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In early March 2011, a 6.2 m (20.3 ft) diameter Rob-bins Double Shield tunnel boring machine (TBM) crossed the finish line in Sochi, Russia. The machine completed a 4.5-km- (2.8-mile-) long section of tunnel that will ultimately become part of the transportation infrastructure for the 2014 Winter Olympic Games. The TBM advanced through difficult ground at aver-age rates of 100 to 120 m/week (330 to 390 ftpw) for contractor OJSC Bamtonnelstroy, a division of the SK Most Company. The section of tunnel will ultimately become a service tunnel for Complex #3 - a section of Sochi?s transportation infrastructure under construction, which includes road and rail tunnels. A second, 10 m (32.8 ft) diameter Robbins Double Shield TBM is currently excavating the parallel 4.6-km- (2.9-mile-) long main railway tunnel using a continuous conveyor system for efficient muck removal. A 13.2 m (43.3 ft) diameter highway tunnel is also under construction. The 6.2 m (20.3 ft) Robbins TBM achieved high rates despite difficult conditions. The tunnels run through mixed ground including massive to completely fractured limestone with clay seams. Some sedimentary rock including sandstone and siltstone is present, along with fault zones consisting of breccias and conglomerates. In May 2010, the machine was stopped after encountering a significant fault zone consisting of broken rock and running soft ground. Field service personnel and crew successfully freed the machine by excavating a bypass tunnel around the TBM, freeing the cutterhead. Following the restart, a combination of continuous probe drilling and ground treatment with cement silicate and foam kept the machine moving forward.

Jan 1, 2011

By Jenny Alsén, Hans Hogard

"Construction of large facilities underground in urban areas has many advantages. In order to show the advantages, a case study of the Norsborg metro depot in Stockholm Sweden has been made. The Norsborg metro depot will be the largest and most modern underground metro depot in northern Europe. The depot has been built in hard rock in an urban area with small impact on the environment and local residents. The paper describes how it is possible to build underground facilities in a cost efficient way and take care of the challenges regarding working environment that comes with locating a permanent working place underground. INTRODUCTION The Stockholm area is one of the five fastest growing regions in Europe and home to more than a fifth of Sweden's population on just two percent of Sweden's surface. The population is growing rapidly, with about 35,000 people per year and is expected to reach 2.6 million in 2030. In order to meet the development and enable continued growth, housing projects and expansion of infrastructure need to keep the same pace; this is an easy conclusion to make but much more difficult to realize in practice. The main challenge is to accomplish development in a sustainable and efficient manner, minimizing the use of resources and land. By constructing facilities underground more urban space will be made available for development and/or for greening of city centers. Considering sustainability factors such as land value in decision making for placing of structures or facilities, underground locations could become a first choice alternative. During 2015 and 2016, several major underground infrastructure projects in the city of Stockholm will start, including a 14 km sewage tunnel and an 18 km by-pass highway tunnel. Furthermore the Stockholm metro system is currently undergoing the largest expansion since the 1970’s, a 19 kilometers extension of the metro system including new trains and new stations is planned. During 2013 - 2015 Skanska Sweden took part in the construction of a new metro depot placed underground in the southern part of Stockholm; the Norsborg metro depot. This is a top modern urban underground facility that in 2017 will serve as depot for 17 new metro trains. The project was selected for “Outstanding Project of The Year” at the ITA Tunneling Awards 2015."

