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By Thomas Boundy, PATRICK TAYLOR

Indium recovery from liquid crystal display (LCD) waste has been the subject of over 50 peer reviewed publications over the last decade; however, the first commercial recycling facilities are just beginning to be built. The low value of indium in the LCD screen material has posed a major challenge to would-be recyclers. Uncommon material combinations and geometries have further challenged development. A review of published literature regarding extraction of indium from LCDs will be presented and themes of advantageous processes will be highlighted. Barriers to rapid expansion of any recycling technology in the form of manufacturin gpractices, environmental regulations, and geographic constraints will be discussed.

Mar 1, 2018

By H. K. Lin

Deepwater discharges of sulfide flotation tailings have been practiced for several decades. Oxygen penetration and organic matter content in such environments are the two major factors that determine their reduction-oxidation condition and hence the rate of sulfide mineral dissolution under such discharge environments. In this study, the effects of solution redox potential and pH on the dissolution of some heavy metals from sulfide flotation tailings were examined. Zn, Pb and Cu concentrations in solution were all higher at a higher redox potential and lower pH. Dissolved Zn concentrations reached 100 ppm even at a low redox potential of 105 mV and near neutral pH after 33 days. Pb concentrations were below 2 ppm at 105 mV and near neutral pH after 165 days. At 105 mV, the Cu concentrations were below 0.2 ppm at near neutral pH after 165 days. At pH 2.3, the Fe concentrations were higher at 420 mV than at 105 mV. But at pH 6.8, the Fe concentrations were lower at 420 mV than at 105 mV, due to the oxidation of Fe2+ to Fe3+ and the subsequent precipitation of ferric hydroxide. Arsenic concentrations in solution were all less than 0.002 ppm. For Zn, Cu and Fe, no significant differences were observed between the tests in solutions prepared using seawater and those using distilled water. However, Pb concentrations reached higher levels in solutions prepared using seawater.

Jan 1, 2009

By R. W. Smith, D. L. Taylor, K. A. Altman

The importance of metallurgical information in reaching appropriate decisions during the development of mining projects is demonstrated. A financial analysis is calculated using a simulation that includes random number generators. The results are compared to the results of a traditional sensitivity analysis. The traditional analysis is shown to have the potential to overestimate the value of mining projects. The type of statistical distribution selected for the random number generator affects the results significantly. The statistical method of analysis provides insight into the amount of metallurgical testing to be completed and verification of how representative the samples are.

Jan 1, 2000

By S. Yerel

In a mineral processing plant, the determination of a preventive maintenance schedule is one of the most important maintenance policies. In this study, to determine the preventive maintenance schedule for the Emet Colemanite Mineral Processing Plant in Turkey, a mean quality control chart was constructed using the historical concentrate B2O3 grade data. The effect of preventive maintenance scheduling on B2O3 grades was monitored using the mean quality control chart. It was determined that recovery increased after each preventive maintenance scheduling. Close examination of the mean quality control charts indicated that there were three periods that showed different grade characteristics. These were identified as the period ?prior to preventive maintenance,? the period ?after preventive maintenance? and the period ?requiring preventive maintenance.? These periods were compared as two independent samples by using the Kolmogorov-Smirnov test. Application of this test for interpretation of the mean quality control chart enabled the authors to analyze the system effectively, and it showed that the preventive maintenance for this plant should be scheduled at four-month intervals.

