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By A. S. Murphy, E. V. Manlapig, C. Green, J. W. Parkinson

Historically in Australia and the United States many coal mines deposited raw wash plant fines into large slurry impoundments. At the time the technology and market economics did not exist to make it viable to recover coal from these tailings. Today better technology exist to dredge and clean the tailings and there are circumstances where government regulations and market forces have come together to make coal recovery from these old tailings impoundments economically viable. This paper discusses the processes and equipment being used in tailings impoundment reclamation operations in Australia and the United States, and discusses the economic forces driving these operations.

Jan 1, 2001

By P. H. S. W. Kulatilake

To exploit an underground mine effectively and safely, it is important to have a good understanding of the geotechnical behavior around underground excavations made in the mine. The aim of this study was to investigate the geotechnical behavior around a tunnel excavated in a metal mine in China at the three-dimensional level. Using the information available on lithology, geological structures, in-situ stress measurements, physical and mechanical properties of intact rock, discontinuities and interfaces between different rocks, a three-dimensional numerical model was built by using the 3DEC software to simulate a tunnel excavation under a high in-situ stress condition. Effect of the discontinuity network, possible intact rock and discontinuity parameter variability, representation of rock masses as discontinuum or continuum material and rock support system on the deformation, stress, failure zone and stability around the tunnel was investigated. A very good agreement was obtained between the collected field deformation monitoring results and the results of the conducted numerical stress analyses.

Jan 1, 2012

By Robert G. Lundquist

REAM (for Rapid Excavation And Mining) is a method of rock fragmentation by high-velocity projectile impact developed by Physics International Company. This paper reports the results of field testing over the last two years. The success of the method is based on the fact that the amount of rock broken per shot scales nonlinearly with projectile impact energy. Thus, high energy impact yields spectacularly low specific energies for rock breakage. The field work reported used 90- and 105-mm military guns to accelerate 8-1/2 and 10-pound concrete and steel projectiles to velocities of 5000 to 5500 fps. All tests were performed in a competent 25,000 psi granodiorite at Hope Valley, California. During the first year of field testing 26 feet of 13-foot-diameter tunnel were produced with the 105-mm gun. The first 20 feet of this tunnel were line-drilled to aid in producing a stable portal. During the second year the tunnel was extended an additional 29 feet using the 90-mm gun. The 55-foot tunnel was produced by 590 shots. Between 1-1/4 and 1-1/2 tons of granite were broken by each shot. A silenced 90-mm gun was placed underground and the tunnel portal closed with a steel barrier. Overpressures of less than 1 psi were measured on the inside of the barrier, corresponding to an impulse noise of about 170 db. The muck produced was similar to drill and blast muck. Overbreak and ground support problems appeared to be less than with drill and blast. The contour of the tunnel was easily controlled using the 90-mm gun; the tests were also conducted using a 57-mm gun for trimming. Projections indicate that advance rates with REAM will be three to seven times faster than drill and blast, at less than two-thirds the cost. This is based on the development of a fully integrated continuous system and an inexpensive propellant giving a total expendables cost of less than $3 per shot. Other applications of the REAM technology are found in secondary breakage for open pit mining, in drilling large diameter holes, and in underground mining for longwall mining, overhand stoping, and raising.

Jan 1, 1974

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 R. Adsero

"A high altitude review of the state of the mining industry provided by a study of multifactor productivity shows a continuation of lower output year on year for the capital and labor inputs applied. The story is sadly similar for both U.S. mining and the Australian mining sector. In fact, according to PwC analysts, the world’s mining equipment productivity has declined 20 percent during the past seven years (Lumley, 2014). Although the reasons for the continuing decline in mining productivity are varied, the need for improvement is clear.The world’s mining industry fleet of more than 400 large draglines moves billions of tons of overburden and ore (phosphate, limestone, etc.) annually. This discussion will review a few of the tools available for improved productivity in dragline operations.Benchmarking equipment performance exposes the possibilitiesIn the September 2013 Mining Engineering cover story Graham Lumley and R. Adsero suggested that analyzing best practice equipment performance from an industrywide database for specific equipment performance improvement goals would be beneficial (Adsero, 2013). Benchmarking equipment performance by normalizing differences and then comparing specific measures of performance will provide a road map to improvement for those following the leaders. For those already performing at best practice levels, a benchmark confirms and bolsters what has already been achieved. As described in the SME February 2014 paper by this author, best practice is the average of the top 10 percent in annual output. Filling performance gaps identified by a comparison to best practice by investigating the details of the why and taking action to change, makes all the difference. This is true for all major mining equipment. Given the large gap between average performance and best practice performance most mining operations can benefit. Best practice performance provides a view of what is possible to the 90 percent majority of mining operations that are performing below the top 10 percent.For dragline mining operations, identifying specific characteristics and practices of leading dragline performance will provide a reference for comparison."

