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By T. J. McKeon

Gravity separators such as spirals are commonly used in multistage cleaning and scavenging circuits to improve the quality and recovery of concentrates produced in the industrial minerals industry. Unfortunately, field surveys suggest that many industrial operations are poorly configured in terms of equipment layout. This shortcoming can often be attributed to a failure by engineers to make use of fundamental process engineering tools for circuit design. One of the most important of these is linear circuit analysis. This powerful tool makes it possible to mathematically compare the relative efficiency of circuit configurations in advance of experimental testing. This article provides a basic review of the linear circuit analysis concept and discusses some of the key insights it provides for the layout of multistage circuits. An industrial case study is provided to show the tremendous impact that this process engineering tool can have on the design of multistage spiral circuits in a heavy mineral wet plant.

Feb 1, 2012

By Carl-Henrik Knudsen, Rolf Tore Arnesen, Eigil R. Iversen

Recovery of iron and copper from acid mine drainage was studied in pilot scale at a continuous treatment plant at the mine site of the King's mine in Roeros, Norway. The average load on the plant was 1 m3/h. The process tested in this project is a three-step process consisting of: 1) Fe(OH)3 precipitation at pH 3.5, dewatering of iron sludge and transport to ferric chloride plant; 2) after filtration precipitation of residual metals at pH 9, concentration of metal sludge by flotation; 3) extraction of metals from the sludge with sulphuric acid followed by recovery of copper by electrolysis. The copper could be used for local production of different crafts, but this condition needs a further evaluation. The process economy at a full scale plant is evaluated.

Jan 1, 2000

By J. O. Costello

Marble is a preferred surfacing material in up-scale buildings. Its use increased in the 1870's with rising national wealth and declined in the 1950's when synthetic materials for these applications were developed. Natural marble is now limited to high-end domestic and commercial structures. Cultured marble is a paste of white marble dust and polyester resin cured in molds yielding fixtures of specific finished dimensions. Dyes incorporated at different stages in the mixing cycle mimic shades and veining of natural marble. This paper discusses the filler requirements for cultured marble production and reviews new techniques to cut and finish natural marble.

Jan 1, 1999

By T. G. Hayes

Economic and environmental regulations in the coal industry have required companies to evaluate their current blasting method of loosening in-situ coal. This paper will review ripping vs. blasting thick in-situ coal seams, handling frozen active coal stockpiles and proper stockpile conditioning and reclaiming. How basic operating technique can improve job efficiency, productivity and cost per ton.

Jan 1, 1995

By R. L. Kloberdanz

Compania Minera Disputada de las Condes S.A. (Disputada) is proactively implementing closure and reclamation planning activities at its mining and beneficiation facilities (mining facilities) in Chile where regulations governing mine reclamation are not yet fully in place. These activities are being implemented to improve currently employed measures to protect human health and the environment and to enhance reclamation and facilitate future closure with regard to these areas when mining is completed. As part of this process, Disputada, with the assistance of Shepherd Miller, Inc., developed recommendations and guidelines for future closure and reclamation of the Disputada sites. These recommendations and guidance incorporate planning and operational and post-operational design considerations and practices, and standards used by the mining industry and regulatory agencies around the world. The criteria presented in the guidance are based on achieving conditions that will be suitable for the anticipated post-mining land use. This paper discusses the process and approach taken, and the results.

Jan 1, 1999

By R. T. Swinderman

This paper discusses how many of the common practices in conveyor specification and design are out of date compared to the current expectations of users for safe, serviceable, reliable, and fugitive material-free conveyance of bulk solids. Ten of the most common mistakes made in the specification and design stages related to user expectations are reviewed along with the cost vs. price implications of those decisions. A general specification and design hierarchy that designers can use to improve conveyor design is included.

Jan 1, 2010

By K. H. McDaniel

An interactive mine ventilation simulation software program (WIPPVENT) was developed at the Waste Isolation Pilot Plant (WIPP). The WIPP is a U.S. Department of Energy (DOE) research and development project located near Carlsbad, New Mexico. The facility is designed to provide a permanent, safe underground disposal of U.S. defense generated transuranic waste in bedded salt. In addition to its regular functions, the underground ventilation system is engineered to prevent the uncontrolled spread of radioactive materials in the unlikely event of a release. To enhance the operability system, Westinghouse Electric Corporation has developed an interactive mine ventilation simulation software program (WIPPVENT). While WIPPVENT includes most of the functions of the commercially available simulation program VNETPC (copyright © 1991 Mine Ventilation Services, Inc.), the user interface has been completely rewritten as a Windows ® application and screen graphics have been added. WIPPVENT is designed to interact with the WIPP ventilation monitoring systems through the site wide Central Monitoring System.

