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By T. Wang, R. G. Reddy

"A new eutectic of LiNO3-NaNO3-KNO3 ternary system was calculated by using thermodynamic modeling and the eutectic temperature was predicted to be 389.15K. The melting point was determined using Differential Scanning Calorimetry (DSC). On repeated measurements, it was found that the melting point of the eutectic composition showed excellent reproducibility with the predicted value. The heat capacity was also measured using DSC and the data as function of temperature were fit to polynomial functions. Subsequently, the thermodynamic properties such as enthalpy, entropy and Gibbs energies of this novel ternary eutectic salt mixture were deduced as function of temperature.IntroductionIn these days, the provision of the large amount of energy required in the peak period relies more and more on the parabolic trough solar power plant and it works by utilizing the thermal transfer fluid. Consequently, the development of inoovative thermal transfer fluid with higher energy storage density is paramount to lower the expense for generating energy [1-4]."

Jan 1, 2013

The probability of detachment of quartz particles from air bubbles during bubble oscillations was investigated by means of a vibration method. Theoretical calculations of the detachment force based on the work of Nutt and Schulze for a single spherical particle show a correlation with the experimental results described. However, the forces that were determined experimentally were considerably lower than the theoretically derived values. Some of the factors which were expected to affect the probability of detachment, such as particle size, bubble size, collector concentration and vibrational acceleration, were also investigated

Dec 1, 1991

By Dajian Wang

To obtain the thermodynamic properties of a multicomponent liquid alloy system over the whole range of concentration at an arbitrary temperature, the free volume cell theory has been applied to derive the formula of activity coefficients of liquid solutions based on the infinitely dilute solutions at some temperature. The linear logarithmic relationship between activity coefficients of binary dilute solutions and reciprocal of absolute temperature have been verified, and are in good agreement with the experimental values from the literature. The Monte-Carlo algorithm was used to calculate the nonlinear end value equations of binary systems, then the free volume parameters obtained were correlated with the activity coefficients of liquid binary, ternary, and quaternary systems at an arbitrary temperature. Three dimensional a-X-T diagrams of some binary systems representing the temperature and concentration dependence of activities were plotted. The calculated results regarding non-ferrous alloy systems have been statistically examined with the experimental values from the literature. Hence, this simple approach could be useful for analyzing thermodynamic properties of liquid alloy systems.

Jan 1, 2000

By Gary L. Hundley

The Bureau of Mines has devised and demonstrated a process for recovering Ni and Co from low-grade domestic laterites. The process consists of four major steps: (1) reduction roast, (2) ammoniacal leach, (3) solvent extraction, and (4) electrowinning. Several solid-liquid separation steps are required that affect the economics of the overall pro-cess. In this study, two techniques for solid-liquid separation, centrifugation and thickening, were investigated. This report presents the results of (1) laboratory and pilot plant studies to determine parameters for sizing centrifuges and thickeners and (2) an economic study of the two techniques, based on the requirements of a commercial-size (5,OOO-tpd) laterite processing plant. Sizing and other equipment-related recommendations, based on data from the Bureau's studies, were obtained from commercial manufacturers. The costs of thickening and centrifugation, including all the unit operations affected, were determined by the Bureau's process evaluation group. The total operating costs ~or separation using the two techniques (including depreciation on the capital cost of equipment) were found to be quite close: $17.26 per ton of laterite for centrifugation and $18.15 per ton of laterite for thickening. For centrifugal separation, the greatest cost was found to be the initial capital cost for the separation equipment; using thickeners, the greatest cost was for re-agent recovery.

