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By Chunli Wei, Mark Jen, Xiaojun Wang

"After more than 85 years of service, a critical link between New York and New Jersey, the Goethals Bridge over the Arthur Kill waterway, is being replaced with two new parallel bridges. Each bridge includes 1,650 feet long signature steel composite cable-stayed bridge, a 2,789 feet long New York approach and a 1,889 feet long New Jersey approach. The superstructure of each approach is supported on a series of two-column concrete piers and each column is supported on a single large diameter drilled shaft varying from 4.5 to 9 feet in diameter and anchored 45 feet below ground into the underlying rock.A performance-based methodology was followed for the strength and extreme event limit states design of the drilled shaft foundations. The design for seismic loads has been performed using the AASHTO Guide Specifications for LRFD Seismic Bridge Design. For all strength and service loads, the AASHTO LRFD Bridge Design Specifications were used. Since the longitudinal and confinement requirements in the two specifications vary, the minimum longitudinal reinforcement was based on the more stringent requirements of the two codes. A design example is presented to illustrate the methodology in bridge deep foundation design using nonlinear time-history global analysis results with soil-pile interaction represented by sets of horizontal and vertical nonlinear soil springs along the drilled shaft, based on the soil and rock properties from the boreholes test results. In this paper the design methodology implements strain limits related to earthquake intensities and damage levels to calculate the capacity using XTRACT analysis, which aids designers to adopt applicable provisions that meet specific design requirements.INTRODUCTIONAfter more than 85 years of service, a critical link between New York and New Jersey, the Goethals Bridge over the Arthur Kill waterway, is being replaced with two new parallel bridges designed to carry vehicular traffic and a future mass transit corridor. They include two 1,650 feet long signature steel composite cablestayed bridges with 260 feet tall V-shaped concrete gateway towers (Figure 1). The approaches consist of continuous pre-stressed concrete girders. The New York approach is a single structure consisting of 18 continuous spans, sloping at 4% for a total length of 2,789 feet without expansion joints. Similarly, the longest continuous portion on the New Jersey approach, with a similar slope, consists of 11 spans for a total length of 1,889 feet without expansion joints. The superstructure of each approach is supported on a series of two-column concrete piers that vary in height from 121.3 feet near the cable-stayed bridges to 11.8 feet near the abutments. Each column is supported on a single large diameter drilled shaft varying from 4.5 to 9 feet in diameter and anchored 45 feet below ground into the underlying rock."

Jan 1, 2016

By C. Hosten, K. V. S. Sastry, D. J. Kawulok-Englund

Since the last decade the iron ore processing industry has undergone drastic changes from supplying screened and natural ores to manufacturing tailored concentrates and pellets. Increased need for the beneficiation of lower grade iron ore deposits and the increased demand for higher grade concentrates necessitate finer grinding of iron ores before concentration. The normal filtration stations used in the past are experiencing difficulties in dewatering the finely ground concentrates to moisture levels acceptable for balling. In addition to finer grinding, applications of complex beneficiation techniques has decreased the filterability of the concentrates and create problems in filtration of iron ore concentrates. An overview of the filtration literature indicates there are few research reports on the dewatering of iron ore concentrate slurries. There exists a need to understand the principles and mechanisms involved in the filtration of iron ore concentrate slurries with a goal of developing more efficient filtration techniques. This paper presents the results from the first phase of our research program that included the development of a reproducible benchscale filtration technique and the investigation of the filtration behavior of eight iron ore concentrates.