Jan 1, 1996

By K. Perry, R. Eades

"Highwall miners continue to be implemented by operations to increase recovery, improve margins, and justify higher stripping ratios as high quality surface reserves become increasingly rare. Many times, operations facilitate projected underground operations by leaving an intact highwall for development purposes. These facts result in larger highwalls that are left standing for increased periods of time prior to reclamation. As a consequence, worker exposure and risk is also elevated, resulting in higher potential for accidents or fatalities relating to surface highwalls. Highwall stability is a complex issue, dependent on both geologic and mining factors. Dynamic numerical modeling offers the capability to assess possible stability issues related to blasting-induced ground vibrations. Research has been conducted to evaluate the effect of highwall stability due to ground vibrations from blasting events. Additionally, the relationship of amplitude and frequency, and their impact on highwall stability is investigated. The results of this modeling indicate that amplitude has little impact on stability. However, frequency has a significant impact on highwall stability. INTRODUCTION The number of mining fatalities has declined since 2010, and 2016 is currently on pace to continue this trend (MSHA 2016). This decline can be directly correlated to the decline in surface mining activity and the overall decline of the coal industry. However, since 2002 the percentage of surface coal mine fatalities associated with highwall activities remains relatively high, constituting approximately 15% of all surface mine fatalities. 2014 was the first year with a highwall failure fatality since 2011. Most recent surface coal mining fatalities are associated with machinery and haulage. Table 1 provides a summary of the total surface coal mining fatalities, and the number of highwall failure fatalities dating back to 2010.Highwall stability is a complex issue, dependent upon geology and geologic discontinuities within the rock mass, along with highwall geometry, standing time, and applied stresses. Another possible concern that has not been previously investigated is the effect of blasting-induced stresses on highwall stability and the stability of web/barrier pillar systems as a result of ground vibrations from blasting events. Many modern surface coal mines employ numerous extraction fronts that rely on blasting for primary rock breakage. This results in highwall and highwall pillar systems experiencing blasting-induced stresses of many different types and magnitudes."

Jan 1, 2017

By J. W. Devon

The coal mining industry is divided into two distinct economic segments based on Coal Supply Agreements. Coal supply agreements generally fall into two categories, spot or long-term, with the selected contract term being driven by the buyer's market expectations, security of supply considerations, fuel tonnage and quality requirements, and economics. Short-term or spot coal purchases are generally market driven and are highly competitive in today's marketplace. Long-term contracts, particularly those involving captive mines and mine-mouth power plants, are commonly driven by considerations other than economics. These other considerations, such as Reserve Conservation and Resource Recovery, Security of Supply, and Maintenance of Levelized Costs may increase the cost of coal, often needlessly and without benefit to the buyer or seller. The basic economic principles which guide the market driven metals industry and generally guide the spot coal sector of the coal industry should apply equally well to the long-term coal supply contract. The artificial constraints imposed as a result of regulated rates of return should be re-examined and in most cases, abandoned. There are many methods of surface and underground coal mining being used today such as, open-pit, contour, mountaintop, and area mining for surface mineable reserves; conventional, standard continuous and super-section continuous miners, and longwalls for deep reserves; and highwall miners, thin seam miners and augers in between. This discussion is primarily directed to surface mining, however the same principles of least cost mining on a Net Present Value basis must be considered in all cases.

