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THERE is at least one concrete indication that Soviet Russia's two most important iron ore producing centers are seriously depleted. While keeping in mind Russia's penchant for reverse propaganda, one piece of evidence indicates that Magnitugorsk in the southern Urals and Krivoi Rog in the Ukraine have been mined to a point where lower grade ores are being recovered. An article in Pravda, Soviet newspaper, by I. P. Bardin. a Russian metallurgist, says that ore presently mined must undergo an expensive enriching cycle before it can be used in blast furnaces. Com- pounding Russian metallurgical troubles is the low quality of coking coals. High ash and sulphur content typifies the coal Badin talks about. Coal from the Ukraine, Eastern Siberia, Kazakhstan, and the Far East requires extensive treatment before it can be used, according to the article in Pravda.

Jan 7, 1953

By C. Demir, M. S. Celik, I. Gülgonul

Na-feldspar (albite) and K-feldspar (microcline or orthoclase) are major feldspar minerals with identical crystal structures and physicochemical properties. Flotation appears to be a unique method of separating these minerals. Fundamental studies on amine/feldspar system in the presence of monovalent salts showed that separation of these feldspar minerals by flotation is possible at certain concentration of monovalent salts in HF medium and natural pH. A comparison between natural pH and HF medium indicates that the latter provides a better selectivity at the expense of higher collector requirement. A general mechanism for both systems involving an ion exchange between the uncommon ions and adsorption of the common ions is proposed to be responsible for creating differences in the charge of albite and microcline unto which amine adsorbs.

Jan 1, 2002

The Morning Session of the Forty-Eighth Meeting of the Rocky. Mountain Coal Mining Institute convened in the Little Theater of the Broadmoor Hotel, Colorado Springs, Colorado, at 9:30 a.m., June 3, 1952, Howard B. Crandell, President, presiding. PRESIDENT CRANDELL: Gentlemen, the meeting will come to order, and I would like to introduce to you your Chairman of this meeting, Mr. John B. Hughes, General Manager of the Union" Pacific Coal Company, Rock Springs... (Applause) CHAIRMAN HUGHES: From the activities around last night, I supposed there would be quite a few that would be unable to attend this morning. I am sorry there are not more here because I am sure we have some interesting papers. First on the program this morning is, The Effect of Continuous Mining on Today's. Coal Industry by Mr. William Wearly, Vice President of the Joy Manufacturing Company. Mr. Wearly: (Applause)

Jan 1, 1952

By W. C. Ellis, M. E. Fine

WHEN certain binary Fe-Ni alloys are worked cold and then stabilized by a stress-relief anneal, their Young's moduli are nearly invariant over a substantial temperature range determined by composition and work-anneal history.' In the present investigation addition of molybdenum to such alloys (besides increasing the yield strength) was found to diminish the sensitivity of the thermal coefficient of Young's modulus to composition changes. Such alloys are of interest for applications requiring 1 a metal with controlled, low temperature coefficient of Young's modulus and substantial magnetic permeability.' Young's modulus ordinarily decreases with rising temperature. In ferromagnetic alloys a change in modulus on heating due to loss of ferromagnetism modifies the .temperature dependence. Far below the Curie temperature ferromagnetism alters the modulus in two ways: a—Addition of the energy of magnetization, a function of interatomic distance, changes the relation between interatomic energy and distance.' This lowers the modulus in the Fe-Ni and Fe-Ni-Mo alloys of this investigation. b—An applied stress changes the ferromagnetic domain arrangement so that linear magnetostriction contributes to the strain and further lowers the modulUs.~ Since in the alloys of this investigation both effects lower the modulus, loss of ferromagnetism on heating changes the slope of the modulus-temperature curve in a positive direction. With increasing temperature the slope of the modulus-temperature curve, due to progressive loss of ferromagnetism, becomes less negative, goes through zero (the modulus is minimum), becomes positive, and resumes its normal negative value above the Curie temperature.' The increase in modulus and decrease in curvature in the modulus-temperature curve occurring on work hardening have been attributed to a reduction in effect (b).'. Vn the absence of ferromagnetism work hardening through introduction of residual strains would be expected to decrease the modulus.' Alloy Preparation—Test Methods Four series of alloys having nominal molybdenum contents of 5, 7, 9, and 10 pct and containing 47 to 58 pct Fe (the analyzed compositions are given in Table I) were melted in air and cast as bars weighing from 2 to 6 lb. The charge consisted of electrolytic nickel, Armco iron, molybdenum (99+ pct) or ferromolybdenum (62 pct Mo), manganese, and aluminum as a deoxidizer. The bars were swaged cold to the desired diameters with intermediate anneals. Alloys in this composition range are reported" to be face-centered cubic and ferromagnetic at room temperature. The Curie temperatures" decrease with molybdenum. For example, keeping the Ni/Fe ratio at unity and increasing the molybdenum from 0 to 17 pct decreases the Curie tempera- ture from approximately 500°C to room temperature. (The 17 pct Mo alloy requires quenching to retain a single phase.~) Young's modulus at a series of temperatures from —50" to 100°C was determined by a dynamic method previously described.', " In this method Young's modulus is calculated from the resonant frequency (in this case approximately 50,000 cycles per second) of a rod sample (approximately 2 in. long) vibrating longitudinally in the first mode. The densities of the samples at room temperature, Table I, were determined by the standard method of weighing in air and reweighing in redistilled bromobenzene. The linear coefficients of expansion, Table I, needed to calculate the sample length and density at the temperature of measurement, were obtained by observing the change in length (22" to 100°C) of an 8 in. gage distance with a two microscope cathetometer. The values of density and coefficient of expansion in the few samples checked are independent of treatment to the accuracy reported. This was assumed to be general for all the samples. The modulus values are accurate to &0.05x101' dynes per sq cm. However, values of thermal change in modulus are accurate to 20.005~ 10" dynes per sq cm. Young's Modulus Values at 25°C: The modulus values of O', 5, and 10 pct Mo alloys at 25 °C are plotted in Fig. 1 as functions of nickel. After working cold, the samples were either recrystallized at 950" to 1000°C or given a low temperature stabilizing anneal at 400° C. The 400°C anneal does not reduce the hardness nor cause recrystallization. Annealing at 400 °C does

