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By Néstor D. Córdova

El presente trabajo revisa las técnicas empleadas y las condiciones previas para el sostenimiento y construcción del tunel Gandolini de la unidad minera Julcani. En esta perspectiva, el túnel sirvió de base para realizar las investigaciones de campo, obteniéndose así la información básica para un mejor entendimiento del comportamiento del macizo rocoso con miras a la solución de los problemas que planteaba su construcción. Por ello, la mecánica de rocas como técnica empleada, evalúa la alteración al equilibrio del macizo rocoso en el que se construye el túnel. Asimismo, se establecen criterios para la determinación de las cargas del techo y se los relaciona a los diferentes parámetros de diseño para llegar al cálculo del sostenimiento, dándose finalmente los aspectos prácticos relacionados a la selección de los tipos de sostenimiento más adecuados.

Oct 14, 1980

Reply to discussion of the paper of C. W. Washburne, presented at the New York meeting, February, 1914 (Trans., xlviii, 687 to 694 (1914)). C. W. WASHBURNE, New York, N. Y. (communication to the Secretary*).-Professor Lane makes an interesting contribution to the study. of chloride waters, in saying that calcium chloride waters occur not only in the greenstones of the Lake Superior copper mines, but also in the interbedded -felsitic conglomerates and "in far-removed sandstones, e.g., near Whitefish lake, and Ontonagon, in the Michigan iron mines, and in the Storm King granite." Surely these are not connate waters preserved from the Algonkian sea, assuming that the Algonkian sediments are marine rather than continental. Finding the same type of water in the Storm King granite points rather toward an abyssal source. The possible connection of these waters with the magma of the greenstone is immaterial, although some basic calcic magma is the most probable source. It is to be expected that the ascending water of the region would be found not only in the greenstones, but in all the rocks which it could penetrate. The ascent of water of this kind along vertical passages, and the consequent addition of a common ion: to the circulating sedimentary salt solutions, would explain the precipitation and localization of the "giant, concretionary" salt plugs of the Gulf Coast, without making the ex-excessive demand for an improbable quantity of salt in the adjacent sediments that is required by the unmodified theory of Harris. With-out such a precipitating medium most of the dissolved sodium chloride would have been lost by passing on to the surface without precipitation. The base to which the chlorine ions were attached is immaterial, providing they were sufficiently concentrated, but the presence of the chlorides of calcium and magnesium in the solutions is indicated by the associated bodies of secondary dolomite.

Jan 4, 1915

By Yahui Feng, Zhiwen Wu, Chen Chen, Xin Hong

Large amounts of copper slag containing about 40 wt% iron is generated during the process of producing copper. Recovery of iron from the copper slag is very essential not only for recycling the valuable metals and mineral resources but also for protecting the environment. The purpose of this study was to investigate the possibility of separating fayalite by oxidation-reduction process into Magnetite and silicate phases in intermediate temperature condition. Experimental results show that when the oxidation reaction at 1000℃ for 120min and the oxygen flow is 0.1L/min, most fayalite decompose to hematite, less part of magnetite and silica. And then, the mixture of carbon and oxidation product is pressed into blocks and reduced to magnetite and silica at 900℃ for 90min. A magnetic product containing about 57.9wt% iron was obtained from the magnetic separation under a magnetic field strength of 100 mT.

Jan 1, 2015

By Andrzej Tejchman

A method of improvement of a subsoil under bored pile base by injection is presented. The method employs a special chamber attached to the reinforcement at the bottom of the drilled borehole. The chamber is made of semi-permeable textile bag. The injection entered under high pressure into the bag, causes prestressing of subsoil under the pile base. The results of load tests of piles improved in this manner have shown a substantial increase of their capacity together with simultaneous reduction of settlements. This technology has been implemented for four constructions such as trestle bridges in Gdynia and Warszawa and the bridges in Szczecin and Gdansk. The injection effects are shown based on the load test results.

