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"In an environment of rising energy prices and mining at greater depths, cost-efficient loading and hauling equipment is essential. Conducted at an underground mining operation, this study analyzes the energy consumption and gas emissions of diesel and electric load-haul-dump machines (LHDs) with similar bucket capacities. Based on energy prices from the first quarter of 2014, results of discrete event simulation show that energy costs for diesel and electric LHDs are US$0.24/t and US$0.07/t, respectively. Also, diesel LHDs emit 2.68 kg CO2 per litre of diesel fuel, whereas using electric machines reduces the need for ventilation to mitigate engine heat and emissions and reduces energy costs.RÉSUMÉ Dans un contexte de croissance des prix de l’énergie et d’exploitation minière à des profondeurs de plus en plus grandes, il est essentiel d’avoir des équipements de chargement et de transport les plus rentables possible. La présente étude, effectuée dans une mine souterraine, analyse la consommation énergétique et les émissions de gaz de chargeuses-navettes (LHD) au diésel et à l’électricité ayant des capacités de godet similaires. En se basant sur les prix courants de l’énergie, les résultats d’une simulation d’événements discrets montrent que les coûts énergétiques pour les LHD au diésel et à l’électricité sont respectivement de 0,24 $US/t et de 0,07 $US/t. De plus, les LHD au diésel émettent 2,68 kg CO2 par litre de combustible diésel alors que les machines utilisant l’électricité réduisent le besoin de ventilation pour atténuer la chaleur des moteurs et les émissions en plus de réduire les coûts énergétiques."

Jan 1, 2015

By Bruce F. Grant

"INTRODUCTION The future of oil production in the part of the Appalachian region included in southwestern Pennsylvania; West Virginia, and southeastern Ohio is directly dependent on the maintenance of existing wells. This report presents an analytical study of the methods used in oil-well reconditioning in this area. The study is part of a research program designed to evaluate those means of stimulating oil production that can effectively and economically maintain present oil-production rates and make it possible to keep existing wells in operation. Well-reconditioning work was curtailed during the war; therefore, an abnormally large number of wells in the Appalachian Region is now in need of repair. Because the lubricant content of Appalachian crude: oils is high and the refined lubricating oils an; particularly suited to use in high speed, high-temperature engines, the demand for these crude oils during the war exceeds, the maximum rate of production obtainable under wartime operating conditions. Increases in operating, expenses, inability to meet war-time reconditioning costs, and inflexible price structures caused the abandonment of an alarming number of wells during the past 4 or 5 years.As a means of increasing regional oil-production rates, new drilling in the older fields for primary production generally is uneconomical because reservoir pressures in most of the fields have virtually been depleted and the production rates of newly drilled wells are small."

Feb 1, 1948

THOSE who dabble in mining are no exception to the general rule that persons who know a little of a subject are apt to think that they know all about it. Some colour may be lent to the belief that anyone may succeed in mining when we hear stories ofsuccessful diggers and others who have accidentally dropped on to something good through no foresight on their part; but we seldom hear the contra account of the far larger number who fail. Those who go more thoroughly into the subject, and take up mining as a profession, know very well that it is not one that can be carried out successfully by rule of thumb, but when they point this out to the public they are credited with trying to make it a closed profession; and outsiders are for ever trying to find out the "trade secrets," at the same time spurning the main one, which is hard study, experience, and the ability to apply their knowledge. The average mining man is not rich. When he amasses a fortune it is generally through speculation rather than professional work, thought no doubt his technical knowledge may have assisted...

Jan 1, 1910

For the sixth year in a row, the value of nonfuel mineral raw materials produced in the United States set a new record, reaching almost $17 billion in 1977. Data provided by the Bureau of Mines show that the 1977 value of domestic nonfuel mineral production exceeded the 1976 value, $16.7 billion, by 2 percent. The $17 billion worth of minerals was the basis for approximately $770 bill ion worth of processed materials of mineral origin. Output of metals decreased $360 mil lion in 1977, while that of nonmetals increased $670 million. Of the 22 metals produced, output of 12 increased, and the value of 13 increased. Among the 46 nonmetallic minerals produced, the quantity of 27 increased, and the value of 34 increased.