Jan 1, 1984

By R. E. Driscoll

The exploration, geologist of necessity has to have a wide working knowledge of many specialties other than hiw own, First he has to use his own technical background to find a deposit,, of a mineral that is of interest, Once found, his problems are Just beginning, He then has to assume the role of an economist, an accountant, a mining engineer, a chemist, a metallurgist,, a salesman and what-have you, In the economic field, he must determine the marketability of either the ore or the refined mineral. He must gauge the supply and demand for the particular mineral he is interested in and make his best guess as to ultimate cash flow from a deposit over the estimated life of said deposit, He must then assume the role of a mining man and estimate cost of recovery, including an, evaluation of the most economic mining method, cost of supplies and labor, and again estimate a net cash flow. He must then determine amenability of ore to economic metallurgical methods, he must determine the legal status of the property involved and, after analysis of the specific situation, determine the best approach to a deal, After all of this he must sell it to the people who will put up the money and then put his deal together and sell it to the people who own the minerals, if that be necessary. Then he has to sit back, with crossed fingers and crossed legs wondering for some months, and in many cases even years, whether or not he is right. The expenditures required to open up a mine in this day of wild inflation are such that he has to be right, and the responsibilities are awesome.

Jan 1, 1958

By T. Sterry Hunt

I HAVE lately had occasion to examine sulphuretted ores of bismuth' both from Tudor, Ontario, and Latete, New Brunswick. The former consisted chiefly of bismuth-glance, carbonated at the outcrop, and within associated with some metallic bismuth, iron-pyrites and graphite, in a quartz gangue. In the second locality, where it appears to be present in considerable quantity, the veinstone is also quartz, but the associates of the bismuth-glance are chalcopyrite and galena. The treatment of such mixed ores in the furnace for the extraction of the bismuth could yield only a very impure product, and in view of the high price of the metal I tried with success a wet method for the treatment of the ore, which is based on well-known chemical reactions, and may, in some cases, be advantageously used. The pulverized ore is dissolved by heat in commercial nitric acid, and the remaining gangue washed by displacement, first with a little strong acid (which is used to attack a fresh portion of ore) and then with a moderate quantity of water, which is added to the first solution. This, if the excess of acid be considerable, may be partially

By W. H. Blauvelt

THat the problem of utilizing anthracite waste is worthy of the thought bestowed upon it, may be shown in few words. In the year 1889, for instance, 35,408,000 tons of coal were sent to market from the anthracite regions of Pennsylvania. According to the report of the State Geological Survey, the amount of coal thrown on the dumps as waste, varies, with circumstancett, from 44 to 60 per cent. of that shipped to market. The lower of these figures represents 16,579,000 tons of waste for that year, and it is obvious that if this, or any considerable portion of it, could have been saved, it would have constituted an important addition to the fuel-supply of the country. It is not surprising, therefore, that so much attention has been given to the utilization of this waste. Among the many lines of experiment pursued with this object in view, the conversion of the carbon of the culm into producer-gas seemg at first to promise the most satisfactory solution of the problem. It is well known that in foreign producer-plants almost all kinds of

Jan 1, 1892

By G. B. Harris

Much has been written over the past decade concerning the disposal of arsenic from metallurgical processes. In Canada, there are proposed regulations which would classify arsenic in the Primary Group of twenty one persistent, toxic pollutants to be banned or phased out. Since many nickel and cobalt ores, not to mention those of copper, gold and uranium, contain significant amounts of arsenic, it is pertinent to assess the current state-of-the-art of its disposal. The literature is reviewed, and it is demonstrated that from a purely chemical point of view, the family of ferric arsenates largely immobilize arsenic. There is clear evidence from laboratory studies that both crystalline ferric arsenate (scorodite) and amorphous ferric arsenates in which the molar Fe/As ratio is at least three (Fe/As = 3) have very low arsenic solubility; plant data are given to support this. The debate over the long term stability of these compounds continues however; the evidence presented for long term stability and for compound breakdown is critically reviewed in the light? of the recent structural studies, and the role of base metals in these compounds evaluated. Finally, conclusions are drawn as to the viability of a purely chemical process for the long term disposal of arsenic from metallurgical processes.

