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By Nik Sokol, Mike Jaeger, Leo C. Weiman-Benitez

Silicon Valley Clean Water signed a progressive-design-build (PDB) contract with Barnard Bessac Joint Venture (BBJV) to design and construct the Gravity Pipeline tunnel in Redwood City, CA. Owner and Design-Builder teamed with designer Arup to provide a final product: 3.3 miles of 182 in. O.D. precast concrete segmentally lined tunnel with 10 ft. and 11 ft. I.D. Fiberglass Reinforced Polymer Mortar (FRPM) carrier pipe, complete with two FRPM Drop Structures. BBJV and Arup collaborated with SVCW to evaluate alternative design concepts, negotiate an agreeable price and reduce contingencies through a transparent estimating process, and deliver the project ahead of schedule.

Jun 13, 2023

By Ray E. Harris

New developments have occurred in Wyoming's industrial minerals industry since the 32nd Forum on the Geology of Industrial Minerals in Laramie, Wyoming in 1996. The soda ash trona and bentonite industries have experienced overall growth. Gypsum and limestone production have remained constant, but have the potential for dramatic growth. The mining of zeolite ceased in 1997. The struggling dimension stone industry has increased production, but development has lagged behind the schedule predicted in 1996. The construction of a container glass plant and associated production of glass raw materials, as predicted in 1996 and imminent in 1998, is now on hold due to unforeseen market factors. Increases in railroad and highway construction have, and will, greatly increase the production of construction aggregate for local uses. An iron carbide industry, not foreseen in 1996, is in the planning stages.

Jan 1, 2001

By John S. Summer

The induced polarization (IP) method of geophysical exploration is capable of detecting even small amounts of metallic luster minerals in a rock mass. Consequently, in the years since discovery, IP surveying has become the most popular ground geophysical survey method. It is not too difficult to understand many applications of IP surveying as used in the search for mineral deposits. However, the basic theory of the IP phenomenon is not well developed or understood, and there has been some disagreement on fundamental concepts. In order to most effectively apply the IP method in the field it is necessary to know the physical characteristics of the sought-for deposit including its size, shape, depth, and electrical properties. With this information an optimum IP search arrangement can be devised and one could use the best possible electrode interval, type of array, and line spacing. With uncertain target characteristics as encountered in the real world, geological guidance must be used to help direct an optimized IP survey.

Jan 1, 1972

By L. E. Sausa

Measuring the specific gravity of a pulp in concentrating plants is a relative, y simple procedure, but the desired accuracy is often difficult to attain. Many plants use the system of weighing a known volume of the pulp on a scale. In many cases, this method is quite accurate, but obtaining a true sample presents quite a problem. This is especially true when the pulp tends to froth, the solids settle rapidly, or the flow is fast at the point of sampling. There is also the problem of the operator neglecting to take the sample because of duties elsewhere, or, if everything Is apparently running smoothly, he assumes the pulp density is also all right. In 1952, the Pine Creek plant of Union Carbide Nuclear Company began working on a better method for measuring and controlling pulp density. After an extensive investigation of different methods for measuring the specific gravity of moving pulps, the Research Department decided that the bubble tube method appeared to be the simplest and most promising for our applications. It consists of two bubble tubes, of different lengths, submersed in a pulp. Low pressure air is supplied to, the two tubes through sight bubblers to maintain approximately equal volume of air to each bubble tube. The bubble tubes are also connected to a differential manometer, one to each side. Therefore, knowing the vertical distance between the outlets of the bubble tubes, the manometere can be calibrated to measure directly the specific gravity of the pulp. (Figure No. 1 illustrates this model.)

Jan 1, 1960

By Keros Cartwright

Distribution of temperature within the lithosphere can be significantly affected by the movement of ground water. Stallman (1960) presented the basic equation for the simultaneous transfer of heat and fluid in a porous medium and first used earth temperatures to determine aquifer permeability. Subsequently, studies of rock and soil temperatures were used to determine the flow of water through clay layers separating aquifers (Bredehoeft and Papadopulos, 1965; and Sorey, 1971), and to locate shallow aquifers (Cartwright, 1968; Birman, 1969). Cartwright (1968) showed that shallow aquifers maintain a nearly constant temperature throughout the year and that heat is exchanged between the aquifer and land surface. These temperature data also suggest that shallow aquifers hydrologically connected to surface-water systems have significantly greater effect on temperature distribution than aquifers in the deep artesian basins. Water wells developed in the shallow glacial and dolomite aquifers to depths of over 122 meters (400 feet) in northern and central Illinois produce water at temperatures very close to the mean annual air temperature. An analysis of the character of the rocks and soils suggests that the tem¬perature gradient should, and does, vary according to changes in thermal conductivity due to changes in lithology. This is because, under conditions of steady and uniform flow of heat from the earth's interior to the surface, a greater temperature gradient is required in poorly conductive rocks than in highly conductive rocks to transmit the same quantity of heat. Based on estimated values of thermal conduc-

