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By Heath E, van Calsteren P, Turner S, McDermott F

U-Th isotope studies of recent volcanic rocks may be used to evaluate the depths and rates of melt generation beneath mid- ocean ridges and ocean islands. Island arc rocks exhibit a similar range in Th isotopes to that seen in both MORB and OIB, but while those with high (230Th/232Th) tend to have excess 238U, many of those with low (230Th/232Th) are in isotope equilibrium. The excess 238U is attributed to the preferential mobilisation of U in hydrous fluids from the subducted slab within the last 100,000 years, whereas the low Th isotope ratios in the higher-K arcs are primarily due to the introduction of subducted sediment. Preliminary results from mineral separates from lavas on Soufriere on the island of St. Vincent indicate that some of the minerals crystallised up to 50,000 years prior to eruption.

Jan 1, 1995

By Zhijing Zhang

A thermodynamic structure model for alkali borate melts is developed to describe the distribution of structural groups in the alkali borate melts as a function of compositions. Fractions of threefold coordinated boron atoms and fourfold coordinated boron atoms in the potassium borate melt are calculated for the entire composition range and compared with results reported in the literature. The model has been used for structural interpretation for the borate anomaly in viscosity, which regards the borate anomaly as a manifestation of the various antithetical effects caused by the introduction of alkali oxide into boric oxide. It has been found that the viscosities of alkali borate melts increase or decrease according to the changes in rigidity and spatial connectivity of the glass network structure, which is a function of temperature and composition.

Jan 1, 2001

"Conveyed coal flows have been diverted on the basis of real time ash analysis since the 1980s. Many coarse particle separation methods are available through screens, jigs, heavy media separation, particle sorters, to name a few, however bulk diversion requires a representative, continuous analysis to ensure diversion decisions can be made with confidence. Sensors also need to be able to provide measurements at useful time increments so that small tonnages can be diverted for maximum selectivity. Particle separation typically requires high capital costs and there are limitations either in throughput tonnage or particle size or both. Few techniques are able to provide robust and representative analysis of conveyed flows in a useful time basis. Prompt Gamma Neutron Activation Analysis provides multi-elemental analysis of conveyed bulk materials and has been proven in the minerals industry since 2003. This paper outlines the success of this technology in minerals applications in iron ore, phosphate rock and most recently in copper-gold ores, including its use in bulk diversion.INTRODUCTION Naturally occurring quality variability, or heterogeneity, in mineral deposits enables separation and recovery of the valuable components through mining and processing operations. There are distinct advantages in processing the minimum quantity of material to achieve the highest possible yield. Unfortunately, declining ore grades has resulted in larger scale operations and a subsequent loss in selectivity for mining operations. As limits are approached on the practical size of equipment, there is more motivation to investigate alternative solutions. Mining companies are subject to increasing social resistance to growing waste disposal requirements in addition to higher energy and transport costs. Major savings are available by reducing the quantities of material processed where pre-concentration can be effectively applied at early stages in the process. One of the simplest ways to pre-concentrate is to measure the bulk material and reject waste soon after mining so that minimal expense is incurred and that only higher quality material is sent to processing operations. This bulk sorting can occur within the mining operations and has major benefits through energy and other consumables savings. This paper discusses the application of real time analysis technologies suitable for bulk sorting within the minerals industry. Technology that has proven representative for conveyed material bulk analysis and its successful applications to date is explained. Analysis using a sensing technique is only one component of a successful bulk sorting process; the importance of effective diversion systems and a bulk sorting strategy are also discussed. The bulk sorting stage may be one component of a system that could include additional downstream technologies such as particle based sorting systems on a diverted stream."

