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By Behdeen Oraee

Constructing tunnels underground is generally described as a high-risk activity because conditions in the surrounding area tend to be unpredictable. This would and can create unique dangers in every situation. It is important to gain a deep understanding of the risks associated with tunneling in order to reduce the likelihood of their occurrence and severity of their consequences should they occur. For this to be achieved, different risks should first be evaluated and ranked according to their relative importance and criticality. The Amir Kabir tunnel is considered one of the most dangerous tunnels in Tehran, Iran, in terms of the risks involved in its excavation and their potential consequences. In particular, part T4 of the tunnel passes through a zone of different strata and also a compound of various soils. This paper studies part T4 of the Amir Kabir tunnel from a risk analysis and risk management point of view. In doing so, factors increasing total cost, causing delay in the project completion time, decreasing the operation rate and downgrading project quality were identified and ranked according to their importance using the aggregate primary index risk method. For this purpose, a comprehensive questionnaire was designed and completed by tunneling experts. By responding to the questionnaires, the experts determined the relative likelihood of occurrence of the studied factors and their potential consequences. As a result, the experts suggested several alternatives to reduce the risks involved in this particular study. Moreover, the experts completed new questionnaires whilst taking into account different alternatives. In the next step, the risks before and after applying the alternatives were compared. As a result of performing the said analyses, it was concluded first that the aggregate primary index risk is an effective tool in identifying the risks involved in such projects. Second, it was concluded that, by taking into account different alternatives when analyzing and ranking the risks, severity of the said risks can potentially be reduced. Also, by considering such matters when analyzing tunneling risks, the projects? efficiency can greatly increase as a result of reducing risks that threaten financial and human resources. The approach introduced in this paper, together with the methodology described, can be adopted by the mining design engineer in all similar situations. They will be of particular advantage in such methods as room and pillar mining, where the number of similar tunnels required is high.

Jan 1, 2014

By Iván Mendoza

La Responsabilidad Social Empresarial (RSE) es una política que adoptan las empresas de manera voluntaria -en tanto relaciona las empresas mineras que instalan las unidades operativas y las poblaciones del entorno. En ese sentido, el presente texto describe los lineamientos que comprende dicha política. Luego, se desarrollan las diferencias entre los ámbitos económicos, organizativos e institucionales en las zonas rurales del país. El aspecto organizativo se aborda enfatizando el papel de las comunidades campesinas, mientras que el institucional destaca los roles de las municipalidades. Finalmente, se revisan las relaciones entre las empresas y la población.

Jul 1, 2013

By C. Bergmann, V. Ross

The concept of underground ore processing, in which valuable ore and waste are separated at a coarse particle size to improve the economics of operations and minimise the environmental impact, seems attractive from a sustainability perspective. Perceived benefits of such an operation include energy and cost savings due to a reduced hoisting load, a reduced footprint of surface operations, and using material for backfill that has not been contaminated by process chemicals. Progress in the South African mining industry in this area has however been below expectation, and opportunities for underground processing in deep, narrow reef operations were therefore explored by an Excel-based simulation with sensor-based sorting (SBS) as concentration technology. Various PGM mining scenarios incorporating factors such as the mining rate, depth of operation, and effects of dilution and particle size on the metallurgical efficiency, were compared. Whilst these initial results can be regarded as indicative only, they have shown that the economics of such an operation are driven by selective mining at significantly higher rates than achievable with conventional methods. Also, the cost of preparing, conveying and placing rock backfill will need to be lower than that of hoisting waste and depositing it on a surface dump. Another aspect to be addressed is whether ore sorting machines would be able to operate under harsh conditions underground and what provision would need to be made to ensure their efficient operation. Further investigations should focus on refining costs, incorporating environmental considerations in the modelling of economics and sustainability, and compare greenfields with brownfield scenarios. Keywords: Ore sorting, hoisting, backfill, mining rate, economics simulation

