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By Jeffrey D. Winterton

Keywords: Copper, ion exchange, sulfonic acid, bis-picolylamine, ion exchange modeling, ion exchange kinetics As part of an investigation into the feasibility of using ion exchange resins to recover copper from aqueous waste streams generated during the manufacturing of semiconductor devices, the uptake of copper onto two ion exchange resins was investigated. The resins studied were DOWEX G-26, a standard gel type sulfonic acid resin, and DOWEX M4195, a macroporous chelating resin with a bis-picolylamine functional group. The equilibrium and kinetic behavior of the uptake of copper were investigated over a range of copper concentrations with constant sulfate concentration and different levels of acidity. The homogeneous structure of the G-26 resin yields equilibrium relationships that fit the Langmuir equation, and equilibration times of less than 30 minutes. The uptake behavior of M4195 is complicated by the need to absorb co-ions to maintain electroneutrality, resulting in uptake profiles that change character with increasing copper concentrations, and extended equilibration times.

Jan 1, 2005

By Martin A. Elliott

The Bureau of Mines began its investigation of the use of Diesel engines underground to provide technical information necessary to assist this development in the United States. It was considered desirable to furnish such assistance because successful European developments/ in this. field had indicated that Diesel mine locomotives might be safer than electric trolley locomotives. The Bureau has recognized for some time the importance of eliminating the hazards associated with underground haulage systems using bare trolley wires. For example, each year 30 to 40 fatalities occur as a result of electrocution by contact with bare trolley wires. In 1943 and 1944, 101 men were killed and extensive property damage occurred as a result of mine fires started by falls of roof grounding the bare trolley wires.

Jan 1, 1948

By G. L. Oldright, Virgil Miller, F. K. Shelton, Keck. W. E., Horst Sieg

Potash is one of the principal foods and is necessary for the growth of most vegetables, grains, and fruits. For many years, this country depended entirely upon foreign sources for its supply of potassium compounds. However, during the last 15 years the domestic production of potash has gradually increased, as shown in table 1. 7/ Imports now supply only half of the American market. In 1936, the equivalent of 207,000 tons of K20 was imported, and 210,000 tons was produced domestically. In 1935, domestic consumption was approximately 420,000 tons of potash, a 57 percent increase over that for 1934 and surpassing previous peaks of 1928 and 1930.

Jun 1, 1937

By Peter N. Calder, J. L. Workman

There are many opportunities for computers to assist in dragline mine planning. Three important areas particularly lend themselves to computer assisted study. These are overall mine design and planning, the computation and display of range diagrams and the calculation of production and production variability. The computation of range diagrams is of particular interest because of the importance of matching the dragline and site geometries. This paper examines the uses of range diagrams in dragline mining and illustrates the application of computer techniques to the computation using one such program as an example. The use of computer generated range diagrams for machine selection, pit design and in parameter analysis is discussed. Directions for further development are also provided. There is a great deal that can be done to additionally enhance the ability to provide accurate designs for the dragline operation. One area that needs special attention is the dumping of overburden around access ramps into the pit. This situation is one of the most difficult dumping sequences and affects machine selection and pit operation. It is also suggested that programs that simulate the production schedule of the drag-line would be useful. It is concluded that large overall mine planning programs are very important in dragline mining. However, smaller programs designed for a specific, task are also important tools in many cases. These are easy to learn and use, well adapted to the PC environment and provide useful information, both for design and for daily planning.

Jan 1, 1989

By Ronald W. Stingelin

This study undertook the development and implementation of a methodology for estimating the impact of coal seam interaction on the eastern bituminous underground reserve base as published in USBM Information Circular 8655. The effects of previous mining in multiple coal seam areas on currently mined and reserve seams are predicted as a percentage coal loss by an engineering assessment model called the Coal Loss Calculation Model. The model utilizes twelve input variables easily derivable from mine maps or other existing data sources and calculates the effects of subsidence and high-stress due to remnant pillars in the previously mined seam. Extensive literature review resulted in the identification, definition, and quantification of the critical variables of seam interaction. Export opinion surveys were made of mining experts, MESA mine inspectors, and coal mine operators. Statistical analysis was used to establish the redundancy of the critical variables and to develop a total coal loss prediction algorithm. A regional analysis resulted in the production of a series of thematic maps on coal characteristics and distribution. A derivative map showing the areas of commonality within the eastern bituminous coal region served as the basis for implementation of the coal loss calculation model. The model was developed and tested using data from four coal mines in western Pennsylvania and southern West Virginia.