Jan 1, 1984

By Kunihiko Takeda, Kimio Imaizumi, Tsuyoshi Arai

"The study on the preparation of mono-dispersed liquid droplet was performed using ultrasonic as one of the steps of producing the perfectly mono-dispersed particle. The ultrasonic system was a 33.6kHz ultrasonic generator, an amplifier, an electric distortion element, and a bolted Langevin type horn installed in .a cell. For the first time, a liquid pillar under a nozzle of the cell ·was stably formed. Then, dense and coarse parts were alternatively constructed by oscillating the wavelength of the ultrasonic.· The diameter of those liquid droplets were found to be· perfectly uniform, therefore, it was measured by ""multiplex photography"" using a synchronized stroboscope with the ultrasonic.- From the results, more than 30,000 of perfectly uniform liquid droplets in 1 second were observed by this method.IntroductionRecently, research on the control of physical form is done in various fields of industry. Some examples are the processing technology of the minute compound material of micro-machines and integrated circuits, and the form control of molecule size like catalysts. There is a need for such material to take on various forms in correspondence to its use. ""Form control"" as used in this study will indicate ""research on physical chemistry factors which determine the size of the material"" and will refer to the contour uniformity of comparatively little particles. A well-known method of preparing particles is to spout a mist of liquid and slurry from a nozzle l) 2). Particles for metals, catalysts and food have been prepared by this method. In this case, although an approximate particle diameter can be decided by controlling the nozzle diameter and the violent outflow velocity, it is not easy to completely control ·the contour and to prepare a particle with uniform diameter. ·However, the preparation of perfectly uniform particles is necessary for solders for the adhesion of electronic wiring 3), ion exchange resins4), catalysts and so on. Large quantities of fine particles and super-fine particles are generated when manufactured in the usual way. Large quantities of these fine· particles and super-fine particles have polluted the internal and external' environments of factories. The products yield' ·decreases, also. From such a background, this study examines the preparation of perfectly uniform particles that could be· collected -100% as products. Recently, NASA has succeeded in the preparation of perfectly uniform particles in zero gravity 5). But the preparation of 'perfectly uniform particles by this method is difficult, and it can not be used in general industry"

Jan 1, 2000

By Ghislain Bournival, Seher Ata, Yesenia Saavedra Moreno

"In froth flotation, frothers are commonly added to the pulp to modify the interfacial properties of bubbles. These properties may be modelled using commercial software packages. The volume of fluid (VOF) method was used to track the interface motion during the post-rupture oscillation of the newly formed bubble. The aim of this research was to provide an insight into the modelling of viscoelastic phenomena through the coalescence dynamics of two bubbles in solutions of various surface tensions using a three-dimensional computational study. Different surface tensions were used to simulate changes in methyl isobutyl carbinol (MIBC) concentration. The computational results were evaluated by comparing the oscillatory motion of the newly formed bubble for the different MIBC concentrations. For known MIBC concentrations, the deviations of the computational damping constants from the experiments were quantified, revealing possible deviations in the VOF surface tension model. In addition, the analysis provided insight into the flow patterns of the fluids and the effect of frother concentration on the velocity magnitude in the liquid and air phases. This analysis provided a further understanding of coalescence dynamic and post-rupture oscillation in froth flotation. Such a process is believed to affect the stability of particles at the interface due to the release of surface energy when the bubble surface is reduced.INTRODUCTIONIn froth flotation, bubble coalescence is an important phenomenon that is highly dependent on the interfacial properties of the liquid film between bubbles. It is known that the frother adsorption at the liquid-air interface changes the interfacial properties, resulting in an increase of surface elasticity and reduction of surface energy (Pugh, 2016). However, in a two-phase system, it is the frother type, concentration, frother molecule conformation at the interface and viscoelasticity properties that dictate film stability (Pugh, 2016). The viscoelasticity phenomena can be explained in terms of surface viscosity, which quantifies the energy dissipation at the interface and surface elasticity that represents the energy absorbed at the interface as result of bubble oscillation (Pugh, 2016). In the case of systems stabilized by nonionic frothers, it has been shown that surface forces alone do not account for film stability, but the viscoelasticity represents the ability to damp external disturbances in the thin film separating the bubbles and prevent coalescence (Santini et al., 2007)."

Jan 1, 2018

By Helio Wiebeck, Vijay Rangari, Julyana Santana, Francisco Valenzuela-Díaz, Esperidiana Moura, Marcus Vinicius de S. Seixas

Closed-cell polyethylene (PE) foams have been extensively used in many applications such as packaging, transportation, sports, construction, and agriculture because of their variety of properties including light weight, chemical resistance, thermal and electrical insulation. The objective of this study is to evaluate the influence of electron-beamirradiation on the properties of LDPE/EPDMblend foams. The LDPE/EPDM blend (80/20 wt%) were prepared by melt extrusion, using a twin-screw extruder machine. The foam structure of LDPE/EPDM blends was obtained by melt extrusion process, using a special single screw for foaming with 1.5 wt% of foaming agent as blowing agent. The foam samples were irradiated by electron-beamat radiation dose of 25, 50, 75 and 100 kGy and submitted to heating in an oven at 100 °C. The specimen tests samples of irradiated and non-irradiated foams were submitted to mechanical tests, DSC, TG analysis and density measurement.

