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By J. F. Edwards

In situ extraction of copper through borehole injection presents a new technology for the mining of copper. For the successful application of this technology, copper recovery at the surface must be specifically designed for borehole injection and the general conditions of the well field. This paper describes the design of a solvent extraction / electrowinning facility specifically designed for in situ leaching of copper. This design is based on commercial solvent extraction / electro-winning with considerations of the requirements of this specific application.

Jan 1, 1988

By Connor Meinke, Shaihroz Khan, Kevin Erwin, Rajiv Chandramohan, Muhammad Usman Siddiqui

A geometallurgy study aims to link metallurgy and geology to reduce technical risk and enhance the economic performance of a mineral-processing plant. It does so by accounting for variability in a deposit to develop cash-flow models with variable throughput rates. High-quality sample selection for metallurgical test work that is representative of the deposit is an essential component of a geometallurgy study, but the large multidimensional data set makes sample selection a daunting task, as classifying the data set while respecting its heterogeneity is difficult. This paper presents a streamlined approach for sample selection, using statistical analysis techniques in Python. It cuts down time to select samples from around 1,200 s per drillhole to about 60 s for data classification and from 12 h to 8 h for handpicking samples from the classified data set, translating to cost savings. The cumulative sum method and k-means clustering method are used in the methodology to elegantly classify the data and select representative samples. The effectiveness of the methodology is demonstrated by presenting data from a prefeasibility study of a copper-iron mine in which 40 samples were selected for flotation test work.

Dec 1, 2024

By Hajime Kitamura, Nobuharu Isago, Yuta Yamanishi, Kosuke Kawata, Hiroshi Yagi, Akira Matsuoka

Mountain tunnels are generally considered to be stable during earthquakes, however, it is known that the portal areas are prone to seismic damages. Characteristics in portals such as the location of the slope, modulus of ground deformation, and the change of overburden are different for each tunnel, and damage degrees are unclear. In this study, we reproduced the seismic behavior to investigate the effect on the tunnel portal by considering some parameters above, using simple static model tests and numerical analysis. As a result, the conditions of the slope condition and minimum distance from slope was confirmed to influence on the mechanical behavior of the tunnel portal during earthquakes.

Dec 1, 2022

By A. C. Alexander

Chevron Resources Company owns and operates an open pit phosphate mine and mill 11 miles north of Vernal, Utah. The plant currently produces 500,000 tons per year of concentrate and has the capacity to produce 750,000 tons per year. The operation is currently being expanded to 1,300,000 tons per year of concen¬trate in order to supply a new fertilizer plant being constructed by Chevron Chemical Company in Rock Springs, Wyoming. A 10-inch, 96-mile pipeline is being built to transport the concentrate from Vernal to Rock Springs. The present and expanded operation will be discussed. HISTORY In 1915, Harry Ratliffe staked nearly 15,000 acres of low to medium grade phosphate rock along the southern flank of the Uintah Mountains. This deposit became the largest privately owned phosphate deposit containing approximately 700 million tons of reserves. Initial development of the deposit began in 1958 by San Francisco Chemical, a joint venture between Stauffer Chemical Company and Mountain Copper Limited. In 1968, Stauffer Chemical Company bought out Mountain Copper Limited and became sole owner and operator. In 1981, Chevron Resources Company bought the property from Stauffer and has operated the mining and milling operations since.

Jan 1, 1985

By E. H. Ahrens

This paper deals with the daily work of operating geologists and should be of interest to recent graduates. Working with development and production is quite different from exploration and many of the required skills and techniques must be learned on the job. Try to obtain your first position at a mine where good geological work is being done because it is important that you establish a solid foundation by learning valid techniques. Many do not! Those who desire to work in exploration are well advised to spend the initial two or three years at an operating mine where they will deal daily with an orebody during development and mining. Attempt to understand the controls of ore deposition and be interested in all phases of the operation. Learn something about factors which can adversely affect profitability and you will be a better explorationist.