Jan 1, 2018

By D Mather, H R. Asche

"In the civil tunnelling field, the use of tunnel boring machines (TBM) has now overtaken the use of conventional excavation methods (drill and blast / roadheader). This is due to a number of reasons, including the increasing availability and reliability of TBMs, the ability to deal with a wider range of face conditions, and the reduced excavation cost that TBMs can bring.Mining companies have spearheaded the advances in shaft boring by mechanised means, both in blind and raise boring. However, mining companies have been slower to adopt mechanised tunnelling.When contrasted with a conventional mining contract, there are good reasons why TBMs in mining applications are relatively rare. A conventional decline contract may have very little geotechnical information. The decline alignment can be subject to change as the tunnelling progresses. The infrastructure requirements are less for a conventional decline, and the sunk cost prior to excavation commencing is lower. Contract documents can be very simple.The history of TBM use in mining is reviewed and lessons are described. From the case histories and lessons learnt, the paper identifies ways that mining companies can maximise the potential benefit of TBM technology.We believe that despite the additional requirements for TBM declines, the cost and time advantage to mining companies is very attractive. The challenge is to recognise and to meet the requirements for success in a TBM drive to achieve the advantages of: faster advance rates reduced rock damage/overbreak reduced support requirements uniform muck characteristics greater personnel safety.From the case histories and lessons learnt, the paper identifies ways that mining companies can maximise the potential benefit of TBM technology.CITATION:Asche, H R and Mather, D, 2014. Use of ?tunnel boring machines in the mine environment, in Proceedings 15th Australasian Tunnelling Conference 2014, pp 655–662 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 17, 2014

Aamot, Olav Crone, Chem. Engr., Norsk Elektrokemisk, Kongensgt. 18, Oslo, Norway. '29 Abbott, Clarence E., V.P., Charge of Raw Materials, Tennessee Coal, Iron & R. R. Co., 1242 Brown-Marx Bldg., Birmingham, Ala. '04 Abel, Raymond L., Prof., Dept. of Pet. Refin., Univ. of Pittsburgh ..Pittsburgh, Pa. '28 Abel, Walter D., Cons. Engr 364 S. Cloverdale Ave., Los Angeles, Calif. '32 Abele, Louis T R.F.D. 1, Adamsville, Ohio. '31 Abell, Leo M., Ore Dressing Investigator, School of Mines Adelaide, S. Australia. '31 Abenius, Hakan V., Mine Supt., Bolidens Gruvaktiebolag Boliden, Sweden. '37 Aborn, Robert H., Asst. Met., Research Lab., U. S. Steel Corp., Lincoln Highway, Kearny, N. J. '19 Abraham, W. E. V., East India United Service Club, 16 St. James' Sq., London, S.W. 1,, England. '28

Jan 1, 1937

By C. G. McLachlan

INTRODUCTION The work described in the following paper was under-taken with a view to determining, if possible, the relative importance of some of the phenomena on which flotation seems to depend, in the hope that, if this information could be obtained, it would be of value in dealing with the problem as a whole. At the outset, brief reference will be made to three papers which had a considerable bearing on the course followed in the present investigation. In 1919, Langmuir, in a paper on 'The Mechanism of the Surface Phenomena of Flotation', showed that mono-molecular films of very great stability could be produced on solid surfaces with oleic acid, but that pure paraffin oil, though spreading readily on a dean dry surface, was easily displaced by water.

Jan 1, 1926

By Jheison Lopes dos Santos

Neste trabalho, pela primeira vez, o sistema cerâmico Al2O3-Nb2O5-LiF teve suas propriedades mecânicas investigadas. Foram investigadas diferentes composições, em peso, para o composto (Al2O3–4%Nb2O5)–nLiF, com n variando entre 0 e 1,50%, a três temperaturas de sinterização diferentes (1300, 1350 e 1400 ºC). Como caracterização mecânica, avaliou-se a microdureza Vickers para todas as composições. A adição de LiF que apresentou os maiores valores de densificação teve seus módulos de Young e de cisalhamento, e as velocidades de ondas elásticas determinadas. Os resultados mostraram que todas as adições de LiF elevaram a microdureza do composto Al2O3–4%Nb2O5. Este fato pode estar relacionado com a densificação e fases obtidas após a sinterização. A adição de 0,5% de LiF ao composto cerâmico Al2O3-4% Nb2O5, promovendo maior densificação, quando sinterizado a 1300 ºC obteve valores de propriedades elásticas comparáveis aos obtidos por Al2O3–4%Nb2O5 sem LiF, sinterizado a 1400 ºC. Os resultados relevaram ainda uma coerente correlação entre dureza, módulo de elasticidade e densificação. Dessa forma, a adição de fluoreto de lítio ao sistema cerâmico alumina-nióbia possibilitou a redução em pelo menos 100 ºC na temperatura de sinterização, com propriedades mecânicas comparáveis.

