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By J. Sohn

The most promising near-term alternative to fuel cell driven vehicles is probably Hybrid Electric Vehicle (HEV or EV) technology. HEV technology combines the best characteristics of fuel-driven engines, electric motor drives, and energy storage components. It is designed with a combustion engine that functions as the primary power source, and an electric power storage system that functions as the secondary power source. The presence of the secondary power source allows designers to size the combustion engine for cruising power requirements. A new energy source for HEV or EV market will become lithium ion batteries (LIBs) in the near future. LIBs for HEV or EV has large scale about more 10,000 times than small size one for IT devices in order to achieve high electric density/capacity and high efficiency, etc. In those reasons, physical treatment of the batteries is more difficult for stable dismantling in comparison with the smaller one. Hybrid vehicle sales will grow by nearly 400 percent during the next seven years, according to a new report from analyst firm ABI Research. By 2013 hybrids will make up 6 percent of annual U.S. auto sales. The traction battery pack will become air-cooled LIBs which consists of several modules of Li ion battery and connected in series/parallel configuration to provide about >450 VDC, >150 kW peak power, and >80 Ah capacity. As the use of these batteries tends to increase significantly for the next years, it is relevant issues that development of new recycling methods as well as optimization of existing processes to treat spent LIBs for HEV have being addressed in order to obtain sustainability. In this study, physical treatment containing stable electrical discharge of spent LIBs for HEV was carried out for recovery of valuable metals from the batteries. Also In order to increase the yield of valuable metals through physical treatments such as electric discharge of spent batteries, crushing, and classification, we also focused on the recovery of cobalt from +8 mesh fraction due to its large portion in crushed intermediates.

Jan 1, 2010

By L. Alagha, O. Molatlhegi, S. Khatibi

"In the present study, the effect of organic/inorganic (hybrid) polyacrylamide polymer on fine coal flotation was investigated. Raw coal samples contain about 37% of ash-forming mineral at a feed size of -75 + 38 um were subjected to flotation tests in the presence of in-house synthesized hybrid Al(OH)3-PAM at different polymer dosages and pH values. Results show a significant improvement in both combustible recovery and ash rejection at 1 ppm polymer dosage. Further improvement of combustible recovery was obtained when flotation was performed at pH 5. Interfacial properties of coal particles before and after flotation were examined through electrokinetic (zeta potential) measurements of coal/water slurries. Zeta potential vs. pH curve were established and compared. In the case of raw coal/water slurry, zeta potential-pH curve resembles the ash-forming minerals (silica and clays) more than coal. After Al(OH)3-PAM-assisted flotation, the zeta potential of froth/water slurry shifted to more positive values point which strongly indicates significant removal of ash-forming minerals from coal by Al(OH)3-PAM. INTRODUCTION Coal has been a major commodity in meeting the world energy demand during the past several decades (Milici et al., 2013). According to the international energy agency, global coal demand will continue to increase for the coming decades. With increasing world population, the global electricity demand would also increase as more people would get access to basic electricity especially in developing countries (Maggio & Cacciola, 2012). Due to this increase in energy consumption, operations in coal mining and beneficiation processes have been highly mechanized to meet the demands. This mechanization has increased the quantity of raw fine coal particles produced which contain high amount of ash-forming mineral matter (slimes). Aplan et al., have reported that the major constituents of ash-forming minerals in U.S.A coal are clay minerals such as kaolinite, montmorillonite and illite (Aplan, 1997). Conventional froth flotation for fine coal cleaning suffers mainly from two major problems: 1) Low recovery of ultrafine coal particles due to slime coating by ash-forming minerals, and 2) The lack of selectivity, which results in the flotation of middlings and entrainment of mineral fines in the froth (Polat et al., 2003). Slime coating on both valuable and air bubbles have been proposed to explain the observed reduction in flotation recovery especially when fine grinding is required. In this case mineral matter may be degraded to extremely fine or colloidal sizes thereby creating difficulty in the water clarification process such as flotation. Slimes inhibit bubble-particle attachment, and increases reagent consumption due to the increase in solid/liquid interfacial area, resulting in low coal recovery."