Jan 1, 1983

By K. N. Mayfield, T. Novak

"The applications for automation continue to expand within the mining industry. These applications can range from the startup, control, and shutdown of processing plants to the autonomous operation of surface haulage trucks. However, the term “automation” should not necessarily be interpreted as the total elimination of human interventions since numerous mining processes can be partially automated. The future survivability of many mining operations will be influenced by a company’s willingness and ability to understand, accept, and utilize this technology. The mining workforce, including management and engineering, should be familiar with the technological capabilities and limitations for effectively implementing automation into mines for improving safety and productivity. The Department of Mining Engineering at the University of Kentucky has recognized this educational gap and developed an automation laboratory, along with project-oriented courses at the undergraduate and graduate levels. The laboratory and the course objectives are described in this paper, as well as the skills and abilities that students obtain at the completion of the course(s). BACKGROUND The touted benefits of automation include: improved productivity, lower operating costs, reduced drudgery of repetitive operations performed by workers, and the removal of workers from hazardous locations. The acceptance of advanced technology by the mining industry, however, has traditionally been slow. This cautious approach is understandable considering the complex and harsh conditions routinely encountered in mining operations. Bad experiences with some premature installations of newly hyped technologies may have also resulted in lingering skepticism by many mine operators. Nonetheless, with thoroughly demonstrated reliability and proven applications, automation based on programmable logic controllers (PLCs) has made significant inroads into the mining industry. Programmable logic controllers (PLCs) are the workhorses of automation. They were originally conceived in the late 1960s, long before the invention of the personal computer (PC). Initial PLC applications were directed towards sequential relay control in manufacturing plants, which subsequently eliminated the use of “relay logic” that was based on hard-wired electromechanical relays. With continuous advancements in electronics and computer technology over the years, PLCs have evolved into sophisticated and powerful devices with very stable operating systems. They are designed for deterministic logic execution with extreme consistency in timing, along with a high tolerance to temperature, humidity, and vibration (Smith 2003). Because of their robust characteristics, PLC networks now provide the backbone for most industrial automation applications."

Jan 1, 2017

By Sunil Jain, Jan M. Mutmansky

As coal mining evolves in this country, underground coal is being mined at greater depth and under more difficult conditions than in the past. At the same time, economic conditions make it necessary to mine more efficiently and economically. As a result, pressures on mining companies arise on two fronts and make the job of mining coal underground very difficult. Recent improvements that have been made in health, safety and productivity have come about primarily due to improvements in existing technology and better management of all the production resources. However, this trend can continue only so far and thus innovation will be needed to continue the improvement. This paper deals with a concept that, on the surface, appears to be more efficient in terms of the costs to provide ventilation. The resulting design is oriented toward increasing the ventilation efficiency through use of a unidirectional ventilation plan but it also promises to increase recovery and decrease the requirements for development entries. To analyze this ventilation concept, two mine layouts with a similar production schedule were planned in a hypothetical 1.83 m (6 ft) coal seam. The first alternative analyzed uses a traditional approach to ventilation with centrally located shafts and a bidirectional ventilation pattern. Using this system, it is necessary to use large-diameter shafts and a large number of main entries. Using the same assumptions on ventilation requirements, the second alternative utilizes unidirectional ventilation whenever possible, a smaller number of main entries and small-diameter blind-bored shafts in the bleeder areas. The comparative analysis is performed using PSU/TDMVS, a computer network analysis program that is capable of determining the ventilation power requirements at any time in the mine life and converting the costs to a present value. The economic analysis is then completed by including the shaft-sinking and entry-driving costs and the costs associated with the recovery of coal that are directly related to the change in the ventilation system. The results are summarized on a present-value basis.