Jan 1, 2016

By Paul Nicholas, Raju Gottumukkala

"India’s economy is expanding with rapid urbanization. Improvement in infrastructure is a keystone to the Indian government’s economic plans, including expansion of transit systems. Most of these systems are designed with elevated and underground sections. New Delhi, a city of 23 million people, suffers from heavy traffic congestion and pollution. The transit (metro) system is seen to be of critical importance. Phase 3 of the Delhi transit system project is 140 kilometers (km), with 40 km of twin-bore tunnels requiring 35 tunnel boring machines (TBMs) for construction. Transit systems are also under design or construction in Chennai, Bangalore, Kolkata, Hyderabad, Jaipur and Mumbai. Most have twin-bore tunnels. At present, 55 TBMs are operating on underground metro construction, and future projects will increase this number. This paper highlights the unique challenges of construction of underground metro systems in highly congested urban environments, using Kolkata and Delhi systems as examples. INTRODUCTION The first transit system in India was constructed in Kolkata (India’s third-largest city by population.) This line is 28 kilometers (km) in length, has underground and at-grade sections, was built in phases, runs north/south, and has 24 stations. This project was sanctioned in 1972, started construction in 1984, and was completed in 1995. The tunnels were constructed primarily by cut and cover methods with some open-face, compressed air shield tunneling. In 2006, the urban transport policy recommended construction of transit rail systems in all urban cities with a population exceeding 2 million. Further, in 2014 the central government stated that it would assist in financing transit systems in all cities with a population of over 1 million. In 2015, the central government approved the development of transit systems in 50 additional cities across India with a budget of $75 billion (see Figure 1). Transit development is just part of a huge expansion in planned rapid transport systems, which include metro, bus, high-speed rail, and monorail systems. Metro systems will include elevated and underground sections with twin-bore tunnels and underground stations. In the Delhi/National Capital Region (NCR), now the largest city in India by population, Delhi Metro Rail Corp (DMRC) was formed in 1995 as a joint venture company between the central government and Delhi state. DMRC operates the Delhi metro system. (see the case studies described later in this paper). DMRC has developed an external function to carry out studies and to offer consultancy to other cities planning transits. Since its inception, DMRC has produced Detailed Project Reports (DPRs) for every metro and monorail project in India. In 2012, DMRC became a partner in the management consultancy for Jakarta Mass Rapid Transit System, its first project overseas. DMRC became a model organization for other cities to follow. These cities have included Chennai, Hyderabad, Kolkata, Bangalore, Jaipur, Mumbai, Ahmedabad, and Nagpur. Other cities (e.g., Lucknow and Patna) are in the metro planning phase. Metro systems are under construction or partially operating in Hyderabad, Bangalore, and Jaipur."

Jan 1, 2016

By Ava Segal, Doga Cagdas Demirkan, Abhidipta Mallik, Sebnem Duzgun, Andrew J. Petruska

Search and rescue operations in mining heavily rely on humans. In the context of emergency situations within underground tunnels, the potential to utilize sensory technology for navigation assistance holds the promise of saving human lives. Our research introduces a device configuration designed to enhance the performance of search and rescue teams. This setup integrates LIDAR and thermal cameras with the Microsoft Hololens, facilitated by the NUC computer and ROS Bridge. Performance assessment involves quantifying the extent to which a user is willing to venture into a light-deprived section of the mine prior to necessitating supplementary illumination. The preliminary outcomes highlight the significant potential of augmented reality assistance in offering indispensable aid to first responders, thereby greatly augmenting the efficiency of search and rescue missions conducted during critical circumstances.

Feb 1, 2024

By S. L. de Moraes

This study aimed to identify a way to reduce the use of bentonite in the pelletization of magnetite. With this goal, different combinations of binders were compared to bentonite by examining the quality of pellets obtained by balling drum agglomeration. Pellets were subjected to routine tests that included simple compression of the wet and dry 105°C pellets, dropping wet pellets to determine their ability to survive handling and submitting pellets to thermal shock to determine how they tolerate drying and preheating. The best results use sodium silicate (1.5%) as a binder and show that it is possible to pelletize iron ore without using bentonite.

Jan 1, 2010

By Bryant Fitch

This paper will review thickening theory, from the ( ) of the practicing engineer, with particular emphasis on ( ) uncertainty or disagreement. It will attempt to outline broadly what we know and what we don't know. This should serve two purpose First, it will warn the process engineer where he might get into trouble. At least it will alert him to the risk involved in uncritically accepting any of the recommended design procedures. Second, it will identify for researchers some areas in which further work might be fruitful. Not too many years ago there would have been little to write on such a subject. We had been designing thickeners for decades, using the classic Coe and Clevenger procedure. As far as we were generally aware, they all turned out to be about the right size. And so if there was anything we didn't know, It certainly wasn't hurting us much. Today we know better. While it is true that in most cases units designed by the Coe and Clevenger procedure (1) will perform satisfactorily, we now know of cases in which they don't. And during the past few years there have been many developments and advances in basic thickening theory. So there is now a lot more room for disagreement, and a whole lot more to be uncertain about. What is "thickening" "Thickening" means different things to different people. For this paper we define it to mean sedimentation behavior characterized by line settling. Solids subside with a clear line of demarcation between settling solids and supernatant. Although the supernatant will usually be clear, in some cases it may be turbid. Line settling must entail that all particles just below the pulp-supernatant interface have the same subsidence rate, so that

