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By Bernd Hagenah, Petr Pospisil, Colin Santangelo

This paper explores the profound implications of high-speed train operation on tunnel planning, specifically investigating ongoing high-speed rail projects in California and Texas. The paper delves into the crucial considerations for designing high-speed rail tunnels, including selecting tunnel sections based on aerodynamic factors, which impacttraction power requirements and pressure comfort. The paper also examines the need for emergency stations, maintenance access, and comprehensive safety and rescue concepts to address train incidents. Drawing from international high-speed rail projects, it shares valuable experiences and lessons learned to promote efficient and secure tunnel designs for high-speed train operations.

Jun 23, 2024

By J. Davies

This paper describes the successful management and construction of the 5.18 m (17 ft) diameter, segmentally lined, North Dorchester Bay CSO storage tunnel in Boston, MA. This 3,300 m (10,830 ft) long tunnel was mined through variable soft ground with only 6 m (20 ft) of cover, using an earth pressure balance tunnel boring machine. These extensive data collected from the projects unique automated and internet accessible geotechnical and TBM monitoring system, will be examined and used to explore the relationships between geological conditions, TBM operating parameters and measured settlements. The paper will also discuss the use of screw revolutions as an indicator of muck volume.

By A. Miller, M. McNinch, R. Jacksha

Each year, hundreds of mine workers are involved in machinery-related accidents. Many of these accidents involve inadequate or improper use of lockout/tagout (LOTO) procedures. To mitigate the occurrence of these accidents, new safety methods are needed to monitor access to hazardous areas around operating machinery, improve documentation/monitoring of maintenance that requires shutdown of the machinery, and prevent unexpected startup or movement during machine maintenance activities. The U.S. National Institute for Occupational Safety and Health (NIOSH) is currently researching the application of Internet of Things (IoT) technologies to provide intelligent machine monitoring as part of a comprehensive LOTO program. This paper introduces NIOSH’s two-phase implementation of an IoT-based intelligent machine monitoring system.

By Alexander N. Winchell

The cities of St. Paul and Minneapolis are located side by side on a double loop in the Mississippi River near the eastern boundary of Minnesota. Both cities lie on both sides 'of the Mississippi River, which in this region describes an S-shaped curve. The two cities together have a population of over 600,000 people, gathered in an area which has grown to be a single urban district inasmuch as the two cities have expanded until they occupy all the territory formerly between them, though the business centers are ten miles apart. St. Paul is located at the head of navigation on the Mississippi River and Minneapolis, farther upstream, at the Falls of St. Anthony. A recent water¬power development below the Falls of St. Anthony, constructed by the Federal Government, has at the same time made possible navigation to the foot of St. Anthony Falls through a lock around the dam which replaces the former rapids. Minneapolis, in 1920, had a population of 380,000 people, and St. Paul, 235,000. The two cities occupy land at an elevation of 700 to 900 feet above sea level. The average elevation is slightly less at St. Paul. Minneapolis has nearly 4,000 acres of parks and park¬ways, while St. Paul has nearly 2,000.

Jan 1, 1920

By Yaxiong Wang, Yong Li, Yuedong Wu, Haigang Dong, Jiachun Zhao

A roasting-leaching process has been developed for concentrating platinum group metals (PGM) from a PGM-containing ferroalloy. The optimized roasting conditions used a NaOH-to-ferroalloy mass ratio of 1.2 at 600 °C for 2 h. The roasted product mainly comprised Na4SiO4, NaFeO2 and Fe2O3. The iron oxide and sodium silicate associated with the roasted product were leached in water and dilute sulfuric acid solution, while the PGM was concentrated in the acid-leached residue. A PGM concentration of 23.4% was obtained with assaying, and the concentration factor of PGM from the ferroalloy to PGM concentration was greater than 9.

Jun 14, 2021

By S. D. F. Rocha, A. L. A. SANTOS, E. M. A. BECHELENI, F. P. C. Silvas

Hydrometallurgical processes are needed to extract nickel (Ni) when it is disseminated in mineral matrix. High-pressure acid leaching (HPAL) and atmospheric acid leaching (AAL) are alternatives, and AAL has the advantage of requiring mild temperatures and pressure. Reducing-reagent tests improved the extraction of metals for the specific limiting portion of the ore. Low dosage of sodium thiosulfate presented better selectivity and safer operating conditions, allowing metal extractions of 50–62 percent at 95 °C. However, the low extraction rate obtained for Ni and the similar levels of impurities — magnesium (Mg), manganese (Mn), cobalt (Co) and iron (Fe) — extracted may represent economical and technological challenges in the downstream process.