Jan 1, 2002

By T. T. Chen

The manganese oxide scales, consisting mainly of MnO2, characteristically occur in banded colloform structures which adhere to porous layers of PbSO4 and PbO2 that oxidized from the rolled Pb-0.7% Ag anodes. Hydrous Mn oxides, Mn3O4 and amorphous Mn oxides are believed to be also present. Tiny particles of gypsum, PbSO4, SrSO4 and AgCl are entrapped in the colloform masses. The gypsum originated from the Zn electrolyte; strontium carbonate was added to the ZnSO4 solution to control Pb, and silver originated from the anodes. Some of the colloform bands contain minor amounts of Pb, implying a limited degree of dissolution of the Pb during electrolysis. Other colloform bands incorporate trace amounts of Zn. Colloform structures permeated with silica gel are presumably caused by the high silica content of the electrolyte.

Jan 1, 2009

By Bruce I. Thomas

In 1943, the Bureau of Mines investigated the occurrence of cassiterite in the gravels of Morelock Creek which flows into the Yukon River 32 miles east of the confluence of the Yukon and Tanana Rivers in central Alaska. Samples of the gravels were obtained by churn drilling test pitting, shaft sinking, and open-cut mining. The gravels along Morelock Creek are about 6 feet in depth and covered with about 2-1/2 feet of overburden. The overburden is frozen, but the underlying gravels are not. Cassiterite, with gold and other heavy minerals, is usually concentrated in the first 2 feet of' gravel above bedrock and in some places penetrates into joint planes in the bedrock. The various methods of obtaining samples are discussed, and drill logs and analyses are tabulated in this report.

Jan 1, 1948

By A. S. C. Owili-eger

The computer-aided simulation model re¬ported here is an extension of the one developed by the author while at The Pennsylvania State University. The present model, however, includes consideration of the deformability and secondary fracturing of the porous system. The modifications enable simulation of multiphase shallow unsaturated-saturated and/or artesian ground water systems in dynamic mining environments. The model has been validated, verified, and evaluated on a number of field case studies and the results have been excellent.

Jan 1, 1984

By G Lane, S Morrell

The design of the 12 m diameter SAG mill installed at the Cadia Hill Mine in New South Wales followed after two years of extensive laboratory and pilot plant testwork. The testwork showed the Cadia ores to be hard and competent necessitating the use of both a variable speed SAG mill drive and pebble crushing. The grinding power requirements for the SAG mill was based on engineering in-house grinding software, pilot plant data and simulations using JK SimMet software. Surveys of the SAG mill operation during the first four weeks showed the feed size distribution, transfer size and pebble rate to be lower or less than those for which it was designed. To compensate for the lower pebble rate, the SAG ball load was increased. This resulted in the total comminution circuit power being some 0.5 kWh/t higher than predicted. The JK SimMet SAG model has been modified to take account of these variations.

Jan 1, 2000

By V. T. McLemore

Deposits of rare earth elements (REE) are found in NM, but they have not been important exploration targets in past years because demand has been met elsewhere. However, with the projected increase in demand and potential lack of available production from China, the New Mexico deposits are being re-examined for their potential. REE-Th-U veins are found in the Gallinas, Caballo, Capitan, and Cornudas Mountains and Laughlin Peak-Chico Hills. Past production of bastnaesite has come from the Gallinas Mountains. Carbonatites are found in the Lemitar and Chupadera Mountains, Laughlin Peak-Chico Hills, Lobo Hill, and Monte Largo (Sandia Mountains). Although carbonatites have not been found in the Gallinas Mountains, they are suspected to occur in the subsurface based upon mineralogy/alteration. Disseminated Y-Zr deposits in syenite are found at Pajarito Mountain, Mescalero Apache Indian Reservation near Ruidoso. In 1990, Molycorp, Inc. reported historic resources of 2.7 million short tons grading 0.18% Y2O3 and 1.2% ZrO2 as disseminated eudialyte. Two additional deposit types have potential for REE in New Mexico: Cretaceous heavy mineral, beach-placer sandstone deposits and pegmatites. Exploration is ongoing in the Lemitar, Gallinas, and Cornudas Mountains.

