Search Documents

By X. H. Li, F. Xie, Q. Zhang, Z. H. Shen, S. Mao

"There is abundant rare-earth element(REE) in our country, but it is very fragmented in the earth's crust, and it is very difficult to mining or mining cost is extremely high. There are few of industrial value rare-earth deposits. There is a lot of concomitant rare-earth deposits, and the comprehensive utilization value is high. There is very rich carlin-type gold resource, associated with a certain amount of REE in the southwest of Guizhou province. In order toutilize comprehensively the resources, this paper conducts the study on the occurrence characteristics of REE in the ore. By the chemical analysis, the gold grade is 3.35g/t, the organic carbon 0.81%, the total REE 0.022%, which is a high carbon fine disseminated gold ore. By the optical microscope and XRD analysis, the major minerals are quartz, pyrite, calcite, limonite, arsenopyrite, mica, kaolinite, clay minerals, etc. In addition, there is a large amount of carbonaceous materials, such as organic carbon, graphite, which is harmful on leaching of gold. By the scanning electron microscopy analysis, there are thorium, lanthanum and neodymium, ytterbium, persimmon and other REE in the ore. Gravity separation shows that REE could be enriched to lighter material mainly, which indicates that REE disseminate closely with lighter materials.INTRODUCTION Carlin-type gold ore is important gold resource in the world, which are mainly distributed in Nevada and its vicinity, as well as the two Golden Triangle of Yunnan, Guizhou, Guangxi and Sichuan, Shanxi, Gansu province in China(Su W.C. et al.,2009; Xia G.X.,1996).Guizhou carlin-type gold ore is the second largest gold resource in the world(Muntean J L et al.,2011), distributing along the southwestern margin of the Yangtze plate, mainly mineralizing in the neopaleozoic-early mesozoic(Xie Z J et al.,2017). Many large gold deposits have been found in southwest in Guizhou in twentieth century, such as Zimuyou,Getang, Lannigou, Shuiyindong and Laowanchang gold deposit, and so on, and the gold reserves reach over 100 tons(Xia Y. et al.,2009).There is a certain amount of rare-earth resource in the carlin-type gold ore in the southwest in Guizhou province, and the current researches might mainly focus on characteristics of REE from the angle of geological mineralization(AnanyevY.,2015), not from the angle of separation and enrichment."

Jan 1, 2018

By John P. Gooch

The solubility of 1,1,2,2-tetrabromoethane (TBE) in water was determined from 1.0° to 97.0° C. The solubility (S) of TBE in grams of solute per 100 grams water was correlated with [S = 1,920.55 [exp (40292L7 11, T2 10 T 737.577 + 9.923962 ] where T is in degrees Kelvin. A thermodynamic analysis conducted on a system consisting of a TBE phase and a water phase in equilibrium with a vapor phase led to the calculation of the activity coefficient, vapor-liquid equilibrium distribution coefficient, relative volatility, and heat of mixing for saturated solutions of TBE in water. Data required for these calculations were the solubility of TBE in water and the vapor pressures of TBE and water as a function of temperature.

Jan 1, 1972

By R G. Moreby

The purpose of this paper is to provide the rationale for decision making when considering the use of three heading gate roads in Australian underground coal mines.There are currently 30 underground longwall mines in Australia with all but two employing two heading gate road longwall layouts. The volumetric capacity of these two heading ventilation circuits is evidently viable in typical block lengths and in low to moderate gas regimes. However, in gassier regimes, potential longwall production rates of 10 Mt/a, and or where block lengths are being extended to well beyond historical norms, a conventional two heading U circuit may not be adequate. Other than seam gas emission, block length and production dependent heat loads together sealed area management requirements also have to be considered.The two mines currently employing three heading gate roads have the opportunity to revert to two headings at any time but, based on operational experience to date, have not done so due to the consequential reduction in gas management capacity and lower production rates associated with gas delays and limitations on tailgate access.Although there are a number of alternative two heading longwall circuits available and employed worldwide, the custom and practice of promoting inert goaf atmospheres in most Australian coal mines to mitigate the risk of catastrophic gas explosions and spontaneous combustion often prevents the use of gas loaded bleeder systems. In this respect, Australian underground coal mines may be considered the safest in the world.The current situation is that three heading gate roads have been proven successful in Australian conditions, albeit at additional cost, where two heading ventilation circuits cannot manage net seam gas emission to the ventilation system at the production rates required. In this respect, a further important driver for decision making is the short to medium term value of CO2-e emission taxation in Australia.CITATION:Moreby, R G, 2013. The rationale for use of three heading gate roads in Australian underground coal mines, in Proceedings The Australian Mine Ventilation Conference , pp 13-26 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By R. G. Coyle

"In an earlier paper the author explored the consequences of price-stabilizing effects, on an industry-wide basis, of various production strategies. These ideas have now been applied to an illustrative case of an individual mine. It is shown that the turning of production and financial policies can affect financial performance over a five-year period by as much as 22 per cent.No generality is claimed for the results and they would differ from mine to mine. It is, however, asserted that the results show that the proper turning of production, reserves and financial policies are more critical determinants of mine performance than has been realised. It is also asserted that the methods of dynamic analysis are the most appropriate means for studying this policy-design problem."