Nov 1, 2016

By U. B. Kodukula

Attempts are made to evaluate the feasibility of using a water-injection cyclone for the concentration of iron ore fines. The separation characteristics of clay fines, containing large amounts of alumina and silica, from the iron values are discussed. The effects of critical variables, such as injection water rate, truncated cone diameter, spigot opening and vortex finder diameter, on the performance of a water-injection cyclone in terms of iron, alumina and silica grades; iron recoveries; and alumina and silica rejections are discussed. A set of 16 full-factorial experiments (24) was carried out to gain an understanding of the individual and interaction effects of the variables. The results indicate that classifying iron ore fines containing 63.0% iron, 2.5% alumina and 3.5% silica through a water-injection cyclone can produce concentrates with iron grades greater than 66.0% and alumina and silica contents less than 1.5% and 2.0%, respectively, at different study conditions. The achievable iron recovery values are greater than 88%, and alumina and silica rejections are more than 80% and 50%, respectively, within the specific study conditions. While the truncated cone diameter, injection water rate and spigot diameter influences the alumina rejection to a considerable extent, it is mostly influenced by the vortex finder diameter. The iron recovery and silica rejection values are mostly influenced by spigot diameter and truncated cone diameter. The effect of injection water on the concentration characteristics depend on the prevalent truncated cone diameter and spigot diameter conditions.

Jan 1, 2008

By Keith Bowers, Frank Mimnagh, Eddie Woods

The CTRL London Tunnels The Channel Tunnel Rail Link (CTRL) London Tunnels comprise 36km of internal diameter bores that were driven by Earth Pressure Balance (EPB) Tunnel Boring Machines (TBMs). The tunnels were constructed between the autumn of 2002 and the spring of 2004. The permanent works also included the 1.1 km long station box at Stratford, five ventilation shafts of depths between 30 and 54 m, 29 cross passages and various large diameter sprayed concrete lined connecting tunnels. The tunnels were driven under densely populated areas of north and east London, as depicted in Figures 1 to 4. Under the parliamentary CTRL Act the project had obligations to make

Jan 1, 2005

By Osvaldo A. Bascur

Intelligent systems (IS) technologies have received much attention in a wide range of process engineering applications including process operations. With the revolutionary progress in information and computer technologies applying the latest technologies in metallurgical complexes has become a serious challenge to both management and technical teams. Objects and components are changing the way everyone relates to their computer and networks. Goals of real time performance monitoring includes maximizing the profitability by maximizing production, improving efficiency, attending product quality, costs, maintenance, environmental and safety regulations. Designers must consider the greatly expanded desktop computing, Microsoft object technology, Internet and how to build these systems. This paper discusses some opportunities and challenges using objects, components in designing applications and integrating intelligent systems tools. Two examples using performance equations and IS technologies applied to mineral processing are presented.

Jan 1, 1997

By Timothy J. Orr, Robin J. Burgess-Limerick, Jennica L. Bellanca, MARGARET E. RYAN

Powered haulage continues to be a large safety concern for the mining industry, accounting for approximately 50%of the mining fatal accidents every year. Among these fatal accidents, haul-truck-related accidents are the most common, with 6 of 28 and 6 of 27 fatal accidents occurring in 2017 and 2018, respectively. To better understand why these accidents continue to occur and what can be done to prevent them, researchers reviewed the 91 haul-truck-related fatal accidents that occurred in the USA from 2005 to 2018 and performed bow-tie analyses using the final reports published by the Mine Safety and Health Administration. The analyses explore the context of the accidents with a focus on the initiating event, event outcome, hazards present, and possible preventative and mitigative controls. Overall, the vast majority of the accidents resulted in a haul truck colliding with the environment, and the majority of these events were initiated by loss of situational awareness or loss of control. The majority of the hazards were related to design and organizational controls. The results of this study suggest a need to investigate operator decision-making and organizational controls and to focus on improving design and operation controls such as mine design and operational procedures.

