all insitu methods, ones that can be used on the soil structure as it exists in the ground, and do not rely on excavation and replacement of the soil. Current practice in the United States, as well as new ideas and methods, will be discussed as they relate to slope stability, retaining walls, and to other uses such as control of mine or cavity related subsidence and to liquefaction control under existing structures. The method is based on the concept of "nailing" or reinforcing the soil in place, and thereby causing a mass of soil to act as a coherent unit. When performed properly, a true gravity structure can be constructed, one that will remain intact under both horizontal and vertical loadings and that will also resist vibrational and seismic loadings.

Jan 1, 1991

By Damon C. Gray

This report contains a recommended program of acoustic research to be conducted by the U. S. Bureau of Mines. The program is directed toward the abatement and control of machinery noise in underground coal mining operations. The study conclusions and specific problem areas which led to the definition of the recommended program are also briefly described.

Jan 1, 1971

By Katri Avarmaa

Aluminum and copper are large volume metals in electronic appliances, while tin and indium exist as common minor elements. All of these non-ferrous metals are aimed to be separated and recycled from the end-of-life electronics into non-ferrous scrap fraction(s), and further through pyrometallurgical and/or hydrometallurgical processes to pure metals. Depending on the mechanical pre-treatment processes, aluminum and copper liberation from each other varies. This study focuses on the influence of alumina on indium and tin distributions between copper alloy and iron silicate slags with 0, 9 and ∼16 wt% of Al2O3. The experiments were executed with an equilibration-quenching-EPMA technique in an oxygen pressure range of 10−10–10−5 atm at 1300 °C. The metal-slag distribution coefficient of indium remains constant as a function of alumina in slag, while that of tin increases. Therefore, aluminum in feed or alumina addition to the slag improves the recovery of tin into copper. Nevertheless, oxygen pressure has clearly more significant influence on the behavior of both the metals in the smelting conditions.

By Mamookho Elizabeth Makhatha, Mbal Henock‑Michel Mwanat, Kubangala Brest Kasongo, Ntumba Edward Malenga

This study investigated the operating parameters that affect the kinetic dissolution of copper and cobalt from sulfidic ores. The sulfuric acid concentration, temperature, sodium chloride concentration, particle size range, and leaching time were selected to deduce the kinetic mechanism of the leaching reaction. Other parameters, such as a stirring speed of 250 rpm and the percentage solid 10% w/v, remained constant. The results reveal that an increase in acid concentration enhances the leaching rate of copper and cobalt. Copper and cobalt dissolution was positively affected by the addition of sodium chloride. The highest leaching rates of copper and cobalt were 24.71% and 15.65%, respectively. The chemical control and diffusion control by shrinking core models are well fitted as the kinetic models representing the dissolution of the minerals. The respective activation energies for copper and cobalt dissolution of 10.92 and 31.023 kJ mol− 1 for the chemical control and 18.83 and 37.28 kJ mol− 1 for diffusion reaction control were established from temperature-based experiments.

Aug 26, 2022

By Zhihe Dou, Jiang Liu, Ting-an ZHANG, Yukun Huang

The paper aimed to propose that mixed rare earth concentrate was decomposed by pressurized calcification where mechanical milling was applied simultaneously (also known as mechanochemical calcification). The bastnaesite and monazite were both decomposed by OH−, where released rare earth formed RE (OH)3, released fluorine and phosphorus formed CaF2 and Ca2P2O7. Then, the calcified slag was leached by diluted hydrochloric acid to extract rare earth and both recover fluorine and phosphorus. The phase transformation regularity, the behavioral trends of rare earth, fluorine and phosphorus were investigated. Results showed under the optimal conditions of ball to material weight 80:1, the calcification temperature 250 °C, the liquid-solid ratio 5:1, the leaching yield of rare earth reached to 92.16%, Ce was 86.47%, La was 97.58%, Nd was 99.99% and the mass fraction of F, P entering into calcified liquor were 8.27, 0.21% respectively. The micromorphology of the mineral has a transition from dense to fluffy, and then became dense again.

Mar 1, 2018

By Maurice Deul

This bulletin summarizes the work conducted under the Bureau of Mines methane control research program during the years 1964 to 1979. This research effort was directed toward improving existing methods and developing alternative methods of reducing the explosion hazard during mining. The research was performed in three general areas: (1) basic factors that control the emission of methane into coal mines, (2) methane control during mining, and (3) methane drainage in advance of mining. Topics discussed in this bulletin include the magnitude of the methane problem; the equipment and instruments developed; the geological, chemical and physical parameters that control the movement of methane in coalbeds; the direct method of determining gas content; the estimates of gas content from adsorption data; and methane drainage, through shafts, through horizontal boreholes, through vertical boreholes, or through slant holes. Improvements in ventilation, control of methane in gob areas, and water infusion are also discussed, as is the potential use of coalbed methane as a supplement to natural gas supplies. This bulletin provides a comprehensive source of information on the accomplishments of the Bureau&apos;s methane control research program, on the technology developed, and on the direction of further research.