The Awareness and Preparedness for Emergencies at the Local Level (APELL) program is a process that helps people prevent, prepare for and respond appropriately to accidents and emergencies. APELL was developed by the United Nations Environment Program, in cooperation with industry groups, governments and local communities. Since its beginnings in1988, the program has been implemented in more than30 countries. APELL is a tool for bringing people together to allow effective communication about risks and emergency response. The program provides a common-sense approach to accident prevention and response.

Jan 1, 2003

By Theodore Balberyszski

The gradual depletion of high-grade sulphide mineral deposits has turned the attention of the mineral industry to the recovery of metals from the oxides and silicates. Anionic (fatty acid) and cationic collectors have in some cases made flotation of non-sulphides possible, although in general, flotation of oxide ores is not as yet an economic process. Consequently, many attempts have been made to sulphidize the surface of the relevant oxide mineral and thus make it amenable to flotation. (1) (2) (3) In recent years, Bautista and Sollenberger(4) have investigated the conversion of a number of oxides to sulphides by reacting them with molten sulpur. This paper presents the results of investigations carried out at the School of Mineral and Metallurgical Engineering at the University of Minnesota to study the flotation characteristics of some sulphidized minerals. It is divided into two parts; Part I describes the sulphidization of a number of oxides and a silicate, and Part II presents the flotation behavior of the products of sulphidization.

Jan 1, 1968

By Peter Schmäh, Tobias Engel

The E-Power Pipe technology was originally developed for the trenchless installation of protective pipes and pipelines of 10" to 28" diameter, over long distances of more than 4,000 ft. The twostage process combines elements from Horizontal Directional Drilling (HDD) and microtunnelling technology. A microtunnelling boring machine (MTBM) excavates the borehole using a specially designed, temporary jacking pipe. A Rack & Pinion jacking frame pushes the equipment during the pilot bore and pulls in the prefabricated pipe string in a second step. The slurry microtunnelling machine is equipped with a jet pump, creating the so-called AVNS machine type. A new generation of small hard rock cutting wheels complements this considerable achievement for the tunnelling industry

Dec 1, 2022

By VIVEK KASHYAP, EVODY TSHIJIK KARUMB, PATRICK TAYLOR

Zinc ferrite is considered an integral phase of zinc residues as their presence can render the processing of zinc and critical metals difficult. It is a refractory phase, formed at high temperature in the presence of zinc (Zn) and iron (Fe) during oxidative roasting in zinc processing plants. Because it is refractory to efficient leaching, unreacted zinc ferrite gets concentrated in the final zinc residue, making it a viable source of zinc and indium extraction. The refractory nature of zinc ferrite makes the extraction of associated critical metals difficult. In order to explore a potential economic and carbon-neutral zinc ferrite processing technique, our previous study proposed the partial reduction of zinc ferrite followed by sulfuric acid leaching of the roasting product [1-3]. As demonstrated in our previous studies, partial reduction of zinc ferrite results in a mixture of ZnO, Fe3O4 and FeO, which can be further subjected to leaching for efficient extraction of zinc and critical metals such as gallium and indium.

Dec 1, 2022

By A. T. Yu

The quest for ore in an open pit is fundamentally an earth moving proposition. This thesis is vividly underscored by the rapidly increasing volume of waste to be removed in newer mines, where in some instances waste to ore ratios have reached as high as 20 to 1. Continuing depletion of high grade reserves, greater demand for raw materials, coupled with ever climbing labor costs, have made the problem still more pronounced and the need for more effective means of earth moving in an open pit even more acute. A conservative approach to the problem has been to upgrade the sizes of conventional earth moving equipment such as shovels and trucks. In many open pits, particularly in the C.S., this has been responsible for the generally down- ward trend of earth moving costs. None the less, the investment costs of these machines are high, and their gigantic engines are seldom fully utilized. Moreover, a large number of operators are required and maintenance remains relatively high. Unfortunately most people have felt that no other viable alternative was in sight within today's technological capabilities.