Jan 1, 1972

By George E. Summers

A salt dome appears to provide the basic medium requirements for the excavation of the 315 foot diameter, unsupported spherical cavity at a depth of 2700 feet required by the AEC in a proposed "decoupling" experiment. Tatum Salt Dome was a natural choice for a site because more geological and hydrological information has been accumulated on Tatum than any other salt dome on the Gulf Coast. The Tatum Dome is a mile in diameter, roughly flat topped, nearly cylindrical in shape and has some overhang at the top. The salt stock has nearly vertical layering of alternating bands of salt and anhydrite. In the vicinity of the dome, adequate fresh water for solution mining is available in surface streams and in subsurface aquifers. A saline aquifer is available for brine disposal. A tentative cavity location was selected near the center of the dome which meets the design criteria established by the AEC.

Jan 1, 1968

By R. Brändle, R. Luis-Fonseca, R. Cornejo, G. Fischer, G. Von Rickenbach, J. Jarufe

Rock damage around underground excavations has been an important hazard in mines and tunnels. Rock dilation generates buckling that needs to be contained before it causes damage to equipment or safety concerns to mine workers. In seismically active mines, rockburst occurrence has been widely recognized as one of the most important hazards in deep mines and tunnels. While there is a wide range of cases where rockburst hazard can be mitigated through dedicated excavation sequences, reentry procedures or exclusion zones, there are still many situations where large unexpected rockbursting may occur, relying only on rock support as the last mitigation measure to prevent production and safety losses. Considering the previous situations, surface support as mesh, plays a major role containing the failed/ejected rock and providing a safe working environment to the underground operations. While there have been considerable achievements in improving mesh resistance, with more than 26Kj/m2 of energy dissipation capacity, there is still a lack of research in the overlapping mechanism and load transfer between contiguous mesh elements. This paper presents the state of the art in static and dynamic analysis of welded and rolled mesh overlaps, based on experimentation carried on by Geobrugg in their Research Center, leaving clearly established that the difference in meshes is not only in levels of energy absorption, but also concluding that in the case of high resistance rolled meshes overlapping is not necessary and the transmission of stresses can be fully guaranteed by using suitable connecting elements. All these characteristics, supported by operational advantages as light weight and mechanized mesh installation, provides a considerable improvement in safety and productivity, improving the economic value of the project

Apr 26, 2022

By BO HYUN KIM, MARK K. LARSON

The floor-heave and no-floor-heave phenomena at a western U.S. coal mine could not be properly simulated in numerical models using conventional shear-dominant failure criteria. Although the previous numerical study using FLAC3D very reasonably demonstrated these phenomena, 3DEC modeling in conjunction with the discrete fracture network (DFN) technique was performed to better understand the true behavior of floor heave associated with underground mining in an anisotropic stress field. As a result, the latter models predicted floor heave that agreed with relative amounts of observed heave from each gateroad system, but the cause of heave was mainly related to the degree of anisotropy instead of the size of the pillar.

Sep 1, 2022

The ability to track miners and communicate with them while they work in underground coal mines is important during normal daily operations, and critical in emergency conditions. As was evident during recent incidents at underground coal mines worldwide, communication with miners and the knowledge of their location is of great importance for rescue efforts and the preservation of life. Numerous technologies have been developed, adapted, and deployed to meet tracking requirements of the Mine Improvement and New Emergency Response (MINER) Act. Evaluating the performance of these systems has proven to be difficult for mine operators, system manufacturers, and regulatory agencies. The MINER Act of 2006 requires operators to improve accident preparedness by developing an emergency response plan specific to each mine. With the recent implementation of the provisions of the MINER Act of 2006, all underground coal mines in the United States are subject to the mandates of legislation concerning communication and tracking system installation. As of June 2011, 203 new or revised tracking and/or communication systems had been approved by the Mine Safety and Health Administration (MSHA), with nearly 50 other systems or revisions in the approval process (MSHA, 2011). At that time, the available approved systems for underground coal mine use included these types: ? Leaky Feeder Communication Systems ? Fixed Node-Based Communications and/or Tracking Systems ? Wireless Node-Based Communications and/or Tracking Systems ? Medium Frequency (MF) Communication Systems ? Communication System Peripherals Other types of tracking systems have since been developed and some manufacturers are seeking approval for use in this application. Some of the new products include Through-the-Earth (TTE) systems and various radio frequency (RF) adaptations. New technologies that are currently being developed and deployed in other industrial applications should also be considered, including acoustical, optical, inertial, and hybrid technologies To date, no uniform method has been employed in the industry to effectively compare and evaluate the performance of installed systems. Neither industry operators nor regulatory agencies can accurately assess the capabilities of installed systems in the continuously changing mine environment. There is need for a uniform evaluation method that provides the ability to assess how different systems and technologies perform in various mining applications, and whether they can satisfy the regulatory requirements.