Jan 1, 1971

By Michael McNinch, LaTasha R. Swanson, Jennica L. Bellanca, Justin Helton

As manufacturers and mine operators develop and implement proximity detection systems (PDSs), they need to be mindful of the systems’ compatibility with mineworkers’ tasks, and possible unintended consequences. Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) interviewed mineworkers at mine sites that currently use or previously have used PDSs on mobile equipment, including shuttle cars, battery haulers and scoops. Mineworkers reported that mobile PDSs affect loading, tramming, section setup, maintenance and general work on the section. Mineworkers discussed the operational effects and increased burden, exposure and risk. Mineworkers also suggested that improved system task compatibility, training, logistics and PDS performance might help address these issues. Manufacturers and mine operators implementing this or similar technologies may also consider mitigating task incompatibilities up front, performing additional site-specific usability testing and restricting the use cases of the system to improve performance.

By B. Cavender

Investments in new technology are often intended to improve the production or cost performance of existing operations. The economics used to justify these projects can be flawed, however, if they do not adequately consider the potential benefits of the alterative: the fully optimized use of the facility's present equipment and personnel. While new technology can be effective, dramatic improvements in production performance can also be achieved through the rigorous application of standard industrial engineering and operations management practices. An intermediate approach may also be effective: many basic improvements In the mine or plant necessary to support new technology will be equally effective when implemented for the facility's present operators. Firms who optimize their present operations are able to save the capital and avoid the risk associated with new technology. These firms will also be able to capitalize more quickly on new technology when it is implemented.

Jan 1, 1999

By H. Zhao, R. Liao, W. Qin

Theoretically, controlling redox potential to a relatively low value and inhibiting jarosite formation on the chalcopyrite surface would be an effective strategy to accelerate the bioleaching of chalcopyrite. In this work, using limonite as seed crystals, the effects of the goethite precipitation process on the bioleaching of chalcopyrite were studied for the first time. The bioleaching results showed that the addition of limonite controlled the redox potential in an appropriate range and promoted chalcopyrite dissolution through the removal of ferric (Fe3+) ions. X-ray diffraction and scanning electron microscope analyses indicate that limonite significantly induced the goethite precipitation process and inhibited the production of jarosite. We conclude that promoting the goethite precipitation process with limonite is an effective strategy in accelerating the bioleaching process of chalcopyrite.

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 PAITIP THIRAVETYAN, KANJANA KUDPENG

The aim of this study is to compare amino acids and organic acids in the extraction of gold from silicate ore. Amino acids were found to have higher efficiency of gold extraction than organic acids at the same acid concentration, which is likely due to amino acids having both carboxylic and amine groups in their structure, while organic acids only have carboxylic groups. Five amino acids (glycine, aspartic acid, glutamic acid, lysine and tryptophan) and seven organic acids (citric, malic, tataric, fumaric, oxalic, succinic and ascorbic acids) were selected to investigate gold extraction efficiency. Aspartic acid was found to have greater capacity to extract gold than succinic acid. The optimal gold to aspartic acid molar ratio was 1:6, and low concentrations of aspartic acid extracted 35 to 42 percent of gold from silicate ore within 15 days. Further studies are needed to increase gold leaching and reduce incubation time. The results imply that aspartic acid can be used as an alternative reagent to traditional methods for extracting gold from ore. This method is nontoxic to humans, is environmentally friendly and can have real applications.

By Pradip

Bastnaesite, a rare-earth fluocarbonate, was separated from associated calcite and barite gangue minerals in the Mountain Pass, CA rare-earth ore beneficiation plant by froth flotation using fatty acids (tall oil) collector, lignin sulfonate depressant and soda ash modifier after high-temperature (steam) conditioning with reagents. Starting with a feed grade of 7.6% REO, concentrates having a grade of 65% REO can be produced at a recovery of around 80%. A detailed investigation consisting of Hallimond tube microflotation experiments, bench-scale tests with a laboratory Denver flotation cell, and predesigned plant campaigns was made to delineate the underlying surface chemistry involved in this separation and to develop an alternate reagent scheme to enhance the selectivity of separation for this ore. Our results clearly demonstrate the superiority of alkyl hydroxamates to the conventional fatty acid collectors that were being used in the plant. Our study also indicates the possibility of achieving the desired selectivity with alkyl hydroxamates even at room temperature, thus obviating the need for steam conditioning. A critical review of the literature on rare-earth mineral flotation suggests the possibility of designing a more selective reagent combination for the beneficiation of Mountain Pass rare-earth ore, using a methodology based on ab initio molecular modeling computations.

