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By Jake Coibion, Elmira Riahi, Dominic Reda, Walter Klary, Vojtech Gall

Progressive Design-Build is becoming a more common delivery method in the tunneling industry. This approach allows the Owner to select a design-builder primarily based on qualification instead of lowest price. The delivery method promotes flexibility and collaboration at all levels from the initial design stage through construction. Using the example of the Atlanta Airport Plane Train Tunnel West Extension, value-added risk management was added during the initial design phase with an independent reviewer. This paper presents the independent reviewer transitioning from constructability review in the very early stages of design to independent design verification to on-site supervision during construction.

Jun 13, 2023

By P. Shang

Fly ash and zeolite have strong absorption to cations since their porous microstructure. The porosities of fly ash and zeolite can also be increased by modification, which improves the absorption of the materials. This research showed that the effects of modified fly ash and zeolite to remove ammonia nitrogen from rainwater. The optimal reaction time, additive amount of materials, and pH value of the stormwater to remove ammonia nitrogen were experimentally determined. For modified fly ash, the optimal removal rate of ammonia nitrogen from 100 ml stormwater was 74.41% with the addition of 10.0g fly ash, 1.5 hours of the reaction time, and 8 of pH value. To the modified zeolite, the optimal removal rate of ammonia nitrogen was 51.22% at the reaction conditions of 2.0g of zeolite, 1 hour of reaction time, and 7 of pH value.

Jan 1, 2010

By Jing G. Yen

When a solid-liquid mixture is conveyed through a pipe,' four hydrodynamic conditions may develop depending upon the properties of the transporting medium, the properties of the transported material, the properties of the pipeline and the flow characteristics. They are classified as homogeneous flow, heterogeneous flow, intermediate flow and saltation. Heterogeneous flow, which is the subject of the present analysis, occurs when solid particles are coarse, of high density, and the mean velocity of the flow is relatively low, such that the combination allows the establishment of a pronounced concentration gradient in the cross-section of the pipe. In this type of system the suspended matter does not change the rheological properties of the conveying fluid, and solid and fluid phases behave somewhat separately. In recent years much work has been directed toward gaining more insight into the hydrodynamics of heterogeneous flow (1,2,3,4,5,) However, almost all knowledge obtained is empirical in nature and limited in scope. Much effort has been extended to collect experimental information on the energy losses associated with systems of slurry flow (6-13) The work of Durand and Condolios(14,15) represents one of the most extensive experimentations in this field. Through systematic test runs, the effects of the major flow-parameters were studied one at a time. From the results, they concluded empirically that:

Jan 1, 1969

By Klaus Rieker

"Since the mid-19th century the River Emscher in the German Ruhr District has been used for disposing of wastewater. In the early 1990s, it was decided to replace the existing open wastewater system with a sewer system and to restore the River Emscher to its natural state. The major Emscher conversion project is divided into a large number of individual schemes, with construction phase 30 being the largest. By applying the pipe jacking method, interlinking tunnels with section lengths in excess of 1,100 m are constructed. USAGE OF THE EMSCHER OVER TIME The 85-km long river Emscher flows right through the Ruhr District. It has its source to the east of Dortmund and flows into the river Rhine near Dinslaken (Figure 1).The Emscher has been used to dispose of wastewater since industrialization began about 200 years ago. Intensive coal mining over the years led to considerable subsidence causing stagnant sewer areas which in turn led to typhus and other deceases. Thus in 1899, the Emschergenossenschaft was founded to create an efficient interceptor system for a catchment area of 865 km² through lining, raising and Emschergenossenschaft decided to free the waterways of the Emscher system from sewage and to improve them in ecological terms by 2020. A budget of 4.5 billion euros was earmarked for this purpose.The construction of sewer conduits began in order to no longer transfer the wastewater into the Emscher. The currently ongoing construction of the “Emscher Interceptor” - the main sewer - represents the heart of the Emscher conversion project. The interceptor will run along the river over a length of 51 km. Three pumping stations are required to confine the sewer’s depth to elevations between 15 and a maximum of 40 m below the surface. Since early 2012, the Emscher has been free from wastewater east of the Dortmund-Deusen clarification plant. There are two further clarification plants situated along the Emscher, which treat the still contaminated river water down-stream. Once the Emscher Interceptor is in operation, they will receive wastewater solely from the tunnel system."