Jan 1, 1976

By I Ross, C deWolfe

Block caving has been the favoured mining method for large underground hard rock mines for the last few decades. The orebody must be of a size large enough to cave and generally amenable to a caving method. Typically, these mines ranged from 15 000 to 50 000 tonnes per day (50 kt/d) and have been some of the largest and most productive underground mines in the world.Now mining companies, in the quest for improved shareholder return, are looking for higher production rates from new underground mines. Whether a ‘Greenfields’ development, or a replacement for ageing large open pit mines, minimising capital and maximising production has been a focus of project teams. These new block cave mines are what have become known as ‘super caves’. These caves range from 80 kt/d to over 150 kt/d and are being planned or constructed by several major mining companies including Codelco, Freeport-McMoRan, Newcrest and Rio Tinto.Issues facing these super caves include high initial capital costs, very long development periods and significant technical challenges. These issues tend to make it difficult to present an attractive business case for such a project.This paper will discuss some of the potential benefits as well as the technical challenges and risks of operating a mine with the block or panel caving method at these very high tonnage rates. Considerations including geotechnical conditions, development rates, panel widths and ore column heights are discussed. The risks associated with these technical challenges and potential benefits for successful approaches will also be discussed.CITATION:deWolfe, C and Ross, I, 2016. Super caves – benefits, considerations and risks, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 51–58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By J. N. Van der Merwe

The data base of failed pillar cases as used by Salamon and Munro (1967) in their original analysis to determine the strength of coal pillars empirically, has been updated for this study. It is shown that the Vaal Basin and Klip River coal fields exhibit similar behaviour that differs from the failures in other areas, i.e. failure at high safety factors within a short period of time. Those collapse cases have been omitted from the new data base. Failures in the other areas that occurred after 1967 have been added. Using a technique to minimize the area of overlap between the populations of safety factors of failed and intact pillar cases, the new data base was re-analysed in conjunction with the original Salamon-Munro data base of intact pillar cases, from which the cases in the areas of weak coal were likewise eliminated. It was found that a linear formula reduced the overlap area by22%. The new formula predicts higher strength for pillars with a width-to-height ratio greater than approximately 2.0 to 3.0 and a lower strength for smaller pillars. It was also found that in order to obtain the same relative measure of stability as with the Salamon-Munro formula, the strength constant in the new formula should be within a range of 2.8 to 3.5 MPa. For most current South African coal mining conditions, using the new formula for pillar strength will result in leaving smaller pillars without sacrificing stability. The reason for this is that the Salamon-Munro formula under-estimated the strength of larger pillars and over-estimated the strength of smaller pillars. The new formula will thus result in improved reserve utilization without sacrificing stability.

Jan 1, 2003

Jan 1, 1987

By Elisiane Maria Berton

Neste trabalho propõe-se o estudo do efeito do processo de SHTPN (Tratamento térmico de solubilização após nitretação por plasma), e do tratamento térmico de têmpera e revenido sobre a microestrutura, dureza e resistência à corrosão do aço inoxidável ferrítico AISI 409. Por meio do SHTPN obteve-se uma camada martensítica de nitrogênio na superfície do aço. Após o SHTPN as amostras foram temperadas de 950°C e revenidas nas temperaturas de 200, 400 e 600°C. A resistência à corrosão foi avaliada por meio da técnica de polarização cíclica e a dureza através de ensaios Vickers. Verificou-se que o SHTPN afetou significativamente a dureza do aço e o tratamento de têmpera refinou e melhorou a distribuição da martensita de nitrogênio. A camada martensítica formada apresentou espessura da ordem de 660 ?m. Os resultados indicam que é possível obter uma camada martensítica com dureza de 620 HV e aumento da região passiva, bem como do potencial de nucleação de pite quando comparado à condição não tratada (ferrítico). O melhor resultado de corrosão foi obtido para a amostra revenida na temperatura de 200°C.