Jan 1, 1987

By M. Li, J. K. Thompson, A. S. Azman

"Powerful mining systems typically generate high-level noise that can damage the hearing ability of miners. Engineering noise controls are the most desirable and effective control for overexposure to noise. However, the effects of these noise controls on the actual hearing status of workers are not easily measured. A tool that can provide guidance in assigning workers to jobs based on the noise levels to which they will be exposed is highly desirable. Therefore, the Office of Mine Safety and Health Research (OMSHR) of the National Institute for Occupational Safety and Health (NIOSH) developed a useful tool to estimate the hearing loss due to occupational noise exposure in a systematic way and evaluate the effectiveness of developed engineering controls. This computer program is based on the ISO 1999 standard and can be used to estimate the loss of hearing ability caused by occupational noise exposures. In this paper, the functionalities of this software are discussed and several case studies related to mining machinery are presented to demonstrate the functionalities of this software. INTRODUCTIONPeople regularly exposed to noise can develop hearing loss at different levels of severity depending on a number of factors. The resultant hearing loss can affect one’s ability to understand speech, learning, acoustic signal perception, or appreciation of music. Hearing loss caused by overexposure to noise has long been recognized in literature. However, it still does not get serious attention by those working in noisy environments because the loss of hearing ability is a gradual process and workers are often unaware until the damage becomes an apparent problem. In the United States, occupational hearing loss is one of the most common work-related illnesses. Depending on the definition of exposure and impairment, in 2012 the National Institute for Occupational Safety and Health (NIOSH) estimated that there are between 5 and 30 million workers in the U.S. who are exposed to noise levels at work that put them at risk of hearing loss.4 In the mining industry, noise-induced hearing loss (NIHL) is particularly severe due to the fact that heavy-duty machinery is widely used to improve production efficiency, and this machinery can generate much higher-level noise than the permissible level defined by regulation. As a result, the mining sector has the highest prevalence of hazardous workplace with high noise exposures (76%) among all industrial sectors."

Jan 1, 2015

By R. Milici

Current federal and State coal assessments estimate resources in the ground, resources available for mining, and economically recoverable resources. None of these assessments predict the amount of coal that may be produced from an assessed area in the near future (~20 years). Predictive assessments of coal production would be based on an understanding of the regional coal geology (coal systems), potential demand, and knowledge of the mining history of the region. The output of the predictive assessment would be a supply curve – a probability distribution of the amount of coal expected to be produced from current and new mines during the assessment period. I

Jan 1, 2004

By John G. Myers, William A. Vogely, Harold J. Barnett

INTRODUCTION, CONCEPTS, AND MEASUREMENT Introduction Periods in the history of man, from his earliest appearance to the present, are often characterized by the principal materials used. In nearly all cases, the material or fuel is of mineral origin-stone, copper, bronze, iron, coal, and so forth-indicating the principal ingredient of the tools or source of power of the period. Each of these periods represented great improvement over the preceding one in terms of human well-being, as measured by population growth and other indicators (Cipolla, 1978). A major reason for the improvements in production and well-being was the nature of the material or fuel, each successively superior to the preceding, which made it possible to produce more food, fuel, shelter, and clothing with a given amount of labor. If we accept this well-documented description of economic progress as accurate, we may then turn to the consideration of two related questions concerning this development. The first, easily answered,-is why man spent long periods of time (millenia, in many cases) making tools from inferior materials, such as copper, instead of passing directly to superior materials, such as iron and steel. The second, closely related question, concerns the relation between the rate of economic growth and the quantity of mineral reserves available at any time. For the first question, the answer is that the technology required to discover, extract, and process each successive material had to be discovered and developed before the material could be used. Once the technology was available, the new material could be and was exploited widely, raising productivity-output per unit of labor- and consequent consumption per person. This familiar idea underlies a fundamental principle of the economics of resources, namely, at any time, available resources depend upon available technology. No mineral or other raw material is a resource unless the technology has been developed to utilize it. But once the technology is at hand, the new resources associated with it provide the means for economic growth and rising levels of living. This principle is subject to certain conditions. For example, governments or other institutions may prevent a mineral from being used, even though the technology is available. And, if a mineral is located in a remote place, transportation charges may make it uneconomic to exploit. Such minor qualifications do not, however, change the thrust of the argument that technology is the overriding determinant. With respect to the second question, it might seem apparent that the greater the quantity of reserves available, up to some point, the more economic growth will be facilitated. This line of reasoning leads to the conclusion that as re- serves are consumed the quantity available will be reduced and economic growth will eventually be restrained. Reasoning of this sort underlies much popular (and scholarly) thought, in which depletion of mineral and other resources is assumed to lead to constraints on economic growth, through higher materials costs and absolute limitations on materials use. Two important qualifications must be made to this explanation, however, which together

Jan 1, 1985

By J. E. Lawver, R. J. Haskin, A. Nussbaum, E. A. Laurila, W. J. Bronkala, D. M. Hopstock, J. H. Brophy, M. Wada, E. J. Tenpas, R. W. Salmi