Jan 1, 2016

By Keh-Jian Shou

"This study adopts and analyzed a shield tunneling case in Taiwan, with a diameter from 5.25m to 6.70m and the smallest radius of curvature 100m, which was constructed in gravel formations as well as a vibration sensitive area. In this case study, a vibration monitoring plan, comprising the sensors inside the shield machine and on the surface, was proposed and performed to provide the vibration data during the construction. In this project, the major vibration reduction considerations were increasing the open ratio of the cutter head (to reduce the cutting function) and reducing the rotational speed of the cutter head. The results of the construction suggest the appropriateness of the above considerations. The findings could provide suggestions to the other similar shield tunneling cases. INTRODUCTION Underground vibrations during shield tunneling are typically isolated and absorbed by the soil. However, a portion of these vibrations may disseminate to the surface. These vibrations are considered micro-vibrations, which generally do not pose a threat to surface structures, and are thus seldom the focus of research. The present project was located in the Hsinchu Science Park where shield excavation bypassed numerous high technology manufacturing plants (e.g., wafer manufacturing plants). The vibrations generated by shield tunneling may affect the vibration-sensitive manufacturing equipment and instruments in these plants, and induce problems in manufacturing processes. Therefore, research to comprehensively understand the characteristics and potential influence of such vibrations is essential. To clarify the characteristics and potential influences of vibrations generated during shield tunneling, the vibration level in the excavation of the Taoyuan International Airport Access (TIAA) Metropolitan Rapid Transit (MRT) Project was examined, as it possesses similar excavation conditions to the present project. The parameters collected from relevant tests were provided as a reference to the firms along the excavation route of the present project to explain the effects of vibrations, and to relevant units for shield machine selection and project execution. No yield problems resulting from shield machine induced vibrations were reported by the firms, and the vibration levels measured in the present project were comparatively lower than those in the TIAA MRT Project. Because the related literature is scarce, this study aims to analyze the collected measurement data and provide suggestions on shield machine selection or designs. Such that we can more properly evaluate and control the impact of shield tunneling induced vibrations in similar projects."

Jan 1, 2016

The leaching of gold and silver by ammonium thiosulfate solutions in the presence of copper has been actively studied in recent years. Newmont Gold Company has successfully tested the ammonium thiosulfate for gold extraction following biooxidation pretreatment of low grade refractory carbonaceous/sulfidic ores. In this paper, the chemistry of the copper catalyzed leaching process is reviewed. Factors affecting both the leaching reactions and the stability of the lixiviants are reviewed and discussed from a solution chemistry perspective.

Jan 1, 1996

By Nic Arrieta

The Arimetco White Cliff Diatomite operation near Tucson, Arizona will be discussed and reviewed across the spectrum of geology, mineralogy, mining, processing and product attributes and market applications. Unique for the operation are the type, quality and the extent of the reserves and several product characteristics of the diatomite.

Jan 1, 1996

By J. D. Miller

X-ray computed tomography (CT) techniques have been developed for the medical services field in order to provide accurate internal images of the human body.(l-7) Now, a decade later, CT techniques are starting to be used in non-medical applications such as, non-destructive testing(8), flow pattern analysis(9), drill core examination (10,11), and coal characterization(12,13). In these fields of application, CT techniques offer the potential to extend our knowledge and understanding beyond that provided by more traditional methods of analysis. Although, CT systems involve very specialized and expensive equipment, the advantage of x-ray CT in revealing the detailed internal structure of an opaque material non-destructively should make it an important tool to provide a more complete analysis of mineral processing phenomena. X-ray CT systems generally consist of an x-ray source/collimation unit and a detector/data acquisition unit. The object to be examined is placed between the two functional units as shown in Figure 1. With this system the density array of selected cross sections of a chosen opaque object can be obtained in two dimensions. There are numerous areas in mineral processing to which x-ray CT technology can be applied and it is the aim of this article to identify these potential areas noting the advantages and limitations of the technology. Particular emphasis is placed on particle composition distribution and multiphase fluid flow measurements. In the case of particle composition distribution, liberation analysis and coal washability are considered. While in the case of multiphase fluid flow, swirl flow in the air-sparged hydrocyclone is given by way of example.

Jan 1, 1989

By Brian Mangogna, Clay McNail, Weishi Mang, Adam Steimel

Together with innovatively applying modern flotation reagents and developing the breakthrough mill enterprise expert control and operating system, Doe Run Buick Mill constructed an advanced large copper rougher scavenger to process its complex Pb\Zn\Cu ore more efficiently. The scavenger circuit, featuring its own motor control center, air blower, multiple reagent loops and FrothSense+™ camera, operates both mechanically and chemically to maximize copper recovery and under expert control. Such scavenger features can be applied to zinc rougher circuits for all Doe Run mills to maximize Cu recovery during Cu special runs when the zinc rougher becomes a copper rougher scavenger.