Aug 8, 2018

By Peter Claus

In the last years, supported gold catalysts with particle sizes smaller than 10 nm have attracted a lot of attention. While gold bulk metal is rather inert in chemical reactions and, thus, is of low interest for catalysis, highly dispersed gold particles supported on oxides as TiO2 or ZrO2 show surprisingly high activities in some reactions important for the chemical industry. The oxidation of carbon monoxide at low temperatures is mainly used as model reaction to study the unusual properties of gold catalysts [1]. On the other hand, to evaluate the catalytic potential of gold, other chemical reactions which allow to control also the selectivity have to be considered. The selective hydrogenation of ???-unsaturated aldehydes to allylic alcohols is of both commercial relevance (e.g. in fine chemical and pharmaceutical intermediate production) and specific scientific interest [2]. Note that thermodynamics favors hydrogenation of the C=C over the C=O group (stronger negative free reaction enthalpy of 35 kJ/mol), and for kinetic reasons the C=C bond is more reactive than the C=O group. Thus, in the presence of most of the conventional hydrogenation catalysts, based on Pt, Rh or Pd, -unsaturated aldehydes such as acrolein and crotonaldehyde are hydrogenated predominantly to the saturated aldehydes and only to a minor extent to unsaturated alcohols. Therefore, it is desirable to find catalysts which are able to control the intramolecular selectivity by hydrogenation preferentially the C=O group while keeping the olefinic double bond intact (Fig. 1).

Oct 1, 2003

By J. M. Campbell, T. S. Buxton

The most widely used methods of predicting the volumetric properties of gas are based on the principle of corresponding states, which asserts that the compressibility factor is a universal function of reduced temperature and pressure. Previous studies have shown that the acentric factor, as proposed by Pitzer, l is an important addition to reduced pressure and reduced temperature as factors affecting the compressibility factor. Results of this study indicate that, if the pseudocritical temperature and pressure used to determine the reduced conditions are adequately predicted, characterization of natural gas-carbon dioxide mixtures with the acentric factor will allow reliable determination of the compressibility factor. Comparisons of predicted and experimental compressibility factors have shown that the pseudo-critical constant rules of Stewart, Burkhardt and Voo 2 are satisfactory for hydrocarbon mixtures. However, these rules fail to predict the pseduo-critical constants for hydrocarbon-carbon dioxide mixtures. Based on graphically determined pseudocritical temperatures for binary hydrocarbon-carbon dioxide mixtures, a correlation which gives the required correction to the Stewart, Burkhardt and Voo rules was prepared and a compressibility factor prediction technique was proposed. To test the proposed technique, compressibility factors for live mixtures of methane, carbon dioxide and either ethne or propane were experimentally determined at 100, 130 and 160F and pressures up to 7,026 psia. The predicted and experimental compressibility factors for these live mixtures had an average absolute deviation of 0.55 percent. INTRODUCTION Two-parameter generalized correlations based on the principle of corresponding states (PCS) are presently available for reliably predicting the compressibility factor of lean natural gas, i.e., natural gas with low concentrations of hydrocarbons heavier than methane. When these same correlations are used for mixtures of natural gas and carbon dioxide, large deviations between actual and predicted compressibility factors are observed. This study was undertaken to provide a means for accurately predicting the compressibility factor for such mixtures. In the past, two avenues of approach have been employed to extend the applicability of the PCS. The first has been to introduce additional parameters. The second has been to develop combination rules for predicting pseudocritical constants which do not suffer from the limitations of the commonly used molal average constants. In this study, both of these approaches have been considered and employed to arrive at a method for predicting the compressibility factor of mixtures of hydrocarbons and carbon dioxide. SELECTION OF A THIRD PARAMETER Failure of the original PCS to predict the compressibility factor for all pure gases, regardless of their mass, shape or polar moment, has led to the introduction of additional parameters into the PCS. Parameters have been introduced to correct for quantum deviations,3-5 non-spherical or globular shapes6-9 and for polar moments.8-12 In addition to these parameters which are based on some microscopic property and intended to correct for some specific cause of deviation, more general parameters based on some bulk property have also been introduced.1913-16 To use additional parameters to correct for each of the possible causes of deviation among the individual constituents of a gas mixture would require a rather complex form of the PCS. To maintain the PCS in as simple a form as possible, it is more desirable to have a single third parameter which is based on some bulk property influenced by several of the factors causing deviations. The third parameter selected for use in this study is a factor originally proposed by Pitzer.9