Jan 1, 2007

By Lawrie D. C

Finely ground beryl was decomposed by mixing with ground limestone and soda ash and heating at 900°C for 4-6 hr. The sintered mater:al was then crushed and leached by boiling under reflux with 5N sulphuric acid for up to 4 hr. The liquor containing Be, AI, Fe and other elements as sulphates, was separated from the residue which consisted mainly of silica and gypsum, either by filtration or bydecantation washing.The clarified leach liquor was first treated to remove Fe+++ by contacting with a primary amine-kerosene solution in 2 countercurrent stages. The iron free liquor was then passed to a 4-stage counter-current extraction unit where it was contacted with O·5M di- (2 ethyl hexyl) phosphoric acid (EHPA) in kerosene. Under the operating conditions, 99 per cent of the Be and 7 per cent of the Al was extracted.The Be and Al were stripped from the organic phase by sodium hydroxide solution of suitable concentration to form soluble "beryllate" and "aluminate" respectively. Most of the Be was subsequently precipitatedas Be(OH)2 by heating the alkaline solution to 90°C, the Al remaining in solution. After filtration and washing, the Be(OH)2 could be ignited directly to BeO at about 1000°C or used as a feed to further purification stages if required.A small counter-current extraction unit was operated continuously using liquor derived from the sintering and leaching stages. Dataobtained in batch laboratory tests were confirmed. A product obtained by ignition of the washed "beryllate" precipitate contained more than 99 per cent BeO.INTRODUCTIONIn 1958 an investigation was commenced into the recovery of beryllium oxide from beryl, as part of a programme to utilize mineral resources of South Australia. A survey of the literature indicated that little work had been done on direct solvent extraction of beryllium from aqueous liquors, so it was decided to apply the experience gained in this field in uranium processing to the current problem.Preliminary extraction tests on solutions of beryllium...

Jan 1, 1965

By Everaldo Afonso Fernandes

O presente trabalho foi realizado com a finalidade de estudar o efeito dos elementos titânio (teor de 0,05%) e de níquel (teor de 0,03%) na liga Al-0,05%Cu-[0,24-0,28] %Fe-0,7%Si para fins de transmissão e distribuição de energia elétrica. Dessa forma, foi adotada uma sequência operacional a fim de caracterizar as estruturas apresentadas pelas ligas. Os processos de solidificação foram realizados via coquilha de aço (forma de “U”). Depois de solidificadas as ligas, os lingotes passaram pelos processos mecânicos de usinagem e laminação para obtenção de corpos de prova com quatro distintos diâmetros (2,7; 3,0; 3,8; 4,0) mm a fim de aproximar estes das bitolas utilizadas em indústrias de cabos elétricos. Todas as ligas foram caracterizadas macroestruturalmente analisando as estruturas brutas de fusão, eletromecanicamente por meio do ensaio de tração [?] e condutividade elétrica [%IACS]. Posteriormente, para a melhor compreensão dos resultados foram avaliados os valores de alongamento [?%] indicando que o diâmetro 3,00mm é a modificação com 0,05%Ti foram os de melhor resultados apresentados.

Aug 7, 2018

By Brian W. Stump

"Seismic waves from explosions can be used to characterize physical processes in and around the source. The quantification of absolute levels of ground motion is important for minimizing impact on nearby people and structures. We contrast work in characterizing seismic radiation from contained nuclear explosions with ground motions from multiple explosion quarry blasts. A physical basedunderstanding of the explosion source function allows prediction and extrapolation to new environments where experimental data may not exist."

Jan 1, 1990

By C. Sunderman, G. Feagan, C. Stazick

Galvanic corrosion between dissimilar materials, such as steel and graphite, leads to safety concerns for many industries, including mining. In this study, researchers from the National Institute for Occupational Safety and Health (NIOSH) analyzed rock samples from two mines in the United States that exhibit electrochemical properties similar to graphite through laboratory measurements to investigate their observed in-situ influence on underground metal support. Uniform corrosion rates of mild steel coupons, inflatable bolt coupons, and friction bolt coupons galvanically coupled to rock samples were obtained using both potentiodynamic polarization and zero resistance ammetry. Increased uniform corrosion rates were witnessed between the coupled rock and steel system, over those of just the steel alone. Surface analysis of the metal samples showed the presence of pitting corrosion, reflective of bolt samples removed from partner mines. Corrosion pitting of ground support structures in contact with graphitic rock in underground mines poses safety concerns for mine workers by increasing the rate of corrosion and decreasing bolt strength over time and will be further investigated for intervention strategies.

