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By H. Utsunomiya, J. Su, K. S. Tamimi, S. Yue, M. Sanjari, L. Kestens, Hara, A. S. Kabir, R. Petrov

Manufacturing of thin sheet is difficult in industries. Some approaches, such as small-draft multi-pass rolling, intermediate annealing, isothermal rolling and high-speed rolling were proposed to overcome the deformability. In this study, different rolling speeds from 15 to 1000 m/min were employed to twin rolled cast AZ31B magnesium alloy to different reductions. The results show thatAZ31B sheets rolled at 15 m/min and 100 °C has fractured for reductions of more than 30% per pass. However, by increasing the rolling speed to 1000 m/min the rollability was improved significantly and the material can be rolled to reductions of more than 70% per pass. The high speed and heavily deformed materials are fully recrystallized even at 100 °C.

Jan 1, 2014

By Paul Miranda, Corby Anderson

"The Center for Advanced Mineral and Metallurgical Processing (CAMP) has recently obtained a Mineral Liberation Analyzer (MLA). CAMP has utilized the technology for several projects with excellent results. The MLA is able to both analyze size and quantify mineral phases. Therefore, the MLA is becoming the Sherlock Holmes of the mining and metallurgical industry. For this presentation, four projects have been evaluated and data was collected using the MLA. The first project involved tungsten mine. Previous mining practices have yielded poor tungsten results and recoveries. By using the MLA, tungsten mineral phases, along with possible contaminants, were verified and the results used to try to increase overall tungsten recoveries. The second project evaluated a molybdenite/chalcopyrite concentrate with surprising results. The third project is a silver project. Initial flotation scoping tests were performed by attempting to separate silver from gangue material. Because of the poor recovery results (less than 5%), MLA was used to determine possible scenarios for increasing silver recovery. Finally, the last project involves gold evaluation in tailings. For all projects, MLA application results will be presentedand discussed.INTRODUCTIONThe Center for Advanced Mineral and Metallurgical Processing (CAMP) has recently received a software add-on to a scanning electron microscope (SEM) located at Montana Tech. The Mineral Liberation Analyzer (MLA) technology was developed by Dr. Ying Gu of the JKTech Center of the University of Queensland. Since August 2006, CAMP has received and processed over 50 samples. These samples include a total mineralogy of tungsten ore samples, gold tailings, lead zinc tailings pile, molybdenite concentrates, copper concentrates, as well as others. During analysis of these received samples, the technology allows the samples to be quantified mineralogically with some surprising results.For analysis, the samples were initially sieved between 170 to 200 screen sized mesh. This ensures that received samples mineral size is fairly uniform. The samples are then placed into epoxy and allowed to harden. Next, the samples are polished and carbon coated for MLA analysis."

Jan 1, 2007

By P Goblet, S A. Séguret, E Cordier, A Galli

In salar-type deposits, lithium grades can be measured by bailers introduced at different elevations in the drill holes at locations where, later, the brine will be pumped out to recover the metal. When they are duplicated, these a priori rudimentary measurements may show large differences without indicating whether this is due to the procedure itself or to some physical causes linked to the dynamic behaviour of the salar (seasonality, rainfall, underground flow etc). In the reservoir presented in the paper, the problem is complicated by the double lack of stationarity of the lithium grades: the grades not only increase importantly with the depth but at the same time their fluctuations decrease, making it necessary to use non-stationary geostatistical techniques to simulate them. Reservoir simulation is developed in two steps: first, geostatistical simulations of the lithium grade create possible realisations of the reservoir; then, each geostatistical simulation is followed by a pumping simulation that calculates, at each drill hole of a given extraction scenario, the lithium produced each year over 40 years. For the set of 100 simulations produced in this way, a scenario reduction is made to choose the five most representative simulations where more complex calculations will be carried out (for example, changing hydrogeological parameters such as porosity and permeability, or the elevation of the filters, the number and the location of the pumping and the reinjection drill holes etc). The paper first presents an analysis of the geostatistical model sensitivity to the grade uncertainty when measured by bailer. Among the 100 measurements at our disposal covering the future production domain, 50 per cent are duplicates measured at the same place but at different times. They are randomly sampled to produce five subsets of 75 values, which will constitute the future 3D conditioning points for the geostatistical analysis and the simulations. For each subset, trend, standard deviation and variogram models are fitted, leading to five sets of 20 geostatistical simulations of grades. In this way, the reliability of the different parameters involved in the procedure is evaluated, as well as its impact on the pumping results. Then, a reconciliation study is conducted between the non-stationary nugget effects encountered in the 3D variograms of the lithium grade and a pure statistical analysis of 25 duplicates measured at different locations and/or different times. The result is that if the nugget effect reaches 20 per cent, which is the case of three conditioning subsets out of five, the reconciliation is good and the nugget effect of the variogram model represents the bailer uncertainty, ie the measurement error. Since the geostatistical simulation incorporates a nugget effect, it handles the bailer uncertainty and the impact on the produced metal is included in the evaluation. The final conclusion is that, after the hydrogeological pumping simulations, the initial differences between the five geostatistical models do not influence the final results: lithium grades measured by bailers can lead to a robust evaluation of the extractable resources, a conclusion that conflicts with conventional wisdom.CITATION:Séguret, S A, Goblet, P, Cordier, E and Galli, A, 2017. Bailer uncertainty evaluation in a lithium salar deposit, in Proceedings Eighth World Conference on Sampling and Blending , pp 395–402 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