Feb 22, 2021

By Jerry Pyatt

Lead has been used by mankind since before the Egyptian pyramids were built. Its durability provides for a continuum of innovation. As the largest integrated lead producer in the Western Hemisphere, The Doe Run Co. is committed to locating, mining, processing and sup-plying lead in ways that are responsible and sustainable. It takes ingenuity and resolve to successfully operate in the heavy industry field today. Doe Run is committed to applying responsibility through sustainability, lean manufacturing, safety, environmental stewardship, education and workforce development, and com-munity support.

Jan 1, 2008

By Stavros H. Constantopoulos

Mediterranean regions such as Greece, Turkey, Cyprus, Corsica and New Caledonia have experienced epidemics of malignant mesothelioma as a result of non-occupational, ??domestic?? exposure to tremolite asbestos and fibrous erionite. This exposure to tremolite asbestos and fibrous erionite is typified ??domestic?? due to its prevalence in regions with natural deposits of tremolite asbestos (or fibrous erionite) where the material from tremolite asbestos or fibrous erionite is used for domestic applications such as whitewashing. However, these exposures may be useful in examining the potential consequences of even small amounts of amphibole asbestos fibers in the ambient air. It can also elucidate the effects of fibers that behave like amphibole asbestos. However, this type of exposure is not useful for studying the potential effects of small amounts of asbestos in the ambient air of big cities due to the differing nature of the fiber types and modes of exposure between the regions. © 2008 Published by Elsevier Inc. Keywords: Tremolite asbestos; Erionite; Domestic; Environmental; Exposure

Jan 1, 2007

By L. Westerstrom

Supply and Demand After a dismal first half, the industry saw a marked improvement in its markets during the final six months of 1983. Domestic consumption was 17.6% higher in the second half of the year, primarily due to a surge in electric power requirements. The sharp increase in demand for electric power during the third and fourth quarters afforded utilities the opportunity to lower stocks that had accumulated to record levels during 1982. Consumer stocks were reduced from 179 Mt (197 million st) at the end of June to 153 Mt (169 million st) by the end of the year. That is the largest inventory drawdown on record during a six-month period without a major coal strike. Despite the huge depletion in inventories, coal production in the second half of 1983 rose 1.3% above output in the second half of 1982. However, because of the disappointing first half, production in 1983 totaled only 712 Mt (785 million st), 6.4% less than the 760 Mt (838 million st) produced in 1982. Demand The extent to which the economic recovery affected coal markets in 1983 varied: • total domestic coal consumption increased 4.2%; • electric utility coal consumption increased 5.3%; • exports declined by about one-fourth; • coal consumption at coke plants declined 9.5%; and • coal consumption in the other industrial sectors increased 2.9%. Domestic coal consumption totaled 667 Mt (737 million st) it 1983, 27 Mt (30 million st) more than 1982. Electric utility consumption increased from 539 M1 (594 million st) in 1982 to 567 M1 (625 million st) in 1983. Coal consumption at coke plants declined from 37 Mt (41 million st) to 34 M1 (37 million st). Residential and commercial use increased 181 kt (200,000 st) - from 7.4 to 7.6 Mt (8.2 to 8.4 million st). Electric Utilities: Electric power generation increased 3.1% in 1983. Demand for electric power increased in all major consumer categories. Residential and commercial use rose 2.7% and 3.3%, respectively. The most striking increase, however, and indicative of the economy's strong upturn, was the increase in industrial electric power use. Industrial power requirements, which declined 9.8% in 1982, rose 4.1% in 1983. The electric utility sector continued to expand its use of coal last year while lowering its requirements of oil and natural gas. In 1983, electric generation from coal increased 5.7%, while genera-