Just 104 km (65 miles) from Phoenix, AZ, Rio Tinto hopes its new Resolution Copper Mine will be a showcase for the Rio Tinto management philosophy. Its goal is to have a net positive impact. In every place that Rio Tinto mines, it wants to be able to have an overall beneficial effect on the local community, environment and economy. ?We?re constantly working to understand our impacts, to understand how to minimize our impacts and understand how to mitigate those impacts,? said Resolution Copper Mining chief executive officer David Salisbury, from the global headquarters of Rio Tinto Minerals in Green-wood Village, CO.

Jan 1, 2010

By Jerry C. Tien

China?s remarkable levels of economic growth during the past three decades have lifted almost 300 million people out of poverty. This amazing achievement has placed an increasing demand on energy and minerals, especially coal, which supplies 68.7 percent of China?s energy (June 2011). It is estimated that China mined more than 3 Gt (3.3 billion st) of coal in 2010, three times as much when compared to merely 10 years earlier. Such an impressive achievement does not come without major costs ?? including concerns with mine safety and an increasing number of occupational illnesses due to fast growth. This article reports on one of the major safety concerns in China?s coal mining, dust and dust control practices, and known cases of caol worker?s pneumoconiosis affiliated with prolonged exposure to excessive coal dusts. The exact size of China?s mining industry is not known, but it is estimated the coal industry is at least five-million people strong, and the metal and nonmetals industry probably employs another three million people. To meet increasing energy demand, China mined more than 3.1 Gt (3.4 billion st) of coal in 2010 from its 15,000 plus coal operations1, most of which are small- to medium-sized operations with annual coal productions ranging from a few thousand tons to 300 kt (330,000 st). These small coal operations are typically in remote areas, inadequately engineered, poorly ventilated and still using rudimentary drilling and blasting mining methods employing antiquated mining equipment and, presenting safety concerns, i.e., methane and dust explosions.

Jan 1, 2011

By R. L. Bonomi

Developing a mining venture in a foreign country, particularly in South Africa, can be a real challenge to those involved in the operation. The mining division of Southland Energy Corp. was asked to offer consultative support to the New Union Gold Mine, located in the Giyani District, Transvaal, Republic of South Africa, to aid in their expansion from an approximately 65 tonne per day exploration- exploitation project into a full scale mining operation of 300 tpd by January, 1987 with further expansion to 600 tpd by mid-year. This paper ad- dresses the development of the expansion plans, which are presently being implemented. History. Located in the Northern Transvaal, Republic of South Africa, the New Union Gold Mine is part of what is known as the Klein Letaba gold fields. Gold prospecting in the Klein Letaba gold field area dates back to the earliest years of European prospecting activities in the Transvaal where, reportedly, gold was discovered as early as 1887 (figure 1). The claims com- prising the present New Union Gold Mine have been explored by a number of individuals and relatively small mining groups since the early 1930's. The work done by these entities was aimed at recovering as much gold as possible in the quickest and cheapest manner possible and, as a result, the area was not explored in a systematic fashion. The long-term potential of the area, therefore, was not known until very recently.