Jan 1, 1994

By C. I. Walker

"Understanding the influence of slurry particle size on wear is essential to maximising the life of centrifugal pumps operating in mineral processing plants and for hydrotransport duties. Particle size influences not only the wear rate but also the wear pattern in pumps. Complicating the situation is the different relative wear rate for different pump parts depending on particle size. A simple Slurry Wear Type (SWT) number based on particle size and size distribution is proposed as a means for categorising slurry pump wear patterns and optimising pump application and material selection. INTRODUCTION The wear of centrifugal slurry pumps in mineral processing and hydrotransport can be quite severe and is one of the major cost concerns of plant operators. Some typical worn slurry pump parts made from high chrome white iron are shown in Figure 1. Erosion wear rates of up to 2 mm/day are not uncommon [1].Centrifugal slurry pumps are required to handle solid-liquid mixtures with a very wide range of particles extending from sub-micron size clay through to 200mm and larger cobbles. Particle size distribution can also vary widely from uniform and narrow (such as graded sand) through to very broad (such as grinding circuit slurries). Slurry particles may also undergo size change due to attrition during the pumping process. The major wearing parts in a slurry pump are the impeller, side liners and casing liner. These are shown with reference to a Warman® MC centrifugal pump in Figure 2. While many particle properties (including size, shape, hardness, density and concentration) influence pump wear, this work will consider only the effect of particle size as it is the major determinant of wear characteristics. Particle size influences the wear pattern, material performance and relative component wear rate in centrifugal slurry pumps. SLURRY WEAR TYPE (SWT) BASED ON PARTICLE SIZE Soil and grain size classification systems abound. Many have different limits to the ranges for a particular classification, albeit not too"

Jan 1, 2018

"INTRODUCTION Foam, unless intentionally created, in any industrial process presents operational problems, or at a minimum, is a nuisance. Some foam problems are unique to a given industry and others are common across many industries. A few problems foam presents to any particular industry are: (a) Poor Housekeeping, (b) Environmental impact, (c) Safety Hazards, (d) Slower Production Rates and, (e) Reduced quality of the end product. Defoamers address these issues. Sadly, the assumption in most industries is all defoamers are alike. In reality, a lot of chemistry is involved in the manufacture of even the simplest defoamer sold today and rarely are any two defoamers “just alike”. Today’s defoamers can include polymer chemistry, fatty esters, alkoxylated alcohols, silicone chemistry, silicone surfactants, ethoxylated and propoxylated block polymers, and a tremendous amount of emulsion chemistry just to name a few. This paper will discuss the various types of defoamers, defoaming mechanisms, the advantages and disadvantages of defoamer selections, and how to choose the proper defoamer for your application. Before a discussion of defoamer can be brought about, foam generation and composition must be discussed. WHAT IS FOAM? Foam is a colloidal suspension of a gas dispersed in a liquid. Most often foam consists of air dispersed in water. If a stream of air is introduced into a liquid, the bubbles produced assume a spherical shape. As the density of the bubble is less than the liquid the bubble rises. When the individual bubbles reach and pass through a surfactant free liquid they collapse. Air from the bubble dissipates and the liquid previously surrounding the bubble flows back.It should be noted a pure liquid will not foam. In the case of air dispersed in water a surfactant is necessary to make the water support a stable foam. A surfactant is a term used to describe a surface active agent; a compound with a hydrophilic end and a hydrophobic end on the same molecule."

Jan 1, 2016

By Timothy J. Matthews, Ted Klemetti, Timothy J. Batchler, Daniel J. McElhinney

Unplanned tailgate collapses and difficult mining conditions in U.S. longwalls have necessitated the use of innovative tailgate support systems. Severe ground movement induced by longwall loading has caused operators to utilize secondary support systems that can match yield and strength requirements with expected ground reactions. Standing support performance requirements depend on the nature of the ground deformation behavior, and therefore require a good understanding of the interaction between the support and ground to achieve an optimum roof support system. Mining operations often employ standing support strategies that are unique to their mine. A support system that functions successfully in one situation could fail in another situation. It is important that the design and installation of the standing support systems provide the highest probability of preventing roof falls. Pumpable roof supports are currently being used to provide a safe working environment for longwall mining. A full understanding of the impact of these performance characteristics is necessary to optimize the support application and to provide a foundation for making further improvements in the support performance. Optimization of roof support applications helps to ensure the protection of mine workers by preventing roof falls due to inadequate support design. The load capacity and stiffness characteristics of a 27-in.-diameter pumpable support system was evaluated using the National Institute of Occupational Safety and Health (NIOSH) Mine Roof Simulator (MRS). Previously, tests to evaluate the performance characteristics were performed on a single pumpable support. The goal of this new research is to evaluate the performance characteristic effects of the pumpable support system and compare it to an individual pumpable test examination. This research of a pumpable support system configuration simulates the current installation practices in U.S. coal mines.