Jan 5, 1984

By David E. Thompson, Andrew F. McKown, Herbert H. Einstein, Amr S. Azzouz

INTRODUCTION Design of supports for underground chambers in rock has undergone considerable development. This becomes evident when comparing support dimensions of subway station caverns built in the U.S. over the past fifteen years. The Porter Square Station cavern, which is a part of the Massachusetts Bay Transportation Authority (MBTA) Red Line extension, is the latest in this series. It is approximately 168 m (550 ft) long, 21 m (70 ft) wide, and 14 m (45 ft) high, and has a permanent support of light steel ribs imbedded in a 0.4 m nominal (15 in) shotcrete lining. An extensive construction control instrumentation program made it possible to evaluate the performance of the cavern and its support. This evaluation, which is presented in this paper, was the objective of a research project sponsored by the Urban Mass Transportation Administration (UMTA) and jointly conducted by Haley and Aldrich, and MIT. The actually used design procedure was compared with other approaches, notably procedures based on Finite Element analyses and empirical rock mass classification methods. Support dimensions predicted with all these approaches were compared to the actual support and its performance.

Jan 1, 1983

By J. R. Parga

In mineral processing, poor froth-flotation performance translates into both an enormous loss of revenue and an unnecessary waste of the ore reserve. In this context, Bacís Mining Company developed a versatile new, high-performance flotation-cell design that can be incorporated into various flotation circuits. The main feature of this circular cell is that it is comprised of two separate sections, namely, a flotation cell that uses wash water to minimize the entrainment of fine gangue particles into the froth product and an external bubble generator that produces small bubbles of relatively uniform size at a specified aeration-rate. The air/water mixture is blended with the pulp by gentle agitation, so as to enhance particle-bubble aggregate-stability. Comparative metallurgical performance with conventional flotation cells show that the power requirements and operating costs for precious metal flotation are three times lower, while the concentrate grade is 7% higher and the recoveries of precious metals are 5% higher.

Jan 1, 2009

By LeRoy D. Loy

Would you believe me if I told you the constant battle between Government regulatory agencies and industry could be won by both sides? No, I'm not crazy, nor have I been soaking up any of that fine Kentucky whitelightning. But I have recently been a participant in a battle where both sides won. Actually, I'm using the term "battle" loosely because, in reality, it wasn't a battle at all - despite the fact that all the ingredients were there for a monumental struggle; i.e.. government, industry, special interest groups and a controversial issue - the development of effluent limitations. I'd like to tell you about it. Historically, on one side of the battle, government has always been ac¬cused of adopting regulations with limited evaluation of existing technologies; and then with seemingly no regard for the economic consequences. On the other side, industry gets punished by government's harsh actions because of their past "do-nothing" attitude toward pollution control. Recently, this battle seems to be losing steam, because both government and industry are beginning to realize that, ultimately, they both will lose. Even more important is the fact that both sides are, or should be, working for industrial expansion compatible with environmental protection.

Jan 1, 1977

By Gordon Cook

American Electric Power Company (AEP operates 31 coal mines in three states, and some 26 electric generating stations (19 coal-fired) located in the Ohio River Basin. Normally the system burns over 36,071,600 tonnes (40,000,000 tons) of coal and generates in excess of 3.6 X 1018 J (100 billion kwh) of electricity per year. In 1975, AEP, in response to the progressively more stringent air quality requirements of the clean air act, acquired large low-sulfur reserves in Carbon County, Utah (Figure 1. Location Map). Price River Coal Company (PRCC) is the operator OF this multi-seam complex, which is part of the Book Cliffs coalfield at an elevation exceeding 1,829 m (6,000 ft.). The topography is mountainous and divided by numerous canyons. Flat areas are at a premium (Figure 2. Castle Gate Area). Modern high production longwall mining takes in some top and bottom waste, and in this particular operation, it amounts to about 14% of the ROM tonnage.