Silica reacts with cryolite at 1010°C in two stages. The first stage is the formation of a sodium aluminosilicate of composition consistent with the mineral jadeite (Na20.AI20s.4Si02). The formation proceeds by atleast two different reactions. Formation of alumina or an aluminosilicate proceeds to its limiting value in the first 30 min while the formation of jadeite proceeds at a steady rate until quantitative conversion is achieved after 150 min. The net overall reaction can be expressed by the equation 6 Si02+2 Na3AlF6? (Na20.AI20s.4Si02) +2 SiF4 +4NaF.The second stage involves a slow reaction that proceeds with the evolution of a little SiF4, The net result is the formation of sodium aluminosilicates that are soluble in 30 per cent AlCIs-HCI solutions. While this could be explained by disproportionation of jadeite to form albite (Na20.Al203.6Si02) and nepheline (Na20. AI203.2Si02), it is more likely that it is due to further but limited reaction between the oxides and fiuoroaluminates.

Jan 1, 1972

By Victor Azbe

Azbe System of Controlled Calcination To obtain good and cheap lime there are certain fundamental requirements that need to be satisfied. These are : (1) Proper combustion of fuel and steady supply of heat to the kiln. (2) Proper heat distribution in the kiln. (3) Uniform drawing of lime through the several shaft sections. (4) Complete cooling of the lime and recovery of the heat. (5) Temperature control of the hot zone by economical means. (6) Ample draft to obtain high capacity. (7) Arrangements to facilitate operation. Figure 17 shows diagrammatically one of the smaller kilns, intended for large stone. Such a kiln can be supplied with gas from a centrally located automatic gas producer, or, as shown, from an integral producer located snugly against the kiln. These producers make very good gas and have a gasification capacity of either 10 or 15 tons of coal a day. The producers have water-sealed ash pits, a rather thick fuel bed that is conducive to the making of high-CO gas, and are under forced draft. No steam is used. Clinkering is prevented by admixing some spent gas from the kiln with the air. Coal feeding is from a coal bunker through spouts into the hoppers over the producer. This is done, at proper intervals, by manual operation of slides, but it is planned to install mechanical feeders. Central mechanical gas producers have the advantage of requiring little labour, but the blowing of soot is a problem, as also is the proper distribution of the gas among several kilns. In the case of integral gas producers, soot from the centre burner is blown back into the producer to be burned, and the supply of gas to the kiln is controlled by regulation of air to the producer. In large plants, the mechanical producer may be preferable, but in small ones, the integral producer is cheaper, better, and more reliable. The kiln shown in Figure 17 is suitable for both systems of gas supply. It will be noticed that there are no side gas burners. All gas enters the kiln through the centre burner in a manner that permits any desired amount of gas to be directed to any of the kiln sections by the aid of regulating slides.