Feb 1, 2025

By R. Venugopal, T. C. Rao, M. Vanangamudi

Introduction The kinetic approach, to understand a process in detail, has been extensively used in the unit operations of many engineering systems. In green pelletization, the kinetic studies have been mainly oriented towards quantifying the growth mechanism (Kapur and Fuerstenau, 1964; Sastry and Fuerstenau, 1977; Capes and Danckwerts, 1965; Kapur and Fuerstenau, 1966; Kapur, 1972) and in a few cases, relating the rate of growth with added liquid content (Kapur and Fuerstenau, 1964; Newitt and Conway-Jones, 1958). Studies on the kinetics of green pelletization, in terms of the order of the kinetics are virtually non-existent. Sastry and Fuerstenau (1970) classified the agglomeration process into "free in-space" (dilute particle system) and "restricted-in¬space" (highly dispersed particle system) and noted that the former is a second-order process while the latter corresponds to a pseudo first-order rate process. The present paper attempts to describe the kinetics of green pelletization, in terms of order of the kinetics, using pyritiferrous shale as the material system. Experimental Pelletization experiments were carried out using -100 mesh pyritiferrous shale, in a laboratory disc pelletizer, at four intervals of pelletization time (15, 20, 25 and 30 min). The green pellets obtained were size analyzed. The size distribution of pellets has generally been represented by a single parameter such as the mean granule diameter, ratio of maximum and minimum pellet diameter, etc. In the present study, the d50 (50% passing size) of pellets has been considered to represent the size distribution of pellet. Kinetic equations The process of size enlargement is considered analogous to chemical reaction and a general kinetic equation of nth order for growth of pellets is given as

Jan 1, 1990

By Frank E. Dalton

BACKGROUND OF TARP The first settlement in Chicago in the 1830's was only 0.61 m (2 ft) above the level of Lake Michigan. The area was flat and swampy with local streams and rivers generally flowing to Lake Michigan. Repeated outbreaks of cholera and typhoid fever in the middle and late 1800's led to the reversal of the river system (away from Lake Michigan to the Mississippi River). As a result of this reversal, the Chicagoland area has had to restrict water withdrawals from Lake Michigan and has had to develop and implement water management programs in compliance with orders set down by the Supreme Court of the United States. In order to comply with restricted lake diversion requirements and to compensate for a natural setting which was essentially hostile to human habitation, it has been necessary to embark on the construction of massive public works which include the world's largest water filtration plants, the world's largest wastewater treatment plants and finally the construction of TARP. The rivers and streams in the Chicago area are the headwaters of the Illinois waterway system. These headwaters are heavily polluted from combined sewer overflows of the area. Present pollution control laws require that combined sewer overflows be eliminated so that the rivers and streams can be used by the citizens of Cook, Du Page and Will Counties and other downstream communities. Fifty-three of the older most densely populated communities including the City of Chicago, covering an area of 971 sq km (375 sq miles), are served by combined sewers. Combined sewers carry both raw sewage and stormwater. Because porous ground surfaces have been covered 1815

Jan 1, 1979

By Stephen J. Klein, Fernando Orduz, Randall J. Essex

INTRODUCTION The Keystone Tunnel project consists of widening an existing 7.3 m-wide (24 ft) highway tunnel to a width of 13.7 m (45 ft) to provide a three-lane, two-directional highway tunnel. The 13.7 m-wide tunnel was excavated in a staged drill-and-blast sequence through foliated schist, and was supported using pattern rock reinforcement and shotcrete. Notable project features are: the low vertical cover over the tunnel is less than the span of the opening; the project is the second instance where the Federal Highway Administration (FHWA) has accepted rock reinforcement as a permanent support element; and the project is the first instance where the FHWA is accepting shotcrete as the final interior surface of the tunnel. This paper covers the design and construction phases of the project. PROJECT DESCRIPTION The South Dakota Department of Transportation (SDDOT) retained Woodward-Clyde Consultants (WCC) to evaluate the feasibility, prepare construction plans and specifications, and provide construction management services for the widening of the Keystone Tunnel. The tunnel is located in the Black Hills National Forest area of South Dakota near the southwest corner of the state. The Keystone Tunnel is on U.S. Highway 16A, about 0.8 km (1/2 mile) north of Keystone which is approximately 32 km (20 miles) south of Rapid City (Figure 1). Highway 16A serves as an important transportation link between Rapid City and the Mount Rushmore National Monument which is located about 2 miles west of Keystone. The road through the tunnel consisted of two lanes about 7.3 m (24 ft) wide, and is being widened [ ]