Jan 1, 1978

By Gerald G. Johnson

The use of the Scanning Electron Microscope to characterize Coal Mine Dust has been possible because of two circumstances. First, the imaging process of the SEM allows multiple signals (secondary electrons, back scattered electrons, x-ray emission, etc.) to be viewed. Second, the use of a computer to analyze the signals and perform statistical tests on the results. The parameters described are size, shape, chemical composition, mass distributions, and particle thickness. Although the system is intended for particular systems, those of agglomerates (whether tile same or not) are handled by special aspects of the computer programs. The work on fibers is not completed at the time of this report. This work discusses the hardware (developed especially for this process) and software (both on an IBM 360/370 and a PDP 11/20). The latter system allows direct interaction between the operator of the SEM and computer for maximum information at the least time.

Jan 1, 1979

By Hal J. Kelly

A number of problems that developed in processing the halloysitic clays of eastern Washington and northern Idaho were investigated by the Bureau of Mines. The deflocculating effect of tetra sodium pyrophosphate is compared with several other compounds, and on the basis of current theory, the advantage of sodium pyrophosphate as a deflocculating agent is explained. The adsorption of the sodium ion by clay in a clay"-water system was established by a radioactive tracer technique, and the deflocculating action of sodium pyro- phosphate was postulated. The effective dispersion of the halloysitic clays was limited by the occurrence of tightly bound aggregates of small, individual crystals. Disaggregation of the agglomerates was investigated by liquid extrusion and ball milling of dilute slurries and by extrusion of the clay in a plastic state. The greatest increase in the production of small particles was by high? pressure liquid extrusion.

Jan 1, 1963

Jan 1, 1900

By H. W. Gillett, E. L. Mack

Prior to 1911 the literature on melting brass by electricity consisted entirely-save for some suggestions made in patent literature but not actually worked out-of a few observations by farseeing men ' on the theoretical advantages of melting brass and other nonferrous alloys in electric furnaces. Roeber was the first to see and clearly state the possible advantages of the electric furnace in brass melting. The same factors tha.t make it desirable to manufacture special steels in the electric furnace rather than in crucibles, he declared, apply to brass as well. He pointed out the possibility of using larger melting units, of eliminating crucible cost, of readily controlling the purity of the product. and of nearly eliminating the loss of zinc. "The replacement of the • old crucible process is sure to come," he said; "perhaps it will come in two years, but it will, necessarily, in ten years .... The inevitable advance along this industrial line will have great influence in the metal world and will also provide, in large cities, a new kind of load for the central station." The years 1905 to 1910 may be termed the purely theoretical period of the development of the electric brass furnace, though the Conley furnace was tried out e:xperimenta.lly about 1910 and a few heats were made in an induction furnace. 2 In December, 1911, the American Chemical Society held a symposium on mineral wastes, at which Bassett s discussed the zinc· losses that attend making brass in fuel-fired furnaces.

Jan 1, 1922

By D. J. Parker

Because of its convenience and availability, natural gas (and to a much less extent manufactured gas) in being used more generally throughout the country for domestic and industrial purposes. With this use, specific and little-recognized hazards have arisen owing principally to the fact that the public and the consumer lack knowledge of the explosive property of this fuel. During the past 8 years gas explosions hove occurred in public and private buildings with loss of more than 300 lives and injury to many others. Such appalling catastrophes can and will be prevented if and when the necessary precautions are taken in the construction of buildings and the installation and maintenance of gas lines and gas appliances, plus adequate supervisions inspection, and education.

Jan 1, 1941

By John I. Kasteler, John H. Hild

"INTRODUCTION The South Hecla mine, one of the principal mines of the Alta United Mines Co., is situated at Alta in thee Little Cottonwood mining district, about 30 miles southeasterly from Salt Lake City, Utah. The mine has produced copper, lead, zinc, gold, and silver, and is reported to have been one 'of the principal sources of this country's bismuth from 1912 to 1925. The tungsten mineral, scheelite, has been found but has not been recovered. The extreme need for these minerals during World War II prompted an examination of the property by the Bureau of Mines and resulted in an unpublished report entitled ""The South Hecla Mine, Salt Lake County, Utah"" (fig. 1).A Bureau of Mines project 3301 was initiated, and operations were started early in 1943. The primary purpose of the project was to increase substantially the reserves of bismuth and tungsten ores. The critical situation in regard to lead, copper, and zinc developed during the early stages of the operation, and the work was expanded to include the development of ores 'of these metals.An investigation of 'the Albion, Rustler, and Greeley workings adjoining the South Hecla mine was made, and this work is also described (fig. 2); ACKNOWLEDGEMENTSIn Its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each investigative project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual investigative work, and prepares the final report. The Metallurgical Branch, O. C. Ralston, chief, analyzes samples and performs beneficiation tests."