Feb 1, 2023

By Robert L. Lagace

The purpose of the work reported herein was to investigate whether available telephone multiplexing equipment offered a means to rapidly upgrade the traffic-handling capacity of present mine telephone systems and provide for selective calling for safer and more efficient mine operation. Common sense was used to decide whether or not an item could be termed "available." Since conventional telephone gear is not designed to interface pager phones for example, existing shelf items would require adapters to compatibly interface these two types of gear for independent operation over the present single twisted pair used in mines. These and similar small items were allowed, but if a system required any extensive design work to adapt it for the mines, we ruled it "not available."

Jan 1, 1975

By Marco Lombard, Paulus Kapolo, Christopher J. Greet

"The conversion of a concentrator from one grinding media type to another is a major undertaking in terms of both financial and technical risk. So, a strategy of completing sufficient laboratory and field tests to mitigate this risk, and give the operation confidence that advancing to plant trial will give a high probability for success.The objectives of this paper are twofold: to provide the reader with a strategy for mitigating risk prior to undertaking a plant trial; and to provide a statistical basis for analysing plant trial data. That is, when employing an electrochemically inert grinding media in the primary grinding circuit it is possible to change the pulp chemistry of the system and improve the metallurgical response of the ore.This paper tracks the changes in pulp chemistry and metallurgical performance of Rosh Pinah Zinc Corporation’s silver/lead/zinc concentrator as the primary ball mill was converted from forged steel grinding media to high chrome grinding media. The changed in metallurgical performance are correlated to the shift in pulp chemistry.INTRODUCTIONTheoryBruckard et al (2011) recently published an article describe the effect of the grinding environment on the flotation of copper sulphides. While this paper confined its discussion to copper sulphides the arguments presented apply equally to other sulphide mineral systems. Broadly, these studies indicate that most sulphide minerals are more noble than the grinding media used during comminution. Therefore, the sulphide minerals are cathodic with respect to the forged steel grinding media, and the following reactions apply:Cathode (sulphide mineral): ½O2 + H2O + 2e- ? 2OH- (1)Anode (grinding media): Fe ? Fe2+ + 2e- (2)A galvanic couple between the grinding media and the sulphide mineral(s) exists, which increases the corrosion rate of the forged steel media. The corrosion products of the grinding media, iron oxy-hydroxide species, invariably precipitate on to the surfaces of the sulphide minerals thereby affecting their floatability (Johnson, 2002).The application of more electrochemically inert grinding media to “real” ore systems at an industrial level to improve metallurgical performance has not gained universal acceptance. The aim of this paper is to provide a protocol for conducting laboratory and plant test work that clearly demonstrate that metallurgical benefits are not only possible, but measureable, by way of example. In this case, the work conducted at Rosh Pinah Zinc Corporation in Namibia is described."

Jan 1, 2013

By J. F. Barkley

During the present war emergency, under the urge of the Federal Government to store coal, the following questions are frequently asked by coal users: (a) Will the coal lose any, of its heating value in storage? (b) Will it slack and give a smaller-size coal? (c) Will its burning characteristics change in any way? (d) Will it catch fire from spontaneous combustion? (e) What precautions should be taken when coal is stored? DISCUSSION (a) Loss of Heating Value Studies by the Bureau of Mines show that the loss of heating value of coal in storage commonly has been overestimated. Various types of storage tests were made on New River, Pocahontas, Pittsburgh gas, and Sheridan (Wyo.) coals. The following is quoted from Bureau of Mines Bulletin 136, Deterioration in the Heating Value of Coal During Storage, by H. C. Porter and F. K. Ovitz (p. 8):

Jan 1, 1943

By Howard N. Eavenson

TWO months ago, just after the coal code hearing in Washington, one of our leading liberal weeklies printed a study of the coal industry made by an economist in the Administration, and on the outside cover bad it featured as "Coal-A Dying Industry." There are, of course, different opinions as to the accuracy of this characterization and I want to present some of the facts about the outlook for the bituminous industry for a short time ahead. In view of what has happened in the industry within the recent past it would be futile to attempt to make any prophecy about what is likely to occur in the future. We all know that a prophet is not without honor save in his own country, but it is likely that anyone undertaking this role about this industry would soon find himself in no man's land. One can, with some slight degree of safety perhaps, outline present conditions and tendencies and draw some inferences as to what the future may hold.