By S. Constantinides

Over the past 100 years we have witnessed a revolution in permanent magnetic materials. Prior to 1932 electrical machinery depended upon steels for both the soft and the permanent magnet structures. Because permanent magnet steels were easily demagnetized, motors, generators, loudspeakers and similar devices often used the interaction between two electromagnets. Motors and generators were mostly of the induction type, depending for function upon induced fields. The discovery of Alnico in 1931 and its rapid commercialization presaged an expansion of the industrial revolution and today, permanent magnet structures are widely utilized. [ ] DEVELOPMENT OF PERMANENT MAGNETS Act 1: Early Days of Permanent Magnets Alnico, which stands for aluminum, nickel and cobalt, is a family of alloys with similar structure and processing requirements. Additional elements, such as copper and titanium, are present in minor amounts to optimize magnetic properties. Alnico is known by many trade names around the world including Alcomax, Hycomax, Ticonal, Nipermag, Koerzit, Oerstit, Nialco, etc(1,2,3). In addition to the generic name ?alnico?, it is usually appended with a number representing the magnetic grade.

Jan 1, 2011

By M. L. Fuller

MOST commercial alloys undergo changes in phase composition after casting. This is a natural result of the fact that the alloys are not in a state of phase equilibrium as cast and phase changes will therefore take place, with more or less rapidity, in an attempt to attain equilibrium. The practical aspect of aging in zinc-alloy die castings concerns the changes in physical properties and in dimensions that may accompany aging phase changes. Harmful alterations have been reduced to a minimum and zinc-alloy die castings are being produced today that are so stable with respect to dimensions and physical properties that they are entirely suitable for most practical purposes1. In the first paper2 of this series, and in this paper, aging phase changes of zinc alloy die castings have been investigated and the possible influence of these changes on dimensional changes of the castings has been evalu-ated and compared with the dimensional changes actually experienced. The change of dimensions has been selected for practical comparison in these papers because the effect of phase changes on the dimensions of a casting is directly calculable; from X-ray crystal-analysis data of the phase structure. The die-casting alloys considered contain, in addition to zinc, 4 per cent of aluminum, about 0:03 per cent magnesium, and from 0 to 3 per cent of copper. It was shown in the former paper that the eutectoidal decomposition of the beta aluminum-zinc phase, while intrinsically capable of causing a considerable shrinkage, can have very little effect on the observed shrinkage of die castings because it takes place within a few days of aging, whereas the observed shrinkage continues for five weeks. It was therefore concluded that the other existing phase change,

Jan 1, 1935

By J. Darlington, A. K. SenGupta

Water-swellable layered silicates, namely, the smectite clays can remove suspended materials (called herein as debris) and metal ions from aqueous streams. The present study shows that the flocculating and metal extracting abilities of smectite clay-based flocculants can be enhanced when these clays are used in conjunction with a specific anionic polymer. Such performance enhancement is attributed to the following: i) the clay-dispersing ability of the polymeric additive, that would translate into an increase in the clay-surface area available for the attachment of the debris particles onto the clay particles; ii) the possibility of dispersant-to-coagulant transition of the polymer during the later instants of the treatment process, as a result of reduction in solvency of the wastewater for the polymer due to the release of cationic species from the clay-based flocculant solids; iii) metal-complexing ability and adsorption properties of the polymer.

