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By F. H. Chen

the Rocky Mountain Region since 1950, drilled pier foundations have been widely used to combat structural movement problems in expansive soils. It is now an accepted practice for engineers to use drilled pier foundations in expansive soil areas. Piers are generally drilled into bedrock in a zone unaffected by moisture change. With some exceptions, such system has successfully prevented damage incurred in the structures as the result of soil expansion. In the last 15 years, no significant advancement has taken place in the design of the drilled pier system on expansive soils. Numerous failures continued to be reported. Causes for the failures were placed on poor drainage, inadequate void under the grade beams or mushrooms on top of the piers. Engineers realize that these are certainly not the major problems. The basic design criteria should be critically reviewed. It is the purpose of this paper to point out the actual problems confronted by designers, the failure module and remedial measures, The writer does not claim to have the solutions. In fact, it will be a long time before real solutions can be found, yet the writer believes the engineering communities, the construction industry and the general public should be aware of the true picture of the problem.

Jan 1, 2010

By H. J. McQueen

Pyro-reduction of ores to metal products developed markedly through the industrial revolution into the great depression. Nineteenth century resource and environmental sustainability were haphazardly improved by many process changes, although the motivation was primarily reduction in labor, feed stocks and fuel. Some notable achievements were coke and hot air for blast furnaces (later from waste heat stoves), puddling of wrought iron and steel ingot production with convertors advancing into oxygen use and continuous slab, billet and strip casting. Although advances in one sector were often counteracted by fall-backs in others, there was progress in that the resource consumption and pollution per unit of production was decreased. Improvements in the 2 decades following WW2 were mixed but popular notice of environmental hazards forced governments to legislate pollution controls and initiate steps in resource conservation. The energy crisis of the 1970’s saw an industrial energy-saving campaign and legislation of technology assessment procedures. Up until mid 18th Century, the training of iron masters depended on apprenticeship with some formalized knowledge from medieval books such as those of Biringuccio (1540) and Agricola (1556). The advances were very slow partly due to absence of scientific concepts of the smelting process. Nevertheless, some iron masters succeeded in improving the process and described procedures to instruct others. With the surge of steam power and the reverberatory puddling process for ductile wrought iron (WI), machinery changed from wood (iron strap reinforced) to WI machinery. With the clarification of the reduction and oxidation mechanisms by Cavendish and Lavoisier (~1780), productivity in iron production surged. The mechanical testing and microscopy of Kirkaldy (1862) spurred understanding of processing and properties of WI and steel. The various forms of C in steels were determined by chemists at the end of the 19th Century. It also became possible to control metal and slag chemistry in the open hearth furnace. But understanding of the transformations during heat treatment of steel only came in the first decades of the 20th Century.

Jan 1, 2012

By Charles B. Carpenter

In general terminology, the West Texas Permian Basin companies the area south of the Texas Panhandle and west of the Bend Arch or Central Basin region. It is outlined more definitely by geologists however, as that area underlain by the south half of the Permian Salt Basin4/ and includes Scurry, Mitchell, Sterling, Howard, Glasscock, Reagan, Crockett, Upton, Midland, Martin, Gaines, Andrews, rotor, Crane, Pecos, Ward, Winkler, and Loving Counties in Texas, and.. Lea and Eddy Counties in New Mexico. The oil fields of the area, of which more than 70 have been discovered, are shown in fire 1. Approximately 4,200 producing oil wells have been drilled in these fields. Oil has been produced from limestones and dolomites of Permian age in most of the fields in the West Texas Permian Basin. Some of the fields produced oil from sandstone beds above the limestone, and in two fields production has been found below the limestone in formations of Ordovician age.

Jan 1, 1936

By Charles B. Carpenter

In general terminology, the West Texas Permian Basin comprises the area south of the Texas Panhandle and west of the Bend Arch or Central Basin region. It is outlined mere definitely by geologists, however, as that area underlain by the south half of the Permian Salt Basin4/ and includes Scurry, Mitchell, Sterling, Howard, Glasscock, Reagan, Crockett, Upton, Midland, Martin, Gaines, Andrews, Ector, Crane, Pecos, Ward, Winkler, and Loving Counties in Texas, and Lea and Eddy Counties in New Mexico. The oil fields of the area, of which more than 70 have been discovered, are shown in fire 1. Approximately 4,200 producing oil wells have been drilled in these fields. Oil has been produced from limestones and dolomites of Permian age in most of the fields in the West Texas Permian Basin. Some of the fields produced oil from sandstone beds above the limestone, and in two fields production has been found below the limestone in formations of Ordovician age.