Mar 1, 2018

By E. Morrice

Techniques developed by the Bureau of Mines for the preparation of high-purity rare-earth metals and their alloys by electrolysis of the oxides in fluoride media are summarized. Cerium, lanthanum, neodymium, praseodymium, dysprosium, gadolinium, and yttrium metals, the mixture didymium, and specific alloys of these metals and samarium with iron, nickel, chromium, and cobalt were prepared. Individual metals were electrodeposited in the liquid state on tungsten or molybdenum cathodes. Alloys were prepared by electrodepositing the rare-earth metal on a consumable cathode, at a temperature above the melting point of the eutectic formed between the rare-earth element and the cathode material. Cells were designed for electrowinning metal products in gram and pound quantities, and methods for continuous electrowinning of cerium and lanthanum were developed.

Jan 1, 1968

By N. Novikov, M. Jastrzebski, N. Kryzhanovskaya, D. Shevchenko, I. Kapran, N. V. Novikov, T. Koehler, B. Zaporozhets

"The PFK FeNi Smelter was re-commissioned by Solway Resources in 2002, ending a long period of economic decline in the adjacent town. In 2009 Hatch was retained to design, supply and install a custom furnace crucible that would accommodate a capacity increase from 34 MW to 40 MW and increase campaign life through binding and cooling technologies, as part of ongoing improvement efforts. The involvement of PFK personnel was critical to the successful integration of the new furnace technology with the existing process and operational practice. The furnace upgrade project was completed in 18 months during 2010 – 2011. Since start-up, the furnace has exceeded production expectations, operating successfully at 42 MW.INTRODUCTIONAfter ceasing operations in the 1990’s, the Pobuzhsky Ferronickel Combine (PFK), located in central Ukraine, was stripped of useful equipment and deteriorated while dormant. The surrounding town experienced a period of economic decline throughout the 1990’s. Solway Industries purchased the complex in 2002 and began a systematic incremental program to re-commission the smelter using both local expertise and specialists from other parts of the former Soviet Union. This led to the re-birth of PFK as a successful toll-smelting complex, and a renaissance for the surrounding economy.As part of the continuing improvement program, PFK approached Hatch in 2009 to study the possibility of a capacity expansion from 34 MW to 40 MW. It was decided, based on the results of the study, to design and install a custom furnace crucible integrating the unique PFK FeNi process with modern Hatch furnace technology. This novel approach had many benefits, including: maximum re-use of existing furnace components (off-gas, feed equipment and transformers), minimal impact on upstream and downstream equipment and building structure, and the retention of a familiar operating regime. The latter was a key factor in the success of the project, as it allowed the extensive operating expertise of the PFK staff to remain highly relevant to the upgraded furnace. This led to minimized capital investment, a rapid start-up and no significant operational challenges switching over to the new equipment incorporating Hatch furnace technology."

Jan 1, 2012

By Horace C. Porter

Most of the bituminous and semibituminous coals of this country will coke, and all of them yield, on carbonizing, more or less marketable gas and byproducts. We need, however, a finer distinction as between various grades of coking coals and between coals of different degrees of byproduct and gas-making possibilities. There is required by the consumer or the coal producer a dependable test to show whether a certain coal or mixture of coals will make coke of good commercial value for blast-furnace, foundry, water-gas, or domestic use; whether any difficulties in operation may arise from properties inherent in the coal; and whether gas and byproducts may be expected of good quality and in profitable quantity. For determining coke quality, the most dependable test is an actual run in an oven, but for byproducts a coal may better and more accurately be tested in the laboratory or in a miniature oven or retort. As to what are the most desirable qualities in blast-furnace coke, the furnace men themselves are not in complete agreement. Some desire a hard, well-burned, "hot" coke, and others get better results from a llgreener," less hardened product that burns somewhat more readily in the furnace. But certain qualities of cell structure and porosity are commonly agreed upon as desirable. Information as to what kind of coke a certain coal may be made to yield is valuable in advance, whatever may be the consumer's ideas as to the particular kind most suitable to his needs. The question arises, Can we predict coking quality with any degree of satisfaction from a small-scale test? It used to be said that coals could not be tested satisfactorily on a laboratory scale either for the coke they would yield or the byproducts. On account of the mystery with which the coking quality of coal has been shrouded and the large determining influences that many believe are exerted by mass, pressure, and the passage of carbonaceous volatile matter through the coking material, it has seemed difficult to reproduce in the laboratory the exact conditions of commercial practice. Great progress, however, has been made in recent years in elucidating the process of carbonization and many of the factors that make for the formation of high-grade coke and the recovery of the best

