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By Yadong Xue, Fei Wang, Hongwei Huang, Yan Sun

"Increasing attention to subway tunnel maintenance is being paid with the high speed development of urban rail transit system in China. A novel moving tunnel inspection equipment based on machine vision is developed in this paper. High resolution image acquisition system is proposed for tunnel crack and leakage inspection. The main components of this image acquisition system includes high speed CCD cameras, linear lights and high performance computer. To inspect the crack less than 0.3mm with a 3-5km/h speed in subway tunnel, we need to consider resolution and line rate of camera, pixels of cameras, range of inspection and illumination intensity of lights simultaneously. The optimization design is proposed to make the equipment more convenient for tunnel use. Entire tunnel situation can be detected and recorded in a single inspection process. This equipment has already been verified in Shanghai subway tunnel for defects inspection.1. INTRODUCTION In China, the quantity of subway tunnel has reached a large scale in recent years. Until 2014, there had been more than 2300km of subway tunnel in China which accounted for nearly three quarters of Chinese urban railway system (Zhang Chen,2015). In some metropolises like Beijing and Shanghai, most of the metro tunnels has already run over 20 years which within maintenance phase. This has brought about plenty of inspection work and maintenance work to guarantee the tunnel under the serviceability limit states. The increase of running mileage of subway tunnels in China has been displayed in Fig 1."

Jan 1, 2016

By Chee S. Theng

As the 2017 president of the Society for Mining, Metallurgy & Exploration Inc., I am pleased to present the 2017 issue of the Transactions of the Society for Mining, Metallurgy & Exploration Inc., Vol. 342. A significant portion of the contribution that we make as a professional society is the publication of professional and technical papers that accelerate the advancement of scientific knowledge and enable the transfer of technology. Communication within the mining community is the key to a successful society. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, PA, that resulted in the founding of the American Institute of Mining, Metallurgical and Petroleum Engineers (AIME). Those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume fulfills that pledge. The 2017 Transactions contains some of the most interesting research and insights from the past year and features an international slate of authors spanning industry, academia and government. Papers include the latest findings from the U.S. National Institute for Occupational Safety and Health (NIOSH), a special review article on Heap Leach Modeling, and articles from two Special Issues on Rare Earths. The 2017 Transactions consists of a total of 54 technical papers, encompassing all 21 papers published in 2017 in the Technical Papers Section of Mining Engineering (Vol. 69) and all 24 papers published in 2017 in Minerals & Metallurgical Processing (Vol. 34). Additionally, this volume contains 9 papers that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All of the technical papers were peer-reviewed. The process of review and publication requires much hard work by authors, reviewers and our Publications staff. As the 2017 president of SME and on behalf of all our members, I would like to extend our gratitude to all whose volunteer efforts contributed to the publication of this volume.

Jan 1, 2017

By E. Watkins, S. J. Schatzel, V. Gangrade, R. Kimutis, J. Addis, C. Hollerich

The recent shale gas revolution in the United States has led to the drilling of hundreds of unconventional shale gas wells in active and future coal reserves in traditional coal-mining regions of Pennsylvania, West Virginia, and Ohio. This paper summarizes the impact of a shale gas well breach on the mine ventilation system of an operating longwall panel. This study utilizes a 1:30 scaled Longwall Instrumented Aerodynamic Model (LIAM) to simulate a single-panel longwall operation. The LIAM will be utilized to identify flow pathways and distribution patterns of gas from breached gas well scenarios in an operating longwall in the Pittsburgh Coal Seam. Sulfur hexafluoride (SF6) tracer gas is utilized to simulate a breached gas well. Preliminary findings suggest that the breached gas is diluted to regulatory levels and does not accumulate in the mine entries or in the longwall gob when the longwall panel is adequately ventilated. Overall, this study characterizes the potential interaction between shale gas wells and the mine environment in the event of a gas well breach, which provides critical information to the industry and regulatory agencies for improving safety, health, and welfare of miners.