Jan 1, 2014

By Sheikh Abdul Rezan, M. N. Ahmad Fauzi, Yong Jing Hui, NORLIA BAHARUN, Noor Izah Shoparwe, Srimala Sreekantan

In this paper, the effect of carbon reductant on carbothermal reduction and nitridation of copper-doped titanium oxide (Cu–TiO ) was investigated.

Mar 1, 2017

By R. W. Coburn

The results of field experiments on wells which required stimulation indicated that engineered well-completions will cause an increase in ultimate recovery at reduced costs. Techniques and tools have been developed which can be used to establish well conditions most conducive to successful stimulation. Cementing, perforating and treating are bound together so completely that the success of one phase is completely dependent on the .effectiveness of the preceding phase. A method of determining the efficiency or effectiveness of any given well-stimulation treatment has been derived. Pressure behaviour during a treatment can be analyzed to yield the total percentage of the formation which has been treated.

Jan 1, 1960

Nationalization of the coal mining industry in Great Britain was one of the first pieces of major legislation enacted by the post-war Labor Government in 1964. It followed a long period of economic depression with high unemployment and bad industrial relations in the coal mining industry during the 1930's, and shortages of coal during the last war. Upon nationalization, the National Coal Board took over control of the industry in 1947 and so became the biggest single employer of labor in the western world. As well as the coal mines themselves, it assumed responsibility for a great variety of other assets including coke ovens, byproduct plants, land, houses, railways and shipping wharves.

Jan 6, 1964

By Limao Zhang

This paper presents a novel model to assess the risk of adjacent buildings in tunnelling environments based on Extended Cloud Model (ECM). ECM is an organic integration of Extension Theory (ET) and Cloud Model (CM), where ET is appropriately employed to flexibly expand the variable range from [0, 1] to (-8, +8), and CM is used to overcome the randomness and fuzziness during the gradation of evaluation factors. The risk level of a specific adjacent building is assessed by the correlation with the cloud models. A confidence indicator ? is proposed to illustrate the rationality and reliability of evaluating results. Ten buildings adjacent to Wuhan Metro Line Two (WMLT) are randomly chosen among hundreds of adjacent buildings for a case study. Results have proved to be consistent with the actual situation. Compared with other traditional evaluation methods, ECM has been verified to be a more competitive solution with high calculation accuracy, wide adaptability, as well as simplified computer programming. There are no stringent requirements on the quantity of training data during the modelling process, and the original data can be directly entered into ECM without a normalization procedure, avoiding the potential information loss. ECM can be offered as a decision support tool for the risk assessment in urban tunnelling construction and worth popularizing in other similar complicated projects.

Aug 1, 2013

By Stephen Tadolini

Standing crib supports have been applied in underground mining programs to resist large roof movements and sustain high¬loads. The strength and deformation capability of these systems has been documented under both laboratory and field conditions. The parameter that has not been examined and is not well understood is the effect that a crib or other types of standing support has on the primary and secondary bolting systems. A crib support system with low system stiffness may allow large amounts of closure and deformation and cause the bolting systems to yield or even fail. Conversely, cribs or standing support that are too stiff may experience brittle or buckling failures, negating the advantage of the intrinsic supports previously installed. Utilizing a combination of field measurements and 3-dimensional finite element modeling techniques, the relationship between system stiffness and the subsequent performance of the installed bolting system is evaluated. Additionally, a simple method for calculating the combined system stiffness for standing supports, when using materials with different strengths such as steel, concrete, wood, etc., is presented.