Jan 1, 1948

By S. Burks

This paper develops the themes explored by the authors at the Fourth International Platinum Conference,. Optimization techniques can be used to significantly increase the value of mining businesses by enabling better long-term planning decisions. Open pit and underground mine design, mine scheduling, cut-off grade and blending, stockpiling, and the linking of these to flexible elements of the metallurgical recovery processes are all evaluated together. Transport or sale of intermediate products and the requirements of the product metal markets can also be considered. Experience shows that net present value (NPV) can potentially be increased by 5-35 per cent or more, usually even before the expenditure of significant amounts of project capital. The case studies presented include: > An existing operation with multiple open pits and PGM concentrators linked to offsite downstream processing facilities, and with infrastructure constraints for which the scheduling of current operations and the potential for expansion were investigated > An existing operation with an integrated portfolio of mines, concentrators, smelter, and refinery, for which the various possible sources of ore for processing were prioritized to match the downstream process plant constraints and the product markets > An underground operation in Zimbabwe for which the optimum mining width was calculated and expansion plans were evaluated > An underground mine with many separate mining sections, for which a revised schedule was developed aiming to keep the shaft system and processing plant at capacity with the highest net value material available at any time throughout the life of mine. In the concluding section of the paper, a few brief notes are included suggesting how the strategic recommendations from enterprise optimization studies may be implemented by the owner's team.

Jan 1, 2013

By Benoit Bissonnette

"The need for production of a competent fill was recognized early by the project partners. Consequently, a 4000 Ud paste fill plant was constructed and commissioned in early August 1994.In order to fine tune the process without risk to the underground workings, a closed pumping loop was devised on surface. After two months of this exercise, the first underground slope was filled according to specifications obtained from the pilot plant trials.This paper will focus on the operational problems encountered and the solutions adopted so far, and on a comparison between expected and actual fill production and characteristics.RésuméLa nécessité de produire un remblai de propriétés mécaniques suffisantes a été rapidement reconnue par les partenaires du projet. Conséquemment, une usine de production de remblai en pate, utilisant les residus du concentrateur d'une capacité de 4000 t/j a été construite et l'opération a débuté au mois d'aôut 1994.Dans le but de roder le précedé sans mettre en danger les installations souterraines, l'usine a été testée dans un circuit de surface. Après deux mois d'essais, le premier chantier souterrain a été rempli avec du remblai en pate selon les specifications dérivées de l'usinage pilote.Cet article présente les problemes d'opération rencontrés et leurs solutions, en plus de faire une comparaison entre les résultats prévus et ceux actuellement obtenus sur la production et sur les charactéristiques du remblai."

