Search Documents

By J. L. Workman

The Putnam Coal Mine, at design capacity, will be the third largest underground bituminous coal mine in the world and will feature the world's longest single flight belt conveyor. Construction is now in process; initial mining will commence in early 1969 and design capacity will be reached in 1971. The Putman Coal Mine reserves are located in south-central West Virginia and contain approximately 27,000 acres of prime Pittsburgh No. 8 coal; reserves are sufficient to support a 3.5 million tpy operation for over 30 years. The mine portal area is located some six miles inland from the Kanawha River. The river loading facility is located approximately 156 miles by way of river from the market.

Jan 1, 1969

The Putnam Coal Mine, at design capacity, will be the third largest underground bituminous coal mine in the world and will feature the world's longest single flight belt conveyor. Construction is now in process; initial mining will commence in early 1969 and design capacity will be reached in 1971. I'm Jerry Workman, Assistant Mining Manager for the Coal Group of the Mining and Metals Division of Union Carbide Corporation, and I am acting as Project Manager for installation and start-up of the Putnam Mine. The Putnam Coal Mine reserves are located in south-central West Virginia and contain approximately 27,000 acres of prime Pittsburgh No. 8 coal; reserves are sufficient to support a 3.5 MM tons per year operation for over 30 years. The mine portal area is located some six miles inland from the Kanawha River. The river loading facility is located approximately 156 miles by way of river from the market.

Jan 1, 1968

By C Catania

Mining companies and operations across the globe typically target best practice financial management, along with a focus on economically driven mine plans. Not only is this inherent in running a successful mining business, but also critical in addressing investor scrutiny. The standards for social and environmental practices is less consistent than this, with most companies adopting standards that are driven through legislative and compliance requirements of the nations in which they operate. Although there is still room for improvement, Australian is a country that stands at the forefront of social and environmental legislation, driving more sustainable planning practices for mining operations, with an ever-increasing focus on mine closure considerations. Of the many nations yet to reach such a legislative position, Kazakhstan is a place where some companies are driving towards world class standards beyond what is government mandated. CITATION:Catania, C, 2018. World-class mine planning for a sustainable future in Kazakhstan Mining, in Proceedings Life-of-Mine 2018, pp 6–7 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By William I. Weisman

Natural sodium sulfate is obtained from both brines and solid deposits. The brines almost always contain other salts with sodium chloride predominating. They may be obtained from surface occurrences, such as Great Salt Lake or from shallow subterranean deposits. Althought many sodium sulfate minerals are known to exist, only three are of commercial significance. These are thenardite, the anhydrous salt; mirabilite, the decahydrate; and glauberite, the double salt of sodium and calcium sulfate. The reader is referred to Weisman (1983) for details on mineralogy and geology of sodium sulfate minerals. Sodium sulfate deposits, either in the form of brine or solid minerals, are found in many parts of the world. Natural sources, by far, provide the primary supply of commercial grades in Canada, Mexico, Spain, and probably in the U.S.S.R., Chile, Argentina, and Turkey. In the United States, production of natural material and synthetic (including by-product) are about equal in volume and have been for many years.

Jan 1, 1984

By J. Silva, T. Worsey

The Worsey-Silva equation determines the optimal row timing for the smallest fragmentation and allows fragmentation models to be adjusted due to row timing. The equation utilizes the concept of dynamic confinement to determine when the best time to fire the next row or sequence series would be if the smallest fragmentation is desired. Full-scale testing was conducted at an aggregate quarry in Ontario to support the theory and equation. The full-scale testing comprised six (6) blasts, two (2) different contractors, and three (3) different sequences. The test parameters were kept consistent, besides changing the timing between sequential charges to explore the timing sequence’s influences on fragmentation. From this research, the theory of dynamic confinement relating to row timing was discovered, and the equation to determine the optimal timing for the smallest fragmentation was derived. An equation to adjust fragmentation based on row timing was derived from the full-scale testing and literature review. The Worsey-Silva equation can be used with other fragmentation models as it takes the fragmentation results from the other models and adjusts them based on the row timing used. The paper explains the theory behind the equation, the research supporting the findings, and the developed Worsey-Silva equation for row timing

Jan 1, 2024

By T. Rahimzadeh, C. W. Trueman, S. Farzaneh, S. V. Hoa, I. Abdalla

This paper presents the shielding effectiveness (SE) of woven continuous carbon/epoxy composite materials. The theoretical and physical concepts behind the experimental results are demonstrated in details. The influence of frequency, the overlapping angle between overlapped layers and the number of overlapped layers upon the EMI shielding of composite sheets are discussed. In this work, in particular, the epoxy layers are considered as dielectric apertures of the conducting carbon fiber slab for the interpretation of the experimental results. The experimental results, using ASTM standard D4935-89, indicate that the SE can reach values greater than 90 dB above 500 MHz.