Jan 1, 2015

By N. T. Mirafuente

The device called "Dynastat" which is described in this paper provides in situ borehole measurements of dynamic and static parameters for use in a wide range of design applications. In the dynamic mode, the Oynastat allows measurement of shear and compressional wave velocities. From these velocities in situ dynamic Young's modulus and other dynamic elastic parameters can be calculated. In the static mode, the device allows measurement of load versus deformation from which in situ static Young's modulus can be determined. Information on in situ horizontal stress fields can also be estimated from the load deformation curves. In both mining and civil engineering applications, in situ measurements of material properties are indispensable for accurate evaluation of design problems. Laboratory dynamic and static test measurements in comparison to in situ measurements are often misleading due to difficulties in obtaining undisturbed samples and in accounting for effects of discontinuities, etc., for mass properties. The authors contend that among in situ borehole measurements, the method employed with the Dynastat is the most accurate and detailed technique of measurement. The Dynastat employs the crosshole method of shear and compressional wave velocity measurements and also performs as a borehole jack to obtain load-deformation relationships of materials at exactly the same location at depth in boreholes.

Jan 1, 1976

By Brajendra Mishra, Himanshu Tanvar

Niobium and tantalum extraction industries heavily depend on fluoride chemistry for metal oxide production. This study concentrates on developing a fluoride-free approach utilizing alkali treatment for selective dissolution of niobium and tantalum phases. The application of microwave heating in the alkali treatment of columbite significantly reduced the processing time, providing a higher reaction rate and recovery than conventional heating. A short duration of microwave exposure (6 min) elevated the sample temperature to more than 900 °C, resulting in the rapid formation of water-soluble niobium and tantalum complex. Metal recovery from the solution was attempted through direct precipitation using guanidine carbonate as the precipitating agent, resulting in a mixed oxide product with > 90% purity. On the other hand, solvent extraction was also attempted using methyltrioctylammonium chloride as an extractant, providing a niobium oxide and tantalum-rich mixed oxide with > 98% purity as the final product.

Mar 23, 2024

By Khosrow Badiozamani

Traditionally the mining industry has been lagging in application of computers in their daily or long range plan activities compared to other industries. The question then remains as to how the technology of higher computing capacity for less cost is going to affect the mining industry and how the lukewarm reception of engineers in acceptance of computerized mine planning in the past is going to change because of the new wave of high techology. These questions and the reasons for the lack of usage of computerized mine planning systems by engineers will be evaluated in this paper. In addition, alternatives available to the mining industry will be analyzed and the direction of the future "user friendly" software will be discussed.

Jan 1, 1984

By Norbert Patzelt

Today the standard method for grinding ore is the wet process. This is mainly due to the fact that the downstream process is wet and considering the total circuit dry grinding is not the most eco­nomical method for the comminution of the ore. Presently in gold ore processing dry grinding is only applied in cases where whole ore roasting is required downstream from the milling plant or if organic carbonaceous matters and sulfides are the primary reasons for the refractoriness. Since dry ore can be fed to the roaster, a dry grinding mill can advantageously be applied. In cases where d1y grinding could be applied advantageously for instance if the ore contains water soluble material and wet grinding is not possible there are serious concerns prevailing within the industty against this technology due to several reasons. Besides of the aspects as discussed later in this paper, there are several plants in operation with little success and considerable operational prob­lems. The reasons for this often lie in the fact that the several com­ponents of such a plant are bought from independent sources with­out considering the system requirements. It is essential that the dry grinding plants require accurate design between drying, pneumatic transport and grinding of the ore in the circuit. This paper will address some of these concerns raised in the industiy from a mill vendor's view along with discussing the development for the selection and configuration of the various dty grinding circuits.

Jan 1, 1998

By Oscar H. Lentz

During 1960, the controversy over percentage depletion reached the level of debate between presidential candidates. Nixon took the position that he would not tamper with the status quo in this matter. Kennedy took the position that he was willing to take a fresh look at the issues involved. Kennedy's position appears to have been based upon two premises: (1) new sources of federal revenue may be needed; and (2) current depletion rates, even if sound in principle, may be too high and, therefore, inequitable. The latter premise constitutes the basis for the claims that depletion allowances are simply "loopholes" of tax avoidance. Very probably the controversy over percentage depletion will remain in the political limelight during most of the coming decade. It is quite possible that the current depletion rates, at least those for oil and gas, will be reduced during this period. The aim of this paper is to isolate the complex causes of this mounting opposition to percentage depletion.