Jan 1, 1996

By William L. Young

There is an old saying in Canada: "Mines are made as much as discovered." What follows is Young's perception of his experience developing and financing the Cochrane Hill gold mine project. In 1974, I came back from rutile and zircon exploration and mining in Australia. I became interested in a copper, lead, and zinc project in the Bathurst District, New Brunswick. Much field work had already been done but I was convinced that a reinterpretation of the geophysical work left room to enlarge on the known mineralization. So, with my own money I put a property deal together, found an underwriter willing to raise $100,000, and had a lawyer produce a prospectus. The prospectus was ultimately accepted for filing by the Ontario Securities Commission and I acquired funding and began work. It did not take many drill holes to determine that the interpretation was not geologically valid. However, while drilling was going on, geophysical and geochemical explorations indicated interesting anomalous zones elsewhere on the property. But by now the base metal market climate had soured and the $50,000 I had left was not enough to evaluate the new results. So I decided to farm out the property. A data folio was produced and the property was optioned to a major mining company, with Northumberland Mines Ltd. retaining a 20% free, carried interest. By 1976, the market for junior issues was so bad no under¬writer would even talk to a geologist and I still had the $50,000 in the bank and was looking for something to initiate. A Project That Went Nowhere Market research indicated that the Toronto area imported fine calcium carbonate fillers from Georgia, Alabama, and Vermont. I was aware of the specs and the fact that there is a large marble belt in Eastern Ontario. After some prospecting, I found an interesting deposit. The product was slightly high in silica and low on brightness. Research work eliminated the silica and corrected the brightness. So, with insufficient money we launched a feasibility study. This included diamond drilling, bulk sampling, special fine grinding and air classification tests, and an in-depth market survey. Our product was as good or better than those on the market. Our advantage was that delivery could be made by a two-hour truck haul to the customer. The present system of rail delivery had many problems, especially in winter. Despite everything looking rosy, we ran into a stone wall. The underwriters were singularly unimpressed because the public saw little glamour in a substance most people had never heard of. The issue would have been difficult-if not impossible-to sell. Banks and government agencies took the position that if we could get long term take-or-pay contracts then they would lend the required capital. None of the suppliers, however, would even consider a contract until production had begun and they could evaluate the production material. It was a classic "catch 22" situation. I have gone into this in some detail to show how tough the industrial mineral market can be. We eventually optioned this calcium carbonate property to a major corporation. The option agreement would give us a free, carried 15% and the right to buy up to 40% for contributing 25% of the production costs. But the experience left my company in poor financial shape. To survive, I think the entrepreneur-geologist must always have at least one project in reserve, an emergency plan. I had been searching out a new project to work on, after the calcium carbonate option was wrapped up. It was gold. Gold intrigued me and I knew quite a bit about Nova Scotian gold. I felt that with any rise in price, many of the former high-grade gold mines would have interesting potential for the larger, low grade portions of the deposits. That is how I happened on Cochrane Hill, where much work had been done in the early 1970s when gold as $4.82/g ($150/ oz). This time my timing was good. No sooner had Northumberland signed an option agreement than gold prices started to rise. In six months, they went to $27.331g ($850/oz). Even so, financing gold prospects in early 1980 was still not easy. It had been years since gold financing had been undertaken. A whole new generation of investors, with no knowledge of gold mining, had grown up. So, with accounting and legal council, we decided on a semiprivate "seed money" offering. Under the new Ontario Securities Act, this was a new-and partly tax sheltered-concept. At the time, it was very innovative.

Jan 6, 1982

By Serge Ouellet

Résumé Six modèles métriques de remblai cimenté en pâte (RCP) ont été suivis durant 120 jours par l?utilisation de deux méthodes géophysiques non-destructives : la résistivité et la micro-sismique. Les RCP étaient constitués de trois résidus miniers et de deux proportions de ciment (3% et 6% en poids). En parallèle, des cylindres de RCP étaient utilisés pour évaluer périodiquement l?UCS. La résistivité augmentait quasi-linéairement de 28 à 120 jours pour tous les RCP investigués. Des variations de résistivité selon le type de résidu et le pourcentage de ciment ont été observées. Une équation empirique a été dégagée entre l?UCS, la résistivité, le temps, la densité relative et le rapport eau/ciment (E/C). La mesure de la vitesse des ondes de cisaillement a permis de dégager une équation mathématique de type exponentielle qui relie la résistance mécanique sans correction préalable par les paramètres de la recette de RCP. La réalisation de ce projet avait pour but de dégager la meilleure approche non-destructive afin d?estimer la résistance mécanique des remblais en chantier minier. Sur la base des résultats obtenus, les deux méthodes utilisées ont donné des résultats probants afin d?estimer la résistance mécanique et les deux méthodes sont donc à même d?être utilisées en chantier souterrain. Abstract Six scale models of cemented paste backfill (CPB) were followed during a 120 days period using two nondestructive geophysical methods: resistivity and micro-seismic. CPB were made up of three mine tailings and two cement proportion (3% and 6% by weight). In parallel, CPB cylinders were used to periodically evaluate uniaxial compressive strength (UCS). Resistivity was increasing nearly in straight line from day 28 to day 120 for all CPB models. According to the tailing type and cement percentage, resistivity variations were observed. An empirical equation emerged from UCS, resistivity, time, specific gravity of tailings and, water/cement ratio. The use of shearwave velocity allowed to identify a mathematical exponential equation related to mechanical strength without prior correction of the CPB?s formula parameters. The purpose of this project was to identify the best non-destructive approach in order to evaluate the mechanical strength of backfill in a mine site. On the basis of those results, both methods gave conclusive results in order to estimate mechanical strength and both methods can be used in underground operations.