Jan 1, 1952

By W. S. Ayres

I AM well aware that this subject is not strictly in the line of mining engineering, yet as it is a subject with which mining engineers at times have something to do, I have thought, perhaps, it might not be wholly out of place to communicate to the Institute something of the method used in determining deflection, and of its final issue. Having felt a need of some simple formula for determining the deflection of girders of uniform cross-section under any load, I have been led through the counsel of Mr. Frederick J. Slade, to whom I am indebted for many suggestions, to undertake a labor of which I shall in this paper give only some of the most important features. The results arrived at agree with those obtainable from the received formula; of Weisbach, Rankine, and others, but the expressions given by these authors, and by all others that I have at hand, are of such a form that they are not easily applied by those whose higher mathematics have become rusty from disuse, and they require, moreover, too much labor in their application to be of practical value. The general formula that I have adopted is similar to that given by Rankine, and is deflection = [mWl3 -El], in which l is the span, W the total load, E the modulus of elasticity, I the moment of inertia of the uniform cross-section of the girder, and m a factor depending for its value on the mode of distribution of the load. The problem then is to find the value of this factor m in the formula, and for some distributions of the load it leads to a number of mathematical difficulties. In this place I shall consider first the girder to be loaded symmet-

Jan 1, 1877

By Danny A. Riley, James R. Sanger, Hani S. Matloub, Lin-Ling Zhang, Ji-Geng Yan

This experimental study was done to determine pathological feature of vibration injury to the peripheral nerves in the hind limbs of rats exposed to 7 days of vibration. Materials and Methods Animals: Twenty four male Sprague-Dawley rats weighing 350-400 grams were randomly divided into two groups: sham control group and vibrated group. To document vibration-induced changes in the experimental model, the sciatic nerve was used because it contains both motor and sensory fibers and is relatively superficial in the posterior thigh. Customized Vibrating Platform: The hind limbs of the rats in the vibrated group were exposed to vibration in a custom-built vibrating apparatus consisting of two platforms: a smaller vibrating platform on which the hind limbs of the rat are secured, and a larger platform on which the remainder of the body rests. The vibration parameters (frequency 43.5 Hz, amplitude 1.5mm, acceleration 4.75G, velocity 6cm/sec., and displacement of 3.0mm) of this model were measured. Methods: Rats were anesthetized with 35mg/kg of intraperitoneal Nembutal (phenobarbital) and their hind limbs fixed to the vibrating platform by Velcro loops. Both hind limbs rest on the vibrating platform while the remainder of the body rests on the larger platform. The rats were vibrated 4 hours a day, for 7 days, with close monitoring of the vibration parameters. The 4-hour duration of hazardous vibration was based on recommendations from the British Standards Institution. The sciatic nerve of rats not exposed to vibration, but similarly anesthetized and secured to the vibrating platform, acted as controls. At the end of seven days of exposure to vibration, nerves from both the vibrated rats and the control rats were harvested after perfusion of the lower half of the body using glutaraldehyde as described below. Neural Fixation: The aorta was cannulated, and the inferior vena cava was nicked and the animal was initially perfused with 0.9% buffered sodium chloride. This was followed by perfusion of a filtered mixture of 3% glutaraldehyde and 3% paraformaldehyde fixation solution, The tissue was subjected to post fixation by routine. The neural tissue was then submitted for light and electron microscopy. Results While light microscopy showed minimal histological differences between vibrated (n=12) and control nerves (n=12), the changes revealed by electron microscopy were dramatic. These included thickening of the epineurium, as well as thickening of the myelin sheath as compared with normal nerve. Also, the axon plasma was detached from the myelin sheaths, and many vacuoles were seen between the myelin laminae(Fig.1); These changes were found in all vibrated animals, and in the whole segment of each vibrated nerve. Myelin balls, consisting of