Mar 2, 2022

By R. M. Powers

The Florida Institute of Phosphate Research (FIPR) has funded a four-year research project to develop a computer model 'which will predict the hydrologic impacts of phosphate mining on surface and groundwater systems. The core of the model is an analytical geographic information system (SPANS) which integrates EPA's Hydrology Simulation Program Fortran (HSPF) surface water model with the McDonald-Harbaugh groundwater model (MODFLOW). The hydrologic model conducts both event and continuous annual Simulations driven by variable precipitation and temperature data. The model is currently being calibrated and will be ready for distribution to the user community in mid-1991.

Jan 1, 1990

By Thomas Camus

"STATE OF THE ART The current situation of ground prediction in TBM is of great concern for tunnelling contractors, and the subject has been quite widely addressed over recent years, for instance by the French Eupalinos 2000 programme, which tested a variety of technological approaches. A number of interesting projects were executed, such as the SOUND and OnSITE projects, part of the German Geotechnologien programme: these projects are focused on seismics, while other techniques such as radar are not considered. Little information and even less industrial applications have been released apart from lab simulations and numerical modelling. A number of field tests in different configurations have been carried out for compression waves, but the results were often not reliable or convincing, and therefore little has been reported in open literature. The advances seem somewhat promising as far as hard rock tunnels are concerned, but ignore the problem raised by concrete lined tunnels such as those bored by a TBM in soft ground. In such tunnels, sending and receiving seismic waves reliably through the lining (and the grouting behind) is quite illusory. A careful analysis of the seismic prediction research results show that the main problem is the source which is poorly controlled and poorly coupled (for instance in concrete lined tunnels, or in approaches that use the TBM cutter head vibrations as a source). Generating waves perpendicular to the tunnel axis is also a problem: aligning with the tunnel axis makes more sense. Radar (Ground Penetrating Radar - GPR) has been used in geotechnical surveys for decades, and also for tunnel inspection. Attempts have been made at using it on a TBM (for example in Japan by Taisei) but mainly using off-the-shelf GPRs, which are not adapted to work in the specific environment of a TBM (because of its huge mass of metal, to start with). Very few results have been published, probably due to the somewhat disappointing performance of such implementations. At present, no TBM has a GPR incorporated in its cutter head that is able to predict ground characteristics while drilling. Another characteristic and drawback of most current methods is that they require dedicated periods of time during which other tunnel construction activities must be stopped. Due to the duration of such operations this leads to performing ground prediction on a weekly basis only, and therefore to a requirement for an investigation range of 100 metres approximately (in order to cover the TBM advance over the coming week). This is not achievable with boreholes made from the TBM, even less if a reasonable accuracy is required, as is usually the case."

Jan 1, 2016

By Uday Kumar

This paper presents details of an availability study for a fleet of diesel engine operated load-haul-dump (LHD) machines used in a Swedish mine. For the purpose of this study, the LHD machines have been considered as a system comprised of many subsystems like engine, brake, transmission, etc., in series. As availability is dependent on both the reliability and maintainability characteristics of the system, together with reliability, the concepts of maintainability are also discussed. The need for exploring the data for the presence of any structure, which is very common in repairable system data sets, is emphasized with suitable examples. Simple graphical techniques are used for verifying the independent and identically distributed (IID) assumption for the data set. The error introduced due to the use of the exponential distribution in place of more appropriate distributions in estimation of availability and reliability characteristics is analysed.