Jan 1, 1946

By Patrick J. Hannigan, Alex Ryberg, Rozbeh B. Moghaddam

Driven piles are widely used for foundation support. In the vast majority of cases, an increase in pile capacity occurs with time which is referred to as “set-up.” However, in a very limited number of cases, a decrease in capacity with time can occur. This phenomenon is referred to as “relaxation.” This paper will provide a brief review of the relaxation phenomenon, as well as pile driving information and dynamic test data on cases where relaxation has occurred. The pile types in the presented relaxation cases include H-piles, open-end and closed-end pipe piles, prestressed concrete piles, and prestressed concrete piles with H-pile stingers. The soil conditions where relaxation occurred includes dense to very dense fine sands, heavily over consolidated clays, and weak laminated rocks. Relaxation information from 36 piles at 26 sites is assessed. The collected data will assist foundation designers by identifying the subsurface conditions where relaxation has occurred, as well as by documenting the corresponding relaxation magnitude. One method of addressing relaxation when it is encountered is to drive the foundation piles to a greater end of initial driving capacity than required long-term. Hence, the identification and quantification of the relaxation magnitude will be beneficial to foundation designers installing similar pile types in similar subsurface conditions. The paper will also present pertinent observations and recommendations on mitigating relaxation when encountered. INTRODUCTION One of the earliest observations of a decrease in redriving resistance following initial driving was reported by Miller (1937). He reported that piles driven into a saturated, coarse grained soil could lose 40 to 50% of their resistance when redriven 24 hours after initial driving. Yang (1956) similarly reported that after a break in driving, a decrease in driving resistance could be encountered for piles driven in dense fine sand, inorganic silt, or stiff fissured clay. Parsons (1966) in his paper that described piling difficulties in the New York City metropolitan area termed this phenomenon “relaxation”. In this time period, pile capacity was most often evaluated from a pile driving formula frequently checked by a static load test. Hence, the true magnitude of the capacity decrease on a given pile was often poorly quantified. Furthermore, dynamic measurements that could determine what influence driving system performance variation had on the observed redriving resistance were not yet readily available.

Jan 1, 2019

By Alexsandro Berger

Many thickener operations continue to be constrained by their ability to process consolidated underflows with high yield stress and associated rheological characteristics. To maximise separation efficiencies within a thickener operation the use of both engineering and reagents are always considered. BASF is developing a Novel Flocculant Technology (NFT), which combines both of these aspects to enhance the performance of the thickener operation, improving the areas of pumping efficiency, underflow density and throughput. The development progression through stages of laboratory scale batch test work to pilot scale dynamic testing has demonstrated the ability of BASF NFT to maintain effective flocculation performance whilst increasing the rate of underflow consolidation, and significantly reducing the associated underflow yield stress of the treated material. This paper will present application data through full scale dynamic testing conducted on a granite washing circuit to demonstrate the performance benefits that NFT offers to a thickener operation. Compared to the conventional flocculant treatment, within the operation parameters and conditions employed during the full scale trials, the NFT produced a reduction in underflow rheology (yield stress) of around 45 % relative to a given solids and improved the underflow consolidation by providing at least 20% relative higher underflow solids loading than the upper limit of the given typical thickener operation. Keywords: flocculation, thickener operation, rheology, yield stress, underflow density, throughput, slump test

Sep 1, 2012

By Víctor Siña

El presente trabajo describe una alternativa de sistematización de las observaciones preventivas generadas en las áreas operativas de la minera Antamina a través del programa de Prevención de Riesgos para así reentrenar, reforzar y evitar perdidas por accidentes en cualquier tipo de industria. En ese sentido, cada miembro ya sea propio o socio estratégico de Antamina, es conciente de la prevención mediante la observación. Dicho enfoque evidencia no solo lo malo, sino también todas las consecuencias que esto conlleva. Por ello, la base de dicho programa es la detección anticipada de los actos y condiciones que nos puedan generar pérdidas.

Sep 9, 2007

By Huw Williams

It is becoming increasingly common practice to re-use existing foundations for new projects, especially on urban sites where geotechnical conditions are congested. A knowledge of the foundation dimensions and capacity is essential for this to take place, however, as-built records are often non-existent. Non-Destructive evaluation (NDE) is now becoming an important tool in assessing old foundation properties and their potential for re-use. Pile dimensions are also critical in the power industry, when they are supporting transmission towers which need to be upgraded, and may carry additional wind loading. This paper describes the application of various NDE techniques that are available and how they can be used to determine pile length, shape and capacity in difficult site conditions, including foundations under structures.

Jan 1, 2006

By J. S. Mason

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. Detailed paragenetic studies of the post-tectonic fracture-hosted vein mineralisation have demonstrated a complex paragenesis, reflecting a multi-phase combination of regional metallogenesis and tectonics through time. Previously published work regarding paragenesis and zoning was oversimplified. Two major epochs of mineralisation resulted in the emplacement of the A1 group of assemblages, from which lead, copper and silver were the main metals mined, and the A2 group, whose galena is only moderately argentiferous but which were major sources of lead and zinc. Tectonic and tentative isotopic evidence points to post-orogenic relaxation as the mechanism for development of the A1 assemblages in the early Devonian, whereas the A2 assemblages are believed to reflect Variscan extensional regimes and regional metallogenesis in the early Carboniferous and Permian

Jun 19, 1905

Modem mineral exploration and development takes place within a data-rich context underpinned by a wide range of data acquisition, processing and interpretation technologies. This leads to requirements for consistent and explicit methods by which the relative risks - or success probabilities - of exploration programs can be assessed and communicated. Bayesian risk assessment methods are outlined which provide a starting point for this more rigorous approach to exploration investment.   Effective governance of information technologies becomes a core function of the modem competitive Board. As such it becomes a component of any business audit and any assessment of the quality and success potential of a company. Limited data however suggest that the average Board may be under-represented in this increasingly critical skill area.

