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By Roland Arnold, Richard Gradnik, Martin Zeindl

This paper presents the details of the Kramer tunnel project in the Federal State of Bavaria, Germany. This road tunnel, which has been under construction since December 2019, is the key component of the western bypass of the town of GarmischPartenkirchen. Once completed, it will relieve the town’s central district from enormous volumes of traffic. The contractor is the joint venture named ARGE Kramertunnel consisting of BeMo Tunnelling and Subterra. The whole project will be completed and handed over to the project owner, Staatliches Bauamt Weilheim, in 2023. The opening of the entire bypass section including the tunnel to traffic is planned for 2024. The tunnel, with a total length of 3,609 m (2.24 miles) and an estimated cost of EUR 178 million (incl. VAT), is designed as a single-tube, double-lane structure with one traffic lane for each direction of travel. The safety issue that exists for single-tube tunnels is solved by a parallel escape tunnel passable for vehicles. All tunnels and ducts are excavated according to the principles of the New Austrian Tunnelling Method (NATM). In order to reduce the geological risk for the owner, the escape tunnel was supposed to be completed before the design process for the main tunnel ever began. The exploratory tunnel was awarded to a competitor with an separate contract.

Jun 13, 2021

By N. Damiano, C. Zhou, R. Jacksha, J. Srednicki

Modern electronic devices and systems used to enhance miner safety and health are becoming commonplace in underground coal mines. The ability for these devices and systems to function properly in the presence of electromagnetic emissions from other electronic and electrical devices and systems is not entirely understood. To investigate potential electromagnetic compatibility issues of critical mine electronic devices and systems, researchers from the National Institute for Occupational Safety and Health (NIOSH) are conducting surveys of electromagnetic emissions in underground coal mines. This paper presents the measurement system, methods, and results of electric field electromagnetic emission surveys conducted in three underground coal mine environments in the frequency range of 10 kHz to 1000 MHz. The survey data show that in some environments electric field electromagnetic emissions in underground coal mines approached or slightly exceeded limits as defined by other industrial sectors.

Mar 2, 2022

By Andrew B. Pervis

With the ever increasing demand for Finer powders by industry there has been a continuing effort by air classifier manufacturers to improve and offer machinery capable of producing these fine powders. Common to these classifiers is the use of a multivaned rotor through which passes all of the air used to transport the particles to be classified. Rotor revolutions per minute and the amount of air passing through the rotor are the main variables in determining the particle sizes which will be able to pass through the spinning rotor. A simplified equation derived by setting the air drag force carrying a particle through the rotor equal to the centrifugal force due to the spinning rotor's action on the entering air and particle is: Diameter of Particle = [ ] Where K is a function of air viscosity, particle configuration, rotor and blade configuration; RPM is rotor revolutions per minute; M3/sec. is air quantity passing through the openings between the rotor blades.

Jan 1, 1983

By Guillermo Krstulovich

Pillar strength is a fundamental variable in the design of room and pillar mining. A number of researchers have investigated the strength of mine pillars by loading cubical, cylindrical and rectangular model pillars to failure in a compression testing machine (1). Several of these researchers have observed an increase in the compressive strength of model pillar with an increase in friction at the platen-specimen interface (2, 3, 4, 5). It has been postulated that the friction prevents lateral expansion of the specimen, thereby exerting a confining pressure at the interface. Seldenrath and Gramberg in their work with cylindrical specimens of limestone and marble noted that the effect of clamping the ends of the specimens, i.e., to restrict lateral movement of the specimen face, was to increase the compressive strength about 10% for marble and from 50-75% for the limestone, as compared to the same type of specimens when tested with the end planes free (6). No attempt was made to determine the confining pressure exerted by the clamps. In recent years, Bureau of Mines has conducted an extensive study, similar to Seldenrath and Gramberg's, with dog bone specimens. The confining pressure exerted by the clamps was determined and an increase in the compressive strength with increasing confining pressure noted (7, 8).