Jan 1, 1993

By Verne E. Hooker

In situ stresses, based on isotropic and anisotropic relations, were evaluated using computer techniques from overcoring data obtained in dimension stone quarries along the Appalachian Piedmont, the Ozark Uplift, and the Ouachita Tectonic Belt. Stresses in the horizontal plane near the surface are compressive and range from 100 to 4,500 psi. The direction of maximum compressive stress seems to be alined with the general tectonic structure for most of the determinations. The ratio of the maximum to minimum elastic parameters in the horizontal plane ranges from 1.05 to 2.46 for these competent rocks. Isotropic versus anisotropic stress determinations show differences only as great as 25 percent in stress magnitude and 25° in orientation.

Jan 1, 1969

By Ximeng Zhu

The electrochemical behavior of mineral and coal pyrites in stirred and quiescent alkaline boratelsulfate solutions @H 7.9-10.5) have been investigated using cyclic voltammetry. Significant differences in the electrochemical response of these pyrites were observed. At the mineral pyrite surface, three anodic peaks at about -0.8 V, -0.1 V and +0.5 V (SCE) have been detected along with their corresponding reduction peaks. The first two peaks correspond to FeIFeOI) and FeOI)lFe(III) oxidation. The third peak is present for quiescent conditions but disappears as a distinct peak when the electrolyte is stirred. In the upper voltage region +0.30V (SCE), the current increases markedly during stirring and the reactions correspond to the oxidation of pyrite with the formation FeOII) oxides plus elemental sulfur. Also there is evidence that Fe oxy-ions form. Coal pyrites, under rapid sweep conditions display only the first two anodic peaks, the associated reduction peaks and an additional reduction peak corresponding to one or more of the high voltage oxidation products. After prolonged exposure to high potentials, coal pyrite displays reactions similar to those of mineral pyrite but at much higher current densities demonstrating the much higher reactivity of the coal pyrite. The reactivity sequence was Upper Freeport coal pyrite > Pittsburgh coal pyrite > mineral pyrite.

Jan 1, 1991

By Prosser AP

The large body of knowledge about the relation between chemical process efficiency and mineralogical features is of only limited use. The profession ought to try to improve the methods of using information as well as adding to the knowledge. One attempt isòdescribed. Correlations between process efficiency factors and the mineralogical features of low- grade concentrates have been developed from both a theoretical analysis and experimental measurements. The ultimate recovery of a reactive phase in an inert matrix can be calcu- lated from simple measurements of the particle size, porosity and pore size of the concentrate, and the grain size of the reactive mineral., The rate of recovery, up to 98% recovery, can be calculated from simple measurements of particle size, porosity, proportion of reactive mineral and tortuosity. Some details are given. The correlations are of potential use in process selection and preliminary design. Satisfactory predictions have been made for near-ideal systems. Improvements in the measurement of pore size and tests on more realistic materials are required. The ultimate benefit of the correlations will be determined by the magnitude and frequency of the effects of mineralogical features other than those specified above.

Jan 1, 1975

By Donald R. Lamont

The paper outlines the reasons for and research behind the recent decision to adopt oxygen decompression in the UK. Currently used measures of decompression illness are critically appraised. The paper describes the main precautions to be taken on site to manage the fire risk from the use of oxygen underground. A summary of the initial results from the use of oxygen decompression in the UK is presented.

Jan 1, 2003

By N. C. Karmakar, Y. V. Rao, M. Aruna

No one can properly work without sufficient light and this is especially so in mines where conditions are difficult. Artificial lighting is very important for the night shift to provide a safe and efficient working environment, which must be evenly illuminated with no obvious dark spaces and a minimum amount of glare. During an illumination survey of a large mechanized surface mine, it was found that the illumination level varied and was not uniform throughout the length of the road; it was high at one side of the road instead of at the centre. There were also different combinations of lamps, with angles of light arm varying from 35º to 70º. In this respect, an experimental study was carried out with a fabricated telescopic light pole to uncover the optimum design parameters of lighting installations. The analysis was done by plotting isolux contours for fixed installations and drawing graphs for various combinations of luminaries, reflectors, light arm angles, and height of lanterns by plotting the horizontal angle of the light arm along the abscissa, and the contour area along the ordinate. The study revealed that the design parameters of the lantern are mainly dependent on the type of luminaires. It was revealed that the pot reflector with a combination of tubular bulbs produces a wide distribution of light, and contributes towards a reduction of luminaries when installed in longer roads.