Jan 1, 1986

The Greymouth Coalfield contains New Zealand&apos;s greatest known resource of bituminous rank coal. The coals are of very high quality, with low ash and sulphur contents and a range of other properties that makes them desirable for a wide range of uses. In fact only a few producers around the world today can offer coals with such exceptional properties. This suggests that Greymouth coal has potential as a premium export trading commodity. These assertions have been largely confirmed by a comprehensive exploration drilling programme funded by Mines Division û Ministry of Energy between 1979 and 1984. The program, forming part of the NZ Coal Resources Survey, was carried out under contract by Lime and Marble Ltd. The drilling of 49 deep, predominantly cored, holes at 1000 m intervals over the coalfield has generated a vast amount of data. It has shown the existence of three major potentially minable coal deposits containing 233 x 106, 33 x 106 and 15 x 106 tonnes of coal in ground. Investigations have at this stage only identified targets and these estimates represent &apos;in ground&apos; resources, not recoverable reserves. Recent geological studies as well as past and present mining have clearly highlighted the problems posed by the complexity of the coalfield geology. The coalfield lies within a mobile zone in the earth&apos;s crust known as the Paporoa Tectonic Zone, which has been active from at least mid-Cretaceous to the present time. Currently this factor poses the greatest obstacle to the determination of mining possibility of the, defined deposit and ultimately will strongly influence any future mining development. The Greymouth Coalfield has, however, had a long and eventful mining history spanning the last 120 years, where 32.5 x 106 tonnes of coal has been won from over 100 mines. In spite of the problems facing development, the large quantities and exceptional quality of the remaining coal will act as a strong inducement to persevere with this difficult but potentially valuable resource.

Jan 1, 1985

By B. O. Odera

The Pt-based alloys have a high potential for replacing some Ni-based superalloys (NBSAs) used in the highest temperature and most aggressive environments, and vanadium would be a beneficial alloying element. Six alloys of average compositions Pt-26.6Al-9.1V, Pt-23.1Al-17.8V,Pt-9.6Al-21.1V, Pt-17.4Al-6.4V, Pt-22.3Al-7.9V, and Pt-6.0Al-10.1V (all in at.%) were manufactured by arc-melting and examined in the as-cast condition using scanning electron microscopy and X-ray diffraction (XRD). Five samples were heat treated at 1 000°C for 1 500 hours and water quenched, then examined. The phases were identified using energy-dispersive X-ray spectroscopy and the identities were confirmed by XRD. In most of the samples, the phases existing in the as-cast condition were different from those at 1 000°C after ~1500 hours heat treatment. A solidification projection, an isothermal section and a liquidus surface projection were determined for the Pt-rich corner.

Jan 1, 2012

By Chang Wei, Zhigan Deng, Minting Li, Cunxiong Li, Xingbin Li

A direct hydrometallurgical process of extraction molybdenum and nickel from molybdenum-nickel ore by pressure water leaching without reagent was studied. The extraction of Mo and Ni from molybdenum-nickel ore by oxygen pressure leaching, which exploit the characteristic of molybdenum-nickel minerals contain high concentration amorphous sulfide which has highly active, and make the most of easily oxide to sulfuric acid and sulfate at low temperature and excess oxygen presence of the amorphous sulfide. Under oxygen pressure conditions, considerable molybdenum and almost all the nickel were extracted into solution in the leaching process. The results show that with the leaching time for 3~4h, temperature at 150o C, liquid-to-solid ratio of 2mL/g, mineral granularity of 0.074mm, oxygen partial pressure of 0.4~0.5MPa without other reagent, molybdenum leaching percentage can be over 80% and nickel leaching percentage can be more than 97%. Furthermore, about 80% sulfur in the Mo-Ni ore has been transformed into sulfuric acid.

Jan 1, 2014

By Daniel H. McClain

A unique partnership between the Colorado Mine Safety and Training Program (CMSTP), the Colorado Rock Products Association (CRPA) and the Higher Education and Advanced Technology (HEAT)Center resulted in a video CD-ROM training program for new miners entering the aggregate industry. Cooperation from everyone involved, including the U.S. Mine Safety and Health Administration (MSHA),made this the product against which other training materials in the mining industry will be measured in the 21stcentury. This product’s versatility and wide application make it a tool that is as critical to a mine’s success as any earthmoving machine. The state and federal grant money involved allows this product to be affordable to small operators and independent contractors. The quality of this two CD-ROM set rivals any commercially made CD-ROM training.

Jan 1, 2003