Jan 1, 2002

By K. Y. Vasioutchkov, Y. F. Vasyuchkov, B. M. Vorobjev

In general a term "unconventional mining or "non-traditional mining technology" getting more and move familiar to the mining engineering media. There are several alternating terminological combinations such as "in situ mining", "borehole mining", "shaftless mining", "mineless mining", "geotechnology" etc.; specific terms denote particular method of unconventional mining technology: "underground coal gasification in situ", "underground coal combustion in situ", "borehole hydraulic coal mining" and others. Principal scheme of unconventional coal mining technology is shown in [Figure 1:] One of the greatest potential for coal utilisation during the beginning decades of on coming cetury is the synthetic fuel-gas derived from coal as a product of coal gasification. It is quite logical to enrich this gas before burning it with natural gas, that is methane, contained in coal measures. Thus it is reasonable to suggest a new concept of unconventional coal mining and utilization technology featuring integrated methane drainage with coal-gas combined cycle. Proposed unconventional technology of coal mining is characterized with: - opening up a coat deposit through boreholes, drilled from the surface and used for coalbed methane drainage as well as for coat gasification in situ; - aggregation of methane producing and coal gasification station on mining side with thermo power plant on the electric power generation side in one integrated industrial enterprise. The further improvement of the conventional coal mining technologies both surface and underground could give only insignificant results in economical, ecological and social aspects, but would not be able to provide basic requirements of the XXI-st century. Significant increase in economical efficiency, cardinal humanization of coal mining and basic improvements in environment protection would be achieved through introduction and implementation of innovative or unconventional coal mining technology. These considerations are applied on both coal production and coal utilization sides as far as coat based energy generation is concerned. Now a general opinion is widely spread that an application in the same manner of the traditional technologies of coal mining and electric power generation would inevitably cause further irreversible damage of the global eco-system, notwithstanding the certain environment protection measures being taken. Keeping the recent pace of the eco-system degradation the whole our civilization would be in danger. Thus the solution of this problem is to be found in developing, promoting and implementing in industry unconventional coal mining and modern advanced clean coal technologies. Coal reserves with favourable conditions at shallow depths are -being rapidly depleted in all countries with developed coal industry. So in nearest future more coat will be mined from deeper levels with higher operational expences and with lower labour productivity. For example in Russia only 20% of proven coal reserves can be specified in quality as easy mined reserves, i.e. coal reserves with a good minability. Unconventional (borehole in situ) coal mining enables us to mine difficult coal reserves, deposited under unfavourable geological conditions with higher economical and socio-ecological efficiency than that in conventional coal mining, in view of these the basic principles and concepts of coal mining and coal utilization for energy generation should be reconsidered taking into account the latest achievments in underground coal gasification/combustion, coalbed methane extraction, clean coat technology and advanced developments in environmental engineering. The authors have developed a new concept of ecologically clean and resource saving coal-gas electricity, protected by a patent of Russian Federation (1995). The main principles and technological features of these conceptual technologies are explained hereupon. It should be a break through into a coal mining technology of new generation, which is known as unconventional coal mining technology. Under current global energy policy, transection to the new generation of coal mining technology is inevitable. Now we are standing at the treshhold of the coat's regeneration based on integrated unconventional coal mining and innovative coal fueled electric generation technologies.

Feb 24, 1997

By Constantin Pitis, Paul Slatter, Behnam Pirouz, Laura Contasti, Markus Zeller, Sadegh Javadi

"The centrifugal slurry pumps feeding cyclones are critical components used in the grinding process. It is well known that for this type of pumps the performance degradation is very intense. To minimize downtime a complete stand-by slurry pump is always installed in a parallel circuit. The replacement decision of slurry pumps is sometimes set on specific periods of time that are empirically determined, based on previous experience; unless a pump failure triggers the second (standby) pump. Given the significant energy costs in the grinding process and a desire to increase competitiveness, engineers and scientists started research in this field while manufacturers also took actions in order to improve pumps reliability and performance. The lack of standardization regarding the methods used to benchmark and evaluate the energy performances of cyclone slurry pump systems in the mining industry makes it difficult for an enterprise to take informed decisions concerning the replacement or optimization of its process based on energy benchmarking of such slurry pump systems. This paper proposes a new methodology of benchmarking slurry pump performances using a new concept of Benchmark Energy factor (BEF) based on Mathematical Model Benchmarking. The concept of BEF has been proven successful in other industries. A new standard addressing the guidelines for benchmarking the energy performance of slurry pumps for cyclones was proposed within the Canadian Standards Association. This standard will provide a unified and consistent methodology for performing measurement activities with the ability to measure and verify the system energy performance in the field through the BEF approach. Practical examples based on the new concept are presented with comments."

