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By Dan Plazak

Discussion by Dan Plazak The authors are to be congratulated for presenting a simple and practical tool for quick estimates of ground water flow rates. At the risk of detracting from the simplicity of the method, I would like to suggest a slight refinement to the equation as presented. As the authors noted, the Jacob-Lohman equation (1952) assumes confined-aquifer conditions. To use confined-aquifer equations in water-table aquifers, Jacob (1963) presented a correction to convert water-table aquifer drawdowns [Ahw] to equivalent confined aquifer drawdowns [Ah,: 2] [Ah Ah = Ah - w(1) Cw 2H where: Ah, = Drawdown in confined aquifer: Ahw = Drawdown in water-table aquifer and H = Original saturated thickness of aquifer] Substituting the above in equation ( I) of Hanna. Azrag and Atkinson [4nT Ah - 2H ) Qj2.25 T t(2) 1 nr2 S W] Since the above expression predicts lower pump rates, it causes the Jacob-Lohman equation to agree more closely with appropriate analytical and numerical models. Figure 1, adapted from Fig. 5 of Hanna. Azrag and Atkinson, illustrates the closer agreement of the modified equation to their numerical model, as reflected in Qm/QJL ratios closer to unity. The agreement improves particularly as drawdown [Ah] becomes large in relation to aquifer thickness H. An additional advantage of the modified equation is that Hanna, Azrag and Atkinson's correction factor C is much more stable as pit depth increases. Assuming, as did Hanna, Azrag and Atkinson, that their numerical model is an accurate predictor, it is clear that the modification incorporated in equation (2) improves the accuracy of preliminary estimates of ground water flow to a pit.[ ] References Jacob, C.E and Lohman. S. W.. 1952, "Nonsteady flow to a well of constant drawdown in an extensive aquifer." Transactions, American Geophysical Union. Vol, 33, No. 4. pp. 559-569. Jacob. C. E.. 1963, `Determining the permeability of water-table aquifers,' USGS Water-Supply Paper 1536-1, pp. 245-271

Jan 1, 1995

Jan 7, 1951

Jan 10, 1951

Jan 6, 1950

By Scott Turner

HOSTS of friends will rejoice that T. A. Rickard has been given honorary membership in the Institute. It might well have been done long ago, since, when one reviews distinguished services rendered by individuals to our organization and our profession, it is at once apparent that his name ranks high and that he has merited this distinction for more than three decades. Our by-laws restrict this list to twenty names; "T.A." becomes the sixteenth living member. Young engineers should particularly be pleased; Mr. Rickard has had a career rich in human interest, and full of useful suggestions to the younger men; he has given them good advice and set them a notable example; he, more than anyone else, has shown them how technical writing can be clear and concise; he has inspired youngsters to do their best; he has been their friend. No one has more first-hand knowledge of these facts than the writer of this appreciation:

Jan 1, 1935

By D. M. Baird

"Enormous deposits of gypsum of exceptionally high grade are readily accessible in southwestern Newfoundland. Coming large-scale production from one of these is resulting in renewed interest in deposits which have been known for more than a hundred and twenty years. General stratigraphy and structure of the Carboniferous rocks in which the gypsum occurs are de-scribed. The stratigraphic position of the basal gypsum-anhydrite zone is described. This massive evaporite horizon, which reaches a thickness of about 1,0001 feet, appears at Fishels-Heatherton, where it is largely undeveloped, and again on the nose of an anticline east of Flat bay, where a present production of 20,000 to 40,000 tons per annum is soon to be expanded to make it one of Canada's major producers. Detailed descriptions are given of the several types of gypsum, the relation of the gypsum and anhydrite, and the distribution of sodium chloride in the evaporite beds, and the bearing of all these on the origin of the gypsum are discussed. Brief reference is made to relation to world markets, mining and transportation, grade, and reserves."