Jan 1, 1983

By C. C. Jobes

Operating large face equipment, such as continuous mining machines, is one of the most basic and most dangerous elements of an underground coal mining operation. The operator usually performs cutting and tramming tasks in a restricted workspace with reduced visibility. During the execution of these tasks, operators often cannot see all of the locations needed to safely operate the continuous mining machine (CM ), which has sometimes resulted in accidents. In an effort to prevent these accidents, researchers at the National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory, examined the continuous mining machine operator?s current information cues, or visual attention locations, so that risk of injury relative to the task, equipment and workplace environment can be evaluated in the future. The eventual goal is to develop interventions to enhance the information cues, and thereby increase the safety and health of machine operators. This paper details the operator interview process, determination of visual attention locations (VALs) and simulation of various mining scenarios.

Jan 1, 2011

By Kevin Beirne

Most people involved in the mining industry are familiar with student-industry co-op work-study programs. Many colleges and universities have used them for years. Northern College’s Haileybury School of Mines student co-op program adds a new dimension of productivity to the college and the mining industry. The college is located in Hailey-bury, Ontario, Canada. An example of the program’s success is the school’s relationship with Sabin Metal’s SMC (Canada) Ltd.’s McAlpine Mill in Cobalt, Ontario. Students gain practical knowledge and experience while industry gains an eager-to-learn worker. And many of the college’s advanced research services are made available to industry to supplement their own capabilities. The McAlpine Mill was established to provide custom milling of slags and ores. It also recovers metal values from other products of the primary and secondary precious metal industries.

Jan 1, 1999

By Forrest C. Neil, Clint J. Keifer

The pollution of our water supply, Lake Michigan, is a continuing threat so long as our overflows from combined sewers exist. The problems have become even more acute during recent years, due to the increase of paved area- which accelerates and enlarges the flows of storm water. After each storm, mixtures of raw sewage and storm water spill into our waterways. If the storm is too large for the drainage systems, the mixture backs up into our streets and basements. Under severe conditions, it may even become necessary to open the locks, and discharge the polluted water into Lake Michigan. Consider the scope of the problem, as shown in Figure 1. The area in which combined sewers exist is 375 square miles, located in the central parts of Chicago and 49 suburbs. There are an estimated 640 overflow outlets to the waterways, each requiring attention. The capacity of outlets tributary to the waterways has increased dramatically over the years. Each time a pocket of upstream flooding is drained into the channels, the problem of its rapid disposition increases. Another difficulty is that the bottom of our waterways is covered with a blanket of accumulated sludge, ranging in depth up to 3-feet. This material harms the water quality by depleting the supply of oxygen dissolved in the water ... a final

Jan 1, 1997

By A. D. Hammond

"The drop in iron ore prices has claimed an unwitting casualty in vanadium. Vanadium is dominantly produced as a coproduct of steel production. The recent shutdown at EVRAZ’s Mapochs steel-vanadium operations in South Africa has cut off 10 percent of the world’s vanadium output. In February 2015, Australia’s Atlantic Ltd. suspended operations at its Windimurra iron-vanadium complex after a fire caused severe damage at the plant. Since then, challenging market conditions has resulted in the permanent closure of this operation.This decoupling of vanadium production from integrated iron ore producers presents an opportunity for vanadium exploration companies to target single-product deposits. This trend is manifested in the increasing number of pure-play vanadium ventures around the world.The mine production of vanadium is dominated by three countries — China, South Africa and Russia, which collectively produce 96 percent of the world’s vanadium. While the use of vanadium as an alloy in the steel industry remains the largest application for this metal, growth in demand is expected to come from the renewable energy industry in the form of batteries for energy storage.This article summarizes the current state of vanadium exploration, briefly describes the vanadium market and lists sources of future demand for the metal.Trend in vanadium explorationThe most active participants in the current vanadium exploration are pure-play vanadium ventures in Brazil, South Africa and Australia. These ventures are targeting deposits with higher vanadium grades than those typically mined in titaniferous magnetite operated by integrated steel-vanadium producers.The 10 percent shortfall in vanadium production resulting from the shutdown at EVRAZ’s Mapochs is expected to be partially compensated by Largo Resources’ Maracás Menchen vanadium operation located in the state of Bahia in Brazil. It commenced operation in August 2014 and is expected to produce between 7.6 and 8.6 kt (8,421 and 9,523 st) of V2O5 in 2016 at a target production cost of $3.71/lb (Largo Resources, 2016). This is the first primary vanadium operation to be placed in production in the Western Hemisphere in more than 35 years."

Jul 1, 2016