Jan 1, 2020

By Nabeel Khan

Annual oil production from the Canadian Oil Sands in Northern Alberta has been rising for several decades, and more ore and overburden are excavated each year from an increasing number of open pit mines. Overburden meeting certain specifications will be used to dam tailings and fill open pits, but the remaining material must be stored in overburden storage structures (OBSS). Well-designed overburden storage structures are more stable and cost less in the short- and long-term. The purpose of this paper is to explore OBSS designs that will be stable yet economical in the short- and long-term. The geological background of the site is briefly discussed, including the effect of each of the main geologic layers (recently deposited till and muskeg, Clearwater Formation clay shales, McMurray Formation oil sands, and the Devonian limestone) on the slope stability of the OBSS. Cost is considered in the analysis when balancing between minimizing costs (steeper slopes) and acceptable factors of safety (flatter slopes), all the while considering the financial consequences of failure. Potential failure planes are identified and probabilistic analysis is conducted on the critical failure surface. The variations in the factor of safety caused by varying pore water pressure, friction angle, and cohesion, are plotted and discussed.

Jun 1, 2012

By H G. Poulos

"This paper sets out a simplified approach by which the practical foundation designer can undertake the relevant calculations to satisfy the requirements for deep foundation design in seismic areas. The following matters are dealt with:a. Design issues that should be addressed;b. Pile design for axial loading, including the possible effects of liquefaction;c. Pile design for lateral loading where liquefaction does not occur;d. Pile design for lateral loading where liquefaction does occur;e. Measures to mitigate against liquefaction effects.The paper is a modified version of a paper presented in 2013 to the 19th NZGS GeotechnicalSymposium, Queenstown, New Zealand.1. INTRODUCTIONConsideration of the effects of earthquakes and seismic loadings is an increasingly important aspect of modern foundation design, and most contemporary standards have a mandatory requirement for such consideration. For example, the Australian Piling Code, AS 2159-2009, states that “a pile shall be designed for adequate strength, stiffness and ductility under load combinations including earthquake design actions”. However, the methods by which such considerations can be undertaken are generally not set out in the standards, and many approaches have been utilized, ranging from very simplistic methods to extremely complex computer analyses. Accordingly, there appears to be scope for an approach that is soundly based but which is neither too simplistic nor too complex.Poulos (1989) has suggested that there are three categories of analysis and design, as follows:1. Category 1: empirical methods.2. Category 2: simplified but soundly-based methods.3. Category 3: more comprehensive methods that are soundly-based, and site-specific.The objective of this paper is to set out a systematic but simplified approach which falls into Category 2 above, and by which the foundation designer can undertake the relevant analyses to satisfy the foundation design requirements for seismic regions. Emphasis is placed on methods that do not require “black box” software or which employ complex soil models in which the physical meaning of the parameters is unclear."

Jan 1, 1900

By Stanley M. Moos, Richard Addison

Introduction The Pueblo Viejo gold-silver mine, located in the Dominican Republic, started production in early 1974 processing ores averaging 4 g/t gold and 20 g/t silver at a rate of 7.25 kt/d. The ore milled is a silicified siltstone with average work index of about 8 that occurs as an extensive oxide capping of a primary sulfide ore body. The sulfide ores are refractory to conventional treatment process and extensive research work is now in progress to develop a treatment process for them. The ore deposit has a long history, having been mined by the indigenous Arawak Indians for some time in the early sixteenth century prior to the arrival of the Spanish, and then by the Spaniards. In the early 1950s, Italian engineers attempted to process the sulfide ores. Mining by the Indians and Spanish was abandoned because of low grade and little coarse gold in the oxide ores and by the Italians because of the refractory nature of the sulfide ore. In 1969, Rosario Resources geologists discovered that there existed sufficient reserves of oxide ore for a viable mining operation and the plant was designed, built, and brought into production.