Electrostatic separation is the selective sorting of solid species by means of utilizing forces acting on charged or polarized bodies in an electric field. Separation is effected by adjusting the electric and coacting forces, such as gravity or centrifugal force, and the time forces act on the particles, such that different species will have different trajectories at some predetermined time. Separations made in air are called electrostatic separation even though there is always some flow of current. Separations made using corona discharge devices are often called high tension separations. Separations made in liquids are termed separation by dielectrophesis if motion is due to polariza¬tion effects in nonuniform electric fields and termed electrophoresis if motion is due to free charge on species in an electric field. There are no industrial applications of mineral concentration by electropho¬resis or dielectrophesis; thus this section is limited to concentration in air. Typical Industrial Separations Typical applications of electrostatic separation are: 1) Beneficiation of ores, such as the concentration of the minerals ilmenite, rutile, zircon, apatite, asbestos, hematite, and many others. 2) Purification of foods, such as the removal of trash and rodent excrement from cereal seeds. 3) Sorting of reusable wastes, such as separating insulation from copper wire shreds. 4) Electrostatic sizing, namely, the sorting of solid particles ac¬cording to their size or shape. Table I is a partial list of industrial separations made by electrostat¬ics. The various types of electrostatic separators and the feasibility of commercial separations are most easily understood by reviewing pertinent basic electrostatic theory and the selected electrical proper¬ties of solids prior to describing the equipment and application. This is the sequence of presentation used in this section. Electrostatic Units One of the greatest sources of confusion and error is due to the multitude of units used in electrostatic literature. The system of units used throughout this section is the rationalized MKS, often called Systéme International (SI) units. In this system the mechanical units are the meter, kilogram, and the serond. The unit of force is the newton (N). This system is completed by the addition of the unit of charge, the coulomb (C). The fourth dimension, viz., the coulomb. could also be considered to be the ampere, since one ampere is the flow in a conductor of one coulomb per second. A more complete definition of the coulomb is given in Chap. 4, p. 6-11. The derived

Jan 1, 1985

By Wayde Esplin

At the Barrick Goldstrike processing facilities in northeastern Nevada, sulfide ore is pressure-oxidized at a temperature of 440° F and 420 p.s.i. in six autoclave circuits. The low pH, high temperature, and abrasive characteristics of the oxidized slurry present many new and unique maintenance challenges. To meet these challenges, the Barrick Goldstrike autoclave department formed a reliability group in August 1998. One of this group's critical missions is to reduce both maintenance costs and unscheduled downtime through the application of predictive maintenance technologies and Reliability Centered Maintenance Analysis. This paper discusses some of the successes of the reliability program at the Barrick Goldstrike autoclave.

Jan 1, 2000

By J. H. Desautels

The modern coal mining industry is subject to a vast array of regulations affecting virtually all aspects of its operations. Probably the most significant over-sight role involves the Office of Surface Mining Reclamation and Enforcement (OSH) established by the Surface Mining Control and Reclamation Act, or SHCRA.1 Although complying and coping with SHCRA can be difficult for coal operators, this complex regulatory process has helped insulate the industry from ongoing efforts to extend regulation under the Resource Conservation and Recovery Act, or RCRA, 2 to aspects of the mining industry in general. The Environ-mental Protection Agency (EPA) has struggled with regulation of mining wastes under RCRA since the mid-1970's, but RCRA itself places most coal mining wastes firmly under the control of OSH and SHCRA. Despite the general exemption from RCRA regulation for waste materials that result from extraction and processing of coal itself, there may be circumstances under which coal mining operators could find themselves subject to regulation under RCRA or a number of other statutes administered by EPA. This paper will review briefly the history of mine waste regulation under RCRA, as well as touch on the policy decisions that led to the exemptions from RCRA regulation. The paper will summarize coal waste requirements under SHCRA, and also will review what operations at coal mines need to be controlled, in order to avoid potential liability under RCRA. In addition, it will mention requirements under other federal laws, including CERCLA, or the "Superfund" law,3 and describe how they may impose restrictions or liability on coal operations for waste or other materials commonly found at surface and underground coal mines.