Feb 1, 2008

Many of the difficulties faced by the U.S. mineral industry in 1982 and 1983 emanated from the worldwide recession, from the high value of the U.S. exchange rate, and, in part, from actions taken by foreign governments to protect selected industries. While some problems will be minimized with continued worldwide economic recovery, others remain and may require special attention by U.S. policymakers. These problems include declining U.S. production capacity in selected mining and mineral processing industries, the impact of the high value of the U.S. exchange rate, and protectionist trade practices by competitor nations. Illustrative of the last is the International Trade Commission (ITC) determination in June 1984 that both the domestic steel and copper industries have been substantially injured by foreign imports. In its July 1984 recommendations to the President, the ITC suggested higher tariffs and quotas for 5 years on 70 percent of steel imports but conditioned the aid on cost-cutting and modernization steps by the domestic industry. In the copper decision, two commissioners recommended increased duties, two recommended that quotas be imposed, and one recommended that no relief be provided. The President decided in September to seek voluntary restraint agreements with nations that export steel to the United States and rejected both quotas and higher tariffs on copper imports. General Economic Setting This decade opened with the U.S. mineral industries struggling to deal with double-digit inflation, record high peacetime interest rates, and almost 7 years of oil-cartel-induced energy price increases that seriously affected the profitability of energy-intensive industries such as mineral production and processing.

Jan 1, 1985

By R. C. M. Minnitt, W. Dr. Assibey-Bonsu, F. A. Camisani-Calzolari

Born in Bothaville (OFS) on the 26th August 1919, Daniel G. Krige grew up in Krugersdorp on the West Rand. Hematriculated from Monument High School in Krugersdorpin 1934 at the age of 15 and graduated with a B.Sc. (Eng.)degree in mining engineering from the University of the Witwatersrand at the end of 1938 (age 19). In 1938 he joined Anglo Transvaal where he worked on a number of gold mines until 1943, gaining a wide range of valuable practical experience in surveying, sampling and ore valuation. He then joined the Government Mining Engineer’s Department where he worked for 8 years during which time he participated in the uranium negotiations with the British and American authorities and designed the uranium pricing formula for the contracts which led to the establishment of South Africa's profitable uranium industry in the early 1950s. During the same period he began his pioneering work in the application of mathematical statistics to the valuation of new gold mines using a limited number of boreholes and of ore reserves for existing mines. His early papers in the application of mathematical statistics, some republished in French, created world-wide interest that led to the development of the science and concepts that surround the spatial evaluation of mineral resources and reserves known as geostatistics. This technique has contributed to improved ore evaluation techniques as well as the reduction of the financial risks associated with investment in mining enterprises. Furthermore, it led to the recognition of his contributions to the evaluations of mineral deposits through the coining of the term ‘kriging’ that is used to describe a spatial mineral evaluation process known and practised in international mining circles. He continued his work in geostatistics throughout his career as Group Financial Engineer of the Anglovaal Group until his retirement in1981 and afterwards for ten years as Professor of Mineral Economics at the Witwatersrand University. He is still active as a consultant and is a registered Professional Engineer. He has published some 90 technical papers both locally and overseas, some in Russia, and has lectured and participated in international congresses in many countries. His contributions were recognized by the Witwatersrand University through the award of the D.Sc. (Eng.) degree in1963, by three honorary degrees (from the universities of Pretoria, UNISA and Moscow State Mining University), by many awards from the South African Institute of Mining and Metallurgy, the International Association for Mathematical Geology, Die Suid Afrikaanse Akademie vir Wetenskap en Kuns, the SME of the American Institute of Mining Engineers, the International APCOM Council in1999, the University of Antofagasta in Chile, and by the South African President (Order for Meritorious Service, Class 1, Gold). He has served on various Government committees, notably that for State Aid for gold mines (1967/8) and designed the State Aid formula which enabled many mines to survive a period of low gold prices; also various taxation committees, and the mining mission to Iran in 1974. He is a fellow and/or honorary life member of various technical societies locally and overseas, including the Royal Society of South Africa. During the period in the Government service he also handled several of the post-war lease applications in the Free State and Klerksdorp goldfields. The fact that decisions on new gold mines of critical importance to the State and the economy as a whole, were being taken on a limited number of drillholes without any scientific analysis of the risks of failure, stimulated him to start basic research into ore evaluation. His approach was based on the application of Mathematical Statistics to these problems, an approach of which very little was known world-wide at that stage but which had already been initiated in South Africa by Sichel via the lognormal frequency distribution model. In Krige's 1951 paper published in the Journal of the Chemical, Metallurgical and Mining Society of South Africa he covered the statistical explanation of the conditional biases in ore block valuations and stimulated the use by several gold mines of regression corrections for routine ore reserve valuations, a technique which, in effect, was the first use on an elementary basis of what is now known as kriging. His 1952 paper introduced, inter alia the basic geostatistical concepts of ‘support’, ‘spatial structure’,’ selective mining units’ and ‘grade-tonnage curves’. His 1951 paper was based on his M.Sc. (Eng.) thesis submitted in the Department of Mining Engineering to the University of the Witwatersrand, and expounded his pioneering work in geostatistics in more detail. His early research papers that had stimulated interest in several mining circles overseas, were republished in French in1955, resulting in a major research effort by French mining engineers in this field. This, in turn, led to the establishment of the now world-renowned French school of ore evaluation in Fontainebleau, Le Centre de Geostatistique de l’École des Mines de Paris. As the Group’s Financial Engineer at the Anglovaal Head Office until his retirement in 1981, he was responsible for