Jan 1, 1970

By R. M. Wilson

Concentrating plants, in common with other types of industrial plants, cannot operate without lectric power. The elctric distribution system and utilization equipment; therefore, must be carefully considered in all phases of plant design. Two important aspects of proper distribution and usage of electric power are the selection of voltage levels and the methods of system grounding. These are not necessarily the most important design considerations, but are perhaps more controversial than other major points, Modern plants demand increasing amounts of power which, since electric power is the product of voltage and current means higher voltages or currents. Higher voltages require more insulation, higher currents more conductor. The equipment designer?s problem is to obtain in his transformer, cable, switchgear, controller, motor, etc a balance of insulation and conductor to obtain a satisfactory design at lowest cost. To provide the most economical system, both in initial and operating costs requires the system designer to select the proper voltage level. Adequate voltage also permits expansion to meet future requirements, and results in better operation of utilization equipment, Relatively little advancement has been made in recent years in improving conductors; however, great progress has been made in improving insulation. Thus modern plants, in general, now find it more economical to use higher voltages than they did previously. For example plants which only a few years ago would have used 2400 volts as a system voltage often find nowdays that 4160 volts is their proper choice. If the plant requires 10,000 kva br more, then an even higher voltage, such as 13,800 volts, will prove economical. However, for the average concentration plant, with less than 10,000 kva demand, the choice of distribution voltages is between 2400 and 4160 volts, and 480 volts will be used for the low voltage utilization system.

Jan 1, 1958

By P. A. Korpi

The angular spiral lining system reduces energy consumption and grinding media consumption in grate discharge ball mills. This paper discusses the effect of this lining system on mill product size distribution. Performance comparisons of a grinding circuit outfitted with angular spiral liners in the ball mills are made with respect to standard double-wave liner installations. The angular spiral lining system was developed by Waagner-Biro of Austria. The installation of this lining system at Magma Copper Company, San Manuel, Arizona, is the first of its kind in a grate discharge ball mill used for wet grinding.

Jan 1, 1979

By Jey K. Jeyapalan

A characteristic common to most tailings dam failures caused by earthquakes or excessive rain storm is that the tailings tend to liquefy and flow for substantial distances as a viscous fluid, with the potential for extensive damage to property and life. Failures of El Cobre, Chile (1965), Mochikoshi, Japan (1978), Aberfan, Wales (19661, Buffalo Creek, West Virginia (1972) are examples of such catastrophic incidents. In these four incidents more than 400 lives were lost, and the loss of property was approximately $200 million. In order to be able to assess the potential for damage in case of such a failure, it is necessary to predict the possible extent of flow slide movement. This paper discusses simple procedures for performing such analyses. Also, in order to illustrate the use of these analysis procedures in tailings dam design, two case histories are analyzed.

Jan 1, 1982

By T. D. Parris

At the Frood Mine of International Nickel, tests were begun in March 1966 to evaluate the use of low profile diesel Load- Haul-Dump equipment in cut-and-fill operations. In December 1966, this test was extended to drawpoint loading of caved ore at the Creighton Mine. The results of these tests conclusively demonstrated the effectiveness of this equipment in the operations at International Nickel. This paper describes the equipment used, the operation of the equipment, production data and operating details. Also discussed in the paper are other trackless equipment which works with the Load-Haul-Dump carrier. Production and Safety comparisons are made with the slusher method in bulk mining, giving the reasons for replacing the slushers at the mines of International Nickel Company of Canada, Limited, Ontario Division.

Jan 1, 1969

By Arthur Miller

Most of the production of copper in the United States comes from a few large companies. Often overlooked, however, are the more numerous small mining operations, which collectively produce a significant portion of the nation's copper. The objective of this paper is to describe the operations of a small mining company - Ranchers Exploration and Development Corporation - how it views its place in this industry of giants, how it exploits the advantages offered by its relatively small size, and how it protects itself from the hazards being small introduces. Environment is, of course, a critical factor for such a company because it does not have the resources which help large companies weather periods of financial stress. Ideally, this environment is characterized by a heal thy economy, strong product demand, relatively stable prices , adequate grades and tonnages of ore commensurate with depth and over-burden, ready access to utilities, a dependable labor pool, and suitable technical "know how". When the environment is right, properties which were previously uneconomical to operate attract the attention of companies whose primary interest is a return on investment commensurate with risk over a reasonable period of time. Naturally, the amount of the investment and the duration of operation determines the size of the company which would be interested in such a venture. Such is the case with Ranchers Bluebird Mine at Miami, Arizona - a small property operated by a small company in a favorable economic environment.

Jan 1, 1967

By Carl-Henrik Knudsen, Rolf Tore Arnesen, Eigil R. Iversen

Recovery of iron and copper from acid mine drainage was studied in pilot scale at a continuous treatment plant at the mine site of the King's mine in Roeros, Norway. The average load on the plant was 1 m3/h. The process tested in this project is a three-step process consisting of: 1) Fe(OH)3 precipitation at pH 3.5, dewatering of iron sludge and transport to ferric chloride plant; 2) after filtration precipitation of residual metals at pH 9, concentration of metal sludge by flotation; 3) extraction of metals from the sludge with sulphuric acid followed by recovery of copper by electrolysis. The copper could be used for local production of different crafts, but this condition needs a further evaluation. The process economy at a full scale plant is evaluated.