Jan 1, 1981

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members) The following is a partial list of members and guests who called at Institute headquarters during the period Mar. 10, 1917, to Apr. 10, 1917. Frederick R. Ahbe, Athens, Pa. Frank M. Leland, San Francisco, Cal. J. L. W. Birkinbine, Philadelphia, Pa. Edwin Ludlow, Lansford, Pa. Samuel D. Bridge, Monterrey, Mex. E. P. Mathewson, Toronto, Canada. J. R. Buchanan, Pasadena, Cal. E. V. Matlack, Webster Grove, Mo. G. M. Colvocoresses, Humboldt, Ariz. E. C. Potter, Clearwater, Mont. F. G. Cottrell, Washington, D. C. R. B. Stanford, Bluefields, Nicaragua. H. N. Eavenson, Gary, W. Va. R. S. Ransom, Jr., Newark, N. J. H. T. Fisher, Englewood, N. J.. M. L. Requa, San Francisco, Cal. E. P. Fleming, Salt Lake City, Utah. John A. Rice, El Paso, Tex. F. L. Garrison, Philadelphia, Pa. W. E. Rice, Ringwood, N. J. W. M. Grant, So. Bethlehem, Pa. Lewis A. Riley, Philadelphia, Pa. J. F. Hanst, Negaunee, Mich. Hallet R. Robbins, Vancouver, B. C. H. D. Hibbard, Plainfield, N. J. Allen H. Rogers, Boston, Mass. B. B. Hood, Chrome, N. J. A. A. Stevenson, Philadelphia, Pa. Henry M. Howe, Bedford Hills, N. Y. Wm. Huff Wagner, Johnstown, Pa. Hennen Jennings, Washington, D. C. E. E. Watts, Denver, Colo. Oscar Lachmund, Greenwood, B. C. Samuel S. Wyer, Columbus, Ohio. H. W. Aldrich, after ten years of service with the Anaconda Copper Mining Co., at Anaconda, has resigned and accepted a position as general superintendent for the Ladysmith Smelting Works, at Ladysmith, B. C. Charles E. Bunker, formerly superintendent of the Keystone mine, has been appointed superintendent of the Bunker Hill mine near Amador City, Cal.

Jan 5, 1917

In the United States water pollution resulting from mining activities has long been recognized as a major environmental problem Mine drainage pollution results from many types of mining activities and includes both physical (i e , sedimentation) and chemical (i e , acidification, metal contamination, etc ) pollutants Active and abandoned surface and underground mines, mineral processing plants, mine and processing plant waste disposal areas, haulage roads, and tailing ponds are typical sources of mine related water pollution (130) One of the most serious pollution problems arising from mining activities is acid mine drainage resulting from the chemical reaction of sulfide minerals (commonly iron sulfides) and air in the presence of water Acid mine drainage is commonly associated with coal and hard rock mining areas in the United States In general the more serious and extensive acid mine drainage problems exist in the more humid coal regions east of the Mississippi River (11) In 1964 the U S Department of the Interior, Fish and Wildlife Service, reported that acid mine drainage adversely affected fish and wildlife habitat in 9,477 kilometers (5,890 miles) of streams and 6,062 hectares (14,967 acres) of impoundments in 20 states in the United States (64) Of the total affected waters, coal mining operations accounted for 97 percent of the acid mine drainage pollution reported for streams and 93 percent of that reported for impoundments In 1970 more than 19,308 kilometers (12,000 miles) of streams in the United States were reportedly significantly degraded by mining related pollution (130) Of the total affected kilometers, 16,920 kilometers (10,516 miles) or approximately 88 percent were located in the Appalachian coal region (Pennsylvania, West Virginia, Ohio, eastern Kentucky, Tennessee, Maryland, and Alabama) In addition, more than 965 kilometers (600 miles) of streams reportedly were degraded by coal mining in states in the Illinois, Western Interior, and Rocky Mountain coal regions The remaining portion of the stream pollution resulted from the mining of (1) copper (california, Montana, Nevada, New Hampshire, Tennessee, Virginia, and Wyoming), (2) lead and zinc (Colorado, Idaho, Kansas, Missouri, Montana, Oklahoma, and Tennessee), (3) uranium (Rocky Mountain States), (4) iron (Lake Superior iron region), (5) sand and gravel (all states), (6) phosphate (Florida and other states), (7) gold (Alaska), (8) bauxite and barite (Arkansas), and (9) molybdenum, gold, and other metals (Colorado) Abandoned mines and abandoned mine waste disposal areas contribute a large portion of the total pollution resulting from mining activities Numerous abandoned underground mines are located throughout the United States and many are discharging mine drainage pollutants In 1966 the U S Bureau of Mines estimated that more than 88,000 inactive and abandoned underground mines were in existance (126) A listing of these mines by state is presented in Table 1 0-1 More recent estimates indicate that this list is incomplete In Colorado alone there is