Jan 1, 2003

By Alessandro Ibarra Mendonça

Embora a metalurgia do pó e o forjamento sejam técnicas totalmente consolidadas no mundo industrializado, surge o forjamento de sinterizados e o sinterforjamento para somar as vantagens de cada processo convencional em uma única técnica de processamento. O presente trabalho propõe a obtenção de uma peça denominada cruzeta, forjada utilizando billet sinterizado como matéria prima. O pó de ferro ASC 100,29 e o grafite UNICARBO 50- fino foram utilizados para obtenção do Billet , através da metalurgia do pó convencional, pressão de 600 MPa, a partir da curva de compressibilidade. Foi escolhida a cruzeta como peça alvo, devido a seu uso na indústria automotiva. A geometria da peça foi modelada em Solidworks e posteriormente realizado o projeto e construção das matrizes para o forjamento. Realizaram-se ensaios de compressão para determinar e analisar a densificação do produto, em função dos fechamentos de poros, do billet sinterizado. Ainda, foram realizados cálculos de volume para determinar a altura do billet necessária para o preenchimento da cavidade da geometria determinada. Confeccionaram-se billet sinterizados a 1150ºC em atmosfera redutora, mantido até 900°C e rapidamente transferida para uma matriz fechada de forjamento para a execução do processo de sinterforjamento a morno. Foram realizados ensaios metalográfico, de dureza e microdureza do billet sinterforjados para validação do processo. Após este processo, obteve-se peças sinterforjadas, onde analisou-se o preenchimento, ausência de dobra e trincas macroscópicas.

Aug 16, 2017

By T. Saastamoinen, N. Heino

"The Olserum deposit located in Sweden hosts an indicated mineral resource of 4.5 million tonnes over 0.6 % TREO, exhibiting a relatively high proportion of HREE. Beneficiation of a composite drill core sample was studied in the flowsheet of magnetic separation of magnetite followed by REE minerals flotation. Primary testwork was performed to select an effective REE mineral collector and then the parameters of grinding size, collector and depressant dosages, slurry pH and density, conditioning time and temperature, and flotation time were tested for optimization of REE flotation. The studies of process mineralogy showed that the REE-bearing minerals monazite, xenotime and apatite were successfully enriched from the concentrations of 0.6%, 0.31% and 2.6% in the feed to those of 17.0%, 8.9% and 65.0% in the concentrate with the recoveries of 79.0%, 81.3% and 71.0%, respectively. INTRODUCTION The Olserum deposit located in Sweden comprises lower grade placer material with higher grade apatite-magnetite veins and hosts an indicated mineral resource of 4.5 million tonnes at 0.6% TREO, with 34% of that being HREO (EURARE, 2017). The mineralization was studied by Andersson et al. (2018). At early stage, high-temperature REE is characterized by abundant monazite-(Ce) and xenotime-(Y) coexisting with fluorapatite and subordinate amounts of (Y,REE,U,Fe)-(Nb,Ta) oxides. During a subsequent stage, allanite-(Ce) and ferriallanite-(Ce) formed locally, partly resulting from the breakdown of primary monazite-(Ce). Alteration of allanite-(Ce) or ferriallanite-(Ce) to bastnäsite-(Ce) and minor synchysite-(Ce) at lower temperatures represents the latest stage of REE mineral formation. The mineralogy and beneficiation were firstly studied by GTK Mintec in the EURARE project for a composite drill core sample. The Olserum is considerably smaller than the Norra Kärr deposit. However, REE are hosted by xenotime and monazite, both of which have well established processing pathways, and meanwhile, the Olserum has a high contribution of the high value critical REE (dysprosium (Dy), yttrium (Y), neodymium (Nd) and terbium (Tb)), which provide a unique advantage for its exploration (Tasman Metals Ltd., 2013). In this paper, flotation of the REE minerals in the Olserum ore was studied."

Jan 1, 2018

By SM Rao

Nuclear Fuel Complex (NFC ) , Hyderabad (IN DIA ) , is engaged in the manufacture of nuclear fuel assemblies and zircaloy structural components required for the Indian nuclear power reactors. The production of zirconium oxide, sponge and zircaloy materials through chemical and hydro - metallurgical processes generates many effluents containing valuable zirconium and hafnium . This paper deals with the various processes such as multiple crystalization, phosphate precipitation, ion-exchanges amine solvent extraction etc, for the treatment of these effluents and subsequent recovery of valuable zirconium and hafnium .