Jan 1, 2012

By A Markham

Stream diversions are a common feature of mine sites worldwide. From an operational perspective, a fundamental requirement of a stream diversion is that it should convey water flows between two points in a safe, controlled and predictable manner. On the other hand, rivers and waterways are naturally dynamic systems, and many of their natural values are achieved through their ability to alter their forms and processes over time in response to flow events - often in a potentially unsafe, uncontrolled and unpredictable manner. In order to ensure that diverted river reaches achieve the dual objectives of short-term operational stability and longer term physical equilibrium with surrounding landscapes, alteration of form and process must somehow be understood and incorporated into the design process. However, performance targets for waterways are not always easy to define and assessing what is good and bad in such variable systems can be difficult. This paper discusses the role of the stream diversion from the operational, environmental and regulatory/relinquishment perspectives, and how stream diversions must achieve physical stability in the short-term, but dynamic equilibrium in the long-term.CITATION:Markham, A, 2012. Mine site stream diversions - A balance of competing objectives, in Proceedings Life-of-Mine 2012 , pp 215-218 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By W. Edwin Dill

For the mining industry, the Internal Revenue Code and regulations offer a range of choices in arriving at the allowable depletion. Each case is essentially unique. Two prerequisites can optimize these opportunities: communications between the mining company's tax specialists and its technical staff; and an understanding of IRS definitions. For the latter, a logical starting point is consideration of exploration and development, since they precede production and depletion is unallowable prior to production. Criteria for selecting engineering and accounting options for exploration and development indicate the necessity of interaction between these company functions to achieve the most favorable tax position.

Jan 1, 1982

By Dwight K. Smith

Fly ash as an additive for oil well cement was introduced to the oil industry by the Halliburton Company in 1949. Since its early usage in the Illinois area of the U. S., the total amount of fly ash pumped into wells has exceeded 30 million sacks, The advantages of using fly ash-portland cement mixtures in wells are fundamentally the same as for concrete except the conditions of placement and curing are variable and the nomenclature of properties are expressed somewhat differently. In some instances deep wells have been cemented with mixtures of fly ash and hydrated lime together with an activator which functions as a catalyst for setting. This fly ash-lime formula has many advantages for high temperature-pressure conditions found in wells.

Jan 1, 1968

By J. G. Morlet, A. R. Troiano, H. H. Johnson

Delayed failure in steel occurs by controlled initiation and growth of a crack. The incubation period for crack initiation was measured. Crack initiation and Propagation are controlled by interaction between hydrogen concentration and triaxial stress state. The incubation period results from stress-induced diffusion of hydrogen to the point of crack initiation. THIS paper describes the phenomenon of delayed failureland the kinetics of crack initiation and propagation in uniformly hydrogenated steel. The investigation was prompted by service failures of high-strength-steel components at applied stresses far below the conventional yield strength, after the part had successfully sustained equal or higher stresses for an extended time interval. This delayed failure phenomenon, often termed static fatigue, is associated1 with the presence of hydrogen. This is not surprising, since the voluminous literature on flaking and hydrogen embrit-tlement demonstrates that hydrogen may exert a potent embrittling influence. Flakes, or internal hairline cracks in alloy-steel forgings, are related to the presence of hydrogen retained from the steel-making process.2 On the other hand, embrit-tlement arises from hydrogen introduced during surface treatments such as acid pickling or electroplating. Laboratory delayed failures have been induced in notch specimens of 4340 steel by electrolytic charging of the specimen surface with hydrogen and subsequent static stressing.l,4,5 Static fatigue was observed over a wide range of applied stresses; however, failure did not occur below a critical applied stress, designated as the static fatigue limit. In this instance the extended time for failure resulted primarily from the macroscopic redistribution of hydrogen. A crack formed to the depth of the hydrogen enriched "case* upon loading; further crack growth naturally awaited diffusion of hydrogen into the material ahead of the crack. The crack-propagation rate was therefore controlled primarily by the macroscopic diffusion of hydrogen into the specimen interior during the test. Thus, in this instance static fatigue was associated with the movement of a gross concentration gradient. However, delayed failure in steel of uniform hydrogen concentration is of greater fundamental interest, as well as commercial significance. With a homogeneous hydrogen distribution a different mode of delayed failure might be expected. As the heterogeneous hydrogen distribution became more uniform,4,5 the initial crack-propagation rate decreased markedly and, in fact, what appeared to be an incubation period for crack initiation was observed. However, the macroscopic concentration gradient precluded an accurate evaluation of these observations. Although the existence of an incubation period, up to this time, has not been established definitely, it is not amiss to point out some implications of the concept. It is of interest in all hydrogen-induced embrittlement phenomena, such as flaking, delayed failure, and hydrogen embrittlement. Much discussion has centered around the possibility of an