Jan 1, 2017

By Chris Bennett, Glen Kosick

"Process modeling and equipment sizing procedures for SAG circuits has advanced significantly over the past two decades. However, no matter how exact the hardness tests, models and scale-up calculations, if the ore samples being used for design do not accurately represent the orebody then major design errors can be encountered. This paper will describe a hardness testing method for identiQing the power requirement profile of an orebody, to an extent that design errors due to poor sampling can be greatly reduced or avoided altogether. It will provide some insight into the magnitude of hardness variability that can be encountered in an orebody. Finally, the paper will preview how detailed hardness distribution data can be incorporated into mine block models, to optimize SAG circuit design for an orebody, both fi-om a capital investment and throughput point of view.INTRODUCTIONIt has long been known that many SAG/AG' circuits experience wide swings in throughput. These throughput variations are almost always of a magnitude not anticipated in the plant design; consequently, they are detrimental to the expected return on investment for the mining companies. It is clear that the throughput swings are mainly caused by changes in ore hardness. In 1993, in an attempt to address this problem, MinnovEX began investigating the possibility of using a small scale SAG test (2 kg charge) to predict SAG power requirements from drill core samples. The objectives of the small scale test were to enable mining companies to do many more SAG hardness tests than currently undertaken for a particular orebody. To make this possible, the SAG tests had to use a minimal amount of sample, be cost effective, and give acceptable accuracy in the prediction of SAG power. If this small scale SAG test proved accurate, then the high sampling frequency would yield results that approach the true hardness distribution of an orebody. This hardness distribution could then be used to derive the distribution and variability of specific energy required throughout the complete orebody. This specific energy (kWh/t) can be thought of as the power required to grind one tonne of ore per hour (kW/tph) to a specified size. Once the true distribution of power requirement throughout the whole orebody is understood, the grinding circuit design team can make an informed decision regarding the hardness value that is most appropriate for sizing the SAG equipment. Throughput losses due to hardness variation could be deliberately planned for or avoided altogether (a capital cost decision)."

Jan 1, 1999

By Robert S. Williams

NO new ferrous alloys have been produced in the last five or six years that are as outstanding contributions to civilization as were the high-speed steels of the early part of the century or the stainless steels announced at the close of the World War. There have been, however, many developments of major importance having to do either with modifications of existing alloys or with new methods of treatment of older iron or steel alloys. Only a limited number of these new developments can be discussed and their selection does not necessarily imply that these are the most important but merely that they are of general interest rather than perhaps of greater importance in highly specialized fields.

Jan 1, 1939

Extending an organization?s knowledge base throughout the entire enterprise can improve operations. Until recently, though, field operations were often left out of the information loop, as extending high-bandwidth communications into harsh environments often proved impossible due to thermal extremes, physical hazards and caustic chemicals. However, advances in the design and manufacture of rugged fiberoptic cables have now enabled the successful installation of 10-gigabit transmission links to places such as mining operations. The experience of Consol Energy exemplifies how plant managers can successfully enlist ruggedized tight buffered cables to help carry the efficiency of ERP communications into even the most challenging work environments. ?As part of our ERP implementation, we extended our corporate network underground into our mines using fi beroptic cable,? said Tom Prokop, manager-site support for Consol Energy. ?We?ve actually had rooffalls bury the cable between rocks and still did not lose data communications. Our maintenance personnel are now able to access our ERP system while underground at locations that can be up to 32 km (20 miles) away from their desks or the warehouse. Access to the corporate network allows them to order parts, look at electronic schematics, access monitoring data, no matter where they are in the mine. With a few hundred workers below ground, this immediate access translates into a time-savings that adds up in a hurry.?

Jan 1, 2009

By George Koenig

I have been granted the outstanding privilege... and pleasure to introduce you this evening to the Grand-Duchy of Luxembourg and to tell you in a few words how this country came into existence, how it managed to survive and what role it nowadays plays in the International Community. Luxembourg, situated between Belgium, Germany and Prance is a small, a very small country... just a dot on a map. After all, it is only a matter of 62 miles from top to bottom and 37 miles across at it's widest... barely covering some thousand square miles... so be careful about stepping on the accelerator... you might be in and out without having realized it... which would be a real shame as the Grand-Duchy enjoys a fairly unique geographical feature in so far as it provides the visitor with an outstanding variety of scenery concentrated in a minute spot.

Jan 1, 1987