Jan 1, 1959

FEBRUARY 26TH. MORNING SESSION: The sixteenth regular meeting of the Rocky Mountain Coal Mining Institute was called to order in one of the private dining rooms of the Albany Hotel, Monday morning, at 11 o'clock, with the President, F. W. Whiteside, in the chair, one hundred and one members being registered. The minutes of the previous meeting were read and approved. The Treasurer reported the finances of the Institute in excellent shape. The President appointed J. B. Marks, J. S. Veach and W. A. Ream as a Resolution Committee, and Frank A. Young, M. B. Urquhart and G. A. Murphy a Nominating Committee. There being no further business the meeting adjourned. AFTERNOON SESSION: The afternoon session was called to order in the Ball Room of the Albany Hotel, with approximately one hundred members present, President Whiteside presiding. A. L. Jones read his paper entitled, "The Power Problem of the Coal Mine," and C. E. Drennan, his paper, "Why Alternating Current." These papers were thoroughly discussed, after which the meeting adjourned. EVENING SESSION: At 6:45 p. m. two hundred and fifty-three members and invited guests met in the Ball Room of the Albany Hotel for the banquet. Harry F. Nash was toastmaster, and George Sanford Holmes the principal speaker. Following Mr. Holmes speech, H. N. Wheeler delivered his humorous oration of the "Annexation of Cuba;" following this certain members of the Institute gave an entertainment depicting a fictitious meeting of the United States Coal Commission. Chester Mott, formerly a member of the Institute wrote the words and songs of the entertainment, and directed it. After the show the assembly enjoyed a dance.

Jan 1, 1923

"The Ohio River Bridge East End Crossing Tunnel requires a 75-year service life of its cast-in-place reinforced concrete lining. This twin-tube 3-lane (each tube) highway tunnel is about 55-ft wide and 30-ft high. Since unified tunnel service life prediction methodology does not exist in the US, challenges occurred during the design-build phase of this project. These challenges include the methodologies in determining the reinforced concrete’s degradation mode, the lining’s surface chloride concentration level, the reinforcing steel’s critical chloride threshold value for corrosion, how to verify the concrete’s diffusion coefficient, and the durability impact from concrete crack width. This paper presents a methodology in verifying the proposed concrete mix can achieve the service life requirements. This methodology can be adopted for service life prediction for future tunnels to be built in the US. INTRODUCTION The Ohio River Bridge East End Crossing (ORBEE) Tunnel is part of a Public Private Partnership project, which connects transportation network between Louisville, Kentucky and southern Indiana. Located in Louisville, Kentucky, the twin-tube highway tunnel provides northbound and southbound lanes of the Kentucky approach to a new bridge across the Ohio River. Tunnel lengths are approximately 1,675-ft and 1,685 for the northbound tube and the southbound tube, respectively. Connected by two cross-passages, both tubes have a roadway width of 40-ft, for 3-lane traffic, and a vertical clearance of 26.5-ft.The tunnel was constructed by drill and blast method with shotcrete and rock dowels as initial ground supports. The final tunnel lining system includes: •,Nominal 16” cast-in-place reinforced concrete lining, with 2” and 3” concrete covers over reinforcing steel for its extrados and intrados, respectively. •,20” cast-in-place reinforced concrete invert slab, with 4” and 3” concrete covers over reinforcing steel on its top face and bottom face, respectively. •,PVC waterproofing system around tunnel perimeter, excluding invert slab. •,Perforated PVC groundwater collection pipes on both sides of the tubes and one below the invert slab of each tube."

Jan 1, 2016

By H. William Ahrenholz

The coal industry had another prosperous year in 1966. Since the turn of the decade, production has been climbing at an average rate of 6% per annum. Although the fast pace slackened somewhat, 1966 production showed a gain of almost 3 % over that of 1965. An impressive record can be drawn from the fact that output per man-day in 1966 was more than twice that of the early 1950's, and more than three times that of the early 1940's. And even though man-power requirements lessened, those men retained by the industry worked longer hours and benefited through higher hourly pay rates. However, cost to the customer increased a little. Such statements can only be made for a healthy industry -one that is constantly improving its efficiency. Coal currently provides more than 25% of the total U.S. energy output. About 50% of all U.S.- mined bituminous coal goes directly to the electric utility market. It should be noted that, now, well over one trillion kwh of electricity is generated annually. Dependence of the giant electric utility industry on coal is based on economy and an abundant, dependable supply of this fuel.