Jan 1, 1989

By Andrew Mackenzie, Paul Rantala

Data is now appearing in literature that indicates many current paste fill systems in Canada suffer from plugged lines and severe wear rates. Both of these conditions suggest: design problems with the pipe distribution system, backfill composed of poorly graded material and/or possibly poor operator practices. Problems that can be prevented in the design stage, but still may be readily solvable with current technology. However, if left untreated will lead to an increasing frequency of down time. The compatibility of the distribution system with the paste fill rheology is fundamental and essential for the reliable delivery of fill. Either many mine operators are not familiar enough with the technology to provide a critical review that could foresee problems down the road, prior to construction and or North American designers are not clarifying their designs to their customers. The objective of this paper is to highlight key concepts to mine operators with the purpose of better enabling a critical review of contractor's/consultant's designs. There is a great deal of understanding about the rheology of backfill over a range of pulp densities from hydraulic slurry to dense to paste. However, outside of deep mines (especially in South Africa) neither hydraulic or dense fill distribution systems have suffered the problems of paste fill. Paste fill is fundamentally different from hydraulic fill principally in its transportation characteristics. These differences have a direct impact on the design of the distribution system. By understanding the practical implications of these differences the operator can play a more active role in their design while better appreciating how to best operate their own system.

Jan 1, 2001

By C. O. Brawner

Geotechnical theory is reasonably well developed to evaluate the stability of rock slopes for surface mining projects. It is recognized widely that structural geology, groundwater pressures and seepage, and blasting are key factors that influence the stability of such slopes. However, our capabilities to model the structural geology, to determine rock strength along discontinuities and to model groundwater pressures and profiles are still very approximate. Plus, practical experience of the rock mechanics engineer is one of the most important inputs to the design of open pit mine slopes. To emphasize the use of practical experience, a number of case examples are reviewed here to illustrate key factors that must be evaluated. These case examples comprise a continuation of other examples presented in the Jackling lecture to the SME in 1986 by the author (Brawner, 1986). Example no. 1 In situations where the orientation of geologic discontinuities will not influence rock slope stability, extremely steep slopes can be developed, providing blasting and groundwater are controlled adequately. An excellent example of this condition is the Republic Pit of Cleveland Cliffs in Michigan. The rock slope in Fig. 1 isover400fthigh with a face angle of approximately 80". The rock is hard and massive, and blasting was carefully controlled. The original design of this slope was at45", a standard design angle at that time. The competency of the rock and the lack of critical geologic structure subsequently was recognized, and the much steeper slope angle was developed successfully. The rock proved to be so competent and the slope sufficiently stable that an underground crusher station was developed with entrance and exit tunnels excavated at the toe of the steep wall.

Jan 1, 1991

By George M. Leonard

Mineral commodities on National Forest System lands contribute to the nation's well being. Access to these commodities is dependent on public perceptions of the effects of mineral operations on other resources. An outlook is described which the Forest Service believes is essential to the minerals industry if it plans to continue seeking minerals on National Forest and Grasslands.

Jan 1, 1991

By C. T. Wallace

Evans Industries, Inc., a management coal consultant and company was assigned to evaluate National Steel Company's coal properties in Knott and Floyd Counties, Kentucky. The results of evaluation showed large reserves of good quality, high volatile metallurgical coal contained in the Elkhorn coal beds and resulted in the formation of Beaver Creek Consolidated Coal Company. Based on results of the exploration and feasibility work, the decision was to install a coal nine, preparation plant and related facilities having a production capacity of one' and three quarter million tons per year with Evans Industries acting as Beaver Creek's management company. The recoverable tonnage assigned to the Stinson Mine is approximately forty-five million tons. This paper discusses the general arrangement of storage, conveying, loading, refuse disposal facilities and the flow sheet of the preparation plant developed by engineers of Heyl & Patterson, Inc., and Evans Industries, Inc., with emphasis on practical flexibility, sulfur reduction in all circuits, and high product yield with the minimum amount of selective mining, Three and one-half miles of railroad have been built by the Chesepeake & Ohio Railroad to service this mine.