Jan 1, 1993

By Robert W. Lawson

INTRODUCTION Prior to 1705, underground mining was limited to mineral deposits located above or a very small distance below the water table. The development of the steamdriven mining pump was motivated by the need to extract minerals from deposits considerably lower than the water table. Today, the majority of mine pumps are driven by electric motors, although some small utility pumps are driven by compressed air. Of the numerous types of pumps that might be applied to mine service, the two types used most frequently underground are the centrifugal and plunger pumps. Each of these types has its proper application. In most instances, plunger pumps are best for handling low water volumes against high heads, while centrifugal pumps effectively handle either low or high water volumes against low heads or high water volumes against high heads. This chapter describes pumps applied to underground mine service, where the mine service consists of mine drainage (removing mine water as it accumulates), mine dewatering (removing water from a flooded mine), and pumping for special applications such as hydraulic mining and hydraulic hoisting. CENTRIFUGAL AND PLUNGER PUMPS Modern mine pumps are classified as either centrifugal (kinetic) or plunger (positive-displacement) pumps. The following paragraphs describe each of these classifications. Centrifugal Pumps Centrifugal pumps may be grouped into various types, depending upon their various features: Number of Stages: In a single-stage pump, the total head is developed by one impeller, while a multi¬stage pump utilizes two or more impellers acting in one casing to develop the total head. Fig. I shows a cutaway view of a single-stage horizontal split-case double -section centrifugal pump. Fig. 2 shows a cutaway view of a six-stage medium-pressure split-case diffuser-type centrifugal pump. Type of Casing: A volute pump has a casing in the form of a spiral or volute. A circular-casing pump has a casing of constant cross section concentric with the impeller. A diffuser pump is equipped with a diffuser that converts velocity head to pressure head. Shaft Position: A horizontal pump normally has the shaft in a horizontal position, while a vertical pump normally has the shaft in a vertical position. Fig. 3 illustrates a vertical turbine-type slurry pump. Suction: A single-suction pump equips the first stage with a single-suction impeller, with fluid entering the impeller on only one side. A double-suction pump equips

Jan 1, 1982

By R. Schuerch, C. Cimiotti, G. Anagnostou, J. Nickerson, P. Perazzelli

"This paper presents experiences gained from the construction of the Lake Mead Intake No. 3 project. The 4.7 km long tunnel was excavated with a hybrid TBM (able to operate in both closed and open mode). The tunnel crossed metamorphic and sedimentary rocks under a hydrostatic pressure of about 14 bar. During the excavation of the tunnel the TBM encountered difficult ground conditions caused by a combination of high water pressure, poor ground quality and locally low depth of cover. The adverse conditions required the TBM to be driven in closed mode at very high support pressures (10 – 15 bar) for approximately 60% of the tunnel length. The paper summarizes the main problems encountered during TBM excavation and analyzes the evolution of the TBM parameters over the entire tunnel length. INTRODUCTION The Lake Mead Intake No. 3 project is located approximately 30 km away from the city of Las Vegas in Nevada, USA. The project consists of the construction of a deeper third intake for the biggest reservoir in the United States, which is formed by the Hoover Dam. The construction of the new intake was required due to the constant drawdown of the lake level (more than 40 m in the past 20 years) and the consequent risk that the shallower intakes 1 & 2 may run dry. The project included the fabrication and positioning on the lake bottom of an intake riser, the excavation and lining of a 185 m deep shaft and construction of a 4.7 km long tunnel. One peculiarity of the project is that the water table is located about 140 m above the tunnel elevation (i.e. corresponding to a hydrostatic pressure of 14 bar at the current lake level). The tunnel was constructed using a tunnel boring machine (TBM) able to operate in both open and closed mode (Mc Donald & Burger, 2009). The present paper focuses on the TBM tunneling experience gained from the Lake Mead Intake No. 3 tunnel. The TBM excavation started on December 27, 2011 and finished on December 10, 2014 with the breakthrough to the intake structure at the bottom of Lake Mead. GEOLOGICAL CONDITIONS The assessment of the ground conditions encountered during construction was mainly based upon qualitative descriptions of the tunnel face conditions (during open mode operations) and analysis of the extracted muck (during closed mode operations)."