Jan 1, 1975

By A. K. Mukhopadhyay, B. Sikdar, V. P. Arora

Introduction During the past several years, persistent concerns about an economic slowdown in India have tempered capital-expan¬sion plans. This has encouraged companies to find methods of increasing the capacity of existing production equipment. One of the more cost-effective methods of increasing produc¬tion capacity without major capital investment is to improve equipment maintenance to prevent needless machine down¬time. This can have a significant financial impact because of reduced maintenance costs and increased machine availabil¬ity. The maintenance program employs different techniques, but the analysis of the vibration behavior of machine compo¬nents to assess their condition was found to be the most accurate technique for monitoring various machine disorders. A dragline that handles overburden in open pit mines is one of the more capital-intensive pieces of production equip¬ment. It is imperative that the machine be run at its optimum capacity under the prevailing environmental conditions. Condition monitoring of the various components of the dragline through vibration analysis not only improves the machines availability but also ensures a long operation time free from sudden failure. This paper describes the application of vibration monitor¬ing and analysis techniques to assess the components of a W2000 dragline. The paper reveals that condition monitoring through vibration analysis can be as valuable in failure prevention as it is in failure analysis. Finally, the paper presents an approach to a knowledge-based expert system to the quick and correct diagnosis of mechanical faults in a dragline. Equipment A dragline is an intermittent-discharge-type excavator having a long boom at one end. Unlike other excavators, the bucket is not rigidly held by the frame structure. In favorable geomining conditions, the intensive operation of these exca¬vators is the least-expensive means of overburden removal. The basic working elements of this equipment are the hoist system, the crowd and retract system, the wing mechanism and the propel mechanism. The walking dragline is accepted as the most economical machine for stripping overburden at depths of up to 60 m (200 ft). They are electrically powered and the various motions are effected by individual drives. The Ward-Leonard system is used to provide the optimum flexibility in controlling different dc-drive motors. To mini¬mize the cost of mineral extraction, the largest such machine in India has a 24-m3 (850-cu ft) bucket with a boom length of 96 m (315 ft). Draglines are very costly, and considerable financial penal¬ties may arise from sudden stoppages due to component fail¬ures. Thus, operational reliability is of the greatest importance. Active measures are now being taken to minimize downtime by adopting condition-based maintenance techniques. Though a number of techniques come under this scheme, it has been observed that assessing the health of the dragline by measuring vibration is the best method of determining the dynamic behavior of its various rotating components to avoid any catastrophic failure. Based on criticality, the vibration-behav¬ior of the following components are studied: • motor-generator unit, • exciter unit, • hoist motor-gearbox unit, • hoist drum-gearbox unit, • drag motor-gearbox unit, • drag drum-gearbox unit and • swing motor unit The approach Increases in the vibration levels in different subsystems of the dragline were observed due to the presence of faults such as unbalance, misalignment, looseness and bad bearings. A vibration behavior study included the measurement of vibra¬tion level, trend analysis of time-domain vibration signals and vibration frequency analysis at bearing points of the components. A vibration meter, a vibration analyzer and a data collector are used. Vibration-level measurement. When the dragline was assembled and put into operation for the first time, vibration data were collected to generate baseline data for the equip¬ment (based on International Standard ISO 2372). After¬wards, the vibration levels were recorded regularly using a vibration meter. The measurements were taken at all bearing

Jan 1, 2000

By H. L. Liu

With the exploitation of mineral resources, valuable minerals are more and more finer and poorer. Priority reclaiming liberation grind particle under rough grinding, will help to pervert loss of melts, raise dewatering efficiency of concentrate, reduce consumption of reagent. And it is propitious to reduce energy consumption and raise the utilization rate of resources. With the feature of coarse particle?s desorption and deposition, CLF flotation machine has special pulp circulating way, which is not only apply to treat coarse particle but also normal size particle. The paper advanced the history, the design principle, the structure feature and the application of CLF flotation machine.