Jan 1, 2005

By D. F. Malan, P. M. Couto

We propose a layout design for the UG2 Reef where weak geological alteration layers are present. The collapse of the Everest platinum mine in South Africa indicated that these layers substantially weaken the pillars. The popular Hedley and Grant pillar strength formula cannot be used where these alteration layers are present. Underground investigations at Everest mine and numerical modelling of the layout were conducted using the TEXAN code and a limit equilibrium model. Simulations of a collapsed area and an intact area allowed for a preliminary calibration of the model. This was subsequently used to explore modified layouts for these ground conditions. An alternative is to compartmentalize the blocks of ore using barrier pillars. The numerical modelling predicted that the barrier pillars appear to remain stable even in the case of large-scale collapses, provided their width exceeds 25 m. Main access routes into the mine can be protected by a double row of pillars at least 15 m wide to provide a safe travelling way. As a cautionary note, these conclusions are based on the model calibration and this needs to be refined in future. Calibration of the limit equilibrium model remains a challenge owing to the large number of parameters involved.

May 3, 2023

By F. S. Crawford

Companies which have been engaged in safety work for a number of years are becoming increasingly aware of the fact that it is not enough to supply guards for various pieces of machinery and equipment and to supply safety inspection to see that rules are being carried out. Studies of many safety organizations have demonstrated that the accidents which could have been prevented by proper guards constitute only a small percentage of the total acci- dents, and amount to perhaps not more than 15 per cent. Evidently, if success is to be attained in preventing all accidents which it is humanly possible to prevent, a company must have the cooperation of every employee. Mining particularly presents probably the greatest hazards of any industry. Prevention of accidents. is made increasingly difficult because men often work alone, although generally in pairs, and only in the concentrated systems of mining do they usually work in groups of more than three or four. Supervision is difficult, therefore, and much reliance must be placed upon the individual workmen. In mining, as perhaps in no other occupation, it is of the greatest importance that individual workmen should receive continuous safety education. Within the last few years safety education has come to the front as one of the most important of accident-prevention measures, although it is true that its importance has been repeatedly stressed by the United States Bureau of Mines and other national safety organizations since the inception of the safety movement many years ago. A review of the safety educational methods of some companies in the Lake Superior district should be of interest. Perhaps better methods are in use in other parts of the country, but the methods shown have been instrumental in many cases in reducing the number of accidents. In one mine in the district whose methods are described the frequency of accidents has been reduced to zero within the last two years. A number of other mines in the district have recently gone into the class having no lost-time accidents for considerable periods of time. One company in the Lake Superior region, operating over 30 mines, succeeded during one month of 1930 in operating every mine without having a single accident which caused lost time beyond the day of the injury. Records like these are increasing in number, and while it is believed that they are the combined result of different means of safety activity, it is undoubtedly true that many of these results were obtained through safety educational methods.

Sep 1, 1931

By R. Brown, A. J. S. Spearing, M. Treinen, M. Theisinger

The mining and use of coal creates a significant amount of waste material that needs to be safely disposed of. It is likely that in the medium term, the Environmental Protection Agency (EPA) in the U.S. will categorize all such products as a new category – special waste. This would make the materials subject to many of the requirements for handling toxic waste, which will complicate the disposal of such products and significantly increase the disposal costs. Underground disposal would, therefore, seem to be the obvious solution, especially if the placed material can have low or no permeability, so that water table pollution does not present a serious long-term issue after placement. Significant additional advantages could be derived from this backfilling, including the reduction or elimination of surface subsidence, increased extraction, reduced surface waste disposal footprint and the elimination of explosion-proof seals in worked out areas. The research using a specific coal waste product as a typical example proved that the method of placing the backfill at a high density with low permeability is technically viable, but it must be made more cost effective and the other potential benefits quantified and costed in order to present a true comparison.