Oct 30, 2017

By A. D. Garman

This paper presents one of a series of digests of foreign mining legislation and court decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the laws of Japan has been prepared from the best available information in Washington but is released subject to correction and amplification , if necessary , by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State . It is based on the law and regulations of 1905 as revised in December , 1915 , and translated by J. de Becker , LL.B. Occasional words and phrases quoted herein are accordingly taken from this translation and have not been checked against the original . The references are to the law ( as distinguished from the regulations ) unless otherwise stated .

Jul 1, 1930

By Brandt Porter, Lawrence K. Nordell, Alexander Potapor

"Improving comminution efficiencies with better machine geometries and motions, improved nip angles, rock movement control, and voids regulation among rocks are some of the next steps to better machine performance. Recent gains (~30%) using high pressure grinding rolls (HPGRS) and vertical roller mills, in theory and practice, are based on Prof. Klaus Schönert’s academic studies (1979–1996) on rock breakage physics. More recently, University of British Columbia Prof. Bern Klein’s studies (2006–present) via the Ph.D. thesis of Z. Davaanyam (2015) further validate theory with practice from laboratory measurements used in this paper.They demonstrated ideal rock compression breakage, within HPGR and vertical roller mill machines using a piston-die apparatus. Similar rock size range is used. The piston-die confine rock breakage behavior. However, these studies do not extend to larger rocks (> 75 mm), and do not demonstrate the influence of rock voids among bifurcation of rocks during comminution. Further, machines fed with larger rock sizes, such as gyratory, jaw, and cone crushers, are not designed or evaluated for geometry nip angle efficiency.Herein we illustrate a performance gain of a new comminution machine, the conjugate anvil-hammer mill (CAHM), first presented at SAG 2011 (Nordell, 2012). The CAHM machine digests rock sizes 400% larger than HPGR, improves rock grip/nip geometry, better improves rock voids, improves surface wear life > 500%, and improves rock containment and slippage during compression. In all, the CAHM machine shows 22 potential improvements over the HPGR. Most importantly, CAHM shows a 50% kWh/ton improvement compared to the HPGR. Our studies use an advanced Discrete Element Method (DEM) computer program called ROCKY. ROCKY simulates moving boundaries, surface wear mechanics, and incorporates rock breakage physics based on the fundamentals of JKMRC T10 protocol [×] with tuned A × b breakage parameters.We calibrate rock breakage in our DEM code to mimicking both UBC laboratory piston-die and HPGR comminution measurements. We then model CAHM with these known ore and machine properties. Differences are illustrated using DEM techniques on each machine, including key points of when each: use geometry; initiate bifurcation breakage; provide a map of particle size distribution by location; illustrate the importance of controlling voids to minimize agglomeration after breakage; machine performance limits; and kWh/ton benefit."

Jan 1, 2016

Firedamp drainage has become an essential part of many mine environmental systems, and new applications are arising. Installations are evolving further to satisfy ever changing basic requirements, standards, and iniilny needs. In this paper, water seal, vacuum based installations are considered, as well as moni- toring, protective and control systems which have been developed for continuous, manless, and trouble free operation. Some factors affecting plant capacity and extractor per- formance are identified and assessed. INTRODUCTION Firedamp drainage applications are incr- easing world wide as mining engineers strive for improved safety and security, and further concentration of coal output. Fewer and fewer mines are able nowadays to satisfy coal prod- uction and firedamp control requirements solely by air dilution or by air dilution and underground firedamp extraction plants. As a result, dependence on surface extraction plants is increasing. This paper deals with som requirements and applications of such installations. I. DEVELOPMENT AND PRACTICE Firedamp drainage has existed for over 250 years following the early work of Carlisle Spedding at Whitehaven (1730). Some fundamentals of current firedamp drainage systems can be recognised in the