Jan 1, 1961

By J. D. Grenia

The Buick Mine is a joint venture of American Metals Climax, Inc., and Homestake Mining Company located 120 miles by road southwest of St. Louis, near the village of Boss, in the 'New Missouri Lead Belt' (See Figure 1). Since start-up in 1969, over four million tons of lead-zinc ore have been mined and milled at Buick. Situated about 1,100 feet below the surface at an elevation 270 feet above sea level, the flat lying sinuous ore bodies are up to 250 feet wide, 85 feet high and several thousand feet long. Mineralization is galena, sphalerite and chalcopyrite in dolomite, Access to the mine is through two 18'Ø concrete lined vertical shafts - one for servicing and the other for hoisting ore (See Figure 2). The mine is being worked by a modified room and pillar method using both rubber tired equipment and a sub-level rail haulage. Ore is broken from first pass headings, back and bench faces and transported by load-haul-dump units to ore passes located on 900 foot centers. The ore is pulled from chutes on the sublevel 90 feet below into 15 ton bottom dump cars and delivered in 10 car lots by a 15 ton diesel locomotive to a 42" gyratory crusher (See Figure 3). A recent innovation has been the introduction of two 50 ton trucks with plans to haul up to 60% of the ore on the mining level to an ore pass feeding directly to the primary crusher (See Figure 4). Ventilation raises up to 16'Ø, which were originally planned for 900 foot centers, are now driven on 450 foot centers.

Jan 1, 1973

By S. Chander

The results of an investigation to characterize the chalcopyrite/solution interface are presented. Several techniques including galvanostatic and steady state polarization, cyclic voltammetry and impedance spectroscopy were used. The results show that the dissolution of chalcopyrite is incongruent. Initially, at low potentials(<O.34V), iron species are released which give rise to the growth of an iron-deficient sulfide (IDS) layer. The dissolved iron might reprecipitate as a hydroxide layer depending on solution composition. Continued oxidation involves diffusion of species through the product layer. At higher potentials (>O.48V) further oxidation leads to dissolution of copper and sulfur species with a resultant breakdown of the IDS layer. The changes in properties of surface coatings resulting from various electrochemical treatments are discussed.

Jan 1, 1991

By J. Driscoll, T. Morson, Ross M. Workman

The study investigates the effectiveness of the canopy air curtain (CAC) in reducing respirable dust exposure for shuttle car and ramcar operators in underground coal mining. Field testing showed that the CAC reduced dust exposure by 11-34% overall and by 57-65% during ramcar loading by the continuous miner. These results demonstrate the CAC’s potential as a significant dust control device.

Feb 19, 2022

By Jonathan G. Price

The 2011 report titled ?Energy Critical Elements: Securing Materials for Emerging Technologies? by the American Physical Society?s Panel on Public Affairs and the Materials Research Society surveys potential constraints on the availability of these elements and identifies five specific areas of potential action by the United States to ensure their availability: 1) federal agency coordination; 2) information collection, analysis and dissemination; 3) research, development and workforce enhancement; 4) efficient use of materials and 5) market interventions. Energy-critical elements (ECEs) are a class of chemical elements that currently are critical to one or more new energy-related technologies. A shortage of these elements would significantly inhibit large-scale deployment, which could otherwise be capable of transforming the way in which energy is produced, transmitted, stored or conserved. The report addresses elements that have not been widely extracted, traded or used in the past, and therefore are not the focus of well-established and relatively stable markets (such as carbon in coal or uranium as fuels, copper, aluminum, nickel and iron, all of which are clearly vital in energy applications).

Jan 1, 2011

By V 9. 0 / 300 dpi

In the time period from the early 1980&apos;s to the present, longwall roof support technology has evolved tremendously. Chock supports and caliper shields were replaced by 2-leg or 4-leg lemniscate shields. The lemniscate linkage for which the support is named offers numerous advantages to the sup-port both as a fabricated structure and to its performance in the mining application. The hydraulic system, which is the dynamic element of the roof support, was essentially unchanged in early lemniscate shields with the exception of the complexity of additional hydraulic circuits to power a canopy tilt cylinder and canopy side-seals. The control of these fluid-powered functions was provided by direct manual control of valves energizing individual functions onboard the roof-support or the adjacent roof-support. This control valve-gear was comprised of multiple individual valves arranged in a "bank" or integrated into a single hydraulic distribution block with a single operating handle to select any independent function.