Jan 1, 1936

By Joseph J. Larry

In hard siliceous sandstone strata overlying coal seams, roof bolting is often the bottleneck in the coal production cycle. In the past, these strata have been drilled by pneumatically operated stopers. Although slow drilling is cumbersome and uncomfortably noisy, the stoper was the most effective drill in these harder strata. However, because of the (U.S.) Coal Mining Safety Act, which limits noise levels for operating drills, FMC Mining Equipment developed the water-through-the-drill-steel method of drilling high-compressive-strength strata. Although water-through-the-drill steel had been developed earlier, the real impact of wet drilling techniques surfaced when the dual-boom roof drilling machines were installed at the Virginia-Pocahontas Division, Keen Mountain, Virginia, in 1974. This paper covers some of the technical details of the water-through- the-drill-steel design and its application.

Jan 1, 1979

By J. Kallioinen

The development of mechanical flotation cells has resulted in larger and better cells. This has led to flotation banks with only a few units, even in large-scale operations. This equipment development makes the old operational considerations ineffective. The flotation cell must be considered as a single reactor unit capable of handling specific tasks and getting excellent metallurgical performance. The result of the unit reactor concept development was the new large TankCell that comes in sizes up to 113 m3 (4,000 cu ft). The TankCell construction includes new modified rotor-stator designs, new tank geometries and a froth-handling capability independent from subprocesses taking place in the pulp (i.e., air addition). The conventional idea of a single flotation cell type for fine, intermediate and coarse materials does not give optimal results. Optimal flotation of coarse and fine particles needs different mechanism designs, impeller tip speeds and different froth control objectives.

Jan 1, 1995

By W. S. Dyer

Introduction In northern Ontario, refractory clay is found on four rivers of the James Bay watershed: the Abitibi, the Mattagami, the Missinaibi, and the Moose. The clay all belongs to the same geological formation ( the Mattagami of Lower Cretaceous age) , and occurs within a structural depression or 'basin', the boundaries of which have never been defined but which appears to cover at least 1,500 square miles of territory. The recently constructed James Bay extension of the Temiskaming and Northern Ontario railway crosses the northeast end of the basin at the Onakawana lignite field, which by rail is 126 miles north of Cochrane, 605 miles north of Toronto, and 60 miles southwest of Moose Factory. Smoky Falls, the northern terminus of the railway owned by the Spruce Falls Power & Paper Company, Limited, is 7 miles south of one other point in the basin, i.e., the outcrops of refractory clay, sand, and kaolin at the foot of Long rapids on the Mattagami river. Smoky Falls is 50 miles north of Kapuskasing. In a very early report(l) , Dr. Robert Bell, of the Geological Survey of Canada, described '"light coloured marl in horizontal beds" from the Missinaibi river, and noted that the lignite also occurring in the river was probably :associated with the marls. This was undoubtedly the Cretaceous refractory day. Other early writers noted the occurrence of fire-clays, but it was not until Joseph Keele(2), of the Geological Survey, visited thee region in 1919 and studied the clays that their real significance was known.

Jan 1, 1933

By Erich U. Petersen

Recognition of mineralogical and chemical zoning patterns associated with mineralization is an integral part of mineral exploration. Even though the origin of zoning may not always be known, zoning patterns as expressed by the systematic distribution of ore and gangue minerals, alteration or elemental assays (soil and rock geochemistry) have received much attention and are extremely useful in guiding exploration efforts toward locating economic mineralization. By contrast, the potential of using zoning information recorded in solid-solution minerals to address practical geological-engineering problems has received less attention. Solid-solution minerals can provide critical information for common problems faced in exploration, mine development and valuation. Mineral zoning information from solid-solution minerals can now be easily obtained because advances in electron microprobe instrumentation have made these instruments a most efficient, accurate, economical and practical tool for analysis of large numbers of samples. Now entire mines and districts can be studied in a timely and cost-effective manner as required by modern mineral exploration and mining practice. This article shows how knowledge of the composition of fahlore minerals can be used in addressing important problems in exploration, development and valuation. Situations are described in which drilling intersected "low grade zones" (Case one: Orcopampa, Peru, precious metal system) and where there was a need to determine the "lateral correlation of multiple ore intercepts" (Case two: Sheep Creek, Montana, sediment-hosted sulfide deposit).