Jan 1, 1997

By Thomas M. Barczak, Dennis R. Dolinar, Gabriel S. Esterhuizen

Longwall mines typically use some form of standing support for secondary roof support in longwall tailgate entries. Although there have been several new support products developed for this application, there remains no universal design criteria to optimize the application of these support technologies. The requirement for optimization and proper support selection is to understand the degree of control that the support has on the ground behavior. The ground reaction curve and numerical modeling was used to evaluate the impact of standing support on ground behavior. LaModel was used to evaluate the impact of standing support on main roof and floor behavior and pillar yielding. The conclusion drawn from this study was that standing supports do not have sufficient capacity to control main roof or floor loading or prevent the resulting convergence of the tailgate entry. However, it is imperative that this “uncontrollable convergence” be considered in the support design to prevent premature failure of the support. A FLAC model was used to evaluate the near-seam roof and floor behavior in conjunction with the global vertical and horizontal stresses. The model suggests that standing roof supports can have some impact on the ground behavior as the elastic response of the rock is exceeded and rock structure deteriorates from the stress concentrations that develop around the tailgate opening. During this phase, the capacity and stiffness of the standing support can be critical to the stability of the opening, as eventually the rock mass will be transformed into a partially detached structure whose weight must be supported by the standing support. This work is part of a ground control program of research at the National Institute for Occupational Safety and Health (NIOSH) aimed at improving mine safety by reducing roof fall injuries and fatalities.

By C. Arthur Carlson

"It now becomes my privilege and duty to call to order this fifty-first meeting of the Rocky Mountain Coal Mining Institute. "I bid you a hearty welcome and I know by your attendance at these meetings you will gain a great deal of valuable information, as well as have a wonderful time. "We have been very ably represented by Mr. John H. Emrick as General Chairman, assisted by our good friend Mr. Fred W. Whiteside, our secretary and treasurer. I know they have worked very hard in selecting the various committees, who in turn - by the looks of our program have gone all out to prepare material that should be of great interest to us. I trust we will be attentive to the subjects presented and freely enter into the discussions, also relating our problems and experiences. I am sure this will prove both profitable and beneficial to all present. "The main purpose of these conventions is to become acquainted with each other, renew old acquaintances, talk over our problems, and have a little fun and relaxation from our every day routine. "Let us not forget the manufacturers, the distributors, the operators, or the press because it is through their splendid support that this organization is successful. "Since our last meeting we have gained many new members, whom we especially welcome. We are sorry to have lost a few. I am mindful, at this time, of two very good members from my home state who have passed away, Walter Wetzel, a former president of this institute, and Lee Alger, at the time of his death, Vice-President from Utah. We also lost very recently our assistant Secretary-Treasurer, Everret Davis. These men contributed a great deal to the institute and the coal industry in general. I am sure they are greatly missed by all who knew them."

Jan 1, 1955

By Michele Ashby

The mining industry is facing new risks from peak commodities, the energy and economic crisis and stock market pressures. The Green Mining Industry Initiative is a risk management strategy for the future of the mining industry. Defining the Risks The bad news is peak commodities, energy and economic crisis and stock markets collapsing are the issues that are already hitting everyone?s bottom line and draining the treasuries of every mining company around the world. Higher energy costs are affecting the bottom line more than ever before, which is creating more risk for companies. Mining companies have major land positions around the world and they have major energy needs. Uncontrollable increases in energy costs, increased regulations for diesel fuel emissions and energy intermittencies are costing mining companies more time, money, and man-power, which are cutting into profits and hitting the balance sheet. The good news is, there are practical energy solutions which are off the grid, tried and true methods which can be implemented in a cost-effective manner and will increase profitability and save shareholder values as well as energy security for these companies and their projects. To date, most of the mining resource industry has not yet considered or used other forms of power like clean, sustainable, or alternative energy for their own energy needs. The reasons have primarily been pushback from the mining industry due to beliefs of older technologies in alternative energy, a lack of understanding of the cost advantages long term, and perceptions of environmental relativity.