Jan 1, 2006

By Darren S. Diehm

"Construction for the restoration and expansion of 102-year-old Wrigley Field in Chicago, Illinois began at the conclusion of the 2014 baseball season. This six year project involves structural upgrades to the Stadium, improvements to the facade, infrastructure, restrooms, concourses, suites, press box, and bullpens, as well as the addition of restaurants, patio areas, batting tunnels, video boards, an adjacent Office-retail Tower and a new Hotel. The Bleachers were demolished and replaced, and a new underground Clubhouse was constructed for the Chicago Cubs beneath a new open-air Plaza. The 1060 Project is privately funded, projected at $750 million (US). The work will be completed in phases during consecutive off-seasons, each with a maximum 23-week duration extending through the Chicago winter. Ownership mandated that on-going construction cause no disruption to the Major League Baseball season, have no impact on hosting concerts and other special events, and it should not adversely affect seating capacity, or diminish the fan experience.The 1060 ProjectAfter purchasing the Chicago Cubs baseball team in 2009 from the Tribune Company, the Ricketts family began planning the renovation and improvement of Wrigley Field and its near neighborhood surroundings in Chicago, Illinois. What came to be known as the 1060 Project was officially announced at the annual Cubs Convention in 2013. Construction began on the $750M privately funded project in October 2014 at the conclusion of the Major League Baseball season. In their vision, the Ricketts committed the 1060 Project to three primary goals. First and foremost as a MLB franchise, the work should provide a meaningful contribution toward winning the World Series and ending the championship drought which stretched to the last win in 1908. Second, the project should be focused on preserving and improving Wrigley Field. Finally, the project should be committed to outcomes that enable the team to be a good neighbor and provide economic and social benefit to the local community.Constructed as Weeghman Park in 1914 for an estimated total cost of $250,000, the stadium provided seating for 18,000 fans and a home for the Chi-Feds and Whales of the National Federal League. The Chicago Cubs were enticed to move from the West Side Grounds in 1915. In the next 100 years, the Wrigley Field would be sliced apart and expanded, double its seating capacity with the addition of double deck grandstands, be enclosed by bleachers (and an ivy covered wall), and, in 1988, experience its first nighttime baseball game with the addition of lighting.The 1060 Project has a total budget of $750M, with an expected construction value of $350M. It is projected to add over 2,100 jobs to the economy and be completed before the 2020 baseball season. The work will be completed in phases during consecutive off-seasons, each with a maximum 23-week duration extending through the Chicago winter. Ownership mandated that on-going construction cause no disruption to the Major League Baseball season, have no impact on hosting concerts and other special events, and it should not adversely affect seating capacity, or diminish the fan experience."