Jan 1, 1920

By C Laming, P M. Hetherington, F A. Pym, M P. Murphy, K E. Crook

Reconciliation is a powerful tool used by mining operations to compare the mass and grade of ore produced with what was estimated before mining. The primary objective of reconciliation is to verify that the estimated planned metal production is achieved during processing, allowing issues to be identified for which adjustments can be made throughout the mining value chain to improve recovery and maximise efficiency. Traditionally, the mine plan is based on estimated mine grades using sampled exploration drill hole or blasthole grades. Reconciliation discrepancies between the mine plan and mill are common due to such factors as insufficient or non-representative sampling, poorly conceived models, or unrecognised blast movement. MineSense Technologies Limited® (MTL) has developed an X-ray fluorescence (XRF) sensor-based ore classification system that is installed on mining equipment to provide real-time grade estimates of run-of-mine material at bucket, truck, or belt-scale. Bucket level grade estimates provide insights into grade variations at the mine face that were never before available. This data set eliminates some of the leading causes of reconciliation discrepancies and enables tracking of tonnages and grades from the mine face to the processing plant at bucket resolution with confidence. Bucket-by-bucket grades at the mine face enable dynamic optimisation of the mine plan to stabilise the mill feed grade through blending of mine and stockpile loads. Beyond stabilising feed grade, Mine to Mill reconciliation combined with the full XRF spectrum response can generate proxy relationships to ore characteristics like hardness and recovery. These properties can then be predicted at the mine face, enabling further optimisation of the downstream mill feed, not only for grade, but also for power and water consumption, reagent addition, and recovery. This paper presents the benefits of MTL technology for grade reconciliation and mill performance optimisation at a Cu Mine in BC (Canada).

Mar 22, 2022

By A. K. Raji, E. F. Orumwense, M. O. Ojumu

This research paper introduces a novel passive method for ocean mining using an electricpowered robotic subsea dredging crawler designed to operate in various subsea conditions, including unstructured and rough terrain. The electric-powered robotic subsea dredging crawler is equipped with two driving tracks and features a complex assembly of tank tread chain link, tank tread idler wheels, tank tread sprockets, bronze bushings, motor hub, motor mount, and a 12-volt direct current motor. To evaluate the performance of the electric-powered robotic subsea dredging crawler, it was compared with existing ocean hydraulic exploration crawlers, such as MK3 ROST, in terms of drive performance on an inclined ramp with five angles of inclination (0°, 15°, 20°, 25°, 30°). The experiment aimed to determine the maximum velocity, torque, and efficiency of the crawler at different angles of inclination. The collected data were analysed and plotted using Python, and the effect of the electric-powered robotic subsea dredging crawler’s weight on its driving performance was also considered. The results of this study demonstrate a quadratic relationship between driving performance and inclination angle, which can be used to optimise the electric-powered robotic subsea dredging crawler’s performance for future ocean mining robot drive applications.

Oct 2, 2025

By J. G. Groppo

A series of performance studies have been conducted using counter-current column flotation to recover a marketable clean coal product from existing preparation plant fine waste streams. The test work was conducted at several preparation plant sites in Kentucky and Virginia and utilized a 0.15m (6 in.) I.D. column that was 5.79m (19 ft.) high. The refuse streams tested included both thickener feed and classifying cyclone overflow with a typical size distribution of 100 mesh X O. The percent solids of the column flotation feed varied from 1.5 to 15% while the ash content ranged from 30-60%. The concentrates produced contained 2-10% ash with BTU recoveries of nearly 90% using 0.12-1.25 kg/ton (0.25-2.5 lbs/ton) fuel oil and 0.12 kg/ton (0.25 lb/ton) MIBC. These results were consistent with or better than results obtained in preliminary laboratory scale column flotation evaluation. Test results from 7 different seams are discussed as well as scale-up relationships utilized to design a full scale installation presently in operation.