Feb 23, 2014

By Yuting Xue, Lihong Zhou, DAVOOD BAHRAMI

The paper discusses the use of machine learning (ML) to develop a predictive model for determining the location and size of underground mine fires using simulated ventilation data. The study highlights the importance of prompt fire location determination for effective firefighting strategies and reducing injury risks. The ML model was trained with simulated data and achieved an accuracy score of 0.920, which improved to 0.962 by grouping closely connected airways.

Sep 1, 2023

By Jianbo Hu, Tao Zheng, Zhao Qihua, Rui Su

Rock mass discontinuities play a significant role in evaluating the stability of rock slopes. It is necessary to collect and analyze these discontinuities to fully understand the mechanical and deformational behaviors of rock masses. Based on the digital images of some slope faces, this paper proposes a framework based on machine learning for detecting and extracting discontinuities. First, digital images and photo poses are combined, the original scene is reconstructed, and 3D point cloud data are obtained. All captured point clouds can be mapped with each image by the direct linear transformation algorithm. Next, the detection machine learning algorithm is used to segment rock mass discontinuities on 2D digital images. Finally, based on the mapping relationship, the 2D digital images that were segmented are transformed into 3D point cloud data. The geometric parameters of the corresponding discontinuities can be extracted by the DBSCAN and the Skmeans algorithm and the characterization of specific rules. The proposed framework was evaluated utilizing a quantity of slope digital images in the Yebatan hydropower under construction, located in Sichuan Province, China, as a case study. The results illustrate that most deviations are less than 10° for the dip direction and dip angle, which verifies the reliability of the proposed framework and maintains acceptable measurement accuracy.

Nov 6, 2022

By Eugie Kabwe

The increase in depth of mines due to the depletion of surface deposits leads to unsafe tunnel construction and overall ore extraction. This is due to tunnel instability associated with the surrounding rock mass’s ability to exhibit creep that occurs over time. However, the explicit description of this mechanism using conventional constitutive models has proven to be difficult and inadequate. Hence, this paper presents an integrated viscoelastic viscoplastic visco-damage model with the Duvaut-Lions function. The presented model is calibrated by experimental data to determine the viscoelastic viscoplastic and visco-damage parameters. It is further implemented in a finite volume numerical code and verified on an experimental scale by numerical modeling of a cylindrical specimen. It describes the 3-phase creep mechanism perfectly as compared to the inbuilt conventional integer-order derivative model. Results from the conducted verification show that it can successfully be employed to describe the long-term behavior associated with the creep mechanism.

May 16, 2021

By George A. Snyder

The presence of moderate to high concentrations of colloidal clays in coal preparation plant waters can cause serious operating and economic problems for a coal company. Among the host of possible problems are the following: 1) Poor separation of clays in the plant thickener, resulting in: a) Increased ash in the clean coal. b) Increased specific gravity of the wash water and decreased coal recoveries at the desired quality. c) Increased thickener operating costs in trying to overcome the problem. 2) Decreased solid concentrations in the thickener underflow and increased pumping requirements to meet solids withdrawal requirements.

Jan 1, 1979

By E. Hasanbas

Vibrating screens and crushers are the workhorses of material sizing. Unfortunately their natural frequency is often in the range of typical supporting structures, thereby making installations prone to vibration problems. Much of the available literature regarding the support of vibrating screens is fairly confusing and outdated. This paper presents the results of utilizing accelerometers and finite element software in the analysis and design of supports for vibrating equipment. It contains data from field studies of vibrating screen and crusher installations, design of new and repair of existing supporting structures, and the correlation between field data and finite element time history analyses. Finally, the paper summarizes a method for analyzing and designing structures subjected to vibratory loads and predicting their behavior.

Feb 23, 2014

By S.K. SHARMA, ANKUSH GALAV, G.S.P. SINGH

This paper proposes a hydromechanically coupled numerical modeling approach to quantify the influence of various parameters on the mechanical and hydraulic performance of protective water barrier pillars (PWBP). The results are validated for two case studies having pillar widths of 16 and 42 m at cover depths of 136 and 190 m and water heads of 25 and 141 m. The outcome can be significantly helpful in the rational design of these pillars in underground coal mines.