Jan 1, 1992

By D. D. Fischer

Recovery and separation of molybdenum and rhenium from a process solution was accomplished by a technique developed by the Federal Bureau of Mines involving a combined solvent extraction and activated carbon adsorption procedure. The processing sequence required treatment of the solution with S02 to reduce the chlorate ion and adjust the pR prior to solvent extraction of molybdenum and rhenium with a tertiary amine. Molybdenum and rhenium were stripped from the organic phase with an NH40H solution, and the strip solution was then passed through activated carbon to preferentially adsorb the rhenium. After washing entrained molybdenum from the column with a brine solution, rhenium was eluted with an MeOH-H20 mixture. The activated carbon was regenerated with water. Molybdenum was recovered as (NH4)6Mo7024 by evaporating the column effluent. Rhenium in the column eluate was reextracted with a tertiary amine, stripped from the organic phase with dilute NH40H, and recovered as NH4Re04 by evaporating the strip solution. The final (NR4)Re04 product contained < 80 ppm impurities. Sodium sulfate was crystallized from the first solvent-extraction raffinate by lowering the solution temperature to 0° C. Precious metals contained in the original process solution were adsorbed onto the activated carbon.

Jan 1, 1975

By Elena L. Chanturiya, Vladimir A. Bocharov, Roman A. Amosov

"In many volcanogenic base metal deposits of Russia the gold is closely associated with copper sulphides and pyrite. The recovery of gold associated with pyrite is especially difficult problem.Investigations of gold chemical state and mineral forms in copper-zinc sulphide ores of Gay and Barsuchiy Log deposits in the Urals have been made using EPMA, optic image-analysis, XRA, SEM, thermo-electrical force measurements and selective gold leaching experiments.Two gold varieties are determined: 1) free native gold particles (from 5 µm up to 0,25-1,0 mm), which can be liberated after grinding of ore up to 0,074 µm and named “free gold”; 2)”invisible” gold, including finely disseminated native gold and chemically bound gold. The second variety can’t be disclosed during grinding. Free gold can be recovered by gravitation and flotation while the processing behaviour of “invisible” gold is determined by properties of gold-bearing sulphides: pyrite and chalcopyrite. According to results of diagnostic leaching experiments in ores of deposits mentioned above the part by weight of free gold reaches 70%, the part by weight of the ”invisible” gold is up to 20%. About 10% of gold is enclosed in quartz and acid-soluble minerals.Theoretically (taking into account gold distribution data) it’s may anticipate gold recovery by gravitation up to 60%. However after grinding up to 50-60% of class –0,074 mm only about 40% of gold passes into oversize product including 30% of free gold and 8% of ”invisible” one. It can be recovered by gravitation. Remaining free gold and ”invisible” gold can be extracted by flotation – 25% in total. Inevitable gold losses in tailings may reach 8-10%."

Jan 1, 2003

For the use of those who prefer manila rope to wire rope for light hoisting and hauling, the Ingersoll-Rand Co. has brought out a new model Little Tugger Hoist which is designated No. 11. The square piston, reversible driving engine, automatic lubrication, inclosed gearing, rum release clutch and worm-operated band brake are essentially the same as in the No. 1 model which was introduced about two Years ago. The main differences are in the diameter and length of the drum, the width of the flanges and, necessarily, the main frame and overall dimensions. The new No. 11 Little Tugger has a hoisting drum 7 in. in diameter by 17 in. long with 5-in. flanges. This accommodates 300 ft. of 7/8 -in. manila, rope. The maximum capacity of this hoist is conservatively rated at 600 1b. The weight of the hoist itself is 358 lb. It is 21 ½ in. long, 31 ¼ in. wide and 23 in. high.

Jan 12, 1916

By Leticia Costa Macêdo

Esse trabalho tem como objetivo analisar por meio da termodinâmica computacional a influência do K2O na dissolução das fases sólidas formadas durante o processo de dessulfuração de ferro gusa. Para isso, foi utilizada a cal como agente dessulfurante e a Sodalita (Fonólio) como fundente, realizando uma adição de K2O no fluxante de 1% a 10%, com uma temperatura de trabalho de 1400ºC. Por meio do uso de software de termodinâmica computacional FactSage, foi possível simular e avaliar as fases sólidas e líquidas formadas na temperatura determinada e comparar com os resultados obtidos com outras análises. Os resultados obtidos mostraram que o aumento gradativo de K2O levam a um aumento do potencial termodinâmico de dessulfuração e melhores condições cinéticas, sendo a mistura que apresentou os melhores resultados a que continha 10% de sodalita com adição de 10% de K2O na fonte.