Jan 1, 2003

By Mark Lawshe, Shosie Serata

The conventional method of mining underground, using narrow rooms and wide pillars, has proven to be poorly adapted to the powerful earth forces that act on underground openings. The high costs of roof bolting, timbering, steel arching, and other means of artificial roof support for both room-and--pillar operations and longwall gate roadways attest to the limitations of traditional mine design. Too often, productivity halts when corners buckle under "cutter roof' stresses, floors heave, and roof strata fall. In the 1960s, an entirely different approach to strata control was developed. The Stress Control Method (SCM) stabilizes failing roofs and heaving floors by removing the cause of failure - highly concentrated stresses around the openings. This is achieved by regrouping three to 10 rooms into a single entry where the rooms are separated by very narrow yielding but stable pillars. SCM employs a specified excavation sequence to redirect earth pressures away from the mine openings. The yield pillars act as scaffolding until a permanently protective secondary stress envelope forms around the entry (lower part of Fig. 1). The result is a dramatic improvement in roof stability and a significant reduction in artificial support costs. Some roof bolting must still be done, mainly to meet Mine Safety and Health Administration (MSHA) requirements. Potash, salt, coal mining The stress control method was first applied to the deep potash mines of Saskatchewan. The new SCM design actually increased room widths to enlarge the stress envelope, redistributing the stress concentration away from the entries (Serata and Schultz, 1972). This resulted in a turnaround from pervasive roof fall/floor heave conditions that threatened operations in the eight new mines opened in the Saskatchewan potash field during the 1960s. In addition to eliminating all roof bolting, SCM successfully stabilized ground conditions and substantially increased productivity over the original design (Serata, 1976, 1982). Similarly, the deep Boulby potash mine of Yorkshire, England, was about to close after various conventional means of combating roof failure had failed. An SCM test area was excavated that resulted in the ground quickly stabilizing without need o artificial support (Serata, 1982; Chilton and Laird, 1982). Another example is the Diamond Crystal salt mine in Louisiana. Here, multiple level mining was being extended from the third to the fourth level downward in the Jefferson Island salt dome. Extensive roof failure was occurring at 396 m (1300 ft) ii the third level. SCM design principles in creased the room size from 24 to 49 m (80 t( 160 ft) on the fourth level at a depth of 457 m (1500 ft). This unprecedented expansion of room width was first questioned and later ap¬proved by MS HA, which expressed satisfaction in seeing the improvement documented by field validation data in 1973. The most recent SUM application to salt mining has been in the Michigan Basin a: Goderich, Ontario. The anticipated abandonment of Domtar Chemicals Group/Sifto Salt Division's deep operation in bedded sale was prevented by a multi-year SCM implementation. The success of SCM in dry mining[lecc] to its application to solution mining of salt This adaptation of the method is now being implemented in bedded salt at Fort Saskatchewan, Alberta by Dow Chemical Co., and in St. Clair, MI by International Salt Co. Application of SCM to solution mining in a salt dome is proceeding at Napoleonville. LA by Dow Chemical. The same technology has also been applied to cavern design for the Louisiana Offshore Oil Port (LOOP), and the compressed air energy storage (CAES)