Jan 1, 1900

Jan 1, 1947

By K. Heatwole, D. Shier, A. Davis, J. Kidder, S. Sunkavalli

"Acid rock drainage (ARD) is produced when sulfides are exposed to oxygen and water. Oxidation reactions typically result in a depression of pH and leaching of solutes and metals. Many oxidation models have been developed based on oxygen diffusion, but in environments with high permeability, other transport processes (i.e., convection and advection) can play an important role. Multiple sulfide mineral phases with differing oxidation rates should also be incorporated. WROC, a finite-difference model, was developed to account for these factors in predicting ARD. The program includes sulfide mineral oxidation using a shrinking core mechanism, heat transfer by conduction, heat of reaction and oxygen transport by diffusion and advection. The model was validated using data from the literature. After validation, the WROC model was used to simulate several different waste rock scenarios, including different forms of sulfide mineralization and the effect of implementing a waste rock cover. The results demonstrate that including specific sulfide mineral phases can have a significant effect on oxidation and that implementation of a cover can also aid in reducing waste rock oxidation.IntroductionAcid rock drainage (ARD) is a notable environmental concern in areas where rock or other material with acid generation potential is disturbed. ARD is defined as drainage that occurs as a result of sulfide oxidation in rock exposed to air and water. ARD is characterized by low pH, elevated metals concentration (especially aluminum, iron and manganese), sulfate and high total dissolved solids. The low-pH water that results from acid generation is capable of solubilizing heavy metals contained within the rock. The principal sulfide mineral in mine wastes is pyrite (FeS2). Pyrite oxidation is complex and can involve chemical and biological reactions. Oxidation of pyrite by atmospheric oxygen produces one mole of Fe2+, two moles of SO4 2- and two moles of H+ for every mole of pyrite oxidized, as described by Eq. (1)."

Jan 1, 2015

By James Aston

A PROPER consideration of this subject is not confined to the technical channels of production and metallurgy. It concerns an industry, and should cover economic aspects which are of material importance in any program of development. The discussion may logically be treated under three subdivisions, as follows: (1) manufacture, (2) characteristics related to quality of material; (3) adaptability and exploitation of product. MANUFACTURE OF WROUGHT IRON The manufacture of wrought iron is the most ancient art of the ferrous metal industry. The eighty years or less of existence of processes identified with our modern "Age of Steel" is a relatively brief interval compared with the several thousand years associated with the production of wrought iron by man. From the primitive early methods of production, manufacture for many centuries followed the line of direct reduction. There were developments as experience was gained through the years; but man's needs for a strong, ductile, forgeable product were met by reducing the ore to metallic iron in a single-stage operation. Following the development several centuries ago of what has become our modern blast-furnace operation, manufacture of wrought iron was gradually transformed into a two-stage method of first producing cast iron and then refining this to the desired degree of forgeability; the forerunner in principle of today's scheme of manufacture of steel. The product retained the essential characteristics of highly refined base metal with iron-silicate slag incorporation, which were associated with the material resulting from direct reduction methods. Cort's invention of the puddling process in 1784 is a landmark in wrought-iron manufacture. It consisted essentially in adapting a coal-fired reverberatory furnace to the refining operation; thus lifting the industry out of the slough of

Jan 1, 1935

By James Aston

A PROPER consideration of this subject is not confined to the technical channels of production and metallurgy. It concerns an industry, and should cover economic aspects which are of material importance in any program of development. The discussion may logically be treated under three subdivisions, as follows: (1) manufacture, (2) characteristics related to quality of material; (3) adaptability and exploitation of product. MANUFACTURE OF WROUGHT IRON The manufacture of wrought iron is the most ancient art of the ferrous metal industry. The eighty years or less of existence of processes identi-fied with our modern "Age of Steel" is a relatively brief interval com-pared with the several thousand years associated with the production of wrought iron by man. From the primitive early methods of production, manufacture for many centuries followed the line of direct reduction. There were developments as experience was gained through the years; but man's needs for a strong, ductile, forgeable product were met by reducing the ore to metallic iron in a single-stage operation. Following the development several centuries ago of what has become our modern blast-furnace operation, manufacture of wrought iron was gradually transformed into a two-stage method of first producing cast iron and then refining this to the desired degree of forgeability; the fore-runner in principle of today's scheme of manufacture of steel. The product retained the essential characteristics of highly refined base metal with iron-silicate slag incorporation, which were associated with the material resulting from direct reduction methods. Cort's invention of the puddling process in 1784 is a landmark in wrought-iron manufacture. It consisted essentially in adapting a coal-fired reverberatory furnace to the refining operation; thus lifting the industry out of the slough of