Jan 1, 2000

By P. M. Soupios

A near geophysical surface investigation of a landfill area close to the Hania city, in Crete Island, Greece, was conducted as inextricable phase of a preliminary geotechnical, geological and hydrogeological study of the area under investigation. Electrical Resistivity Tomography (ERT), one of the most promising prospecting techniques mainly concerning its effective contribution to resolve several environmental problems, was applied for the geophysical modelling. ERT is a robust imaging method the theory and implementation of which are well documented in geophysical research literature. The survey site is located in Akrotirion Peninsula, about 7km east of Hania city in Crete I. The geological setting comprises Trypalion limestones, marly limestones and a clayed weathered layer. Cavities are also identified at various scales which are recent tectono-karstic voids resulted from the combined actions of karstic erosion and tectonic stress on the Trypalion limestones where they are located. Due to the above-mentioned geological singularity and in the light of the requirement for an environmentally safe construction of the landfill, an ERT survey was carried out by deploying the dipole?dipole electrode configuration. Specifically, seven geoelectrical tomographies were conducted reaching the prospecting depth of 36m. The resulted images conduced, a) to overcome geotechnical problems, b) to plan the future sites for waste disposal and c) to reliably estimate the thickness of the already deposited wastes.

Jan 1, 2005

By Albin E. Anderson

The PSM System has been available to the mining industry for nine years. During this time, many of the more than 160 Systems sold have been put to practical use and have provided the owners a handsome return on investment. In this paper, the author will briefly discuss how the System works and how it can be put to use in automatic grinding circuit control. Throughout, detailed consideration will be given to the many factors that can significantly influence how successful a specific application is.

Jan 1, 1979

By Diler Katircioglu-Bayel

This study aims to investigate the effect of combined mechanical and ultrasonic milling on the size reduction of talc. Firstly, the talc sample was wet ground in a stirred media mill for five different times (30, 60, 90, 120, and 150 min), and the optimum result was subsequently achieved with treatment by ultrasonication. The effects of amplitude (20, 35, and 50 μm), solid content (2.5, 5, 7.5, and 10%), and sonication time (60, 120, and 240 min) on the sizes of the final product were investigated. The pre-milling by wet grinding caused a decrease in the grinding resistance of talc. Sequential ultrasonic treatment, which was applied to the talc sample, generated smaller particles in comparison to those acquired by stirred media milling alone. Experimental results were assessed based on the product particle size (d10, d50), reduction ratio, and specific energy consumption. Submicron particles prepared by ultrasonic treatment were perfectly stable compared to stirred media milling alone as investigated in terms of particle size. In addition, the effects of mechanical and ultrasonic milling on structural properties of talc particles were characterized by XRD analysis.

By T. McCallum, C. Cooper, B. Hutzler

"In copper solvent extraction, managing the quality of the organic phase is a key parameter to ensure optimal physical and metallurgical performance in the plant. Increased throughput as a result of declining ore grades coupled with advances in plant design and practice, resulting in reduced organic losses, has pushed the limits of the status quo with respect to organic quality. Clay treatment of plant and recovered organic at the optimal dosage is critical in maintaining quality, however, achieving the optimal dosage through existing filtration capacity and practice can be difficult. Cytec has developed a process aid that increases efficiency of existing filtration equipment that has been successfully implemented at two commercial SX operations. ACORGA® CB1000 enables higher dosages of clay while allowing for more efficient use of existing filtration capacity. This study analyzes results from commercial trials and demonstrates that improved organic quality and clarity is achievable through optimization of current treatment practices. INTRODUCTION Decreasing ore grades have prompted copper solvent extraction operations to raise PLS flow rates, increasing plant throughput to maintain production1. The ability to process higher flow rates through existing mixer-settlers historically came at the expense of increased entrainments2. However, advances in mixer-settler design, practices and improvements in organic recovery processes have enabled operations to maintain, and in some cases reduce organic losses while achieving higher flow rates through existing equipment. Based on the increased demand on the SX equipment and reduced losses (or more efficient recovery) maintenance of the circuit organic quality through efficient clay treatment is now more important than ever. This paper discusses common industry practices and related issues in organic clay treatment, and presents benefits achieved in commercial operations through the use of ACORGA® CB1000 Clay Binder. IMPROVEMENTS IN DESIGN AND PLANT PRACTICE Mixer-settler design has improved since the first commercial copper SX operation in the late 1960s. Advanced designs in mixer, settler, and settler internals have contributed to reductions in entrainments. For example, improved impeller designs have been reported to decrease organic in aqueous entrainment from the ‘old designs’ of 50-200 ppm3 to as low as 4 – 10 ppm confirmed via diluent and reagent consumptions . Similarly, operations are reporting a 20-50% decrease in reagent consumption when compared to the original design criteria3. Operations have optimized settler internals to increase coalescence and have improved settler operating practices which have been shown to reduce entrainments7. Comparison of the SX world operating data from 1999 and 2007 shows reductions in organic entrainment losses with increases in flow rates."