Jan 6, 2006

By Rafael Alves Frederico de Alencar

O comportamento mecânico dos diferentes tipos de materiais é influenciado por diversas variáveis, dentre as quais, as condições adotadas para o processamento mecânico dos mesmos, as características estruturais e os aspectos metalúrgicos, por exemplo. Considerando essas variáveis, este trabalho apresenta o estudo do comportamento mecânico do aço inoxidável ferrítico AISI 430, estabilizado ao nióbio, para diferentes modos de pré-deformação: estampagem (estiramento) e tração com o subsequente carregamento em cisalhamento. Os resultados indicaram que o comportamento mecânico do material variou em função da direção de aplicação do esforço mecânico e do modo usado para a pré-deformação desse aço, ocasionando endurecimento e amaciamento.

Aug 17, 2017

By K. [Muthukkumaran

An extensive program of laboratory model tests was undertaken to study the effect of slope on p-y curves under passive loading in dry sand. The paper concerns the method developed in a series of laboratory model tests to experimentally determine p-y curves. Bending moment curves are differentiated by using curve fitting method of cubic polynomial function. The study includes effect of slope angle and relative density on bending moment and non-dimensional p-y curves. The non-dimensional p-y curves for piles on sloping ground under passive load are developed modifying API method by including a Reduction Factor (R) using the experimental results.

Jan 1, 2006

The relationship between comminution testwork results and the milling circuit that is subsequently selected is not a direct one and frequently involves recourse to databases of past test results. This in itself reflects the lack of a systematic engineering approach in the design process. This paper reviews comminution tests for SAG mill design in an attempt to identify where the essential information comes from that will be used in mill selection. The conclusion is that results from traditional test methods, including obscure and little used procedures like the Mokken test, are more valuable from an engineering perspective than parameters for breakage rate based modelling. Suggestions are made on ways in which existing test procedures can be enhanced in order to generate parameters that can be directly related to characteristics of the milling circuit being designed.

Jan 1, 2002

By J. Jorge, J. Mariño-Salguero, B. Álvarez-Rodriguez, J. M. Menéndez-Aguado, J. J. de Felipe

"This work focuses on the characterization of heat generation during dry fracture by direct impact of a tantalum ore. Moreover, an attempt was made to quantify the heat energy loss to the environment during the grinding process of a ball mill. The study was carried out using mineral samples from a Spanish mine that were characterized by measuring their density and specific heat. During the experiments, increases of temperature ranging from 5.9 to 7.3 °C after the fracturing process were observed. A numerical model was then applied to calculate temperature distributions through the mill wall. Three possible combinations of heat transfer coefficients were analyzed, from (1) Kapakyulu and Moys, (2) Duda and (3) the heat transfer laboratory of Universitat Politècnica de Catalunya. The models with the coefficients from Kapakyulu and Moys and the heat transfer laboratory of Universitat Politècnica de Catalunya were found to provide results that were in best agreement with the experimental data. IntroductionEvery year, several billion tons of metallic ores, minerals, cement and other solids used in the ceramic and chemical industries are subjected to size reduction in ball mills around the world. The U.S. Department of Energy (2005) reported that in the United States about 29 percent of the total energy used by the mining industry, or 0.4 percent of total U.S. energy consumption, is used in comminution. In Canada and Australia, comminution is responsible for about 2 percent and 1.5 percent of total energy use, respectively. In nonindustrialized countries where mining constitutes higher fractions of their industrial sectors, comminution costs represent a significant contribution to mine operating costs. The specific energy consumption values for the grinding of these materials typically range from 5 to 50 kWh/t. Thus, a significant amount of electrical energy is consumed in the ball mill grinding operation (Aguado et al., 2006; Gupta and Sharma, 2014). Grinding can represent up to 50 percent of the direct operating cost in a mineral processing plant, especially as comminution devices operate in highly inefficient ranges of 4 to 8 percent (Wang, Yang and Yu, 2012)."