Jan 1, 1935

By Steve Karl

"The International Tunnelling and Underground Space Association (ITA) held its 42nd General Assembly along with the 2016 World Tunnel Congress (WTC) April 22-28 in San Francisco, CA. The event was co-organized by the Underground Construction Association of SME (UCA). This was the first time the event has been held in the United States in 20 years.As cities demonstrate strong needs in tunnels and underground spaces for public transportation, subway stations, hydroelectric infrastructures and other underground infrastructure needs, the WTC 2016 provided the 2,319 attendees from around the world a unique occasion to discover the latest state-of-the art innovations in urban planning and underground construction projects in the United States and worldwide.The Congress, held in lieu of the UCA’s North American Tunneling Conference, included an exhibit that attracted 226 exhibitors in 298 booths. The exhibit had on display the latest in technical equipment and services from some of the largest and best companies in the international tunneling industry. The exhibit hall was also the place where participants were able to interact with the authors of the 168 posters and receive answers to various topics directly concerning civil engineers: innovative procurement processes, cost and risk management, contractual methods, BIM technologies and examples of innovative underground infrastructures built worldwide. And the technical program included 353 technical presentations – 185 podium and 168 posters.What is ITA?ITA-AITES is a nonprofit, nongovernmental organization that promotes greater use of underground space as a key instrument in sustainable development. Established in 1974 and based in Lausanne, Switzerland, ITA-AITES is made up thousands of professionals involved in the tunnel and underground space industry, including engineers, project owners, town planners, architects, industrial designers, companies specialized in public works and major structures, suppliers of construction site facilities and equipment, lawyers, politicians, researchers and academics, economists, financial experts and other stakeholders.ITA-AITES consists of 73 member nations and 300 affiliated members, including 15 major sponsors and 60 donors. The association is run by an executive council made up of 15 members elected by the 73 member nations, each representing a different dimension of the tunnel community."

Jun 1, 2016

By J. B. Hess, R. L. Dietrich

IN the mechanical twinning of magnesium on the {1012} planes the crystallographic deformation is such that, in the direction of the hexagonal axis [0001], twinning is possible only under tension stress, while in the directions perpendicular to the hexagonal axis, twinning is possible only under applied compression. Thus in extruded magnesium and magnesium alloys where the extruded textures are best described as either [1010] or [ 1120] fibers,1 the basal planes are all nearly parallel to the extrusion axis and such material is susceptible to {1012 } twinning by compression in the direction of the extrusion axis. In order to explain the results of cyclic stressing in alternate tension and compression upon the tangent elastic modulus in such material, Dorn and Thomsen2 have postulated that, following twinning under applied compression, a retwinning or untwinning occurs as a result of residual microtensile stresses immediately upon removal of the applied compressive force. Recently, Carapella and Shaw3,4 have used this supposition of untwinning in magnesium in discussing their results on indentation hardness and on cold drawing of MI sheet. In trying to confirm this hypothesis by suitable direct experiments, the authors have been unsuccessful in detecting any evidence whatsoever that untwinning follows the release of applied compression and are forced to conclude that this hypothesis is improbable or, at least, that the quantity of material involved is small. For the experiments, small cylindrical specimens 0.040-in. diam. X 0.120- to 0.140-in. long were etched from 0.0625-in. extruded rod. The ends of the specimens were accurately faced off parallel in a jeweler's lathe. The compression jig was simply an ordinary set of micrometer calipers with an anvil interposed between the spindle and the specimen. The anvil was free to move axially but restrained from rotating so that the rotation of the spindle would not introduce a twisting stress on the specimen. With this arrangement the compressive strains could be estimated to 0.0001 in. and X ray pinhole photographs could be taken with or without load as required. Fig 1 is the pattern of an uncompressed specimen of AZ31 alloy, showing the approximate [1010] extrusion fiber. The X ray beam is normal to the extrusion axis; in this position it is particularly sensitive in detecting twinning if one directs his attention to the diffraction ring from the basal plane. Since twinning on {1012} planes produced an 86° reorientation of the crystal lattice, the original basal reflections occur at the 3 and 9 o'clock positions while the (0002) reflections from any twinned material will occur at the 6 and 12 o'clock positions. Fig 2 shows the same specimen compressed 3.0 pct, photographed while still under load. This strain has been just enough to produce a detectible amount of twinning and the sensitivity is roughly indicated by the fact that no alterations were produced in the intensities or maxima of the other diffraction rings. A strain of