Jul 1, 2023

By J. D. Miller, C. L. Lin, J. Dong

Nano clay mineral particles such as kaolinite — with primary particles typically smaller than 2 μm in size — can cause significant problems in flotation processes and tailings disposal, including the processing of Florida phosphate rock and Canadian oil sands. In this study, the consolidated state of flocculated kaolinite sediment was examined, and high-resolution X-ray microtomography (HRXMT) was applied to describe the structure of the consolidated sediment. Using this tomographic information, the complex geometry of the channel network structure for the consolidated flocs was established for the first time. With the establishment of the experimental channel network structure, permeabilities were estimated by flow simulation using the Lattice Boltzmann method. Results for kaolinite sediment with and without polymer are compared and discussed. Results for flocculated kaolinite sediment in a gravitational field are also presented and discussed. The results show that as polymer dosage increases, the permeability of flocculated kaolinite sediment increases, and as suspension pH increases, the permeability of flocculated kaolinite sediment decreases.

By B. I. Pålsson, H-Å. Häggblad, J. F. Stener, P. Jonsén

"Understanding mill charge motion is important. In the charge, the center of gravity is shifted from the rotational center of the mill system, and its motion is induced by rotation of the mill. At the same time, the charge creates a torque in the mill system. Breakage of ore particles and wear of liners/ball media are closely linked to this motion. To study these phenomena in a physically correct manner, numerical models for different parts of the mill system are needed. Validations of such models are scarce, because of the difficulty of measuring inside a tumbling mill. Experimental measurements in a lab mill were done for a number of load cases: varying feed material, mill filling, mill speed and pulp liquid. The mill is set up to measure the charge-induced torque. The accuracy is good, with relative uncertainty less than ± 2% for relevant load cases. A full three-dimensional numerical model of the whole mill is used to predict induced torque. Agreement between predicted and measured torque at steady-state is good. In addition, the model can accurately predict the mill startup behavior for torque and mill power. This proves that the model is physically correct, and can be used for modeling large-scale mills.IntroductionUnderstanding of the charge motion within the mill is of importance in mill optimization. The breakage of ore particles and the wear of liners/ball media are closely linked to the charge motion. To study these phenomena in a physically correct manner, appropriate numerical models for different parts of the mill system must be used. Validation of these models is of major importance. This has led to an increased interest in obtaining an accurate and direct measurement of mill load and the behavior of the mill charge.For structural analysis, the finite element method (FEM) is the most developed and most frequently used numerical method. FEM is a numerical solution method based on continuum mechanics modeling. A constitutive relation for the actual material is described, and the governing equations are solved in Zienkiewicz and Taylor (2000). Varieties of different constitutive models for a large number of materials are implemented in modern FEM code. The computability of nonlinear problems in solid mechanics is investigated in Belytschko and Mish (2001), among others."

Jan 1, 2015

By R. Perlo

"INTRODUCTION Peoples’ and operators’ safety in construction are tightly linked to the engineering choices, as much as the necessity of reducing time and costs of realization. Therefore, it is of paramount importance to address them properly from the earliest stage of the design, identifying the risks connected to the work and the variability of such during the different phases of the project. Risk is often measured as the expected value of an undesirable outcome. Regarding to occupational safety and health, the risk is the likelihood that a person may be harmed of suffers adverse health effects if exposed to a hazard. This combines the probabilities of various possible events and the assessment of the corresponding harm into a single value. However, the actual occurrences are often more complex than a single binary possibility case. In a real case scenario, with several possible accidents, the total risk is the sum of the risks for each different accident, provided that the outcomes are comparable. The semi-automatic tunnel support system along with its erector machine proved to be a solution with improved structural performance, able to reduce the time and yet to deliver an enhanced, quality-aware and safer working environment for the operators. The implementation of the system provides the engineers, the contractors and the owners with an effective alternative option shortlisted in 2015 for the ITA Award for the Safety Innovation of the Year. In a market industry driven by safety and time constrains the efficiency shall be the ultimate goal, in order to provide solutions able to negotiate with the most challenging ground conditions. In this paper, the authors describe the recent developments on regard of this whole new tunnel support system, including design approach and presenting related case histories OFFSETTING THE RISKS Considering the above factors, from the manufacturers’ point of view, an effective way to limit the construction risks is to focus on the material and technological characteristics, their application and the risks related to them including any residual risks. Finally addressing the construction needs also involves time and cost-effective solutions. The path to follow is an integrated approach where the efficient management of the risk is supported by a flexible, user-friendly, and time effective product that is able to provide a safe, reliable and viable solution to address the construction requirements. Therefore, in a market sector driven by safety and time constraints, the efficiency is a key goal, in order to avoid redundancy and yet to deliver a safe working environment able to meet the construction schedule. The safety of all the parties involved is given by stable working conditions, either for the workers, or the operators and eventually the public. Therefore, the solutions provided should ‘strengthen’ the overall condition and such “to limit or to reduce the deformations within acceptable designed limits and to prevent [the tunnel] to collapse” [1: Clause 207.1.4]."