Jan 1, 1970

By J. Perlacia

Introduction The Bulk Handling Technology has already started its transformation to the Industry 4.0. Having some of the harshest working and environmental conditions of the industry, the possibility of remote analysis and maintenance of the components seems a perfect target to focus on. The most important and expensive tools have been adapted to the digital era during last years, from remotely controlled haul trucks to monitored conveyor belts. However, these big parts of the installations rely in smaller parts that have been left aside for a while, mainly due to the difficulty to adapt them to IoT (Internet of Things). The paradigmatic example is the lack of monitored rollers whereas all the other components of the conveyor belt installations (the belt itself, motors, drums etc.) were monitored some time ago. The main problem is that a failure of a single roller can cause the stop of the whole conveyor, due to the possible damages to the belt, thus the implementation of an integral monitoring system of all the components of the conveyor is a must. The R&D Department of ULMA Conveyor Components, has been working since early 2012 on the development of Monitored Rollers, facing all the problems until its final installation in very different demanding conveyors, from the Australian extreme heat to the freezing cold Norway. All the tests done under actual working conditions, in real installations, have given a valuable knowledge in the identification of problems, their solution and the final advantages of a roller monitoring system. Background and Current State The malfunction of a single roller in certain conveyor belts can suppose the standstill of the whole installation until its replacement, due to the risk of greater and more expensive failures like the rip of the belt. In the case of a bulk handling installation where a continuous supply of material is necessary, an unexpected stop of one hour could entail huge economical losses. What’s more, many conveyor belts are several kilometers long or the access to some parts of them is very complicated. Due to these difficulties the inspection and maintenance operations can become expensive and hard going, with staff going over the whole area checking the correct condition of the conveyor and rollers, which means a dangerous activity. As in many other industry products, the condition of rollers can be recognized measuring key parameters like the temperature of the bearings, the vibration level etc. The traditional way is to use the characteristic noise of a failing bearing, but this method usually implies to change several rollers because the maintenance team is not able to identify a single source of the noise. In recent years different attempts to measure the temperature of the bearings have been made, but the result is not accurate enough due to the proximity of the rollers in the idlers

Jan 1, 2019

By J. Girard-Dwyer, T. Camm

Direct costs such as medical, legal, administrative, and worker’s compensation costs, property damage, lost earnings, and lost benefits are typically used to compute the economic impacts of occupational injuries. However, there are also a number of less obvious, indirect costs that substantially contribute to the overall loss costs. In fact, for every $1 of direct costs an estimated $3 to $5 of indirect costs are also incurred. This paper presents a systems approach that incorporates engineering, economics, psychology, and sociology in order to evaluate the total value of investments in safety. By studying the interrelated system comprised of the injured worker, their family and coworkers, as well as the organizational structure that was the setting for the incident, a methodology can be developed that will more accurately capture the true costs of mine injuries.

Jan 1, 2004

By C. Copeland, S. Kawatra

Airborne particulates can be generated by combustion processes, comminution, or materials handling, and regulation of these particulates by EPA are becoming progressively more stringent. Regulations will soon include “nanoparticulates,” particles finer than 100 nanometers, which are believed to have significant health effects due to their high surface area and reactivity. Although it was argued that nanoparticulate concerns were only important for combustion, studies here have shown that material handling and comminution release significant quantities of nanoparticles into the air. Laboratory studies have shown that sodium metasilicate reduced airborne particles finer than 10 micrometers (PM10) by 86% and particles finer than 2.5 micrometers (PM2.5) by 80% for iron ore. Additional studies were conducted which revealed that nanoparticulate emissions were present in the types of operations conducted at pyrometallurgical facilities.

Jan 1, 2007

By James P. Rider, Robert P. Vinson, Fred N. Kissell, Jon C. Volkwein, Gregory J. Chekan, Jay F. Colinet

The Thermo-MIE personal DataRAM dust monitor (pDR) is a light-scattering instrument approved for use in gassy underground mines by the U.S. Mine Safety and Health Administration (MSHA). However, the use of lightscattering monitors has been inhibited by concerns about inaccurate readings resulting from changes in dust size distribution and composition, as well as concerns about the impact of moisture in the mine air. Because of this concern, the National Institute for Occupational Safety and Health (NIOSH) has evaluated the pDR using available data from laboratory tests and mine surveys. The data show that accuracy can vary widely from test to test and mine to mine. In most cases, the results can be improved by using a companion gravimetric measurement to adjust the pDR data.

Jan 1, 2005