Jan 1, 2017

By C. Siac

"It is a widely held view that in the 21st century, the mining industry will be dominated by a relatively small number of large companies, truly global in scope and internationally staffed (Gooding, 1997). Interestingly enough, most of the exploration and exploitation activities are being carried out by junior and major mining companies from common law jurisdictions in civil law countries, in particular in Latin America, where in recent years, the region has ranked first as a destination for exploration dollars, thanks to the reforms undertaken by some countries to amend their legal framework to attract foreign investment. From a lawyer’s point of view, this is where the main challenge lies: how to bridge the gap between the two legal systems.In order to avoid pitfalls, common law lawyers should be more diligent and proactive when dealing with civil law jurisdictions, given the different systems of law, standards, traditions and customs. Common law lawyers cannot be expected to be well-versed in civil law but they should not be completely unfamiliar with it either. A balance should be struck to ensure clients’ needs are professionally taken care of and that common law requirements and standards are met."

Jan 1, 2003

By S. Slottee

The technology of making and using ?paste? from mine tailings is increasingly well known by the minerals industry. The primary applications are water recovery and ?stacking? of tailings with minimal use of dams and ponds. This paper highlights some applications, other than water recovery and stacking, that have come to the attention of a paste thickener equipment supplier. As generated by thickeners, paste (also called ?thickened tailings?) is a non-settling, relatively high concentration, suspension of solids that can be pumped. Paste deposits with an angle of repose, allowing minimal use of dams. High solids concentration allows more water recovery at the paste thickener than is achieved in conventional and high rate slurry tailings thickeners. This paper is based on paste as produced in a flow sheet that includes a thickener, underflow pumps that are typically centrifugal, transfer pumps that can be centrifugal or positive displacement, and a distribution system at the deposition site. Examples of paste applications other than water recovery or stacking include: ?mine? an existing tailings pond by removing slurry, recovering coal or iron ore values, and return the new tailings to the pond as a paste that does not res-suspend; use paste to seal an existing tailings pond from leaking to groundwater or to an underground mine; extend the life of an existing tailings pond by thickening the tailings to paste; move an existing dry tailings impoundment to a new location by slurrying, pumping, paste thickening, and redeposit; minimize the size of a filter by paste thickening the feed; operate a paste thickener and filter in parallel on a tailings stream with re-mixing to achieve a high solids concentration. The use of paste tailings technology has been expanding over the last 15 years. The applications, both implemented and under consideration, are increasingly diverse and include all minerals tailings. Tailings handling designers should always consider a paste option to the conventional slurry solution.

Jan 1, 2011

By John Yenter

"Unique blasting problems during reconstruction and expansion of 100 year old buildings toaccommodate gambling. Located on steep mountainous terrain and linked by narrowroadways, the towns of Central City and Black Hawk challenged blasters to exceptionalmeasures in order to control over_break, vibration, public exposure and damage to thecharacter of these historic mining towns. Utilities were also upgraded to fit demands of asmuch as 800% volume change in one year."

Jan 1, 1993

concentrations) and physical nature of receiving streams, which in turn affects the stream ecosystem. Benthic macroinvertebrates are used to illustrate these impacts, and to investigate natural recovery in affected streams. In Charming Creek, a severely impacted stream in the Buller District, the macroinvertebrate community recovers diversity and the proportion of sensitive species (EPT) in the community is more significant with increasing downstream distance from the source of AMD. This is most likely due to dilution of AMD contaminated water by tributaries to the Charming Creek mainstream. Other impacted systems with less dilution from tributaries did not display similar levels of recovery. The effectiveness of remediation products BauxsolÖ and Zeolite was investigated using laboratory trials. Both products mitigated the toxicity of AMD and enhanced the survival of mayflies exposed to AMD contaminated water. Such products may be of use in the New Zealand environment but are likely to be most effective in conjunction with other systems (eg wetlands). Mitigating the impacts of AMD on stream ecosystems needs to include systems to directly address water chemistry issues (low pH, high metal concentrations) as a component of a holistic approach to restoring environmental conditions.