Jan 1, 1948

By T. A. Wilson, S. L. Hoyt

THE plastic deformation of slender single crystals of zinc has been described in some detail in the paper by Mark, Polanyi and Schmid,1 which has become a classic, and also by one of the present authors in a somewhat shorter account.' The study of single-crystal zinc is termed classical because zinc single crystals offer, perhaps, the best material yet available for the study of atomic behavior during deformation and the effect known as "strengthening" in metals. A considerable amount of additional work has also been done on single-crystal zinc, but as it is not closely related to the present paper it will not be considered. Throughout all the former work, the mechanism of plastic deformation first described by Mark, Polanyi and Schmid has been assumed to hold. This may be said to offer the strongest confirmation of its correctness. Even so, the picture of the process has never been as completely portrayed as is desirable. The first object of the present paper is to describe work that has been done in this field, and which is even yet being carried on, in the hope that a more complete picture may be obtained. Mathewson and Phillips' have recently described a new mechanism of the deformation of zinc based on their study of large rectangular crystals. One of their conclusions was that deformation produced twinning with a rotation of some of the basal planes into positions 94° removed from their original position; a position almost the same as that of the prismatic planes before twinning. A second conclusion was that fracture occurred along these basal planes in their new position, and, therefore that fractures previously regarded as prismatic were in reality basal. Such findings are of great significance and they raise a question as to the generality of such behavior. Professor Mathewson's opinion is that even the slender cylindrical single crystals behave in the same manner as his large rectangular crystals when strained by simple tension.

Jan 1, 1928

By T. A. Wilson

THE plastic deformation of slender single crystals of zinc has been described in some detail in the paper by Mark, Polanyi and Schmid,1 which has become a classic, and also by one of the present authors in a somewhat shorter account.2 The study of single-crystal zinc is termed classical because zinc single crystals offer, perhaps, the best material yet available for the study of atomic behavior during deformation and the effect known as "strengthening" in metals. A considerable amount of additional work has also been clone on single-crystal zinc, but as it 'is not closely related to the present paper it will not be considered. Throughout all the former work, the mechanism of plastic deformation first described by Mark, Polanyi and Schmid has been assumed to hold. This may be said to offer the strongest confirmation of its correctness. Even so, the picture of the process has never been as completely portrayed as is desirable. The first object of the present paper is to describe work that has been done in this field, and which is even yet being carried on, in the hope that a more complete picture may be obtained. Mathewson and Phillips3 have recently described a new mechanism of the deformation of zinc based on their study of large rectangular crystals. One of their conclusions was that deformation produced twinning with a rotation of some of the basal planes into positions 94° removed from their original position; a position almost the same as that of the prismatic planes before twinning. A second conclusion was that fracture occurred along these basal planes in their new position, and, therefore that fractures previously regarded as prismatic were in reality basal. Such findings are of great significance and they raise a question as to the generality of such behavior. Professor Mathewson's opinion is that even the slender cylindrical single crystals behave in the same manner as his large rectangular crystals when strained by simple tension.

Jan 1, 1927

By Sabri Ergun

This report gives the result of investigations of coals of different rank, coal com¬ponents, chemically and thermally treated and irradiated coals, and sedimented organic matter. In most studies the arbitrary parameters obtained from the usual quantitative profile analyses are not given largely because they lack physical meaning. Instead comp interpretations are offered. X-ray patterns of high-volatile bituminous and lower rank coals are not self¬-sufficient for structural interpretation by the methods of analysis developed to date. The patterns of hydrogenated and dehydrogenated coals indicate that the basic change in the structure of bituminous coals with increase in rank is the conversion of alicyclic structures into aromatic layers. In low-rank anthracites the aromatic layers are about 10 A in size. The increase in rank is the result of coalescence of layers. High-rank anthracites have layer sizes of 25 to 40 A and exhibit the development of three-dimensional (hkl) reflections of graphite, indicating ordering of adjacent layers. In meta-anthracites the layers are > 1000 A and the basic structure is that of defective crystalline graphite. The well-known petrographic components in low-rank coals have different structures; the differences dissappear in low-volatile bituminous and higher rank coals. The patterns of sedimented organic matter, except impsonites, differ from those of coal hydrogen contents are high, and their X-ray patterns are consistent with those of structures. In contrast to normal coals, the patterns of uranium-bearing coals show increased diffuseness with decrease in hydrogen content. The diffuseness is accompanied by increase in the uranium content of the coal. It is very likely that high uranium-bearing coals have predominantly tetrahedral structures.