Jan 1, 1989

By Nien-Yin Chang

The contemporary seismic response analysis of structures using a finite element analysis code requires six elastic spring constants to address the six degrees of freedom ground/foundation contribution to the response of a structure to earthquake shaking. However, the ground response is nothing but linear. Thus, it is critical to address the effect of the nonlinear ground response to the performance of structures under strong earthquakes. This study specifically addresses the effect of pile foundation on building vibration using finite element analyses. The effect of single pile was first investigated and the load was applied at the pile head using the single-degree-of-freedom load at a time, including three translational loads in the x, y and z directions and three moment loads about the three respective axes. In this study, the coupling effects between two or more different loads were not investigated. A load is increased monotonically to investigate the nonlinear behavior of pile under various loads. The Mohr-Coulomb model was used to represent concrete. To explore the effect of soil models on the nonlinear spring functions, the following constitutive models of soils were used: linear elastic, Mohr-Coulomb model, Cap model, modified Cam-Clay model, and Duncan-Chang hyperbolic model.

Jan 1, 2007

By Hamid Maleki

Prudent design of coal pillars in any mining system requires an estimation of in-situ pillar strength, overburden lateral load transfer capability, and a failure criterion. Pillar strength is typically determined using one of several different empirical pillar strength formulas. For coal reserves in the U.S., a new pillar design method was proposed based on extensive U.S. field measurements in underground mines (7) which accounted for confinement effects. Field measurements in seven U.S. seams indicated highest strength for some Utah mines where the coal seam developed high confining stresses. Lower strength was measured in structurally controlled seams. This method is expanded here including the data from the weaker tertiary coal measure rocks and lower confinement for pillars with low width-to-height ratios. The determination of how much load a pillar is expected to take is partially dependent on the ability of overburden to transfer load laterally; this is useful for selection of panel width and barrier pillars size in select mining applications where long-term stability is required in conservative designs. In caving mining systems, caving of the strata is influenced by geologic, mining and stress conditions and the released energies influences how the pillars react at loads approaching pillar strengths. Overburden deformation and caving mechanisms are analyzed in this paper in multi-panel extractions to enhance the understanding of load transfer, seismicity and coal bump control in deep western U.S. operations.

Jan 1, 2008

By Steve Hubbard, Brad Marchant, Rolando Cuadra

"Triton Mining Corporation acquired the rights to Mina El Limon in Nicaragua in 1993 by international bid. The bid included the gold operations at Limon and an exploration concession of approximately 4000 km2. Triton assumed control of operations and exploration in May 1994.The Limon mine is located in west-central Nicaragua, approximately 100 kilometers northwest of Managua. The climate is tropical, characterized by a wet season from May through October, and a dry season November through April. Gold at Limon is associated with both banded quartz and silicified breccia veins in Tertiary volcanic rocks, belonging to the lower Coyol Group. Mining is from two open pits and one mechanized underground operation. A second underground mine is currently under development for production during 1997.This paper describes the expansion of the milling facility at El Limon from a nominal capacity of 400 tonnes/day, producing approximately 20,000 ounces of gold annually, to the existing 900 tonne per day mill operation. Engineering of the new mill facility was initiated in September 1994 and construction was completed a year later."

Jan 1, 1997