Jan 1, 1959

By Frank S. Palkovits

Over the past 30 years, underground paste backfill systems have been implemented across the globe in many configurations, each with a primary focus of providing high quality backfill to enhance mine operations. However, a number of key design drivers are not always well understood within design engineering firms that occasionally undertake this work, leaving opportunities on the table. Perhaps not always obvious to those newly embracing paste technology, identifying key drivers and opportunities attainable through a paste backfill system is generally not straightforward, requiring innovative approaches to securing higher productivity, availability, performance, maintainability, and operator health and safety. This paper describes a number of applications and audits of paste backfill systems for several challenging mine operations. Key challenges include iterative design aspects of availability of good backfill materials, plant location and configuration, general arrangement, and binder receiving/storage systems.

Oct 1, 2010

Mixed integer programming (MIP) has been used for optimizing production schedules of mines since the 1960s and is recognized a shaving significant potential for optimizing production scheduling problems for both surface and underground mining. The major problem in long-term production scheduling for underground orebodies generally relate to the large number of variables needed to formulate a MIP model, which makes it too complex to solve. As the number of variables in the model increase, solution times are known to increase at an exponential rate. In many instances the more extensive use of MIP models has been limited due to excessive solution times.

Jan 1, 2010

1.1 The parties agree to submit all claims, disputes or controversies arising out of, or in relation to, the interpretation, application or enforcement of this agreement, including dispute resolution procedures, to sequential mandatory discussion, mediation and arbitration for resolution of all disputes before, and as a condition precedent, to self-help, arbitration, judicial action or other remedies. This mandatory procedure will resolve each dispute within one-hundred (100) calendar days. Any deadline falling on a federal holiday or weekend will be the next working day. Breach of this disputes process shall constitute a material breach of contract for which the aggrieved party may recover all costs, including attorneys fees, interest and other expenses necessary to resolve the dispute through litigation. The obligation to discuss and then mediate and arbitrate covers all disputes arising from every aspect of the Project to be built by the owner, including, but not limited to, design, engineering, bonding, indemnification, labor, material and services, and the acts or omissions of any related party for whom a party to this agreement may stand responsible.

Jan 1, 1994

By V. Sheikhzadeh, M. Saghaeian, R. Hejazi, M. Zare

High Pressure Grinding Roll (HPGR) plays a major role in increasing specific surface area of iron ore concentrate for producing pellet feed. HPGR grinding mechanism implies that material be compressed between the two rolls, therefore layer of material must be able to resist required pressure for achieving suitable grinding conditions. In this study for determining a simple relationship between material pressure resistance ability and HPGR main design parameters, piston press tests were performed on different iron ore concentrate samples along with HPGR Blaine increasing tests. Piston press tests results showed that by decreasing moisture content, material pressure resistance increased and in constant moisture content this parameter will change based on material specifications. HPGR Blaine increasing tests results showed that by decreasing moisture content, HPGR specific throughput and working gap increased and in constant moisture content this parameter will change based on material specifications. For all of the studied samples at worst condition, we got the results including: HPGR delta gap equal to zero, specific throughput lower than 200 ts/hm3.According to the tests results, HPGR Applicability Index (HAI) can be introduced at four different class types from 1 (weak) to 4 (excellent). This index determines achievable specific throughput and possibility of using HPGR according to material specifications, i.e. for HAI 1-4 the pressure resistance is <90, 90 to<125, 125 to <150 and = 150 bar, respectively. Similarly for HAI 1-4 specific throughput is <200, =200, =220 and =250, respectively. So based on design moisture content, if concentrate HAI is 3 or 4, HPGR is a correct choice. For HAI 2, HPGR can also be used. But for a material with HAI equal to 1, HPGR is not a good solution. As a result in order to apply HPGR for HAI 1, material condition such as moisture or slime content should be decreased.