Jan 1, 1973

By Mark E. Smith, Gerald J. Gierszewski

Introduction The purpose of this paper is to present a procedure used by the authors for evaluating and designing soil liner systems. This method is particularly valuable in evaluating various treatment schemes for chemically amended soil liners. A tabulation of laboratory test results on various soil types are presented to quantify the effectiveness of certain treatments. A typical liner design program includes developing and proving soil borrow sources, designing the cross-section of the liner system, developing construction specifications, and providing construction services to ensure the intended product is achieved. Material Source Development The first step in designing a soil liner is to identify and evaluate suitable borrow sources within an economical haulage range. This is best done in a two step approach: a reconnaissance level investigation to identify target areas and a detailed evaluation of those targets. Reconnaissance: The goal of the preliminary investigation is to locate potential borrow sources for liner quality soils. This includes all natural materials which can be compacted, chemically treated, or otherwise amended to yield an installed permeability at or below some target value. This requires utilization of all available data sources: Soil Conservation Service, BLM, aerial photos, USGS geologic maps, and project geologist records. The goal at this stage is to locate shallow deposits of favorable soil types. The Unified Soil Classification System provides an excellent first pass grouping. Clays, clayey sands and silts are the most favorable soil types, although silty sands and occasionally clayey gravels can make excellent liners, and are often amenable to chemical modification. The lowest permeabilities are generally achieved with CH, CL and MH soils. Once preliminary targets have been identified using visual examination, laboratory classification tests should be performed to further refine the selection. Testing at this stage should include gradation, plasticity and hydrometer analyses. Additionally, "preg-rob" testing should be done as early as practical. Preg-rob is a phenomenon where gold or silver ions in solution associate with the clay, or other, minerals. When this occurs, a portion of the gold or silver leached from the ore is actually tied-up by the clay and thus a reduces recovery. Testing for this consists of agitating a small sample of the soil in a solution containing dissolved gold or silver, preferably of similar chemical make-up as the solution which will contact the actual liner. The solution and soil are assayed before and after agitation to determine loss to the clay. A reliable estimate of the hydraulic conductivity, commonly referred to as permeability, can be developed from the D10 value by the use of Hezen's formula: K = 100 (D1012 This relationship is limited to soils where the finer particles do not move due to the force of flowing water (i.e.: "hydrodynamic stabilitym)(1). Additionally, the effect of platty particles on permeability is not as predictable as the effect of equidimensional particles. D10 is the sieve opening size at which 10% of the material is finer. Plasticity is also important from several standpoints. Constructability is directly related to plasticity. Very plastic clays and non-plastic silts both tend to be difficult soils, while medium plastic clays and clayey sands are generally very desirable. Post construction performance is also related to plasticity (e.g. swelling, shrinkage cracking, frost heave, etc.). Additionally, low plasticity silts and silty sands generally do not respond well to chemical amendment. Source Development: The result of the reconnaissance evaluation should be an estimate of the relative probability of developing a suitable borrow source within an economical haul distance. Of course, "economical distance" depends on the degree of handling and treatment the borrow material requires, as well as the cost of synthetic alternatives. The purpose of the detailed investigation is to prove out quantity and quality of material sources, and determine design parameters such as degree of compaction, mixing, treatment and thickness of liner. The emphasis of the testing program should be permeability and strength. Strength becomes increasingly important as the slope of the liner and the height of the heap increase. Permeability testing should evaluate the effects of compaction, water content, mixing and chemical treatment where appropriate. The effects compaction and water content during compaction have on

Jan 1, 1987

By William F. Hahn

It is a pleasure to speak to this group about special crusher installations which are in the bauxite and phosphate rock processing industries. The installations to be discussed demonstrate the variety of conditions, materials, and results desired which must be evaluated before a selection is made from the specialized crusher technology available today. Those of you who are closely involved with phosphate rock and phosphate products processing will find some of this information a bit interesting and perhaps alien to your own descriptions or every day references. It is given from a "crusher" manufacturer's viewpoint and therefore is infused With our flair and language. General features of six (6) different crushers will be shown in cross-section With slides and will be discussed in the same order.

Jan 1, 1978

By William R. Yernberg

The early part of the decade was marked by world-wide problems and economic difficulties. In 1980, President Jimmy Carter ordered the failed military mission to rescue hostages in the U.S. Embassy in Iran, Mt. Saint Helens, WA erupted killing 60 people and the Soviets and Mujaheddin guerrillas clashed in Afghanistan after the Soviet invasion. Later in the year, Ronald Reagan was elected president, defeating Carter. The first launch of a space shuttle (Columbia) occurred in 1981. Also in 1981, the first IBM-PC’s begin to roll off the lines. In 1982, Argentina invaded the Falkland Islands and Mexico’s economy was in collapse. In 1980, the U.S. unemployment rate stood at 7.1 percent, and by 1982 the rate increased to 9.7 percent. 1980 marked SME’s first full year in its new office building in Littleton, CO. The new facility was dedicated in November 1979. Claude L. Crowley was executive director of SME in 1980 and remained in that position throughout the decade. SME’s membership stood at about 26,000 throughout this period (1980-1982).