Mar 1, 2023

By L. O’Connor, E. Tarshizi

The objective of this work is to provide a detailed review and a list of references in chronological order, comprising 80 recent technical papers, on the use of discrete-event simulation (DES) modeling in mining engineering. In this article, the review papers of published mine simulation projects through 2007 are summarized, and then a comprehensive review of individual articles published from 2008 to 2015 is presented. This survey work also includes analyses of the simulation tools used in the published projects, mining types and applications in order to assess these key features and evaluate the recent state of research in mine DES simulation. In addition, an interactive map visualization for the locations of the simulated projects is made available on a website to benefit current and prospective scholars in the field. The results of this investigation revealed that the most common application of DES in mining had been mining equipment selection and analysis, while ore processing and risk management projects were less frequently reported. The results also showed that modeling surface mines were in the majority, but the trend of publications for underground mine simulations had also increased. According to the results, ARENA was the most popular simulation software package, but several simulation tools that were only used once or twice in the mining projects are also included in this review.

Jan 1, 2018

By L. O’Connor, E. Tarshizi

The objective of this work is to provide a detailed review and a list of references in chronological order, comprising 80 recent technical papers, on the use of discrete-event simulation (DES) modeling in mining engineering. In this article, the review papers of published mine simulation projects through 2007 are summarized, and then a comprehensive review of individual articles published from 2008 to 2015 is presented. This survey work also includes analyses of the simulation tools used in the published projects, mining types and applications in order to assess these key features and evaluate the recent state of research in mine DES simulation. In addition, an interactive map visualization for the locations of the simulated projects is made available on a website to benefit current and prospective scholars in the field. The results of this investigation revealed that the most common application of DES in mining had been mining equipment selection and analysis, while ore processing and risk management projects were less frequently reported. The results also showed that modeling surface mines were in the majority, but the trend of publications for underground mine simulations had also increased. According to the results, ARENA was the most popular simulation software package, but several simulation tools that were only used once or twice in the mining projects are also included in this review.

Jan 1, 2017

By Jorgen Elbrond

The capacity calculation of complex transportation systems involving variable activity times such as encountered in the mining industry are often worked out by means of simulation, which reconstructs waiting times and cycle times. The queuing theory, which mathematically calculates waiting times, has been used mainly to describe the, phenomena. This is due partly to the difficulties encountered in modelling complex systems and partly to the difficulty of reconciling the required time distribution laws with the real phenomena by means of the queuing theory. It is, however, obvious that formulas for capacity calculations would be preferable to simulation procedures because of their higher calculation speed, shorter and more flexible programs and shorter programming work. The calculation procedure presented in this paper is composed of some rather simple models, which are based on the queuing theory, and on some probabilistic and some deterministic considerations. The models are supported by observations, and to some extent by simulations. It has been attempted to find all the components of the cycle time and to include them in a comprehensive model. It is the intention to demonstrate that even quite complex mine transportation systems can be treated by means of the queuing theory with the advantages mentionned above and, without sacrificing the precision of the estimates. The speed of calculation of a wide range of parameter combinations is such that the procedure can be used extensively by a project engineer in the search for optimal modifications of the entire transportation system.

Jan 1, 1979

By Daniel A. Wasson

A review of the history of boosters is given with examples of the prominent types that have been made commercially. The performance and design features of protected core boosters are discussed in detail. A new gel booster is discussed with its advantages to the mining industry. Booster size, hole configuration, performance and safety aspects are reviewed. Important features of boostering in above ground and underground blasting are related to an economic analysis. This presentation will cover different types of boosters commonly used in mining. However, for the purpose of this paper a few terms need to be defined to clarify the action of different parts of a priming system. Booster* - "Any unit of explosive or blasting agent to be used in a charged hole for the purpose of perpetuating or intensifying the initial detonation". Primer* - "A unit, package or cartridge' of explosives containing a detonator or detonating cord which is used to transmit detonation to other explosives or blasting agents". Detonator - A device for initiating a detonation from a flame or a small electric current, the former being represented by a fuse cap and the latter an electric blasting cap.

Jan 1, 1981

By Richard Newcomb

Since the report of the 1972 Rapid Excavation Conference in the city of Chicago, speculation has continued concerning the estimates of tunneling demand. Little has been published that would persuade me to modify substantially the rather tentative estimates that originated with the National Academy of Sciences-National Academy of Engineering (NAS-NAE) study of 1968 which were recomputed by the United States in the survey of the Organization for Economic Cooperation and Development (OECD) in 1970. The OECD estimates, of course, hedged the really difficult question of forecasting civil construction tunneling demands. In the United States contribution, this was done by predicting both an upper and lower bound for important categories of demand. A discounting procedure was then applied to each of the major sectors of expenditures, permitting a forecast that reflected the current subjective assessment of how extensively and how likely cities were to adopt plans that required tunneling. This was done for water, utilities, transportation and other novel underground facilities. The purpose of this paper is a modest one. In it I wish to describe the efforts made since 1972 to generate more thoughtful and more robust estimates of urban sector demands, and to apply what has been learned to the most difficult category of predictions: those for urban mass transit systems. The estimates of the Underground Construction Research Council funded by the National Science Foundation have been described at an earlier panel of this Conference. The principal effort I am familiar with is that of

Jan 1, 1974