Jan 2, 1967

By V. V. Clark

WHEN a district is more or less primitive, and a trained mining engineer attempts single- handed to prospect it according to old standards, he generally fails. He has not the ability to live out in the open alone for months at a time and carry on with enthusiasm and determination like the old-time prospector. But the same engineer, placed in an organized group where modern prospecting methods are employed, is immediately put on his mettle and his chances of winning are greatly increased. Marsman Investments, Ltd., with headquarters in Manila, has at the present time, Sept. 4, 1937, six prospecting parties in the Netherland East Indies. Three of these groups are combing their assignments for lode mines, studying structures, developing and reaching out into veins and zones with diamond drills. The other three are searching for placer mines with pans, pits, and Empire drills. I am in charge of one group seeking commercial gold placers on the Island of

Jan 1, 1937

By Edward R. Lauer

Energy conservation is an integral part of Canada's energy strategy. We must pursue conservation and energy management vigorously if we are to remain competitive in domestic and world markets, and minimize our reliance on external energy sources. Energy management in industry is discussed from three viewpoints: (l) as a means of directly improving profitability; (2) as a major factor in the supply picture; and (3) as a significant influence on Canada's balance of payments and over-all economic well-being. The Federal role in promoting a voluntary industrial energy conservation program is described.

Jan 1, 1977

By P. I. James, M. R. Baker

Este artículo analiza la nueva producción de cobre a partir de "minerales de desecho" de baja ley usando la tecnología de Blue Planet Strategies DEMET™ (Dynamic Electrode Mining Effluent Treatment, por sus siglas en inglés), que tiene como objetivo salvar la brecha de procesamiento entre la solución débil de lixiviación en operaciones de extracción por solventes/electrowinning (SX/EW), removiendo electroquímicamente los metales a partir de corrientes débiles y a la vez generando productos concentrados en metales objetivo en un análogo funcional de extracción por solventes (SX). Se estudió el tratamiento de la débil solución de lixiviación pregnant (PLS por sus siglas en inglés) y se usó para estimar los impactos económicos y de producción para una hipotética lixiviación en pilas de cobre brownfield y una operación aumentada DEMET usando SX/EW para tratar el "mineral de desecho." Se presenta la remoción de cobre a un 86% de eficiencia en las placas por debajo de 0,1 g/L de cobre con un consumo de energía de 0.55 kWh/lb de cobre y una concentración del producto mayor a 10 g Cu/L. El modelamiento arrojó aproximadamente $2/ lb para la producción total de cobre y costos de tratamiento menores o iguales a $1/lb con un inmediato aumento del margen bruto de operación del 12% para el brownfield incrementado. Se indicó también un aumento de la vida de la mina con un margen bruto promedio de 38% en la producción aumentada de "mineral de desecho" con valores de cobre de $3.25/lb.

Jan 1, 2014

By Frank E. Lathe

During the war the National Research Council at Ottawa sent out questionnaires to the managers of nearly all the industrial plants in Canada. Inquiry was made as to the research equipment possessed, the number of research workers employed and the nature of the research problems which still remained unsolved. Practically all the companies reported that they had no special facilities for research, had no re-search workers and did not require the assistance of the National Research Council-because they had no research problems. Perhaps we have here one of the chief reasons why certain of our manufacturers find themselves unable to meet foreign competition. For hundreds of years the Indian tribes of northern Chile worked, in a small way, the copper deposits at Chuquicamata. They had no research problems and made no striking success of their mining operations. Then came an American company with a research problem, which they proceeded to solve. To-day the stock of that company has a market value of about $140,000,000.