Jan 1, 1933

General recognition of the potential benefits of utilizing advanced technology has focussed public attention on the organisation of tertiary education. This has produced a situation where opportunities exist for significant changes to be implemented. The challenges to Mining education in this environment of change are analysed with respect to the setting of education objectives, the role of centres of education, course structures and student access to courses. The scope of the analysis includes formal courses for professional education and technical training, and programmes for continuing education and postgraduate research. Previous significant advances in mining technology illustrate the importance of encouraging the establishment of an extensive involvement with mining education. Education cannot be the sole responsibility of professional academic organizations; significant industry participation is essential. Methods of achieving this interaction are discussed. Major changes in techniques available for disseminating information provide a significant incentive to assess the relevance of existing course structures and restrictions on student access to courses. Establishment of a less rigidly progressive system of education is discussed with respect to the development of the full potential of computer based learning. This will expand the availability of mining education to include remote locations. The practical feasibility of such changes and recognition of the value of education as a commercial resource could also increase overseas involvement in Australian mining education. Benefits of such changes and problems that may develop if accreditation systems are not also changed to take account of new technology are outlined.

Jan 1, 1989

By B Vorster

Falls of Ground is one of the highest causes of incidents, accidents and fatal injuries in our mines today. These falls of ground may occur as soon as the face is exposed after blasting or after machine cutting. The falls of ground can also occur after support has been installed. There are many reasons why these falls occur before and after supporting of the face. It is therefore important to support the exposed face as soon as possible to prevent the falls of ground. It is also very important to support the face with the correct support products and to support the face as designed and required by the mining engineers. The possible reasons for falls of ground, possible support methods and the products available will be discussed in this presentation. In typical conventional narrow vein stoping operations, the use of conventional temporary support components to offer some support to workers, whilst the permanent and generally more elaborate support system gets installed or constructed, still results in injuries to people. The author wishes to discuss the following items in this paper:- ? Introduction ? Basic face behaviour after exposure ? Controllable Parameters ? Mining Engineers support designs ? Primary and Secondary Support ? Products available for prevention of falls of ground

Jan 1, 2008

By George Piscsalko

There are numerous methods currently available to assess the integrity of drilled shaft and ACIP piles. Each method has its advantages and limitations. This paper will compare the various available methods as well as introduce a new method for assessing integrity of drilled shafts and ACIP piles. This new method, known as Thermal Integrity Profiling, determines the integrity of the shaft both inside and outside the reinforcing cage by measuring the hydration temperature of the concrete along the length of the shaft. These temperature measurements can be made by either passing a thermal probe through a standard Cross Hole access tube, or from embedding thermal wires within the shaft. This Thermal Integrity Profile method will be described in detail and one case history will be presented. Additional testing methods which will be compared include low strain Pile Integrity Testing and Cross Hole Sonic Logging. Advantages and limitations for each method will be discussed.