Jan 1, 1992

The Wednesday morning session started with a film "The Greatest Good" presented by the Colorado Mining Association, courtesy of A. George Setter. President Joe Taylor opened the business meeting at 9:30 a.m. He called for a report from the Auditing Committee. The report was read and a motion was made for approval. It was made, seconded and approved. The report from the Resolutions Committee was submitted by Mr. Robert Delaney, Chairman of the committee. It reads as follows: RESOLVED: Whereas, in the year since the last convention of the Rocky Mountain Coal Mining Institute, the Institute and the coal mining industry generally have suffered the loss through death of the services of:

Jan 1, 1968

By Hugh Neill, O&apos

In previous papers,' the author has reported the results of experiments on the straining in tension of a single-crystal test piece, about 0.6 in. long, of vacuum-melted electrolytic iron containing 1.8 per cent. of silicon. The crystal was originally in the "as cast" condition, and was stressed slowly along a tetragonal axis so that slipping along conjugate gliding planes finally transformed the original cylindrical portion into a pair of fracture wedges. One of these fracture wedges was sectioned along the stress axis in a plane at right angles to the edge of the wedge. A metallographic study of this plane of section led to the conclusion that slip had taken place in the (111) direction along (112) planes making a V shape with the stress axis. The present paper describes the results of scratch-hardness tests conducted on the same section, in order to determine the distribution of strain hardness therein, followed by annealing, and considers the resulting variations in hardness. These observations supplement those made by Krivobok2 on similar material reduced 25 per cent. by hammering (i. e., by impact) in the cold. In order to investigate ageing effects, two small crystals of the same alloy were also tested. The Specimens Employed The principal specimen, A, was prepared for the metallographic examination leading to the determination of the slip planes of the crystal. Therefore the work described in this paper was conducted on metal which had been repeatedly etched and had been allowed to rest for about 30 months after straining. It consisted of a section of the fracture wedge and contiguous unstrained head of the test piece taken along a tetragonal axis parallel to the direction of stressing, the plane of section originally being not far removed from the (011). Several subsequent grindings

By D. Harrington

"In at least three out of every four working faces in metal mines there is no attempt made to cause air circulation other than by use of compressed air, and in at least nine cases out of ten the compressed air is released merely by opening, or partly opening, the valve and allowing the compressed air to escape through open air hose used to convey the compressed air to the drilling machines. Usually no blowers are in use during periods of drilling, as the exhaust from the drill provides cool, comparatively fresh air for the driller; however, in some instances, the compressed-air line is provided with a tea connection, which permits taking air for the drill from one side of the tee, and air for ventilation through a separate hose used as a blower, simultaneously with drilling.Table 1 contains temperature and humidity data as to compressed-air blowers from open end of air hose at 36 working places in eleven metal mines of four States, embracing the mining of gold, silver, copper, lead and zinc ores, and at horizons ranging from 500 feet below the surface to as low as 4900 feet.It is noticed that the ordinary air surrounding the worker at the face gives an average wet bulb temperature of 81.7° F. for the 36 working faces, with 84.7° F. dry bulb and 87.2 per cent relative humidity. The average wet bulb tem¬perature of 36 readings at these working faces of compressed air at the end of the,hose as the air issues from the hose was 67.4° F., or 14.3 degrees lower than the average wet bulb readings of the air of the working places; however, the average dry bulb temperature of the 36 readings of compressed air as it issued from the end of the hose was 79.7° F., or only 5 degrees less than that of the general air (84.7°); the relative humidity was 51.1 per cent as against 87.2 per cent for the surrounding air. Readings were taken in five raises, seven crosscuts, ten drifts and 14 stopes.It will be noted that the velocity or movement of the general atmosphere at each of the entire 36 working faces, was found to be practically imperceptible; this might readily be inferred since compressed air is rarely used on blowers if there is adequate circulation of the general air of the place. Where rook temperatures could be obtained readily, they are shown; it is noticeable that the dry bulb temperature of the air of the working place varies little from the rock temperature, and that the dry bulb temperature of the compressed air as it issues from end of air hose varies only a few degrees from the temperature of the surrounding rock; in some instances the dry bulb temperature of the compressed air as it issued from the end of the air hose was higher than the rock temperature or the dry bulb temperature of the surrounding air."

May 1, 1921

By G. K. Livingstone

"This paper describes mining conditions in the Kaiser surface and underground coal mines in the Sparwood area of southeastern British Columbia. Mining methods are explained, major mining equipment is listed and production rates are given. Reclamation methods and results are described. Data are given on safety organization, safety practices, accident statistics, safety inspections and absenteeism. IntroductionThe coal mines of Kaiser Resources Ltd. are located in the southeast corner of British Columbia. All present mining is in the Sparwood area, where operations began in 1900 with the opening of the Michel underground mines. Production increased rapidly at first, then went through successive periods of depression and prosperity. Following are the highlights. Quantities are in clean, short tons. 1900 1910-Rapid rise in production to a peak of 512,000 tons in 1910.1911-1924-Reduced rate of production, averaging 238,000 tons per year, due to strikes, manpower shortage during World War 1 and post-war depression.1925-1929-Second prosperous era, with production climbing to 383,000 in 1929.1930-1933-Second depression-production falling to 231,000 in 1933.1934-1942-Third era of prosperity-production recovered and new production peak of 908,000 tons reached in 1942 during World War II.1943-1956-Corttinued prosperity, with production averaging 720,000 tons per year.1957-1959-Loss of markets to oil and gas; production dropping to 517,000 tons in 1959.1959-1969-Recovery due to new coal market in Japan; production climbing back to the 900,000-ton level.197D-Present-Jump in production reaching 6.6 million tons in 1975. This was the result of the purchase of the property by Kaiser Steel, who negotiated a large-volume, long-term contract with Japan, built the coal port of Westshore, reduced shipping costs by instituting unit trains, and reduced production costs by investing in large-scale mining machinery and a new preparation plant."