Jan 1, 2015

By Diler Katircioglu-Bayel

This study aims to investigate the effect of combined mechanical and ultrasonic milling on the size reduction of talc. Firstly, the talc sample was wet ground in a stirred media mill for five different times (30, 60, 90, 120, and 150 min), and the optimum result was subsequently achieved with treatment by ultrasonication. The effects of amplitude (20, 35, and 50 μm), solid content (2.5, 5, 7.5, and 10%), and sonication time (60, 120, and 240 min) on the sizes of the final product were investigated. The pre-milling by wet grinding caused a decrease in the grinding resistance of talc. Sequential ultrasonic treatment, which was applied to the talc sample, generated smaller particles in comparison to those acquired by stirred media milling alone. Experimental results were assessed based on the product particle size (d10, d50), reduction ratio, and specific energy consumption. Submicron particles prepared by ultrasonic treatment were perfectly stable compared to stirred media milling alone as investigated in terms of particle size. In addition, the effects of mechanical and ultrasonic milling on structural properties of talc particles were characterized by XRD analysis.

By R. E. Snow

The analysis of ground water inflow and discharge from underground mines has received increased attention in recent years due to environmental issues which must be addressed under current state regulations for coal mining and processing operations. In particular, coal operators must assess the probable hydrologic consequences associated with mining activities, and must plan for mine water handling during operation and following completion of mining. The prediction of ground water inflow rates with future mine development allows preparation for potential operational problem and identification of inflow reduction methods. Similarly, evaluation of mine discharge rates is necessary to address potential long-term acid mine drainage (AND) concerns. As part of mine discharge analyses, methods. to control seepage and AMD can be considered. The objective of this paper is to discuss the practical applications of mine inflow and discharge analysis, describe the typical flow components, outline the procedures necessary to perform the analysis, and illustrate the modeling procedures and potential results of mine inflow and discharge predictions.

Jan 1, 1990

By Donivan L. Gordon

One of the several problems facing society today is that of disposing of its solid waste. Each year this nation spends approximately 4.5 billion dollars to collect, transport and dispose of some 360 million tons of domestic and industrial solid waste. Although considerable sums of time and money have been spent in researching various techniques for solid waste disposal, it is presently agreed that sanitary landfilling represents the most economic and universally adaptable solution to the problem of solid waste disposal. However, regardless of the factors favoring sanitary landfilling as the waste disposal method of choice, it should be recognized as carrying with it a potential for the degradation of ground- and surfacewater resources. Through an interdisciplinary effort regulations were promulgated during 1971 in the State of Iowa to govern sanitary disposal projects. Consistent with a set of rationales developed to preserve environmental quality, these regulations set forth hydrologic and geologic standards designed to protect Iowa's water resources. Minimum requirements have been outlined in the regulations through which the natural favorability of potential landfill sites may be evaluated. Natural favorability is primarily defined in terms of the hydrologic and geologic relationships between a proposed landfill site and those in the locality of the site. The regulations specify that leakage from a landfill to a subcropping aquifer must be less than 0.04 cu ft/day/sq ft at the base of the landfill. This factor is offered to quantify the maximum allowable leakage for all sites in unconsolidated sequences underlain by subcropping bedrock aquifers, Based on groundwater research in Iowa, the assumption is made that 50 feet of till will be sufficient to inhibit the downward flow of liquids from a landfill into bedrock aquifers. This assumes a difference of no greater than 40 feet in hydrostatic head between the water table in the unconsolidated sequence and that in the bedrock aquifer. Owing to the fact that bedrock aquifers in many areas of the state are mantled by less than 50 feet of till the regulations provide for site modification, through engineering, to meet the specified leakage standard, In such instances the leakage factor is evaluated by means of the generalized Darcy's Law Q = PIA where:

Jan 1, 1974

By Vaughn E. Livingston

Washington State has a variety of industrial minerals and although not many are produced currently (1982) most have a history of production (table 1). The value of industrial minerals produced in the state exceeds by several times the production value of metallic minerals. In 1981, 15 minerals - cement, limestone, clay, gemstone, pumice, sand and gravel, stone, diatomite, gypsum, olivine, peat, talc, garnet, silica, and dolomite - were produced. Combined value of nonmetallic production for 1981 is estimated at $218,999,000. Cement had the largest estimated value at $102 million, followed by sand and gravel at $47 million, and crushed stone at $29 million. These figures are from the US. Bureau of Mines preliminary production figures for 1981.

Jan 1, 1982

By W. G. Lawrence

The rapid development of science and technology in Russia has been the result of well laid plans since 1918. At that time the Institute of Silicates was established is Moscow and later the establishment of similar more specialized institutes for the study of cement, glass, refractories, construction ceramics, electrical ceramics, building materials and asbestos provided the necessary research facilities for studies related to all types of ceramic inorganic materials. The' Institute of Ceramics and the Institute of Silicate Chemistry, Academy of Sciences, USSR, were founded in Leningrad. The work now going on in these various research' institutes covers every branch of silicate science and ceramics The impetus behind such establishment of special¬ized laboratories is no doubt due to the 5-year plans and the necessity of improving the scientific knowledge regarding the materials being used and the products being manufactured.

Jan 1, 1960

By A. Pezzuto

"Pipes are used on mine sites in a variety of applications including transport of slurry, conveying clean and processing water, and in mine dewatering. Mine waters and slurries can cause pipe wear and failures via several mechanisms (or combinations thereof) such as abrasion, scaling, and corrosion. Polyethylene (PE) pipe materials have grown in popularity over the past several decades due to their chemical and mechanical properties (e.g., inertness, flexibility, relatively low density) and low cost. While PE is generally resistant to corrosion, it is subject to abrasion. To combat this, a novel, rubber-like liner is in development. In addition to comprehensive abrasion testing, however, the liner must be evaluated to see how it performs under other conditions. Here, a brief field study is described that tested PE pipes with the new liner against traditional PE pipes to specifically assess mineral scale buildup. The study was conducted in the Reiche Zeche study mine in Freiberg, Germany in six different locations with varying water qualities and flow conditions. INTRODUCTION Water and slurry conveyance are major operations on and around mine and mill sites, from mine dewatering, to tailings transport, to water treatment processes. Conveyance systems in such applications can include great lengths of pipe materials along with pumps and monitoring instruments, and thus represent significant capital investments. Due to the variability of the physical and chemical properties of water and slurries, pipe materials are subject to a wide range of conditions. These can cause pipe wear and eventually failure leading to serious economic, environmental and social, consequences. While pressure-induced pipe failures (e.g., ruptures or ""bursts”) can be immediate, most failure mechanisms involve gradual processes. Scaling and sedimentation can present major problems for pipe systems conveying highly mineralized waters. Sedimentation generally refers to the deposition of suspended solids, such as sand, clay, silt, or organic matter onto pipe surfaces. This phenomenon can occur due to a decrease in water velocity or particle collisions with the pipe wall. Scaling, on the other hand, commonly refers to the deposition of precipitated mineral salts (including oxides and hydroxides) onto pipe surfaces. Mine waters often have extremely high ion concentrations (i.e., high dissolved solids content) due to their interaction with enormous surface areas of minerals, which are exposed during mining and processing operations (Brown and Barley, 2002). As these waters are transported, slight changes in temperature, pressure or chemistry (e.g., pH or ORP) can cause instability with respect to ion solubility such that salt precipitation begins to occur. “Seed” crystals can rapidly grow and attach to pipes, either due to local surface phenomenon near the pipe wall (e.g., which can promote coagulation) or sedimentation of the precipitated solid. Whether due to suspended or precipitated solids, as the solids begin to stick to pipe walls, “aging” or hardening processes can commence; and the build-up of scale can become self-perpetuating as the scale itself provides an attractive “nucleus” for further attachment of particles or crystal growth (Muryanto et al., 2014). Over time, scale-buildup reduces the effective pipe diameter, which can ultimately result in decreased flow velocity, clogging and, in some instances, bursting (Dirany et al., 2016)."

Jan 1, 2017