Jan 1, 2018

By B. Derin

In this study, the Reddy-Blander model was applied to predict the sulfide capacity (CS) values of FeOx-CaO-SiO2, FeOx-MnOx-SiO2 and FeO-MgO-SiO2 ternary slags, which were experimentally studied in the literature within the temperatures between 1,673 and 1,923 K. As expected, sulfide capacity values of the slags increased with increasing temperature and decreased with increasing acidic content. The model was found to be in agree-ment for all slag systems at the temperature range of 1,773-1,923 K. However, a disagreement occurred when the basic content was relatively high, at 1,673 K for FeOx-CaO-SiO2 and FeO-MnOx-SiO2 slags. The effect on the CS of high amounts of Fe+3 and Mn+3 in the slags is discussed.

Jan 1, 2011

By Mala R. Ciancia

Planned tunnel projects with advanced geotechnical investigations are more frequently being suspended because of changes in funding, politics, or local priorities. Some of these projects are ultimately canceled, some decelerate and stall, some resume after a short pause, and some restart after being mothballed for several years. The restarted project often differs at least slightly from the predecessor project in terms of alignment and design concept. This paper describes approaches to evaluating the quality and completeness of previous geotechnical investigations for a re-activated project, considering technological advances as well as changes in regulatory requirements, contracting approach, and site conditions which may have taken place in the time since the project was suspended.

Jun 13, 2021

By B. C. Litzinger

Minerações Brasileiras Reunidas S.A. - MBR is a brazilian iron ore mining company geared for the export market. It is controlled by Companhia Auxiliar de Empresas de Minerações - CAEMI through its subsidiary Empreendimentos Brasi leiros de Minerações - EBM which holds 51% in MBR and is formed by CAEMI, the six major japanese steelmills and five japanese trading companies, Universe Tankships, Inc., and Indústria e Comércio de Minérios S.A. - ICOMI. The remaining 49% of MBR's capital are held by St. John del Rey Mining Company, a subsidiary of The Hanna Mining Company. MBR iron ore reserves exceed 1.5 billion tons of high grade ore distributed in 36 deposits located in the so-called IRON QUADRANGLE in the State of Minas Gerais. The Aguas Claras Mine is the largest presently known and highest grade deposit owned by MBR. Other mines such as Pico, Mutuca and Jangada are in operation at a combined rate of production of about 2 to 2. 5 million tons per year. The project consists of mine, railroad and marine terminal (slide). The Aguas Claras deposit, which is located about six kilometers southeast of Belo Horizonte the Capital of Minas Gerais, was selected for initial development. The Sistema Regional Centro of the Rede Ferroviária Federal, through its 6th Division known as the "Central " is responsible for the transportation of MBR ore, and provided the necessary railway construction to connect Mine and Terminal. The Terminal is located on Guaiba Island near the entrance to Sepetiba Bay, at about 120 kilometers west of Rio de Janeiro.

Jan 1, 1974

By T. Braun

A greenfield open pit gold mine in Latin America suspended operations less than three years into an eight-year mine plan after a waste rock dump and heap leach facility sustained substantial damage from a deep-seated landslide. No injuries to employees were recorded because of the slow-moving failure. Due to early detection by the operations team, the owner had sufficient notice of the potential failure and successfully rinsed the heap leach facility prior to the failure event. Engineers estimated approximately 35 million cubic meters of mass movement below the waste rock and heap leach facilities. The original eight-year mine plan produced approximately 60,000 ounces of gold per year. After the failure, the owner terminated gold production, re-configured the mine site to a safe, standby condition and launched a detailed investigation into the root-cause of the failure. Approximately two years after the shutdown, legal interests filed a statement of claim and named three engineering design firms and individuals involved in the project. Several years of litigation, including discovery and deposition proceedings, followed as the legal process considered evidence spanning a 20-year timeline. Changes in project ownership and consulting firms during the development and operations phase complicated the process. In 2017, the plaintiff and last defendant settled. The author was involved as the corporate representative for one of the engineering design firms.

Mar 2, 2022

Australia is a hub for mining technology development. The paper describes many of the key players involved in mining research in this country along with some of the interesting research outputs to emerge over the past decade.

Jan 1, 2010