Jan 1, 2014

By S. R. McCutcheon, D. R. Lentz

"Abstract - The 12.1 Mt Brunswick No. 6 Zn-Pb-Cu-Ag massive sulfide deposit (New Brunswick, Canada) lies between two subaqueous felsic volcanic formations near the base of the Middle Ordovician Tetagouche Group. The footwall comprises rhyodacitic pyroclastic rocks (Nepisiguit Falls Formation), whereas the hanging wall comprises a sequence of rhyolitic flows, breccias, and hyaloclastites (Flat Landing Brook Formation), with an age difference of less than 3 m.y. The Brunswick No. 6 deposit is a proximal autochthonous deposit with a well-zoned massive sulfide body and a basal Cu zone that, at depth, develops into a stockwork stringer sulfide (feeder) system. The massive sulfides are capped sharply by a layered magnetite-chert unit that extends regionally beyond the deposit. The deposit has a keel shape (sheath) formed by the F1F2 interference pattern. The heterogeneous ductile deformation and upper greenschist-grade regional metamorphism has transposed many of the epigenetic stockwork structures and alteration within the host sequence. Hydrothermal alteration is much more extensive, both vertically and laterally, in the footwall (a few 100 m) than in the hanging wall (<100 m). Anomalies farther up in the hanging wall sequence seem to be associated with independent alteration systems related to the rhyolite domes. The least-altered footwall units exhibit keratophyric alteration (albite or adularia) and weak Mg enrichment (chlorite). More intense micaceous (sericite and Mg-rich chlorite) alteration occurs around the footwall sequence. The transposed stockwork stringer sulfides are typically composed of Fe-rich chlorite (± sericite, ± silica) with pyrite, pyrrhotite, chalcopyrite, arsenopyrite, and sphalerite. The (Fe2O3T+MgO)/(Na2O+K2O) and base metal alteration indices are the best practical lithogeochemical vectoring tools at this deposit. Sommaire - Le gîte de 12.1 Mt de sulfures massifs de Zn-Pb-Cu-Ag Brunswick No.6 est localisé entre deux formations volcaniques felsiques sous-marines situées près de la base du Groupe de Tetagouche d’âge Ordovicien Moyen. Le mur consiste en roches pyroclastiques rhyodacitiques (Formation de Nepisiguit Falls) tandis que le toit consiste en une séquence de coulées, de brèches et d’hyaloclastites de composition rhyolitique (Formation de Flat Landing Brook); la différence d’âge entre les deux est de moins de 3 m.y. Le gisement Brunswick No. 6 est un gîte autochtone proximal comprenant un corps de sulfures massifs clairement zoné ainsi qu’une zone cuprifère basale qui passe progressivement à un stockwork de filonnets de sulfure en profondeur (feeder). Les sulfures massifs sont abruptement surmontés d’une unité laminaire de chert et de magnétite dont l’extension par delà le gisement est régionale. Le gisement affecte la forme d’une quille (fourreau) résultant d’un patron d’interférence F1F2. Plusieurs des structures épigénétiques du stockwork et des patrons d’altération de l’encaissant ont été transposés par la déformation ductile hétérogène ainsi que par le métamorphisme régional au faciès des schistes verts. L’altération hydrothermale est beaucoup plus importante, tant verticalement qu’horizontalement, dans le mur (quelques 100 m) que dans le toit (<100 m). Les anomalies situées plus haut dans le mur semblent être reliées à des systèmes d’altération indépendants associés aux dômes de rhyolite. Les unités les moins altérées du mur une altération kératophyrique (en albite ou en adulaire) ainsi qu’un faible enrichissement en Mg (chlorite). Une altération en mica (séricite et chlorite magnésienne) plus intense est présente autour de la séquence du mur. Les sulfures du stockwork de filonnets transposés consistent typiquement en chlorite ferrifère (± séricite, ± silice) accompagnée de pyrite, de pyrrhotite, de chalcopyrite, d’arsénopyrite et de sphalérite. L’indice d’altération (Fe2O3T+MgO)/(Na2O+K2O) et l’indice des métaux usuels sont les outils d’exploration les plus appropriés dans ce gisement."