Jan 1, 1987

By Emily Wortman-Wunder

As the 2009 president of the Society for Mining, Metallurgy, and Exploration, Inc., I am pleased to present the 2009 issue of Transactions of the Society for Mining, Metallurgy, and Exploration, Vol. 326. A significant portion of the contribution that we as a society make is the publication of professional and technical papers that contribute to the advancement of scientific knowledge and information transfer. Communication within the mining community is the key to a successful society. Through the information-transfer mechanisms of books, magazines, meetings and electronic media, the technology exchange that is fundamental to the existence of the Society is accomplished. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, Pennsylvania, that resulted in the founding of AIME; those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume certainly satisfies that intent. In keeping with SME’s tradition of promoting technological developments while honoring the past, the 2009 Transactions represents an important milestone. It is the last Transactions to appear as a bound volume. Future volumes will appear as e-books only, with some of the Transactions-only papers appearing online prior to the ebook (exactly what form the new Transactions will take is still in development). The decision to go to an all-digital format for this longstanding publication was a difficult one, but one which we hope will better serve the mining community, especially our international members. This 2009 Transactions of SME, Vol. 326, contains a total of 73 technical papers (510 pages), including all 23 papers (136 pages) that were published in 2009 in the Technical Papers Section of Mining Engineering magazine (Vol. 61) and all 32 papers (232 pages) that were published in 2009 in Minerals & Metallurgical Processing (Vol. 26). In addition, this volume contains 18 papers (142 pages) that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All 73 technical papers were peer-reviewed and approved. The process of review and publication requires much hard work by authors, reviewers and publications staff. As the 2009 president of SME and on behalf of our members, I would like to extend our gratitude to all whose efforts contributed to the publication of this volume.

Jan 1, 2009

By QUANWEN PU, Yonggang Wei, Bo Li

With the advancement of industrial science and technology, more and more catalysts are used. The spent catalysts produced are solid waste products, which cause environmental pollution if they are not treated. At the same time, the spent catalysts contain some precious metals such as platinum in concentrations that are often higher than in their ore resources. Therefore, the recovery of valuable metals in spent catalysts is a hot research topic at present. However, due to the complex structure of the spent catalysts, dealing with them is a lengthy process. The first step of recovery, enrichment of the spent catalyst, becomes particularly important. In this paper, a pressure solution method is investigated for this purpose, in which the alumina carrier is dissolved and platinum is enriched in the leaching residue.

By C. W. Hunt

I wish to register strong disagreement with the choices of drilling sites chosen by the Continental Scientific Drilling Committee, while endorsing the stated objectives. Of special significance is the lack of any site involving the metals most needed today in the US, while 9 to 13 km of drilling are allocated to gold and silver districts and 11 to 17 km to base metal (mainly copper) districts. Why is nothing proposed for platinum group or chromite? Is this because the committee did not know of such a site? If so, I offer such a site in California (see Fig. 1). The mineralization shown in Table 1 occurs in a large peridotite body in western Tehama County, CA. Petrography has demonstrated unequivocal evidence of migrated PGE deposited in peridotite and chromite of hypabyssal nature. Active diapirism (due probably to serpentine buoyancy) above a reactivated mantle to surface conduit marks the position of the conduit. Young explosion breccia cemented loosely by volcanic glass and tuff demonstrates the significance of the conduit as the prime source of the various emissions. Deep drilling could result in major metals discoveries as well as shedding light on the grand questions of platinum group mineralization. What role water has played in this occurrence is not yet certain; but chlorine and asphaltite have been detected in and adjacent to native PGM, suggesting a major role for water. The explosion breccia suggests that this excellent site could overlie entrapped geothermal steam.

Jan 1, 1988

By I. Iwasaki, K. A. Smith, X. Cheng

A cathodic decomposition model was examined for both pyrrhotite and chalcopyrite in an attempt to analyze the formation of surface coatings in deoxygenated solutions at natural, near neutral pH. Combination potentials established between the mineral-grinding media pair were simulated by applying a potential of -0.455 V (vs. a standard hydrogen electrode) either to a pyrrhotite or to a chalcopyrite electrode. Chronoamperometry was used to study the polarization behaviors and alteration of mineral surfaces through cathodic processes. The kinetic parameters of cathodic decomposition of pyrrhotite and chalcopyrite were determined and compared. It was concluded that pyrrhotite decomposed faster than chalcopyrite in near-neutral pH solutions. Both minerals were then covered by a film consist¬ing mainly of iron hydroxides, which adversely affected their flotation.

Jan 1, 1999

By W. Blake, J. Whyatt

Sixty years of rock bursting in the Coeur d'Alene district has taught painful lessons and led to a number of practical advances in controlling rock-burst hazards. This paper summarizes these lessons, concentrating on practical measures that have been successfully adopted to reduce hazards. These lessons are explained in the context of district mining history and current understanding of rock-burst phenomena. Overall, the paper provides the practicing mine engineer with an appreciation of rock-burst hazards and an overview of practical measures that can be used to control these hazards in the context of Coeur d'Alene district experience.

Jan 1, 2003