Jan 1, 2018

By Anivaldo Chevane, Leonardo Xerinda, Rogério Sendela, Andre Vilanculos

Moatize Coal Mine is located in Tete Province, in centre of Mozambique. The deposit contains Gondwana allochthonous coals, and has a large amount of mudstone and siltstone banding. Phosphorus levels in the coal can be high which impacts the use of the coals in steel making where phosphorus is considered a contaminant. The Chipanga seam in the Moatize deposit shows considerable variability, vertically within the seam and laterally across the deposit. The data available from the exploration work indicates that the phosphorus is predominantly present as Apatite but the Crandallite minerals also are significant. The concentration of phosphorus varies with coal particle density with the highest phosphorus levels found for the mid density coal which also shows the highest likely levels of apatite or fluorapatite. Crandallite minerals show higher potential concentrations in the Lower density coal..

Oct 3, 2019

By Jack D. Webber

The successful use of oil well packers requires, in part: an understanding of the pressures which exist at the packer in various applications and an understanding of the characteristics of the various types of packers. It is with these pressures, the resultant forces, and the characteristics of packers. that this paper is primarily concerned. An oil well packer may be defined as a mechanical device for blocking the passage of fluids in an annular space. In the more usual case, the annular space is that between the tubing or drill pipe in a well and the casing, and packers which block such an annular space are broadly referred to as casing packers. In the other case. the annular space is that between the tubing or drill pipe and the walls of an open hole, and packers for blocking this space are generally called formation packers. While the hydraulics involved are essentially the same for casing and formation packers. a greater variety of conditions are encountered in the use of casing packers and only casing packers will be discussed. After a packer has been set and a pressure seal effected between tubing and casing, the packer is comparable to a piston in a cylinder. Pressures acting upon a piston result in forces which will move the piston unless some means is provided to prevent such movement. In the same manner, pressures acting upon a packer will move the packer unless there is present a sufficiently great restraining force. PACKER CLASSIFICATIONS Packers may be classified according to the pressure conditions under which they are capable of blocking the annular space between tubing and casing. Fig. 1 shows schematically two types of packers in common use. These packers are capable of blocking the annular space against the passage of fluids under a differential pressure of significant magnitude only when the pressure in the annular space above the packing element is greater than the pressure below. It may be seen that in Fig. l-a. slips with teeth which bite into the casing and prevent downward movement are provided. In Fig. 1-h. an anchor prevents downward movement. In each case, there i-only the tubing to prevent upward movement when differential pressures act to move the packers upwardly. Packers which hold only a significant differential pressure acting downwardly have been in use since the early days of the oil industry and will hereafter be referred to as conventional type packers. In many packer applications operating conditions will 1.crult in differential pressures across the packer which will at times act to move the packer upwardly, and at other times, act to move the packer downwardly. For these applications, designs are available which will block the annular space and resist movement in either direction. Fig. 2-a shows schematically a packer of this type which is designed to be run into a well and set, and removed when desired by merely pulling the tubing. It will be noted that two sets of slips are provided-— one set above the packing element to prevent upward movement, and another set below the packing element to prevent downward movement. This packer is built around a mandrel which is essentially a part of the tubing. and which is free to move longitudinally within certain limits through the set packer. Fig. 2-b shows schematically a permanent type packer which is capable of holding pressures from either direction. Here again, two sets of slips are provided to prevenl movement of the packer. This packer is designed to become virtuallv a part of the casing when set and it is made of drillable material so that it may be drilled out when its removal is desired. The seal nipple shown effects a pressure seal between the tubing and the packer. This seal nipple is a part of the the tubing, and the nipple and tubing may be withdrawn from the well without disturbing the packer. It should be noted that these figures are not representative of all available packers which are designed to hold pressures from both above and below. Packers which resist movement in either direction will hereafter be referred to as universal type packers. There is a third type of packer in general use and this type is designed to block the passage of fluids when the pressure below the packing element ii greater than that above. This type is provided with slips which prevent upward movement of the packer and is somewhat similar to a conventional type packer run upside-down. Packers designed to hold pressure only from below are made in a variety of designs and are usually owned and operated by service companies.