Jan 1, 2006

"Coupon testing has been used to investigate stress corrosion cracking (SCC) of rockbolts in a laboratory based experimental program. This program has focused on the use of ASTM G39 three- and four-point bent beam coupon specimens, immersed in an acidified sodium chloride test solution containing hydrogen sulfide. The specimens were loaded to a range of stresses from zero, to just above the materials yield strength. It was found that only specimens above an applied stress of 580MPa failed by means of SCC, showing that rockbolts loaded to near their yield strength may be susceptible to SCC in-situ.INTRODUCTIONStress corrosion cracking (SCC) is a failure mechanism that affects material through the growth of hairline cracks when exposed to a corrosive medium while under stress (Jones and Ricker, 1999). SCC has been found to affect rockbolts in the Australian underground coal mining industry and has the capacity to cause the catastrophic failure of ground support systems, potentially leading to falls of ground in underground excavations, injury or death to mine personnel, damage or loss of equipment, and loss of productivity through the loss of roadway access (Crosky et al, 2002).Coupon testing utilises small scale samples that are intended to be indicative of the behaviour exhibited by a material in-situ (ASTM G39). The small scale, and usually high surface area to volume ratio of coupon specimens mean that they corrode at faster rate proportional to their mass, greatly reducing testing times. The small scale of the specimens allows them to be more easily prepared and handled, loaning them to mass manufacturing techniques.A previous study conducted by Vandermaat et al (2012b) into the use of three- and four-point coupon testing in-situ in an underground coal mine failed to result in SCC of the specimens. This paper serves as a follow up laboratory investigation in order to understand why these specimens did not fail. Previous studies into the SCC in rockbolts carried out by Gamboa and Atrens (2003) determined that rockbolt steel has a critical stress threshold of approximately 90% of the material ultimate tensile strength (800-900MPa). This study will focus on this critical stress threshold as a possible explanation for the lack of failure in the in-situ specimens (Vandermaat, 2012b)."

Jan 1, 2015

By G. Babut

The restructuring of mining operations in Valea Jiului coal basin imposed by the transation to the market economy calls for an increased coal production. Under the circumstances, the role of drainage networks grows ever more important. The paper describes an original mathematical model and software developed on its basis, with enables the ventilation engineer to assess the configurations of different systems, as well as to test their reliability and prognose their future performance before conceiving another methane drainage system or changing the existing one. The paper also includes the underlying principles of an optimization program for methane drainage networks, which will enable the detection of the optimal methane drainage system, both from a technical and an economic point of view.

Jan 1, 1996

By A. Lopez-Valdivieso

Particle size enlargement processes play an important role in solid/liquid separation, and in beneficiation unit operations. In the latter, not only the size of the formed aggregates but also their surface properties are very important. Oil agglomeration has a special place among such processes: it is a selective process in which hydrophobic particles are agglomerated into hydrophobic agglomerates which can be recovered by flotation. This explains the broad applications of oil-assisted beneficiation processes not only in the beneficiation of fine coal, but also in agglomerate flotation of many different types of ores, and in coal/gold agglomeration.