Jan 1, 2010

By L. Y. Wang

In order to produce the iron and steel products with high quality and decrease the output of steel tailings, the quality of molten iron is a critical factor for iron and steel companies, especially the content of sulfidic in molten iron. Hot metal pre-treatment, an important and effective method to desulphur, is widely used in steel production. Millions of tons of slag from desulphurization and slag skimming are produced each year in China, and many more times this amount is stored in slag dams because of the lack of effective means to deal with it. In order to achieve the goal of sustain-able development, recycling these slag becomes necessary. The main objective of this paper is to study the composition characteristics of slag that from desulphurization and slag skimming. The sample was obtained from Anshan Iron and Steel Group Corporation, processed by hot metal pre-treatment. In this study, the chemical components and the mineral compositions of sample were tested. The results of chemical components and iron chemistry phase analysis showed that the iron and sulphide content in this sample were high, and the iron products existed mainly in the form of magnetite, metallic iron, ferrosilite. X-ray diffraction (XRD) and scanning electron microscope (SEM) results indicated that the sample included metallic iron, ferrate, wustite, metasilicate, aluminate, aluminosilicate, white lime and soon. Grading magnetic separation test work showed that magnetic separation was an effective method to recovery iron products and decrease the sulphide content in concentrate, and the tailing could be used as the raw material or padding in cement production.

Jan 1, 2014

By J. A. Cruise

With the end of the official apartheid legislation in the early 1990s, South Africa was heralded as a non-racial country. However, racial awareness has been reintroduced into the country with the Affirmative Action and Black Economic Empowerment legislation. Gender and racial transformation are the current order of the day. All organizations are required to reflect in their make-up the demographics of the population as soon as possible. Scorecard shave been drawn up to measure the rate of transformation for gender and race in organizations. The mining industry in South Africa has been in the forefront of this transformation legislation and scorecards. This paper seeks to show the effect of gender and racial transformation on mining engineering education and professionalism by analysing the changing demographics of graduating mining students at both the South African universities offering a degree in mining engineering, the professional registration of mining engineers with the Engineering Council of South Africa (ECSA), and the membership of the Southern African Institute of Mining and Metallurgy (SAIMM), the vocational institute for mining engineers. It also demonstrates the absurdity of gender and racial quotas based solely on the demographics of the current population of the country. This paper shows the degree to which mining engineering has transformed in both gender and race.

Jan 1, 2011

By Douglas Bunting

The first presentation of this paper was before the Pennsylvania Anthracite Section of the Institute in May, 1914, after which a committee was selected to verify and add to the data contained in the original paper. The author is indebted to G. W. Engel, H. W. Montz, R. V. Norris, and H. H. Otto, of this committee, for additional information. I also wish to acknowledge the courtesies extended me by a number of the mining companies for information relative to accidents, systems of proving, and mining practice. The paper should bring forth additional criticism and recommendations, which will be of value in establishing future practice relative to this subject. Throughout the northern anthracite field of Pennsylvania glacial and alluvial deposits of sand, gravel, and clay exist in varying quantities. The extent and character of these deposits are described by N. H. Darton in Bulletin 45 of the U. S. Bureau of Mines, entitled, Sand Available for Filling Mine Workings in the Northern Anthracite Basin. It is estimated that the northern field contains 10,000,000,000 tons of these deposits, or a sufficient quantity to cover the 176 square miles of coal area to a depth of about 25 ft. These deposits of sand, etc., overlying the coal measures attain a maximum depth of more than 300 ft., and are usually saturated to such an extent as to render them semi-fluid. It is this condition of fluidity that limits the mining of coal seams cropping in or in close proximity to these deposits, and it is in the interest of safer and more efficient mining methods under these conditions that the study of this subject is here presented. The dangers incident to mining under deep deposits of sand have long been realized by operators in the northern anthracite field, and much has been done to prove the contour of the rock and vein croppings underlying these water-bearing deposits of sand and gravel. Although, as far as we know, the accidents of the past have not resulted in the loss of life, except in two instances, yet nearly all were attended with more or less miraculous escapes of men working in the vicinity of the breaks, so that the probable existence of pot holes, etc.,