Jan 1, 2016

By Andrew J. Neale, Brian C. Flintoff

A review of the current literature, combined with the authors' knowledge of the western Canadian coal industry, indicates that the development and implementation of process control in coal preparation, particularly in flotation applications, is significantly lagging behind that seen in mineral processing. The reasons for this include the lack of inexpensive and reliable sensors, incomplete understanding of the flotation process, limited experience of process control in the coal preparation industry and depressed coal prices, all of which have combined to hinder plant automation. This paper illustrates the benefits of process control in coal flotation, provides a general discussion of the control problem and concludes with two examples drawn from Australian experiences.

Jan 1, 1989

By M. Heger, V. Lund, P. Mongeon, D. Bogunovic, V. Kecojevic

The U.S. coal mining industry consumes a significant amount of energy, primarily diesel fuel and electricity. The continuous global increase in energy demand, high energy prices and environmental issues related to carbon dioxide emission represent a substantial challenge for the mining industry. This paper presents the result of research on development of an integrated data environment system for analysis of energy consumption in a surface coal mine. A case study on an operating surface coal mine is carried out to demonstrate the practical application of the developed system. The research work presented here may be used by mining professionals to help provide the answers to the crucial questions of when, where and how much energy is being used. This developed system represents a framework for efficient management of energy consumption.

Jan 1, 2009

By S. A. Jeric

In-pit crushing and conveying of waste has been utilized in the mining industry for over 30 years. In recent years, innovations in crushing, conveying, and particularly waste and leach stacking technology have sparked a renewed interest in continuous haulage systems for large-scale open pit applications. A review of the advantages/disadvantages and operating techniques of crushers, feeders, conveyors, and stacking systems currently available is made. The paper examines some operations that are currently using large scale continuous haulage systems. Finally, a case study is presented that evaluates the application of a continuous waste haulage system in a large open pit mine in the Western United States, The case study includes a economic comparison with the existing truck haulage system.

Jan 1, 1997

By Ramarao Inguva

Feasibility studies being conducted to investigate the use of electromagnetic methods for insitu volumetric heating of oil shales will be discussed. A two dimensional numerical model which describes eletromagnetic heating of oil shales is outlines. The model includes equations for temperature, pressure, saturations, chemical reactions, mass conservation, and source terms. The gases are all assumed to form one bulk species and the oil is assumed to remain in liquid form. The chemical reactions include pryolysis of kerogen and char, release of bound water, coking, and decomposition if carbonates. Porosity and permeability are dynamic functions of the organic materials. Calibration of the model is accomplished by comparison of the model results with experimental data obtained by IITRI. Nonlinear relationships for viscosity, thermal properties, and source terms and used as inputs to the model. A finite difference approximation to the differential equations is derived and solved using Newton's iteration technique. For the cases studied the solutions are quite stable. Numerical resultes are included and a preliminary study of the optimization of the heating process is presented.

Jan 1, 1984

By Ronald E. Heuer

The significance of surface settlement over soft ground tunnels is well recognized. Cracked buildings, streets transformed into lakes, broken utility lines, to underpin or not to underpin--all are familiar problems. The basic causes of surface settlement are recognized. Possibly the most common and troublesome cause is "lost ground" during construction. Lost ground refers to removal of a larger volume of ground (Ve) than is eventually occupied by the final tunnel structure (Vt). A number of sources of lost ground in shield tunneling have been identified, as illustrated in Fig. 1. These include 1) face loss, 2) overcutting loss, 3) annular tail void loss, and 4) loss through the lining. The ground generally does not stand unsupported around the completed tunnel lining as illustrated in Fig. 1, but moves in to fill the lost volume, resulting in subsidence of the overlying ground surface as shown. As suggested in Fig. 1, lost ground and surface settlement associated with overcutting and the annular tail void tend to occur systematically along the tunnel length. This "systematic" lost volume is "limited" in the sense that it is restricted to an upper limit determined by the shield and lining geometry. Partially controlled face loss may sometimes contribute to this systematic loss. This lost volume is commonly a few percent of the nominal tunnel volume. The resulting surface settlement over the tunnel is commonly in the range of a few inches or less and develops over a period of hours to days. Although they may have a significant impact on surface facilities, systematic ground loss and settlement frequently have little adverse effect on tunneling progress.

Jan 1, 1976