Jan 1, 1989

By P. N. Eksteen, G. E. Greig

The South African mining industry currently installs about 6 km per month of plastic pipes for conveying compressed air and water. Plastic pipes have a number of desirable properties and are favoured by many mining engineers because of their low mass, which facilitates ease of erection and assembly, and their excellent corrosion resistance and durability. However, they are combustible, and if involved in an underground fire can contribute to the overall toxicity of the combustion gases emitted. Furthermore, plastic pipes have the potential to conduct a fire from one part of a mine to another, and, by so doing, exacerbate an already hazardous situation. The limitations of small scale tests and the need to establish a large facility where underground conditions could be simulated was recognized by the South African mining industry. This paper briefly describes the Industry's full scale fire test facility and presents the conclusions drawn as a result of a number of full scale combustibility tests conducted on pipes manufactured from unplasticized Poly Vinyl Chloride (uPVC) and High Density Polyethylene (HDPE). Based on these findings, some practical solutions to prevent the spread of fire along the length of pipe columns of various pipe diameters and suspension configurations are presented. Recently some new and exciting developments in the field of intumescent coatings have occurred which are proving effective in minimizing the incidence of fire underground on South African mines. The potential benefits of these coatings are briefly discussed. INTRODUCTION Plastic pipes used underground on mines are predominantly in the form of protective cladding on insulated chilled water pipes and as service pipes for the conveying of water and compressed air to the workings. Plastic pipes have found wide use in the aggressive environmental conditions encountered underground due to their favourable properties relative to steel; these include being lightweight, easily installed and virtually immune to corrosion. However, plastic pipes are inherently combustible and can contribute to the overall hazard in three ways: (i) they are easily ignitable and can provide the initial fuel for a fire. (ii) once ignited, they can propagate a fire along their length and by so doing ignite other combustibles in their path, thereby contributing significantly to the overall conflagration. (iii) they can contribute to the overall heat, smoke and toxic gas emissions from a fire. While conscious of the value of small scale fire tests, the South African mining industry recognized the need for full scale testing to determine the combustion characteristics of plastic pipes under conditions closely approximating those underground and, as a consequence, a full scale fire tunnel test facility was commissioned with the objective of being able to (a), accurately evaluate the potential hazard of the various types of the plastic pipes found in mines, (b) use this information to suggest suitable fire engineering practices to minimize the hazard and (c), to practically verify the efficacy of the practices suggested. THE FIRE TUNNEL The fire tunnel is situated on a mine in the Western Transvaal and is 40 m long with a cross section of 3 m x 3 m which is typical of many haulages currently in use in South African gold mines. The ventilation drawn through the tunnel is provided by a 110 kW centrifugal exhaust fan and air velocities can be varied from 0 to a maximum of 5,8 m/s.

Jan 1, 1993

By M. T. Errington, P. C. Miller, W. E. Hardwick

Paper discusses in general terms the techno economic merits of various types of aerated biological reaction systems. The current status of the technology leaves many questions unanswered and hence the choice of the best system to employ is open to discussion. Reasons are given for the choice of the reactor system to be built and operated by Davy McKee. The pilot plant has been designed to provide answers to a number of the questions posed by this technology.

Jan 1, 1998

By William J. Miles

For compliance with the Hazard Communication Standard and other federal and state regulations, numerous minerals, chemicals and products need to be evaluated for crystalline silica content at a threshold of 0.1 %. The polymorphs of crystalline silica that can occur in chemical and mineral products are quartz, cristobalite and tridymite. Other natural, industrial and synthetic amorphous silicas and hydrates must be distinguished from these polymorphs to prevent over-regulation in the workplace and environment. A number of industrial silica products are composed of glasses, expanded perlite, diatomite, slags, and precipitated and fumed silica products. Amorphous silica hydrates used for industrial products, include opal (hydrated silica of biogenic or inorganic origin), perlite, pumice and tuffs. In addition, crystalline and amorphous silicate minerals and chemicals, abundant in nature and industrial products, must be distinguished from the polymorphs of crystalline silica.

Jan 1, 1997

By Joel Lööw, Johan Larsson, Stig Vinberg, Malin Mattson Molnar, Mats Jakobsson, Jan Johansson

The mining industry is undergoing rapid transformation, driven by technological advancements, sustainability concerns and demographic shifts. This transformation will put more younger people in management positions. This study provides valuable insights into the leadership behaviors of younger and older managers within a large Swedish mining company, highlighting the importance of managerial experience and targeted training programs to foster effective leadership, particularly in the context of change management. The findings emphasize the need to create work environments that support managers to develop their leadership, contributing to improved employee well-being, operational efficiency, and adaptation to the changing demands of the modern mining sector.