Jan 1, 2004

By Adam Jordens, Olga Kuzmina, Christopher Marion, Kristian Waters

"In order to meet the growing demand for non-Chinese rare earth suppliers many new rare earth (RE) mineral deposits are currently under development, however these deposits typically include many minerals for which there is little processing information available. One of these deposits is the Nechalacho deposit located in the North West Territories of Canada. This deposit contains multiple RE minerals including bastnäsite, zircon, fergusonite, allanite and monazite. The work presented here investigates the use of different classes of flotation collectors (carboxylic acids, hydroxamic acids, phosphoric acids) typically used in RE mineral flotation to float the Nechalacho ore directly. Flotation tests are also conducted as the final step in a beneficiation process incorporating centrifugal gravity concentration and magnetic separation. This combination of centrifugal gravity concentration and magnetic separation rejects low specific gravity gangue minerals such as K-feldspar and plagioclase and concentrates high specific gravity minerals such as magnetite and hematite. The removal of low specific gravity gangue helps to improve flotation and the removal of ferromagnetic iron oxides is important prior to flotation using certain chelating collectors."

Jan 1, 2014

By N. J. Themelis

The basic chemical, thermal and transport principles that underlie sulfide smelting of. copper, nickel and lead are reviewed. Two basic types of modern smelting processes are distinguished?: flash-smelting, where the predominant reactions occur between oxygen-bearing gas and concentrate particles dispersed therein; and bath-smelting where the concentrate is enveloped and reacted in a turbulent bath of matte, slag and gas. The controlling heat and mass transfer phenomena are discussed, and appropriate correlations are proposed.

Jan 1, 1983

By W. G. Pariseau

A study of coal pillar strength at the Beehive Mine in central Utah was done in the 1970s. This study was a cooperative effort by the University of Utah, RE/SPEC, Inc., and the American Coal Company and was funded by the U.S. Bureau of Mines. Mine measurements of closure at 117 points and pillar stress using 119 vibrating wire stress gauges were made during retreat mining in this room-and-pillar operation. Laboratory testing for the strength and modulus of 372 coal cylinders up 0.3 m (1 ft) in diameter and 0.6 m (2 ft) in length was also done. Two-dimensional finite element model analyses complemented the study. However, the real world of mining is three-dimensional and in consideration of the significant advances in computing power since the time of the original study, a revisit of the data seemed warranted. In this regard, a novel finite element method was used that allows for the whole-mine analysis of tabular excavations on the kilometer scale and yet enables details to be obtained at pillar walls on the meter scale. The effects of material properties variability in situ and of joints can also be taken into account. Results that compare computed two- and three-dimensional seam-level closures with mine measurements show noticeable differences; three-dimensional results are reasonable, while two-dimensional results overestimate closure by nearly a factor of two.

Jan 1, 2014

By Irving Wigden

The world is fast becoming information based. Mine companies migrate business infrastructures to be handled electronically. Suppliers move onto the worldwide web. In this ?e-world? successful suppliers will recognize they no longer trade in just equipment, but in knowledge. Companies can no longer just provide products and services, but instead must find ways to harness their knowledge to provide new value for customers. Mine customers will be attracted to suppliers that can help them streamline the process and use Information Technology to optimize operations, increase profit, reduce cost and enhance shareholder value. With the continued move to industry standard communications and software platforms, technology that formerly stood alone can now be integrated with other technologies. This creates more powerful systems that mine operators can use quickly, easily and cost effectively. These unified architectures improve productivity, provide higher asset optimization and allow more informed decision-making. As a leading supplier of process automation solutions for the industry, ABB provides a dynamic range of such control systems. These systems are designed for instrumentation controls, variable speed drives, electrical distribution, electrical equipment and related services for Mine Automation. Enhanced by ABB´s new family of integrated software solutions ? collectively known as Industrial IT ? ABB´s control and Scada systems place you in the best position to optimize your plant, process and enterprise operations. The paper discuss system integration and installation of High-Tec system in an underground mine. ABB has the ambition to be a System Integrator and co-operate with partners in different areas of technology. To day it is a problem to find one Supplier that can be responsible for the complete Automation System. The design of the system is also much depending of the design of the mine and also which caving procedure that is used in the current mine. Much of the work must be done in a feasibility study and during the design phase. If there is careful planning and consideration during these phases is vital in order to avoid costly changes during the commissioning phase The paper will also include a presentation of the benefit of using Automation in an Underground Mine, and how important the integration of the Human Being is to the Automation System. The most profit gained in mining industries are received when the mines can reduce internal and external disturbances in the production flow and speed. Must of the experience and discussed in this paper is from advanced technology, that has been developed in Scandinavian and adopted of LKAB in Kiruna. The author of this paper has been responsible för the Automation projects in the Kiruna Mine during 1994 - 1999. These projects include: Broadband communication of data, audio, compressed video in one data stream. Control System for Haulage -1045m Automation of Load Haulage and Dumping machines (LHD) Control of Production Drilling Riggs from a Central Control Room.