Jan 1, 1915

By Evan Just

Engineering education for the mining industry has been undergoing a gradual change in recent years, to an extent that many employers may not realize. The result of this change is that the new graduate comes to his first employment with very little knowledge that is immediately valuable in operations. He is in fact, simply "half-baked" and needs much education on the job before his schooling will pay out in any significant way. To the employer who fails to recognize this, and fails to give the necessary training to finish the educational job, the modern graduate is likely to be unsatisfying. Moreover, the young fellow's future competence will be impaired. However, to the employer who assumes the educational burden, the effort should pay out as the half-baked products, after a few years, ought to be more useful than their predecessors and should have a greater potential to solve problems or cope with change. The reasons for this development are given below in the foreword to a questionnaire survey circulated by the SME Committee for On-the-Job Training.

Jan 6, 1964

By L. W. Eastwood

PART 1. EFFECT OF HEATING RATE UPON RECRYSTALLIZED GRAIN SIZE OF ALUMINUM AND ALUMINUM ALLOYS AMONG those concerned with the annealing and heat-treating of aluminum and aluminum alloys, it is well known that after cold-working a coarser grain is usually produced by slow heating than by more rapid heating. Consequently, for the control of the grain size produced by annealing or heat-treating cold-worked aluminum and aluminum alloys, the heating rate is of considerable practical importance. References in the current literature on the effect of heating rate are numerous, but it appears neither necessary nor desirable to give here a review of the former work done on this subject. It became evident during some preliminary work on the recrystalliza-tion of aluminum and aluminum alloys that the effect of heating rate depended upon the type of microstructure of the metal. This observation led to the following study of the relationship of the type of microstructure of the alloy to the effect of the heating rate.

Jan 1, 1939

By M. Y. Levesque

The Australian Government?s Energy Efficiency Opportunities (EEO) program launched in 2006 obliges companies that use more than 0.5 PJ (petajoule) or roughly 139 GWh (gigawatt hour) per year to conduct an energy assessment in order to identify measures to improve energy efficiency. The opportunities identified by the mining sector were assembled in the Mining Significant Opportunities Register that permitted companies not yet embracing and adopting an energy management program to see what those who are, were doing and how much energy was saved, and helps disseminate best practice. The measures can be filtered by company, year, category or equipment type. The creation of a central repository of energy efficiency initiatives is valuable but this existing database could be improved; fields identifying the energy and carbon emission savings associated with a given initiative are a surprising omission. Consequently it does not permit the relative effectiveness of different measures for energy and carbon reductions to be readily assessed. A review of energy management efforts implemented in the mining industry, published in peer reviewed journals, corporate sustainability reports or industry publications during the last 40 years has revealed many examples of best practice. However, the lack of a standardized reporting framework in any of these sources has made it difficult to assess the effectiveness and compare the adopted energy management measures ? just as is the case with the Australian register. In an attempt to address these issues, an improved database structure has been created for energy management measures from the mining industry which identifies energy and financial savings arising from energy management initiatives, classifies applications to specific processes or equipment, and recognizes leaders in the mining industry with respect to energy management. The structure of the register includes the key data relevant to energy management in mining that is absent in the Australian version. The mining industry energy management database has been made available in the public domain where stakeholders can examine the best practice examples. Mining energy champions may also contribute to the register by providing case studies; a standardized entry template affords a quality assurance dimension that is absent in other reporting initiatives. Adoption of this database with its standardized reporting mechanism will enhance transparency of the mining industry in energy matters and help it maintain its social license to operate.

Aug 1, 2013