Jan 1, 2007

By Guangming Zhao, Nianjie Ma, Demao Guo, Denghong Chen, Yingming Li

Based on the mechanical essence that large-scale plastic failure zone appears in all or part of surrounding rock in soft rock roadway, the numerical simulation method is used to study the rectangular roadway in layered rock strata. It is clarified necessary conditions must be met for soft rock: firstly, the strength condition is that the maximum confining pressure is greater than the uniaxial compressive strength of rock strata. Secondly, the stress environment condition is that the ratio of maximum confining pressure to minimum confining pressure is greater than 3. Thirdly, the angle condition is that The direction of principal stress action enables the plastic zone of weak rock layers to fully develop. At the same time, the quantitative description method of soft rock is given, and the soft rock roadway is redefined. Soft rock roadway refers to the roadway that meets the strength conditions, stress environment conditions, and rock structure angle conditions under certain surrounding rock conditions and in-situ stress environment conditions. After the excavation of the roadway, a large-scale plastic failure can be formed, that is, a butterfly-shaped plastic zone is formed, and the conventional support cannot be adapted. It is difficult to support in engineering. It provides a theoretical basis and engineering analysis method for the identification of soft rock roadway, and the research results have engineering value Soft rock tunnel engineering in coal mines constitutes a vital aspect of soft rock engineering. This field broadly encompasses rock engi- neering concerning large plastic deformations, e.g., soft rock slope engineering and soft rock tunnel engineering. The intricate geological conditions encountered in soft rock tunnel engineering present a significant challenge to support, which has harmed coal production in China. China leads global raw coal production with the annual output of 4.6 billion tons. Annual tunnel excavation supporting this production spans approximately 11,000 km, with over 10% of these tunnels classified as soft rock formations. Soft rock is commonly associated with soft rock tunnels due to their prevalence in engineering projects. However, reaching a consensus on the definition of soft rock has long been an enduring challenge for scholars and engineers. Numerous definitions have been proposed, includ- ing descriptive, index, and engineering definitions. For instance, the International Society for Rock Mechanics defines soft rock based on its uniaxial compressive strength σ ranging from 0.5 to 25 MPa. China's Engineering Rock Body Standards, established in 1994 (GB 50218-94), take a qualitative and quantitative approach to classifying rocks. Rocks are categorized as hard or soft based on criteria such as hammering sound, fragmentation, water immersion effects, and weath- ering degree. Additionally, the integrity of rock bodies is assessed across five categories intact, relatively intact, soft fractured, fractured, and extremely fractured. This classification considers factors like the number and spacing of structural planes, their combination, and the types of structures. Descriptive and index-based definitions fall under the category of geological soft rocks, providing a comprehensive geological perspective on the surface features or strength characteristics. However, these definitions have limitations in engineering practice, which leads to contradic- tions. For instance, rocks with uniaxial compressive strength less than 25 MPa may not exhibit soft rock characteristics if the tunnel is shal- low with low horizontal stress levels. Conversely, rocks with compressive strength exceeding 25 MPa at sufficient depth and high horizontal stress may exhibit soft rock characteristics. Definitions originating from engineering practice have emerged after realizing the inadequacy of discussing soft rocks without considering engineering. For instance, Dong's loose circle theory defines soft rocks as rocks with a loose circle thickness exceeding 1.5 m, which chal- lenges conventional supports. This intuitive definition, widely accepted by engineering professionals, emphasizes the difficulty in supporting tunnels due to extensive damage. However, various tunnel damage poses a challenge in relying solely on the loose circle thickness of tunnels for determining soft rocks. He introduced the concept of engineering soft rocks, which are defined as rock formations exhibiting significant plastic deformations under applied engineering force. Two fundamental mechanical properties of soft rocks are identified the critical softening load and critical soft- ening depth. Rocks below the critical softening load threshold are categorized as hard rocks, while those exceeding it exhibit substantial

Jun 25, 2024

By S. C. Termes

This paper discusses recent Federal Bureau of Mines research on the selective flocculation of various minerals with insoluble crosslinked starch xanthate (ISX). ISX is insoluble, has a shelf life of over a year when kept cold, and has a higher molecular weight due to cross linking than the soluble noncrosslinked starch xanthate used in previous flocculation studies on nonsulfide minerals. ISX readily flocculates a number of sulfide mineral fines but not silicious gangue. Floc formation, floc size, and settling rate are strongly dependent on pH, with the pH dependence differing for each mineral. Bornite has been selectively flocculated from bornite-quartz mixtures, and the bornite-containing flocs were separated from the unflocculated quartz using decantation and washing procedures.