Jan 1, 1980

By Rayner J. G, Leckie J. F, Moorehead C. F

The Coronation Hill gold-platinum-palladium prospect is located in the valley of the South Alligator River (latitude 13'35'S, longitude 132'36'E), about 80 kilometres east of Pine Creek in the Northern Territory. Coronation Hill was one of thirteen sites in the South Alligator Valley at which uranium was mined between 1955 and 1964 after initial discovery by the Bureau of Mineral Resources in 1953. Most of the mines were operated by United Uranium No Liability. The Sleisbeck mine 25 kilometres south of Coronation Hill was operated by North Australian Uranium Corporation and the group of mines at Rockhole about 20 kilometres to the north-west of Coronation Hill was operated by South Alligator Uranium No Liability. The uranium mine at Coronation Hill produced about 26000 tonnes of ore averaging 2.6 kg/t U308 with an estimated average gold grade of 10.4 g/ gold. Gold was commonly associated with the uranium mineralisation and was recovered at the gravity treatment plant at El Sherana. Gold was also recovered in 1986 by Pacific Gold Mines Limited by treating the tailings from the Moline and Rockhole uranium leach plants at a CIP plant at Moline. With the completion of uranium contracts in 1964 mining in the South Alligator Valley ceased. Exploration for uranium continued in the area during the 1960s and 1970s with no success. The Coronation Hill Joint Venture (BHP Gold Mines Limited 45 per cent, Pioneer Minerals (Gold) Pry Ltd 45 per cent, Notgold Limited 10 per cent)carried out the first exploration specifically targetted at gold in 1984 with the drilling of five vertical drill holes which indicated high potential for a substantial gold resource at Coronation Hill with no associated uranium. The Joint Venture has sub- sequently drilled about 25000 metres of diamond drill holes at Coronation Hill alone. Analytical results from 1985 drilling established that platinum and palladium were associated with gold. An indicated resource of 3.49Mt at 5.12g/t Au, 0.21g/t Pt and 0.56g/t Pd has been calculated using a lg/t Au cut off.

Jan 1, 1991

By Yaxiong Wang, Yong Li, Yuedong Wu, Haigang Dong, Jiachun Zhao

A roasting-leaching process has been developed for concentrating platinum group metals (PGM) from a PGM-containing ferroalloy. The optimized roasting conditions used a NaOH-to-ferroalloy mass ratio of 1.2 at 600 °C for 2 h. The roasted product mainly comprised Na4SiO4, NaFeO2 and Fe2O3. The iron oxide and sodium silicate associated with the roasted product were leached in water and dilute sulfuric acid solution, while the PGM was concentrated in the acid-leached residue. A PGM concentration of 23.4% was obtained with assaying, and the concentration factor of PGM from the ferroalloy to PGM concentration was greater than 9.

Jun 14, 2021

By A. P. Williams

"This paper presents an overview of plant electrical systems in general, a discussion of the problems that may occur due to plant growth, the maintenance required to maintain the reliability and safety of the electrical system, and the selectivity of the relay protection system. It is divided into two main areas: short circuit levels within the plant electrical system; and relay protection systems.This information is directed at maintenance supervisors, mine managers and electrical superintendents who have been away from detailed short circuit and relay coordination calculations for some time. It points out the potential problem areas within an operating plant electrical system. Short Circuit LevelsTheoryThe electrical equipment in a plant such as breakers, switches and starters has two short circuit ratings, the momentary rating and the interrupting rating. These ratings may be given in MVA or current (amperes) depending on the equipment and manufacturer's preference. Since for a three-phase system MVA and amperes are related by the formula"

Jan 1, 1987

By Leon C. Botham

?? Review of Requirements ?? Components of Modeling ?? Water Management ?? Tailings Management ?? Primarily a water management problem ?? Solids relatively easily contained ?? Process flows and runoff a continuous stream over life of mine ?? Need to allow this to safely happen over wide range of conditions

May 1, 2008