May 1, 2025

By D. R. Gibbons

This morning I would like to speak to you about an area of chemistry that is enjoying a revival-organometallic compounds. This renewed interest, principally stimulated by defense needs, has already created new markets for the products of the mineral industry. Although the consumption of metals in these new products is modest at oresent, several hold promise of importance. Because this is a new and growing market, I am sure the Council of Economics is aware of many of its facets and is interested in new developments. Of course, the chemical industry has been a significant consumer of minerals for many years. I estimate that in 1957 the chemical-industry purchased a total of $1175 million worth of minerals as raw materials (not including fuels). This estimate can be broken down as follows: [Metals and metallic minerals $375 million Nonmetallic minerals (excluding hydrocarbons ) 330 million Hydrocarbons 470 million $1175 million]

Jan 1, 1958

In subterranean mining operations, access to communication networks deep underground is critical for transporting data, voice and video, and other supporting applications that are essential for efficient and safe operations. Whether accessing sophisticated ERP or maintenance management systems, engaging in fleet management, video surveillance, or access control, or protecting miners with wireless locator systems, these networks serve as a literal lifeline between workers deep within mines and surface operations. For this, mining networks require more than permanently installed network cabling, it also requires unique deployable systems designed for quick installation, extension and even relocation as the active mine site area moves, or equipment is moved in and out.

Mar 1, 2014

By Peniti Niskanen

Outokumpu metals & Resources (OMR) is a sub-group of Outokumpu Oy. OMR is a Mining and Metallurgy group of about 75 companies in 16 countries. The main activities are exploration, mine development and, mining and metallurgical processing of base metals.

Jan 1, 1996

By J. A. M. Cano

An extensive research work was developed by Samarco Mineracao S/A to study the quality characteristics of blast furnace pellets produced with high content of MgO. Comparative blast furnace simulation tests were conducted both in Samarco and foreign laboratories. The objective was to evaluate the behavior of high MgO and normal Samarco pellets in the blast furnace operation. Additives such as dolomitic hydrated lime, dunite and magnesite were used for increasing pellet MgO content. The test results showed that pellets produced with high MgO content are similar in quality to normal Samarco Pellets.

Jan 1, 1991

By Ralph H. Light

The recent surge in demand for uranium in the United States, accompanied by a significant increase in price, has resulted in exploration, mining, and milling of lower grade ores than have been exploited in the past. To sustain production levels of uranium with lower grades of feed requires larger tonnage mill operations. Also, because of recent environmental regulations, mill operations must be prepared to properly contain large tonnages of tailings, and recycle, treat and discharge, or evaporate mill effluents. Thus, the advent of lower grade ores, larger tonnage mills, and environmental considerations has made the cost of milling a critical factor in today's uranium production economics in the United States. Three basic milling methods are employed for extracting uranium from ores: 1. Acid leach, countercurrent decantation, and solvent extraction. 2. Acid leach, resin-in-pulp, and Eluex. 3. Alkaline leach, solid-liquor separation, and precipitation. Vanadium often occurs as a valuable by-product in ore deposits located in the Uravan mineral belt in Western Colorado. Also, lesser amounts of vanadium may occur in ores from South Dakota, New Mexico, and Utah. Vanadium is usually extracted in the acid leach solution with uranium and recovered by solvent extraction after recovery of the uranium. By-product recovery of uranium from phosphoric acid and porphyry copper dump leach solutions is now receiving considerable attention. Pilot plant studies are under way and construction of commercial plants is in progress.