Jan 1, 2003

By Detnet Solutions

1. “Daisy-Chain” concept The term “daisy-chain” stems from the fact that when the HotShot? detonators are connected there is a chain or electrical path for electrical current to flow from detonator A to detonator B, detonator B to detonator C etc until the path is terminated by an electrical means. The “daisy-chain” concept has long been used in electronic detonator systems, historically used in Expert Explosives’ ExEx 1000 5/6 wire system and currently in use in African Explosives Limited (AEL’s) Electrodet? electronic detonator system and has been adopted as the basis upon which the “auto-programmability” of the HotShot? electronic detonator system functions. HotShot? Detonators are connected to each other in a string, completing a “daisy chain”, and during the auto-detection mode of the control equipment, it is possible for the equipment to determine the order of hookup of the detonators as well as map the entire blast layout. The auxiliary components (Row Controllers & Branch Controllers) assist the control equipment in mapping the entire blast by indicating different points on the blast, i.e. The inflection point of a row of blast holes on a closed chevron timing pattern, the beginning of row of blast holes on open chevron timing pattern and extra blast holes or extra blast rows.

Jan 1, 2004

The combined production value of natural abrasives, which consist of tripoli, special silica stone, garnet, and emery, decreased in 1985. Shipments of processed tripoli increased slightly in quantity but decreased 6% in value, Production of garnet, an abundant iron-aluminum silicate, increased 24% in quantity and 20% in value. There was an 11% increase in the quantity and a 7% increase in the value of refined garnet shipped when compared with 1984 shipments, a new record high. Production of crude special silica stone decreased 10% in quantity and 14% in value, and shipments of finished special silica stone products decreased 85% in quantity and 68% in value. Both the quantity and value of special silica stone finished products sold or used were the lowest since 1981. Production of emery, an impure aluminum oxide, decreased 56% in quantity and 61 % in value of product mined and shipped. [ ]

Jan 1, 1987

By Rebecca Hope, Derick Moolman, Frikkie Malan

"Despite the lip service that has been paid to pro-active plant maintenance processes over recent years, a significant portion of maintenance in industry is still reactive. The business driving force to prevent expensive production opportunity costs arising from “break-down maintenance” is obvious. Various benefits can be derived from successfully deploying remote equipment diagnosis technology and associated business processes.From an end-client’s viewpoint these include the ability to predict and take actions to prevent equipment breakdowns, increasing the lifetime of equipment by responding to appropriate operating instructions and therefore improving the return on capital expenditure. Better planning and scheduling of maintenance priorities and resources with performance measures like an Equipment Health Index are also possible. The knowledge that a qualified supplier engineer is constantly in touch with the operating conditions of their equipment, albeit remotely, is more than a comfort, and can be translated into quantifiable cost savings and improved supplier service levels."

Jan 1, 2003

By Henri-Louis Jacob

Le secteur des substances non-metalliques repose au Quebec sur !'exploitation et la transformation d'une dizaine de mineraux ainsi que sur la production de materiaux de base destines surtout a l'industrie de la construction. L'ensemble de cette production representait en 1982 une valeur estimee a plus de 797 millions $, soit tout pres de 400Jo de la production minerale du Quebec. L'amiante et Jes scories de titane destines a la production de pigments, qui comptent parmi Jes plus importantes substances minerales produites au Quebec, representent respectivement 370Jo et I 70Jo de la valeur totale des non-metalliques tandis que le groupe des materiaux de construction represente pres de 400Jo. Les autres substances, parmi lesquelles ressortent nettement la tourbe, la silice et la magnesite, representent une valeur totale de 61.5 millions $.

Jan 1, 1984

By He De-wen

The municipal solid waste is a by-product of the daily life of urban residents. The quantity and ingredients of municipal solid waste has exceeded the current management and disposal ability, which has done a great harm to municipal environment and sanitation quality and threatened people?s health. On the basic of analysis on the amounts and main elements of municipal solid waste of Changsha City, the sanitation landfill, incineration, composting, reclamation and utilization technology of household waste were compared specifically in this paper. Based on the concrete conditions of Changsha City, the paper has proposed a disposal proposal combined with reclamation and landfill of municipal solid waste of Changsha City, and the environmental benefit, social benefit and economical benefit of the prepared processing routes were also analyzed in the paper.

Jan 1, 2009

Jan 1, 1967