Jan 1, 1926

By W. P. Yant, G. W. Jones

During the testing of porcelain insulators with a " 60 - cycle flash - over apparatus " , gases are liberated having an odor greatly resembling that of ozone . Since the two main constituents of normal air are nitrogen and oxygen , and high voltages (approximately 90,000 volts ) are used during the tests , the conditions are favorable for the production of ozone or oxides of nitrogen , and perhaps both simultaneously . The presence of these gases is only noticeable during the testing period . They soon disappear after the test is over . No fatalities have ever resulted from these gases at the plant visited nor are there any records of any of the men who worked on the tests being confined to their homes from this cause . New employees sometimes complain of a depressed feeling and shortness of breath , which is most noticeable after leaving work and getting into fresh air , but they som become accustomed to it and no ill effects are noticed . In view of previous work*** which the Bureau of Mines has done on oxides of nitrogen in connection with mine gases and problems in gas analysis , tests were made at the plant of the Westinghouse High Voltage Insulator Company at Derry , Pa . to determine the kind and amount of gases liberated .

Jun 1, 1923

By Jalna R. Zatko

Coal-clay waste slurries were dewatered in laboratory-and small-scale continuous tests by the Bureau of Mines using polyethylene oxide (PEO) as a flocculant. Dewatering from a nominal 7-wt-pct solids to over 50-wt-pct solids was accomplished using 0.5 lb of PEO per ton of feed in small-scale continuous tests. Parameters such as pH, initial solids content, and PEO concentrations were investigated. Water recovered from dewatering was reused as dilutant for PEO solutions.

Jan 1, 1982

By M. Baumann

Operating and maintaining the heavy equipment used in open-pit mining operations is an ongoing challenge for mines. Typical operations employ a combination of shovels, wheel loaders, and haul trucks to excavate and transport the material for further processing. As this is the first point of contact for the material after blasting, it is often a bottleneck of all downstream processes, thus, equipment uptime and efficiency is crucial. Automated systems for bucket tooth monitoring, payload measurement, proximity detection, and rock fragmentation analysis will be examined. The impact of these systems on operation safety, efficiency, and reliability, in real-world scenarios will be investigated. The process of managing all the above fleet of equipment in a mine can be streamlined by connecting the equipment monitoring systems to a central server. Using the central server, the distribution of this information can be automated to ensure that the right people see the data in a timely manner, improving both proactive and reactive responses to threats to safety and productivity.

Feb 23, 2014

The following are available from Metal Bulletin Books Ltd, Park House, Park Terrace, Worcester Park, Surrey KT4 7HY, England. . World aluminium-a Metal Bulletin databook. 2nd ed. 1990. £71.50 surface, £76.50 airmail. This is a compendium of information listing salient details of companies mining bauxite and producing alumina, primary aluminium, secondary ingot, master alloys, and semi-fabricated products; aluminium trading companies; and a memoranda section listing associations, brand names, and other useful information. It is a userfriendly international reference book for aluminium buyers, traders, and producers.