Jan 1, 1977

By Gabriel K. Nzulu, Lars Hultman, Per Eklund, Martin Magnuson, Abu Yaya, Prosper M. Nude, Hans Högberg

Pyrite is the most common among the group of sulfide minerals in the Earth and abundant in most geological settings. This gangue mineral in association with garnet, hematite, magnetite, and other sulfide minerals acts as an indicator mineral in the Kubi concession of the Asante Gold corporation in Ghana. X-ray diffraction (XRD), air annealing in a furnace, energydispersive x-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) were applied to investigate the crystal structure, identify individual elements, permanence, transformation, and chemical/electronic properties of such pyrite. The study aims to identify individual elements and to gain an understanding of the surface reaction mechanisms, as well as the properties of precipitated pyrite particles observed during the hydrothermal formation of the ore deposit. XRD shows that pristine and annealed samples contain some hematite and quartz besides pyrite. Results from air annealing indicate that the relationship between pyrite and hematite-magnetite is controlled by temperature. EDX reveals that the sample has O and C as contaminants, while XPS in addition reveals Ba, Au, P, Al, and N. These elements are attributed to pyrite that bonds metallically or covalently to neighboring ligands/impurity minerals such as oxides, chalcogenide sulfides, as well as the gangue alteration minerals of magnetite and hematite in the pyrite sample. These findings suggest that during the hydrothermal flow regime, pyrite, pathfinder elements, and impurity minerals/metals were in contact with quartz minerals before undergoing hematite transformation, which thus becomes an indicator mineral in the Kubi gold concession.

Feb 27, 2024

M.S. Azun I have many objections to the content of the author's paper. Before discussing it, however, I would like to repeat the property of semivariogram function. Second order stationary properties of regionalized variables (ReV's) such as semivariogram function y(h) are perfectly known in geostatistics. Also, the kriging equations in the language of mathematical statistics using second order stationary properties are well understood. However, the way to use the sample (estimated) semivariogram function in any one of the kriging procedures is vague. The sample semivariogram function is given as follows: [ ] where N is the total number of samples, Xi is the sample value at the i - th location, Xi+h is the sample value at the i + h - th location, and h is the distance among the samples. An estimation variance of sample semivariogram function of first lag is smaller than that of higher order lag. The theoretical semivariogram function reaches the variance of samples asymptotically. But this is not easily observable because of the larger variation involved in the estimate of semivariogram function. In general, an estimation procedure is done for h = 0, 1, 2, up to the greatest integer less than N/2, even though sample semivariogram function can be computable through N-1. After estimating semivariogram function, the critical question of how to model sample semivariogram function arises. As seen in the above equation, sample semivariogram function is discrete and can be smoothed by the model being selected. Therefore, modeling of sample semivariogram function is the most important step in geostatistics. It not only smoothes a discrete function but also affects the results of the kriging procedure. When the only aim is to model the semivariogram function, which is the basic point of the author's paper, one can employ any fitting techniques, such as curve fitting, or any arbitrary functions, which are called submodels in the paper. The term "arbitrary function" is used rather than "submodel" because there is no basic understanding of developing them. The author suggests that the sum of those submodels can also be used for the modeling of sample semivariogram function. The combination of any arbitrary functions brings many problems instead of giving an insight of the domain structure considered. The author used two arbitrary functions and the nugget effect in response to sample semivariogram function (Fig. 10). For the same example, he stated that the parameters involved in the mixed arbitrary function model can be accepted when the discrepancy between sample semivariogram function and the model is small visually. For verifying the fitting behavior of any selected model, one should not be contented with the visual satisfactory. Some statistical measure such as goodness of fit has to be used. The author's practice is no more than an exercise in curve fitting without any fundamental understanding or conceptualization of the underlying physical mechanism. Furthermore, the selection of any model is not an easy task if the purpose is the search for the "best" response to the observed second order properties of ReV's. I suggest that the Markovian model (Azun, 1983), on the basis of a theoretical understanding of underlying mechanism, which gives more information about the occurrence of regionalized variables, is used to respond all properties of ReV's. There are a lot of problems for modeling of one-dimensional sample semivariogram function. Thus, it is not appropriate to go to higher order dimensional sample semivariogram function modeling. In the meantime, I would recommend that one can connect the values of standardized sample semivariogram function rather than simple values of semivariogram function in the two-dimensional estimation. The standardized values can be computed in dividing the semivariogram function value by the number of sample pairs involved in each lag regardless of the directions. In conclusion, geostatistics is an interdisciplinary area in mining that uses the principles of mathematical statistics. Thus, it should not violate any probabilistic and statistical rules. When Matheron was developing the theory of geostatistical study in the early years of geostatistics, many mining people had a reservation accepting the geostatistical tools. However, this does not mean that we, the geostatisticians, might try to convince those people using some "strange" tools or rules as some authors implied (Baafi and Kim, 1984). Instead, we have to develop and explain the geostatistical tools staying only in the framework of statistical concepts and properties. References Azun, M.S., 1983, "Stochastic Process Modeling of Spatially Distributed Geostatistical Data," Columbia University, Ph.D. Thesis. Baafi, E.Y., and Kim, Y.C., 1984, "Discussion - Comparison of Different Ore Reserve Estimation Methods Using Conditional Simulation," Mining Engineering, Vol. 36, No. 3, p. 280. Reply by J.M. Rendu The interactive method proposed by Rendu allows practitioners to develop semivariogram models that take into account not only the numerical information obtained by sampling, but also highly significant additional information that often cannot be quantified. The geology of the deposit - including hypotheses concerning its genesis, sampling methods, assaying methods, and mathematical methods used to calculate the semivariograms - all have an influence on the numerical results obtained and on how these results should be interpreted. If all the information concerning the spatial distribution of values in a mineral deposit was contained in the sample values, it could be argued that statistical techniques alone would produce optimum models. However, this is rarely, if ever, the case. Methods that allow the user to take into account his experience and his geologic understanding of the deposit should not be rejected for the sake of theoretical statistical purity.