Jan 1, 1949

By Jack D. Webber

The successful use of oil well packers requires, in part: an understanding of the pressures which exist at the packer in various applications and an understanding of the characteristics of the various types of packers. It is with these pressures, the resultant forces, and the characteristics of packers. that this paper is primarily concerned. An oil well packer may be defined as a mechanical device for blocking the passage of fluids in an annular space. In the more usual case, the annular space is that between the tubing or drill pipe in a well and the casing, and packers which block such an annular space are broadly referred to as casing packers. In the other case. the annular space is that between the tubing or drill pipe and the walls of an open hole, and packers for blocking this space are generally called formation packers. While the hydraulics involved are essentially the same for casing and formation packers. a greater variety of conditions are encountered in the use of casing packers and only casing packers will be discussed. After a packer has been set and a pressure seal effected between tubing and casing, the packer is comparable to a piston in a cylinder. Pressures acting upon a piston result in forces which will move the piston unless some means is provided to prevent such movement. In the same manner, pressures acting upon a packer will move the packer unless there is present a sufficiently great restraining force. PACKER CLASSIFICATIONS Packers may be classified according to the pressure conditions under which they are capable of blocking the annular space between tubing and casing. Fig. 1 shows schematically two types of packers in common use. These packers are capable of blocking the annular space against the passage of fluids under a differential pressure of significant magnitude only when the pressure in the annular space above the packing element is greater than the pressure below. It may be seen that in Fig. l-a. slips with teeth which bite into the casing and prevent downward movement are provided. In Fig. 1-h. an anchor prevents downward movement. In each case, there i-only the tubing to prevent upward movement when differential pressures act to move the packers upwardly. Packers which hold only a significant differential pressure acting downwardly have been in use since the early days of the oil industry and will hereafter be referred to as conventional type packers. In many packer applications operating conditions will 1.crult in differential pressures across the packer which will at times act to move the packer upwardly, and at other times, act to move the packer downwardly. For these applications, designs are available which will block the annular space and resist movement in either direction. Fig. 2-a shows schematically a packer of this type which is designed to be run into a well and set, and removed when desired by merely pulling the tubing. It will be noted that two sets of slips are provided-— one set above the packing element to prevent upward movement, and another set below the packing element to prevent downward movement. This packer is built around a mandrel which is essentially a part of the tubing. and which is free to move longitudinally within certain limits through the set packer. Fig. 2-b shows schematically a permanent type packer which is capable of holding pressures from either direction. Here again, two sets of slips are provided to prevenl movement of the packer. This packer is designed to become virtuallv a part of the casing when set and it is made of drillable material so that it may be drilled out when its removal is desired. The seal nipple shown effects a pressure seal between the tubing and the packer. This seal nipple is a part of the the tubing, and the nipple and tubing may be withdrawn from the well without disturbing the packer. It should be noted that these figures are not representative of all available packers which are designed to hold pressures from both above and below. Packers which resist movement in either direction will hereafter be referred to as universal type packers. There is a third type of packer in general use and this type is designed to block the passage of fluids when the pressure below the packing element ii greater than that above. This type is provided with slips which prevent upward movement of the packer and is somewhat similar to a conventional type packer run upside-down. Packers designed to hold pressure only from below are made in a variety of designs and are usually owned and operated by service companies.

Jan 1, 1949