Jan 1, 2011

A single aggregate mix design was developed based on a slag/Portland binder blend and crusher sand. The primary design criterion, after performance, was the fluidity of the shotcrete and concrete product to ensure compatibility with existing manufacturing and shotcrete equipment as well as the pipeline transport system Cullinan Diamond Mine was investigating. Initial work had determined an optimum slag/Portland to aggregate ratio while retaining a water to slag/Portland binder ratio of approximately 0.4 to maintain the flowability of the product. A super-plasticizer was used to further increase the flowability of the product as opposed to increasing the water content. Finally a polypropylene reinforcement fibre was included in the wet shotcrete product to improve the energy absorption characteristics of the shotcrete. Previous work on the strength development of the slag/Portland based shotcretes and concretes suggests that strength class based on the EN 206 specification is C40/50 while the toughness classification based on the EFNARC plate test is c, or greater than 1000 joules1. Typically, Cullinan Diamond Mine wanted a shotcrete with a uniaxial compressive cube strength of 45 MPa and an energy absorption, based on the EFNARC plate test, in excess of 700 joules. This is an EN 206 strength class of C36/45 requiring a uniaxial compressive core strength of 30.5 MPa and a toughness classification of b1. In addition to the shotcrete development, Cullinan Diamond Mine required concrete products with a compressive strength range of between 25 and 60 Mpa for differing construction operations underground to be manufactured from the same mix design and raw materials as for the shotcrete. Finally, Cullinan Diamond Mine carries out extensive dry shotcrete operations and an investigation into the possibility of using the single aggregate mix design for dry shotcreting was also entered into. This paper presents data that indicates that, under the terms of reference, a wet and dry shotcrete and concrete product appears to be possible from a single aggregate less than 6.7 mm in size, and that a slag/Portland binder is suitable for use as the hydraulic binder in all the products, and that the necessary performance parameters of strength and energy absorption can be achieved.

Jan 1, 2006

By R. Raghavaraju

Estimation of the dynamic stress field in terms of its amplitude and decay around a blast hole is a key input parameter in all numerical modeling and blast prediction exercises. However, there is very limited information available in literature on these critical parameters, which would be considered essential in any blast modeling exercise. A laboratory-scale experimental study has been carried out in two different rock types to study at very close range the stress wave decay from a blast hole at distances ranging from 3 to 10 borehole radii. The single–hole blasting experiments employed a centrally located detonating cord (5.3 g/m) in 6 mm(1/4 inch) and 10 mm (3/8 inch) boreholes. The coupling medium employed was air and water, in addition to using a thin-walled copper tube in intimate contact with borehole wall to prevent of penetration of explosion gases into the emerging cracks. The paper describes the nature (amplitude and decay) of the transmitted shock pressure and their evolution in the two rock types for these various experimental conditions, which are present to varying degrees in all blasting operations.

Jan 1, 2014

Study on Mineral Processing for a Cassiterite Ore in Southwest China

Sep 13, 2010

By Sibabrata Patnayak

A major problem during shovel excavation in oil sand mining is the variability of material diggability resulting in varying mechanical energy input, cycle time, energy consumption, wear, and stress loading of shovel dipper-andtooth assembly. This variability greatly influences the mining equipment performance. Different approaches such as empirical ground classification systems, analytical methods, and performance monitoring that are used to determine diggability of groundmass are reviewed. It is concluded that the existing empirical diggability classification systems are site specific and mostly based on rock and therefore, cannot be used for shovel excavation in oil sands. The O&K wedge test is a simple and useful index test for establishing correlations between cutting resistance and geotechnical properties of coal and other soft rock overburden material. But this test, when performed on small size unconfined oil sand samples, may not give reliable indication of diggability because of the boundary conditions on the specimens. Digging predictions made using analytical and laboratory digging models need to be verified with performance monitoring data to better understand the digging effort in oil sands.

Apr 1, 2005

By Paul Meadows

This Bureau of Mines report presents operating practices and results of pressure maintenance and secondary recovery by water injection or by water injection supplemented by gas injection. Particular emphasis is placed on the results of water injection, which is the principal oil-recovery method employed in projects covered by this report. No attempt is made to study gas-injection projects or operations that are considered water-disposal projects. Also, this report does not include water-injection projects that have not been in operation long enough to evaluate results. Figure 1 is a map of north Louisiana showing the geographical locations of the projects included in this report. Most of the data used in this study were supplied by unit operators, operating companies, and the Louisiana Department of Conservation. Reservoir information and recovery data are generally those supplied by the operators, but include revisions where deemed necessary.

Jan 1, 1962