Oct 30, 2017

By Wang Xuguang, Tian Ruigi, Xiong Shangbin, Xiong Daiyu

Combining action features of explosive shock with those of natural lignocellulosic biomass structure, we have successfully developed a new explosive shock dilatation and separation technique for pretreatment of natural lignocellulosic materials in the laboratory. Based on a brief introduction to the technical background and experimental procedure of this new method, some preliminary experimental results are given and discussed: the scanning electron microscope (SEM) qualitative observation results show that for treated natural lignocellulosic sample such as corn cob etc., their length of fibre bundle shortens, fibre bundle arrange disorders, biomass appearance and structure of samples largely change to be dilatation and loose state. The dilute acid hydrolysis quantitative measure results show that for treated samples, the overall yield of the reducing sugar largely increases, hydrolysis rate of corn cob sample is over 80%, rate and speed of hydrolysis are increased by times.

Jan 1, 1998

By D. Prince, G. Nollet

"Since 1994, Aur Ressources has operated Louvicourt mine, a zinc and copper mine close to Val d’Or, at a rate of 4300 t/d. Ever since the start-up of the plant, management has encouraged innovative approaches in reliability.The first of three papers will discuss the vibration monitoring program in place. The program will be described and two examples will be given: detection of a rolling bearing defect on a pinion driving the ball mill and identification of wear on the bearings of the flotation cells. Figures on the return on investment and the costs of a monitoring program will also be given.The second article will discuss the lubrication aspect. Since the establishment of a good monitoring and oil analyses, Louvicourt mine decreased its oil consumption by more than 38 000 L/yr. In addition, the company set up an oil regeneration system that restores the original properties of oil.The third article will cover the management aspect. Work organization as well as the management philosophy enabling the employees to push predictive technology to higher levels will be examined in detail. The key elements which made it possible for Louvicourt mine to position itself among world-class companies in the organization of maintenance will be discussed. IntroductionThis article is the second of three on predictive maintenance at the Louvicourt mine operated by Aur Resources Inc. The first article, published in the October 2002 issue, was about vibration analysis for rotating machines. This article describes how lubrication and oil analysis for stationary machines permitted Louvicourt to save more than $150,000 within two years and presents the evolution of the oil analysis program.Louvicourt mine, located near Val-d’Or, Quebec, is a copper and zinc mining and milling operation that processes 4300 t/d of ore and employs 289 people. Production began in 1994. Louvicourt mine is a partnership between Aur Ressources (30%), Teck Corp. (25%), and Novicourt (45%)."

Jan 1, 2003

By S. K. Kawatra, S. J. Ripke, T. C. Eisele

"An estimated 600,000 tons of bentonite clay are used annually in the U. S. as binder for production of iron ore concentrate pellets. Since this is a significant cost item for the plants, and the addition of bentonite to the pellets contributes undesirable silica into the finished pellets, there is considerable incentive for finding methods to reduce bentonite use. One way to reduce bentonite levels is to selectively use those bentonites that are most effective in this application, so that a lower dosage will still produce a sufficiently strong pellet. Unfortunately, there are no satisfactory methods available for accurately predicting which bentonites are actually most effective, short of using them to actually make pellets. One of the popular methods for attempting to evaluate bentonites is the “Plate Water Absorption” (PWA) test. While some plant operators accept the PWA results as indicating the relative quality of bentonites, others disagree and claim that, over a fairly broad range of values, PWA does not correlate with bentonite performance.Since both Ca+2 and Mg+2 ions are known to reduce the swelling and water absorption capacity of bentonite, it was believed that the presence of these ions in plant recycle water could be changing the bentonite performance. Since the standard PWA test uses only distilled water for its measurements, it could not detect these effects. Experiments were therefore carried out on a number of different bentonites using a modified PWA tests, with plant recycle water replacing the distilled water. These experiments showed little effect of the plant water on the PWA value, and chemical analysis of the water showed that the levels of dissolved salts were quite low.Water and accompanying salts were then extracted from a magnetite concentrate filter cake by rinsing with distilled water. Analysis of this water showed an extremely high level of dissolved salts, particularly salts of calcium and magnesium. When concentrations were compared with the recycle water from the plant filters, it was determined that levels of Ca+2 and Mg+2 retained in the filter cake were over 500 times higher than levels in the recycle water. This extreme elevation of soluble salts in the filter cake is believed to be due to adsorption of these ions into the electrical double layer of the magnetite particles."

Jan 1, 2003

By Lucas Breder Teixeira

Vasos metalúrgicos podem ser revestidos com linhas de tijolos refratários, com ou sem argamassa. Devido ao grande número de interfaces entre os tijolos, o sub-sistema tijolo/junta impõe dificuldades computacionais ao projeto da montagem. Buscando comparar a influência do projeto refratário nas tensões presentes na estrutura, um revestimento com juntas secas foi modelado utilizando um material homogêneo equivalente. As propriedades termo-mecânicas deste material equivalente foram determinadas usando o método de Homogeneização Periódica e dependem tanto da temperatura quanto do estado da junta (aberta ou fechada, nas duas direções). Este modelo foi usado para simular uma Panela de Aço através do Método dos Elementos Finitos (MEF) com o intuito de demonstrar a influência dos seguintes parâmetros: presença ou ausência de juntas; espessura da junta e projeto refratário. O trabalho pretende auxiliar o desenvolvimento de projetos refratários e fornecer melhores estimativas da aplicabilidade de uma dada configuração.