Jan 1, 2008

By G W. Swana

Elastoplastic parameter is a parameter that describe how much materials behave elastically up to certain stress states and plastically thereafter (Hudson and Harrison, 1997). In the continuum analysis, two main parameters of the elastoplastic parameter are modulus elasticity and Poisson’s ratio. In the slope, elastoplastic parameter holds the main role for stability related to deformation in ductile type of rock. There’s a limitation to determine elastic or plastic deformation at the field for ductile rock type. Field manifestation commonly showed that there was no accumulation zone during and after the sliding failure mechanism, in other hand, at the research area, manifestation of deformation at the toe of slope only indicated by bulging shape. This paper will focus at the sliding failure occurred at Coal mining Pit Y owned by Arutmin Indonesia, which according to failure investigation report similar with the condition described above. This paper also will be based on two hypotheses, first hypothesis is claystone rock mass has not been reached plastic deformation yet and the second hypothesis is there is a chance that elastoplastic parameter of the rock mass has been changed during the deformation/sliding failure process. Research method of this paper are back analysis using probabilistic analysis in Finite Element Method (FEM), which conducted before and after failure. Then, the result of the displacement or deformation of the analysis will be checked with the actual deformation shape. Meanwhile, the change of the elastoplastic parameter will be analysed and interpreted. This paper hopefully able to be developed to study about elastoplastic behaviour of rock mass in actual condition and the influence of another uncertainty factor which determine the slope stability.

Nov 29, 2022

By C. W. Owings

The number of major coal-mine explosions occurring annually in the United States is decreasing, due mainly to fuller recognition of explosion hazards in coal mines and knowledge of methods to prevent them, which can be attributed largely to the dissemination of information by the United States Bureau of Mines, State departments of mines, and other coal-mining agencies. Conditions vary considerably from one coal field to another; consequently, outstanding causes of and methods of combatting explosions vary, also. The Safety Division of the United States Bureau of Mines is making a critical study of coal-mine explosions in the various coal-mining States, and an analysis of the results is published as each study is finished. It is believed that, with completion of the series enough information will be at hand which, if applied, will prevent all coal-mine explosions. ACKNOWLEDGMENTS The data in this circular are based on records of the United States Bureau of Mines and the Industrial Commission of Ohio. The cooperation and assistance of T. P. Kearns, superintendent of the Division of Safety and Hygiene of the Industrial Commission of Ohio, and of James Berry, chief inspector of the Division of Mines of Ohio, is acknowledged.

Jan 1, 1937

By Gus Pantages, Bernard D. Blaustein, Charles Zahn, Irving Wender

Oils from coal hydrogenation have been examined at the Bureau of Mines to learn whether any centers of the optical activity reported in coal would survive catalytic hydrogenation at 450-525 ° C and about 8,000 psig pressure , and , if so , to obtain information about the nature of the active products . Oils from carbonization tars also were examined . Optical activity was found in the majority of the distillate fractions of the hydrogenation oils and in almost all distillates from the carbonization tars . No activity was observed in the tar - acid and tar - base fractions examined . Methods for isolating optically active concentrates included distillation through a packed column , liquid chromatography on silica gel , and adduction with urea . For the materials so processed , the optical activity segregated mainly in the paraffin - naphthenic and the hydroaromatic fractions . Although the specific compounds responsible for the optical activity were not isolated , experimental and spectrometric findings indicate that alkylsubstituted cycloalkane , cycloalkene , and hydroaromatic structures are most likely responsible for the optical activity of the concentrates . The optically active centers probably derived mainly from the steroids and terpenes in the biological materials that participated in the formation of coal .

Jan 1, 1964

Jan 1, 1959

By Ewan Selers, Gary Cavanough

Drilling automation technology is well advanced and automated drill rigs are in use at a number of operating mines. This is not the case for the other drill and blast processes due to significant technical challenges to overcome. These challenges, with regard to the current “on bench” practices, include placing the initiators, loading the explosive and connecting up the initiation system. Although difficult, these challenges will be solved with engineering advances.

Jan 1, 2016

By Paul S. Goodman

Volume I This report presents the first national survey of miners' attitudes and opinions about their-work. The goal is to present attitudinal data that bears on coal production. Interviews were conducted in 26 mines with 2,000 miners. High levels of cooperation were exhibited by management, union and the employees. Data are presented about miners' attitudes about general aspects of their work such as pay, supervision, their jobs, etc. Another section of this report reviews opinions about specific aspects of work performance. Recommendations are presented.

Jan 1, 1985