Jan 1, 1982

By Lui Bin, Li Xinghua, Jiang Guoan

By employing decision support system and Borland C++ and Foxpro 2.58 For Windows as development means and tools, this system comprehensively applies the price decision theory, fore- casting and optimization techniques as a complete theoretical system, realizing the computerization of analysis, forecasting and decision process of coal price.

Jan 1, 1996

By Chen Bingchen, Zhang Jian, Liu Jiaxiang

The influence of various installation angles of hydrocyclone on its operation indexes was investigated, and the correspondent mathematical models were established in this paper. The models developed in this paper can be used to the optimizing control of hydrocyclone and make the hydrocyclone as a particle size sensor.

Jan 1, 1995

By D. Burkhard, E. Herth

"Geologic structure and properties are the primary influences on ground control at San Juan Mine. Geotechnical properties of the coal seam and near seam strata, the presence of above seam sandstone paleochannels and water, are thought to be the leading contributors to ground control issues. It is the confluence of specific geologic conditions rather than isolated features that most often produce adverse conditions. Altering primary support installation and mining practices are done when unfavorable conditions appear during development. Installation of standing support is most often employed when adverse conditions develop at later dates. REGIONAL GEOLOGIC SETTING San Juan Mine is an underground coal mine located on the western flank of the San Juan Basin in northwest New Mexico. The San Juan Basin is contained within the south eastern region of the Colorado Plateau geographic province. The basin contains multiple coal bearing formations and is also a major producer of coalbed methane gas. San Juan Mine is stratigraphically located within the Fruitland Formation. From a prominent monocline marking the western boundary of the basin, the formation dips gently to the east towards the center of the basin. The primary driver for the deposition of coal bearing formations within the basin was the Cretaceous Inland Seaway. Multiple cycles of transgression and regression driven by sea level rise and tectonic subsidence deposited rock types from marine shale’s to terrestrial sandstones. The Sevier Mountains to the west of the seaway likely provided the sediment supply for the Fruitland Formation. During a major cycle of seaward regression, the Pictured Cliffs Sandstone Formation prograded over the marine Lewis Shale. The coal bearing Fruitland Formation followed, being deposited over the Pictured Cliffs. The Fruitland Formation contains numerous coal seams and is approximately 400 ft. thick at San Juan Mine. Fruitland Formation coal seams are numbered in order of superposition. San Juan mines the Fruitland number 8 seam. Dating has placed the age of the seam at approximately 73 to 75 million years [1]. LOCAL GEOLOGIC SETTING The Fruitland 8 coal seam dips approximately 1-3 degrees towards the E-NE. At San Juan Mine, the seam displays a mild plunging, synclinal structure, the axis roughly bisecting the mine from west to east. The number 8 seam consists of five coal benches and four volcanic ash band partings labeled sequentially based on superposition. The lowest portion of the seam is the 8-1 bench, the 8-2 through 8-5 benches following sequentially to the top of the minable seam. Ash band partings are labelled P1 through P4 from bottom to top respectively. The presence of distinctive partings and benches allows for seam definition and aids in identifying mining horizons."

Jan 1, 2016

By C. Brown, N. Rayyan, T. H. Dubaniewicz

Lithium-Ion batteries (LIBs) have the potential to go into thermal runaway which introduces a new ignition source in hazardous environments such as gassy underground mines that may contain methane in the surrounding air. Researchers from the National Institute for Occupational Safety and Health (NIOSH) used an accelerating rate calorimeter (ARC) to induce thermal runaway in individual lithium-titanium-oxide (LTO) and lithium-nickel-cobalt-aluminum-oxide (NCA) LIB cells within a sealed enclosure with either no methane, a lean, a stoichiometric, or a rich methane-air mixture in the surrounding canister to determine if these LIB types would ignite the methane, causing an additive effect on overpressures. Canister pressures and maximum temperatures reached by the cells, surrounding air, and exhausted gases were measured in this study and remained consistent with varying methane concentrations.

Feb 1, 2023