Oct 30, 2017

By A. P. Bois, K. Saleh, A. Ghorbal, V. Hajiabdolmajid, G. Ballivy

"The knowledge of the initial stress field is not always sufficient to ensure the stability of mining stopes due to the high-stress variations generated by mining. Monitoring of these openings is then necessary and can provide quantitative information (deformations and stress variations) as well as qualitative information (state of stability).An applied technique for following the variations of stress and deformation in static and dynamic conditions, in relation to the evaluation of the stability of underground openings known as “Cylindre Instrumenté de l’Université de Sherbrooke” (CIUS) is discussed in this paper. In addition, a data acquisition system combined with a rock failure warning system has been developed to be connected to the CIUS for detecting the instabilities, which can endanger the stability of underground openings. Also, the installation of six CIUS and a data acquisition system as well as the selected procedure of programming in a warning system are briefly described."

Jan 1, 2003

By Irving Hartmann

1. Under the conditions of the tests described herein, the proper use of an incombustible stemming plug of the type discussed prevented ignitions of gas in all tests during the firing of 21 single shots of permissible explosive in cool. In two tests with multiple blasting (four and five shots each) no ignitions resulted. 2. The results of a few tests in this investigation and of numerous tests made previously indicate that fire-clay stemming of the same weight as an incombustible plug provides about the same degree of protection as the plug against gas ignitions during blasting of coal by permissible explosives. 3. The hazard of gas ignition on firing charges of non-permissible 40-percent gelatin dynamite in coal was reduced but not eliminated when the shot holes were stemmed with one or two incombustible plugs or with an equivalent weight of fire clay. 4. On the basis of this investigation, the Bureau of Mines considers the proper use of incombustible stemming plugs of the design tested, under the conditions of the tests described in this paper, to be of equivalent safety as the same weight of fire-clay stemming. This report does not constitute approval or disapproval of the incombustible stemming plugs by the Bureau of Mines. 5. The test data indicate that misfired charges in shot holes stemmed with the incombustible stemming plug cannot be disposed of with certainty by the procedure recommended by the manufacturer. In this investigation the misfired charges failed to detonate in 30 percent of the trials.

Jan 1, 1950

The New Zealand Minerals Industry is small but growing. Over the next 10 years it will be facing stiff international competition for skills to support this growth, particularly from Australia who are forecasting that a further 70 000 people will be employed by 2015. &nbsp; The value of commodities mined and quarried in NZ continues to increase; and the value of coal, metals and industrial minerals production reached $1.505 billion in 2006, an increase of 15 per cent on 2005. Production increases will continue à. Latest Crown Minerals statistics show that national prospecting and exploration expenditure rose to $29.9 million in the year ended March 31 2006 û an increase of 46 per cent from the $20.4 million spent in the March 2005 year. The equivalent 2001 year expenditure was only $2.48 million. &nbsp; The industry already experiences difficulty in recruiting the people it needs with ongoing demand for skilled underground miners, trades people, and mining professionals. This discussion paper will outline the national context with regard to labour, skills and training. It will suggest options and provide an opportunity for conference participants to discuss the way forward.

Jan 1, 2007

By James P. Rider

Significant advances in longwall mining technology and equipment have occurred over the last decade. By the late 1990s, longwall mine output accounted for 40 percent of all underground output in the U.S., and today longwall mines account for approximately 50 percent of coal produced underground in the United States. A 53 percent increase in average shift production rates has occurred over the last fifteen years. This increased longwall productivity has meant that far more dust is being produced and controlling respirable coal dust provides an ongoing challenge for coal mine operators. The National Institute for Occupational Safety and Health (NIOSH) has completed a series of benchmark surveys at longwall operations across the country to identify current operating practices and the types of controls being used. Gravimetric and instantaneous dust sampling was completed to quantify dust generation from major sources on the longwall section and to determine the relative effectiveness of the different control technologies in use today. Substantial reductions in dust levels were realized at sampling locations on the face when compared longwall surveys conduct in the 1990?s. This paper summarizes the results from the underground dust surveys and discusses current longwall dust control technology and operating practices.

Jan 1, 2010