Jan 1, 1968

By Zhuofei Yang, Jidong Kang, David S. Wilkinson

The fatigue behavior of AM60 high pressure die casting magnesium alloys was studied in a straincontrolled manner. The fatigue test was interrupted every 2,000 cycles for X-ray tomography scanning. The specimen was removed to be scanned on a desktop micro-CT system. The value of using X-ray tomography in a fatigue properties study was assessed with respect to porosity, cracks and fracture surfaces. The 3D analysis and model results showed porosity could be well measured and modelled in 3D. Defects bands are made of pores under 50 µm in volume-equivalent sphere diameter. Larger pores are randomly distributed in the region between two defect bands. Observation of cracks by X-ray tomography occurs in three ways such that the 3D model gives the best illustration of crack-porosity interaction while the other two methods have better detectability on crack initiation and crack tip observation. X-ray tomography is also of value in failure analysis on fracture surfaces. By summarizing X-ray tomography data during fatigue testing and observing fracture surfaces on a 3D model, a better understanding on the crack initiation, crack-porosity interaction and the morphology of fracture surface is achieved.

Jan 1, 2014

By J Kuva, M Parian, B I. Pålsson

One of the main factors affecting the suitability of an ore for autogenous grinding is the ore’s competency, ie providing enough critical stones for the grinding process. Several experimental test routines exist and are used for assessing the viability of the ore for autogenous grinding. However, very little attention is given to the generation of fatigue in large stones experiencing repeated shocks in the mill. To investigate this, large pebbles sampled from an industrial autogenous grinding mill running hard and soft ores were categorised based on the grinding energy. From the pebbles, small drill core samples were prepared and went through a series of fatigue cycle tests. Both hard and soft ores showed similar average resistance to failure in compression tests, but the hard ore had a consistent resistance with lower variations. The cores were scanned by XCT before and in-between fatigue tests at the highest reachable resolution, 1.5 µm voxel size. The outcome showed that a higher number of micro-cracks were visible in the soft ore compared to the hard ore. The frequency of micro-crack development in the soft ore may be the reason for its lower specific grinding energy compared to the hard ore. It is obvious that for realistic conditions in an autogenous grinding mill, stones are pre-weakened by fatigue before they fracture. Therefore, shortcut methods focusing only on running tests on fresh and small samples may operate in unrealistic conditions by ignoring the fatigue phenomenon. This is even more important for ores that are on the borderline to be considered as competent for autogenous milling.

Aug 24, 2022

By Finn Ouchterlony, José A. Sanchidrián

"A model for fragmentation in bench blasting that originates from dimensional analysis of fragmentation in asteroid collisions is presented. Percentiles of the size distribution are obtained in the basic model as the product of a rock strength-to-explosive energy ratio, a bench shape factor, a scale factor or characteristic size and a percentage passing-related factor. The parameters of the model are fitted to 169 bench blasts in different sites and rock types, bench geometries and delay times, for which thefragmentation of the muckpile was obtained by sieving. The basic model is found to significantlyimprove with an additional factor describing the rock mass structure in terms of the spacing and orientation of discontinuities, and another one describing the delay between successive contiguous shots; the latter is conveniently formulated as a function of the P-wave velocity and the holes spacing. The rock strength property chosen is the strain energy at rupture that, together with the explosive energy density in the rock (or energy powder factor), forms a combined rock strength/explosive energy nondimensionalfactor. The model, called xP-frag, is applicable from 5 to 100 percentile fragment sizes, with all parameters determined from the fits significant to a 0.05 level. The expected error of the prediction is below 25 % at any percentile. These errors are half to one third of the errors expected with the best prediction models available to date."

Jan 1, 2017

By Gao K, Wu C, Xia J, Burdett M

X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques have been adopted in this study, to investigate the structure of carbonaceous materials such as graphite, brown coal char as well as coke, in order to explain their dissolution performance during ironmaking. These materials have been selected for study since they are commonly used recarburizers in the metallurgical industry. It was concluded that the crystal structure in a carbonaceous material can have a significant influence on its dissolution into iron melts. The material with the highest degree of ordering, which is graphite, showed the best dissolution performance. In contrast, the material with the lowest degree of ordering, which is brown coal char, showed the worst dissolution performance.

Jan 1, 1996