Jan 1, 1982

By D Baas, D Bennett

This paper describes how Brisbane-based PanAust Limited develops process control strategies that are implemented at all operations and are used in functional descriptions for plant upgrades and new projects.The process control strategies are determined by operating management philosophies designed to maximise returns from the company’s assets.The approach is endorsed in the project planning and design phases to ensure facilities and equipment that form the major production assets are fit for purpose and capable of enabling the production managers and operators of the projects to maximise shareholder returns.PanAust’s process control approach has been to develop sets of process control standards which focus on two key areas. The first area covers hardware requirements and architecture, software objectives, control models and individual loop tuning methods. The second area defines control room layout, graphic standards and the alarm philosophy. The application of these standards in a new plant or upgrade decreases the time required to achieve design capacity and optimal performance.The PanAust process control strategy changes the operator’s role from one that controls a number of individual loops to one that sets the control objectives of the processing plant. To achieve optimal performance, all the process areas of the plant are analysed to identify opportunities to improve throughput, recovery and stability. Once a key opportunity is identified, a process control strategy is developed which defines the objective of the control, its functionality and how an operator will interact with it. After development of the control model the operators assist engineers to test and debug it. Once the model is robust, it can then be duplicated throughout the group and developed as a group process control standard.CITATION:Baas, D, Bennett, D and Walker, P, 2014. Developing process control standards for optimal plant performance at PanAust Limited, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 325–334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By Franciele de Almeida Silva

A escória utilizada no refino secundário deve possuir propriedades adequadas para que auxilie no controle inclusionário dos aços. Tendo isto em vista, há vários parâmetros que devem ser levados em conta para se obter uma escória ótima que irá auxiliar na limpeza dos aços. Como uma técnica de medição, o valor de oxigênio total no banho está diretamente relacionado com o número de inclusões óxidas presentes no aço líquido. O presente trabalho tem como objetivo geral o acompanhamento da limpeza inclusionária por meio dos teores de oxigênio total presentes nos aços, para variáveis selecionadas de escória e de processo. A partir das análises químicas de amostras de um aço alto carbono acalmado ao alumínio, foram gerados gráficos com os valores de oxigênio total em função dos parâmetros %CaO/%Al2O3, %FeO+%MnO, basicidade binária, tempo de flotação na torre do lingotamento contínuo e pick-up de nitrogênio; seguido da análise dos resultados obtidos e sua comparação com os dados da literatura. Pode-se então concluir que, para as análises anteriormente citadas, o aço apresentou resultados coerentes com a literatura para todas as análises.

Aug 8, 2018

By Roy L. Soderberg

Ground support for metal, nonmetal, and coal mines was examined through fill placement with a pneumatic stower to increase extraction, reduce ground pressures, and improve general mine safety. Several pneumatically stowed stope-fill products were tested to determine the effects of specific gravity, gradation, moisture, and impact velocity on the in-place density of the stowed fill. Hydraulic sand filling has now served the mining industry for several decades but because of the low density does not always provide ample support to the hanging wall; therefore, the sill and crown pillars sometimes build up excessive stresses that are detrimental to mining. Cementation of a dense fill adjacent to a pillar to allow 100-pct extraction of the pillar, or a fill that can be placed without the use of water and where water is a detriment to rubber-tired mining equipment, was found to be a possible use of pneumatic fill. Placing of coal mine washery products into abandoned underground workings is another possibility in order to completely eliminate surface impoundments.

Jan 1, 1976

By L. L. Oden

The U.S. Bureau of Mines and the Department of Energy (DOE), through its contractor EG&G Idaho Inc., are collaborating on a multiyear research project to evaluate the applicability of three-phase, electric arc furnace melting technology to vitrify materials simulating low-level radioactive and mixed wastes buried or stored at the Idaho National Engineering Laboratory and other DOE sites. The melter is a sealed, 1-t (1.1-st), three-phase, 800-kV?A electric arc melting furnace with 10.2-cm-(4-in?) diameter graphite electrodes, water-cooled roof and sidewalls, and four water-cooled feed tubes. A water-cooled copper fixture provides for continuous tapping of slag. An instrumented air pollution control system (APCS) with access ports for analysis and a feeder based on screw conveyors and a bucket elevator are dedicated to the facility. Test data are provided by an arc furnace analyzer and by sensors indicating feed rate; slag temperature; and temperature, pressure, and velocity in the APCS. These data are received by a data logger, digitized, and transmitted to a personal computer for storage and display. This unique waste treatment facility is available for public and private use on a cost-sharing basis.