Jan 1, 1990

By G. H. Blackwell

Sequences in open pit mining must be planned and regularly revised to incorporate changes in the variables which affect profitability. Interactive computer planning with colour graphic facilities is an effective tool for this purpose in the short and medium term. An interactive computer planning system for medium-size, low grade porphyry copper-molybdenum open pits is described. The planning system proved especially valuable during the critical stages of pushback mining when deep, inner pit ore was nearly depleted and the erratic grades of the next pushback provided ore and marginal material at a time of depressed metal prices.

Jan 8, 1993

By William W. Adams

Accidents to men employed in the quarrying and related industries of the United States were more numerous, absolutely and relatively, in 1937 than in 1936. Fortunately, the entire increase was in the category of nonfatal injuries, as accidents causing death declined in number and in proportion to the number of man-hours worked. Employment increased. More men were employed, more man-days and man-hours were worked, and the average employee had more hours of work than in 1936. Reports covering all commercial operations showed that 84,094 men were employed an increase of 5.1 percent over 1936. The number of man-hours of work performed by the industry was, 158 millions, an increase of 7.6 percent. Seventy-seven men were killed by accidents, a, reduction of 14 from the year before, and 6,348 men were injured and disabled for more than the remainder of the day on which the accident occurred, 11 percent more than in 1936. The fatality rate of 0.49 per million man-hours of exposure in 1937 compared favorably with the rate of 0.62 for the previous year, whereas the non-fatal-injury rate of 40.10 was 3.2 percent higher than the rate of 38.87 for 1936.

Jan 1, 1940

By Paulo Couceiro, Juan Navarro

The impact of rock blasting fragmentation and heave on digging performance in open-pit mining operations is usually the first true indicator of blasting outcomes. Within the typical excavation cycle, the bucket loading time or instantaneous digging rate are the ones that present the strongest correlation with rock fragmentation size distribution, swelling, and shape of the muckpile, a part of rock mass hardness, equipment size, power, and others. As the efficiency of unit operations becomes increasingly important for long-term mining strategies, cost-effective approaches are needed to increase mine productivity. In this line, the performance of downstream operations, such as digging, hauling, and comminution, may be affected by the energy input in blasting. This requires a better understanding of the explosive’s energy role in such unit operations in order to drive consistent improvements. Therefore, this paper examines the impact of the explosive’s energy distribution on shovel diggability from production shots carried out with different explosives in an open pit gold mine, with the aim of modelling the interface between blasting and excavation.

Jan 21, 2025

By P. M. Yavorsky

Using a mine roof simulator press capable of duplicating the expected magnitude of vertical and horizontal forces experienced by underground mine roof supports, load capabilities of some roof support cribbings were measured. Comparative ultimate vertical support strengths are reported for cribs of old and new timber and nonreinforced and steel-fiber-reinforced (SFR) concrete blocks. In terms of load- bearing capability, cribs of new hickory and nonreinforced concrete blocks have about equal strength, and SFR concrete blocks are three times as strong. Wood aged 2 years underground lost 43 pct of its support strength. These data were obtained during the course of the initial familiarization exercise of the complex press.