May 1, 2002

By Irving Wigden

The world is fast becoming information based. Mine companies migrate business infrastructures to be handled electronically. Suppliers move onto the worldwide web. In this ?e-world? successful suppliers will recognize they no longer trade in just equipment, but in knowledge. Companies can no longer just provide products and services, but instead must find ways to harness their knowledge to provide new value for customers. Mine customers will be attracted to suppliers that can help them streamline the process and use Information Technology to optimize operations, increase profit, reduce cost and enhance shareholder value. With the continued move to industry standard communications and software platforms, technology that formerly stood alone can now be integrated with other technologies. This creates more powerful systems that mine operators can use quickly, easily and cost effectively. These unified architectures improve productivity, provide higher asset optimization and allow more informed decision-making. As a leading supplier of process automation solutions for the industry, ABB provides a dynamic range of such control systems. These systems are designed for instrumentation controls, variable speed drives, electrical distribution, electrical equipment and related services for Mine Automation. Enhanced by ABB´s new family of integrated software solutions ? collectively known as Industrial IT ? ABB´s control and Scada systems place you in the best position to optimize your plant, process and enterprise operations. The paper discuss system integration and installation of High-Tec system in an underground mine. ABB has the ambition to be a System Integrator and co-operate with partners in different areas of technology. To day it is a problem to find one Supplier that can be responsible for the complete Automation System. The design of the system is also much depending of the design of the mine and also which caving procedure that is used in the current mine. Much of the work must be done in a feasibility study and during the design phase. If there is careful planning and consideration during these phases is vital in order to avoid costly changes during the commissioning phase. The paper will also include a presentation of the benefit of using Automation in an Underground Mine, and how important the integration of the Human Being is to the Automation System. The most profit gained in mining industries are received when the mines can reduce internal and external disturbances in the production flow and speed. Must of the experience and discussed in this paper is from advanced technology, that has been developed in Scandinavian and adopted of LKAB in Kiruna. The author of this paper has been responsible för the Automation projects in the Kiruna Mine during 1994 - 1999. These projects include: Broadband communication of data, audio, compressed video in one data stream. Control System for Haulage -1045m Automation of Load Haulage and Dumping machines (LHD) Control of Production Drilling Riggs from a Central Control Room.

May 1, 2002

By I. R. Miller

The purpose of this discussion is to try to offer some suggestions as to how the zinc and lead markets will perform over the balance of the decade, review some of the factors influencing production and come to some conclusions regarding prices. The past 2 years have been simply awful in terms of consumption, prices and overall profitability for the industry. In looking ahead to the year 2,000, it is probably not a bad idea to look back about 20 years to see where we have been and how we got to where we are. Zinc consumption from 1950 to the early 1970&apos;s increased steadily and rather nicely at an annual average rate of close to 4.0%. It was starting in the early 1970&apos;s that things started to get volatile and at times, difficult for the industry. The general economic boom of the early 70&apos;s was marked by annual consumption rates close to 5.0 million tons, a level not seen again for over 10 years. The First Oil shock of 1973-74 was followed by the sharpest consumption drop in memory. In two years, Western World zinc consumption fell 27%. While our chart shows a rather dramatic recovery thereafter, the average annual growth rate since 1970 has only been a rather modest 1.5%.

Jan 1, 1992