Jan 1, 2010

By Dave Thomas

?Uranium is a common trace metal at the earth?s surface, but these are amazing super-high grade (up to 25%) pods, veins and disseminated uraninite (UO2) near unconformities between Proterozoic siliciclastic red beds and metamorphic basement with graphitic metapelite and radiogenic granite. ?Pitchblende fills extensional features in reactivated fault zones and replaces matrix in sandstone ?One mining district in Canada ?the Athabasca Basin ->30 deposits /prospects -most in eastern ¼of basin -produces 1/3 of world?s U -employs northerners -VERY high tech -VERY high safety standards Unconformity-associated uranium depositsUnconformity-deposits

May 1, 2006

By P. A. Crane, N. Shirley, Aung Moe, H. M. Nicholson, D. Kan

Kazakhstan’s first commercial copper-leach solvent extraction-electrowinning plant, Central Asia Metals’ Kounrad project, was commissioned in April 2012. Exploiting low grade waste stockpiles produced during Soviet era open pit mining, a 10,000 tpa copper cathode plant was designed, constructed and commissioned within 18 months. Overcoming initial challenges with a workforce unfamiliar with the technology and with extensive periods of sub-zero conditions during winter the project has consistently met targets and produced high quality copper cathodes at cash costs of less than US$1/lb. Challenges encountered during the first two years of operation are described and future plans briefly discussed.

Jan 1, 2014

By Hill KC, Foster DA

Methods for ore reserve estimation are classified. The amount of information needed to asses ore reserves is analysed. Reference is made to gold sampling. Consideration is given to nugget effects and ore reserve estimation procedures where they are significant. Computer methods are discussed

Jan 1, 1997

By B. R. Mohal, F. F. Aplan, S. Chander

"The wetting behavior of coal has been determined in the presence of nonyl and octyl series of nonionic surfactants containing polyethoxy groups of different sizes. The wetting behavior was determined by a modified Walker technique and contact angle measurements. The results show that the wetting rate of coal varies with coal rank, structure of the hydrocarbon chain and number of ethoxy groups in the hydrophilic group of the surfactant. A close relationship has been observed between the wetting rates and the short-time advancing contact angles.INTRODUCTIONNonionic surfactants are used in many applications to improve wettability of solids. They can be used as dispersing agents [ 1 ] or dust suppressants [ 2-5] and to control the flotation, flocculation, filtration and flowability of particulates. This study was undertaken to study the effect of a series of nonionic surfactants on the wetting behavior of coal. Two series of surfactants, namely, ethoxylated nonyl and octyl phenols were used. The nonyl phenol series contains a linear hydrocarbon chain containing nine carbon atoms ( CH3 ( CH2 ) 8-C6H4-( OC2H4 )""' where n is the number of ethoxy groups). The octyl phenol series contains a branched hydrocarbon chain containing eight carbon atoms ( ( CH3 ) 3CCH2C ( CH3 ) 2-C6H4-( OC2H4)"").Initial wetting rates - modified Walker techniqueWalker et al. [ 6] developed a sink test to determine the wettability of coal particles. In this technique, coal particles are dropped individually onto the surface of surfactant solutions of different concentrations, and the most dilute concentration in which coal would sink ""instantaneously"" is determined. This technique is a variation of a procedure initially developed by Draves and Clarkson [ 7] to determine the effect of surfactants on wettability of cotton fibers."

Jan 1, 1989

By Bernard G, Limpach R, Ulveling L

A major aspect in competitive ironmaking is to replace metallurgical coke by injecting alternative cheap fuels. Whereas in the past, heavy oil injection as well as on a lower scale natural gas injection have proved to be reliable, the progressing high price level of these fuels has prompted international interest in looking for alternative cheaper fuels, especially pulverized coal. Theoretical analysis and practical operations showed that for constant adiabatic flame temperature, potentially more coke may be replaced by injected coal than by heavy oil, because of less endothermic cracking of hydrogen components. Since about 1974, the ARBED-Group has been looking for alternative fuels and in 1976 came to conclusion to select for first trials pulverized lignite for the following reasons:

Jan 1, 1981

By M. Kanda, W. D. Bensema, J. W. Adams

Two different techniques were used to make measurements of the absolute value of electromagnetic noise in and above an operating coal mine, McElroy Mine, located near Moundsville, Nest Virginia. The electromagnetic environment created by 300 volt dc and 480 volt ac machinery was measured. In one technique noise was measured over the entire electromagnetic spectrum of interest for brief time periods. The noise was recorded using broadband analog magnetic tape. The noise data was later transformed to give spectral plots. In the other technique, noise amplitudes were recorded at several discrete frequencies for a sufficient length of time to provide amplitude probability distributions. The specific, measured results are given in a number of spectral plots and amplitude probability distribution plots.

Jan 6, 1974