Jan 11, 1985

By Harry Wolf

The chemistry of the element uranium enables industry to employ either an acid or alkaline carbonate leach solution for most uranium ores. Either method my be used for conventional, in-situ, or heap leaching. Uranium recovery in the leaching process depends both on the solubility of the uranium minerals and, on the access of the leach reagent to them. The uranium leaching rate is proportional to the liberated mineral surface area and the chemical reactions involved in the dissolution step. The dissolution of U(VI) and the oxidation of u(IV) to U(VI) are the basic chemical reactions in the leaching process. The active surface area is a function of the effective porosity and the particle size of the ore (1). Ore pieces, with a high porosity and high permeability, may provide a large active surface area even in coarser fractions. This type of ore might be suitable for heap or in-situ leaching techniques. Nonporous and impervious ores are usually more amenable to conventional milling where the active mineral surface is exposed by grinding the ore down to the liberation size of the mineral.

Jan 1, 1981

By Donna Wallace

Past EPA groundwater monitoring programs required that contamination not leave the boundaries of a disposal facility. New regulations under the Resource Conservation and Recovery Act (RCRA) require that once hazardous waste constituents are detected beyond the limits of the disposal area, a program to define the rate and extent of contaminant migration must be instituted. Future regulations are likely to include even more stringent groundwater protection criteria. The implications of both the existing and probable future groundwater protection and monitoring requirements in terms of using geologic containment as a means of disposing of hazardous waste are explored in this paper.

Jan 1, 1981

By R. Krog, S. Schatzel, H. Dougherty

Longwall coal mine operators in the U.S. are required to ventilate multipanel longwall districts, but may have little or no knowledge about what happens to the ventilation air between the inlet evaluation points (IEPs), bleeder evaluation points (BEPs) and bleeder fans. The effectiveness of bleeder performance can directly influence the ability of a ventilation system to remove and dilute coal bed methane emissions. U.S. coal mining stakeholders have acknowledged their belief that the T-junction split at the longwall face tailgate corner is very important in controlling the distribution of ventilation air. To obtain direct measurements of bleeder performance, a tracer gas, sulfur hexafluoride (SF6), was released into the ventilation air stream on active and inactive longwall panels. Testing was performed on multiple longwall panels that included various phases of longwall development and variable path lengths of ventilation air transport to bleeder fan installations. Changes in the T-junction ventilation air distribution over the life of a longwall panel, and its variable effect on panel ventilation airflow are discussed. These findings will assess the effectiveness of commonly applied ventilation strategies for improving air distribution and ventilation controls to meet statutory requirements.

Jan 1, 2011