Jan 1, 1993

By Andrew Hall

Many Latin American countries are facing a scarcity of water. As such, infrastructure decisions are quite different from those made in parts of the world that experience a positive water balance. In the latter case, the water treatment approach tends to be ?treat and discharge.? For Latin American regions facing the challenges that go with a negative water balance, the focus is on resource optimization and reuse. Historically, the water challenge has had a significant impact on economic development in Latin America, especially in sectors such as mining, where water usage is high. At the same time, countries such as Chile and Brazil are major development targets for mining and oil and gas operations. Given the water supply challenge, industry is increasingly turning to technologies and processes that maximize water recovery and reuse. With sulfide precipitation and ion exchange water treatment processes for example, it is possible to treat and recover more than 99 percent of water for reuse onsite. These technologies have been applied successfully in other regions of the world where water conservation practices are essential to economic survival.

Jan 1, 2012

By B. Hester

Many Third World countries of Third World Africa are well-endowed with minerals, especially gold. Political and economic conditions discouraged interest by Western capital for the several decades since colonial rule. Influence from Eastern Block countries has gone and the left wing orientation widely favored by Third World countries has almost disappeared. Under International Monetary Fund influence, these countries now solicit Western finance to expand their industries. Mining is especially encouraged. The paper describes the financing of some recent developments and examines trends and opportunities in some of the more attractive countries.

Jan 1, 1993

In order to overcome some of the deficiencies associated with conventional fine coal cleaning methods, a novel process known as microbubble column flotation (MICROCEL?) was developed at Virginia Tech. This article provides an overview of recent commercialization efforts and in-plant testing of this technology. The results of the in-plant test work indicate that the MICROCEL technology offers several advantages for the upgrading of difficult to clean coals. The test data have also been used to develop guidelines for the design of coal flotation columns and to validate existing scale-up procedures.

Jan 1, 1991

Sedimentation is used to clarify process effluents or to thicken process slurries. The sedimentation cycle of a suspension is presented as a settling curve. This curve is simply a plot of the height of the interface between the settled suspension and clear liquor versus time. Figure 1 shows a series of graduate cylinders which contain a suspension at various stages in its settling cycle. Cylinder 1 shows the suspension completely mixed at time zero. After a brief period of time (see cylinder 2), the suspension is observed to settle from its initial height Ho to height H1, leaving behind a volume of clear (or turbid) liquor, called the supernatant. The interface between the supernatant and suspension is termed the mud line. It is also possible to distinguish at the bottom of the cylinder a layer of sludge representing solids which have settled from the suspension. The interface between it and the suspension is called the sludge line. The sludge line moves upward in the cylinder.

Jan 1, 1992

By Roberto Pimentel de Souza

Since 1976 CVRD is carrying out tests to develop a type of pellet made with organic binder. One binder that showed good possibility to be used in industrial plants is Peridur. An extensive framework of tests was run in CVRD&apos;s pilot plant. The results are presented in this paper. Finally, the decision was taken to carry out an industrial production of 50.000 t of pellets. It was scheduled for March &apos;81. The results are shown in this pager. It was not observed any detrimental effect of the peridur neither in the process nor in the product quality.

Jan 1, 1981

By J. -M. Lopez-Cuesta, C. Petter, B. Otazaghine, M. Batistella, R. Sonnier

"Kaolinite is a dioctahedral aluminosilicate widely used as paper filler and coating pigment. At the best of our knowledge, kaolinite is not widely used in polymer industry. Therefore, in this study, the flame retardant effect of kaolinite in ethylene vinyl acetate copolymer (EVA) and polypropylene (PP) were studied and compared with an alumina trihydrate (ATH) and Talc. Cone calorimeter results shows that the weight percentage of ATH in EVA/ATH composites must be at least 50 wt. % in order to reach an improvement in fire retardancy in terms of pHRR. In the case of EVA/kaolinite, even with 35 wt. % the pHRR is largely reduced. Comparing PP/Talc and PP/kaolinite composites at 30 wt. %, both fillers leads to same reduction in pHRR with a slightly better performance for PP/kaolinite composites. In both cases an intumescent behavior of kaolinite composites was observed that could slow the rate of the rising degradation products, allowing radical recombination reactions. Also, it was observed that kaolinite forms a protective layer on the surface of the samples, which could insulate the material. These behaviors (intumescence and formation of a protective barrier) could reduce the transfer of the degradation products to the flame and explain the better performance of kaolinite composites. INTRODUCTION The use of mineral fillers as fire retardants in polymer matrix are well known and widely studied [1]–[10]. Aluminum and magnesium hydroxides (respectively ATH and MDH) are the most widely used inorganic fire retardants. To achieve fire retardancy with these mineral fillers, about 50-60% loading is required which decrease the physical properties of the composites. The fire behavior of composite EVA has been the subject of many studies [4], [7], [9]–[15]. EVA copolymers are commonly used in the cable industry, due to their high ductility, even at high loading rates. In such applications, the flame retardant systems should be introduced into the polymer to improve the fire reaction. Many flame retardant systems have been tested but the most used industrially relates to formulations based on hydrated mineral fillers (aluminum hydroxide and magnesium hydroxide). Their low cost and reduced fumes generation explains their success. However, to obtain good performance with this type of flame retardants, it is necessary to incorporate high levels (up to 65 wt %), which severely impact other properties such as processability and mechanical behavior. The main modes of action of these flame retardants are the dilution of the gas phase, the endothermic decomposition and a barrier effect created by the inorganic oxide residue which may be improved by the incorporation of other components such as montmorillonites, silicas or talcs."