Jan 1, 1991

By B. R. Mohal, F. F. Aplan, S. Chander

"The wetting behavior of coal has been determined in the presence of nonyl and octyl series of nonionic surfactants containing polyethoxy groups of different sizes. The wetting behavior was determined by a modified Walker technique and contact angle measurements. The results show that the wetting rate of coal varies with coal rank, structure of the hydrocarbon chain and number of ethoxy groups in the hydrophilic group of the surfactant. A close relationship has been observed between the wetting rates and the short-time advancing contact angles.INTRODUCTIONNonionic surfactants are used in many applications to improve wettability of solids. They can be used as dispersing agents [ 1 ] or dust suppressants [ 2-5] and to control the flotation, flocculation, filtration and, flowability of particulates. This study was undertaken to study the effect of a series of nonionic surfactants on the wetting behavior of coal. Two series of surfactants, namely, ethoxylated nonyl and octyl phenols were used. The nonyl phenol series con tains a linear hydrocarbon chain containing nine carbon atoms (CH3 ( CH2 )8-C6H4- ( OC2H4 ) n, where n is the number of ethoxy groups) . The octyl phenol series contains a branched hydrocarbon chain containing eight' carbon atoms ( ( CH3 ) 3CCH2C ( CH3) 2-C6H4- ( OC2H4 ) n ).Initial wetting rates — modified Walker techniqueWalker et al. [ 6 ] developed a sink test to determine the wettability of coal particles. In this technique, coal particles are dropped individually onto the surface of surfactant solutions of different concentrations, and the most dilute concentration in which coal would sink ""instantaneously"" is determine& This technique is a variation of a procedure initially developed by Draves and Clarkson [ 7 ] to determine the effect of surfactants on wettability of cotton fibers."

Jan 1, 1989

By M. Grave

Rock Engineers are required to design safe cost effective support systems and stoping layouts for their respective mines. As each stope has its own unique environment, continual re evaluation is required in all stopes to maximize extraction and achieve value from the support standard. This paper presents numerical modelling used to plan early mining within the shaft pillar and a reevaluation of an existing stope support standard.

Jan 1, 2009

1. Book reviews Nonparametric geostatistics, by S. Henley. London, Applied Science Publishers, 1981. xiv + 145 pp. Reviewer: Douglas M. Hawkins Mineral deposits and global tectonic settings, by A. H. G. Mitchell and M. S. Garison. London, Academic Press, Geology Series, 198!. Reviewer: J. Lurie The mining and mineral laws of South Africa, by B. L. S. Franklin and M. Kaplan. Durban, Butterworths, 1982. Cloth, 240 X 150 mm, Lxxcii + 853 pp. R197,50 + GST. Reviewer: M. J. Martinson Aluminium- Volume II, by M. H. Govett and J. Larsen. Sydney, Australian Mineral Economics (Pty) Ltd, 1982. Reviewer: D. G. Maxwell International technology for the nonferrous smelting industry, by Noyes Data Corporation. Reviewer: D. A. Viljoen 2. New publications Coaltransport- an analysis of technical and economic factors, by Dag Pike. London, Financial Times, 1982. £86 (D.K.), D.S. $175 (overseas including first class airmail postage). Small solute concentration differences determined by interferometry, by H.E.L.G. Schweigart. Pretoria, CERG-CSIR (P.O. Box 395, Pretoria), 1982. 3. Mintek reports Report M8A determination, using solid zirconia electrolytes, of the activities of chromium oxide in ferrochromium alloys and slags at 1650°C. Report M31Software for the design of multivariable control systems by use of the Inverse Nyquist Array. Report M37A literature survey of the metallurgical aspects of minerals in Witwatersrand gold ores.This survey reviews the information in the literature Report M 39 The use of masking agents in the determination, by hydride generation and atomicabsorption spectrophotometry, of arsenic, antimony, selenium, tellurium, and bismuth in the presence of noble metals. Report M40 The use of X -ray-fluorescence spectrometry in the determination of uranium, cobalt, and sulphur in materials from mine dumps. Report M44 A n on-line dilution system for spectrometry ustng an inductively coupled plasma source. Report M47 The separation of trace elements from iron, and the analysis of iron-rock ores for use as reference materials. Report M49 A programme in BASIC for the appending of computer files. Australian coal The editors of World Coal and World Mining have announced plans to sponsor the IVth International Coal Exploration Symposium. The symposium will be held in Sydney (Australia) from 15th to 19th May, 1983. Small mine economics The editors of World Mining and World Coal have announced plans to sponsor the Second International Symposium on Small Mine Economics and Expansion in Helsinki, Finland, from 12th to 16th June, 1983. The first symposium was held in Taxco, Mexico, in May 1981.

Jan 1, 1982