Jan 1, 1984

By A. C. Watts

FOR several years, a mine in Colorado experienced considerable trouble from small fires caused by the blasting of coal. Although a well-known make of permissible powder was used, it was first thought that the powder ignited gas that might be present and that this, in turn, set fire to line brattices or to the coal. Experiments were, therefore, conducted with another make of powder, but the results convinced the superintendent of the mine, Robt. Williams, Jr., that the fires were not caused by the powder but by the high-voltage electric current used for detonating the shots. The mine "makes" gas very freely, giving off from three-fourths to a million cubic feet of methane per 24 hours. The coal is a good grade bituminous of a very free burning quality. Electric shot-firing from the outside after all men and animals were outside had been practiced for a number of years. The shooting circuit was connected with the main power circuit at the mouth of each entry. Shooting circuit switches were mounted in boxes, which were kept locked with the handle of the switch, in open position, showing through the bottom of the box. The door of the box could not be shut and locked when the shooting switch was closed. At the entrance to each room, or working place, a small switch, called the miner's switch, was placed on the shooting line. It was the duty of the miner, when entering his place at the beginning of the shift, to see that this switch was open and that it was kept open until he left the place at the end of the shift to go out of the mine. Grounded return was used for main power lines. The current was 500 volts, direct current, with 100 to 300 amp. The nearest working face was 9600 ft. from the shot-firers' switch outside the mine and the most remote working face was 2 ½ miles. The various working faces were scattered over a wide area between these two points.

Jan 9, 1925

By G M. Jeffress, D C. Arne

There are two discrete aspects to collecting portable X-ray fluorescence (pXRF) data to obtain reliable results and to comply with reporting requirements under the 2012 edition of the JORC Code (JORC, 2012) – sampling method and quality assurance. A robust sampling program is required to obtain representative material for analysis. The appropriate method should be established for a particular project using a small orientation study. A variety of approaches to sampling soils, drill cuttings, rock faces and diamond drill core are discussed. These include using multiple spot analyses, scanning using a single operating beam and the collection of cutting saw pulps. The operator must also be aware of the attenuating effects of analysing through sample bags of different material types for various elements as well as the limitations of current pXRF instruments in reporting reliable data for certain elements. The analysis of the samples must also be accompanied by a quality assurance program in order to generate data that are ‘fit for purpose’. This includes recording X-ray tube resolution on a routine basis, using matrix-appropriate standards for which total elemental concentrations are available, using silica blanks, capturing sufficient duplicate analyses to constrain data precision and obtaining check assays to calibrate pXRF data against laboratory data. Examples of quality control approaches and data are presented. Table 1 of the 2012 JORC Code also recommends that information on instrument make and model, reading times and calibration be provided in any reporting of pXRF data. To this should be added information on operating mode and temperature, software version and moisture content of the samples. A robust sampling methodology with a suitable quality assurance/quality control program should produce pXRF data of sufficient quality for public reporting purposes, provided that the data are presented using appropriate cautionary language and adequate supporting information.CITATION:Arne, D C and Jeffress, G M, 2014. Sampling and analysis for public reporting of portable x-ray fluorescence data under the 2012 edition of the JORC Code, in Proceedings Sampling 2014 , pp 57–64 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

"Chairman: Professor J. Elbrond Rapporteur: Miss V. E. MartingPapers.Aids to planning production in coal mines by F. H. Deist and M. P. RobertsCapacity calculations, investment allocation and long-range production scheduling in German coal mines by F. L. WilkeOre reserve evaluation and open pit planning by J. M. Marino and J. P. SlamaThis session was devoted to the economic aspects of planning and scheduling. After Dr F. H. Deist had introduced the paper Aids to planning production in coal mines, Dr T. V. Falkie summarized the following formal contribution prepared jointly with Dr R. V. Ramani, describing the work that has been done at the Pennsylvania State University in the development of simulation programs for mine planning over the past 15 years:During the late 50's and early 60's, Monte Carlo simulators were developed to model continuous miner-shuttle car transport systems, track haulage systems, belt conveyor networks, etc. In the mid-60's attention was directed towards deterministic simulation of equipment performance, given the equipment characteristics and the system profile. In the late (10's all these systems (miners, shuttle cars, belts and trains) were integrated together to form a complete coal mine simulator and the program could predict the output potential of the system, given the mining dimensions, method and equipment employed. The actual sequence of coal-cutting operations is entered into the computer through the use of a special programming language which permits any type of mining configuration to be simulated. The simulator is hybrid in nature in that the shuttle cars, trains and belts are simulated deterministically, whereas rate functions with delay frequencies are entered for the continuous mining operations of sumping, shearing, fleeting, cleaning, etc. With suitable manipulation of the data, the program may be applied to all belt or conventional mining sections. Most of these simulators were developed through the assistance of grants from the Department of Mines and Mineral Industries of the Commonwealth of Pennsylvania and are available from the Coal Research Board of the Commonwealth,"

Jan 1, 2014