Jan 1, 2015

By N. Myung, G. Hwang, H. Kim, Y. Han, S. Choi

"According to research presently being conducted on selective lithium recovery in seawater, inorganic adsorbents with high selectivity and capacity for capturing lithium ions from liquid lithium resources are called lithium ion-sieves (LISs). Their low toxicity, low cost and high chemical stability make LISs suitable for lithium recovery from seawater. In the present study, the ultrathin LMO nanofibers with controlled diameter were successfully fabricated by an electrospinning technique with a hypothesis that greater aspect ratio (i.e., smaller diameter) would lead to the enhanced recovery of lithium ion from seawater. Design of Experiment (DOE) and dimensionless analysis were performed to systematically optimize the diameter and morphology of nanofibers. Several complementary techniques including FE-SEM and XRD were used to evaluate the physical/physicochemical properties of the nanofibers. Lastly, the lithium ion recovery was tested for the nanofibers with different physical properties using lithium ion solution. INTRODUCTION Demand for lithium resources is increasing in many industries across the world.1-2 However, the conventional resources for lithium is very limited, and it even gets worse to secure the resources due to low grade and/or complexity of feed materials. Much effort has been, therefore, devoted to obtaining lithium from aqueous lithium resources. Several methods such as solar evaporation3-4, co-precipitation5, and solvent extraction6 have been proposed for recovering lithium from an aqueous lithium source, but there are limitations on its use; It takes a very long time or conditions such as temperature, pH and Mg/Li ratio are severe. Lithium ion-sieve (LIS) materials are considered as a good lithium adsorbent because of their unique chemical structure that can selectively separate lithium ion from brine and seawater.7- 10 Furthermore, their low toxicity, low cost, and high chemical stability make LIS suitable for lithium recovery from aqueous lithium resources. Spinel hydrous manganese oxide (HMn2O4) derived from spinel lithium manganese oxide (LiMn2O4) after topotactically extracting lithium from the spinel structure by acid treatment is most widely investigated LIS.10, LIS materials have been actively studied in various forms for easy handling and high efficiency (i.e. membrane11,12, foam13-14, granular15,16). Among them, the 1-D nanostructure LIS with high specific surface area is excellent in efficiency.9 In this study, we present the part of our recently submitted work17. Specifically, we fabricated systemically lithium manganese oxide nanofibers with different diameter as a lithium ion adsorbent using electrospinning technique through design of experiment (DOE). Enhanced lithium ion adsorption properties of the HMn2O4 nanofibers with different diameter were investigated in lithium liquid resources."

Jan 1, 2018

By Robert T. Chapman

Many of us are privileged in that we have witnessed the transition from mining methods used in the first quarter of the twentieth&apos; century to those practiced today. In the late Twenties, for example, many mines still used hand mucking methods. In the middle Thirties, more than one large metallurgical limestone quarry still used the 4 cubic yard railway steam shovel formerly in use at the Panama Canal. Mules could occasionally still be found underground, where they provided the-main-source of motive power. Within the last decade, and even within the past five years or less, great improvements have been made in blast-hole drilling, ore loading, and ore hauling equipment. Industrial demand for minerals can be expressed in exponential terms as compared to that at the turn of the century. Even marine mineral resources are receiving accelerated attention. One overall result is that larger and lower grade orebodies can be exploited at a profit. This profit must be made despite, for example, a static monetary price for gold, and despite the continual cost escalation involving labor, materials, supplies, and equipment. Accordingly, the application of the necessary degree of knowledge and judgment required to meet production, cost, and profit goals is paramount.

Jan 1, 1966