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By B. Anderson, P. Churak, S. Dewar, A. Johnson, P. Eger

Although vegetation can be successfully established on fine taconite tailings, innovative approaches are needed to reclaim the coarse tailings used for dam construction. Through a series of cooperative projects with various government agencies and industries, EVTAC has been able to develop a unique closure plan. This plan will not only meet current reclamation standards, but also provide mitigation for a disturbed wetland and possibly create a tree plantation in the interior of the basin. By using waste products and exchanging materials, reclamation of the entire basin will be accomplised in a cost effective manner.

Jan 1, 2002

Komatsu America International has introduced two new hydraulic excavators. They can work in congested and confined areas. The tight tail swing radius of the PC128US-2 and PC22-8USLC-2 enables the excavators to minimize the work space. The units can operate in confined work settings that are inaccessible or counterproductive to traditional machines. Even the door is designed for tight working conditions. A convex door slides open along the exterior curve of the cab, rather than swinging out on hinges past tracks. And the excavators’ tight tail swing design allows them to load within the track width of the machine.

Jan 1, 2000

By T. Tamagawa, N. S. Fu, I. Iwasaki, M. Kobayashi

A 3-stage fluidizing bed process of chlorination, selective oxidation and sulfur chloride conversion was tested for processing of a chalcopyrite concentrate. It was found that the use of excess oxygen was essential to a stable operation in the oxidation reactor. The oxygen-excess gas will inevitably cause the oxidation of the sulfide concentrate in the chlorination and sulfur chloride conversion reactors. A new flowsheet is proposed to separate the chlorination and the selective oxidation steps with separate flow paths of the fluidizing gases, thereby preventing the passage of oxygen-excess gas in the chlorination and sulfur chloride conversion reactors. The feasibility of the proposed flowsheet was demonstrated in a laboratory-scale fluidizing bed setup.

Jan 1, 2000

Grouting is mainly used to improve mechanical properties or decrease the permeability of rock mass around civil and mining projects. The purpose of this paper is to present the most effective factors on grout penetration depth in rock mass. Such factors are essential for reliable estimation of the grout penetration depth and the expense for cement take of any grouting project. In this paper, about 50 different types of the relations presented so far by various researchers to estimate the depth of penetration in fractured rock were studied. The effective factors are classified to rock mass properties, grout properties, and operational factors. Results show that firstly, the discontinuities aperture and Lugeon value are respectively the most investigated factors of rock mass properties influencing on penetration depth. Secondly, the yielding stress, viscosity, and density of grout are the most effective factors of grout properties. Finally, grouting pressure has an intense effect among other operational factors. The investigations were also verified in Siah Bishe dam case study. Keyword: grout penetration depth, rock mass properties, grout properties, operational factors.

Feb 27, 2013

By Tony Szwilski

Indonesia has enormous mineral resources. Its population of more than 180 million people inhabit most of the more than 13,000 islands. The country is becoming a significant economic power in Southeast Asia. Indonesia is the largest Muslim country in the world. Java, its largest island, is the most densely populated area. The country's diversity is its strength. However, as only an estimated 16 million inhabitants speak bahasa Indonesia as the first language, communication problems endure. Although burdened with large debts, Indonesia has been able to service the debts better than most developing nations. This has given it high credibility and, with increasing frequency, creditor nations compete to provide Indonesia loans with the most the most favorable financial terms. Recent rising prices of petroleum crude has further improved Indonesia's economic status. It maintains a policy of stable oil prices that it promotes in OPEC, of which it is an influential member. As a result, Indonesia is becoming increasingly attractive to foreign investors. The South East Consortium for International Development (SECID) is made up of 34 universities in the southeastern US and Indonesian partners Lembaga Afiliasi Penelitian dan Industri (LAPI) of the Institute of Technology in Bandung, West Java. SECID bid successfully against international competition to develop new academic programs and campus for the Sriwijaya University UNSRI) in Palembang, South Sumara. Funding for the project was provided by the government of Indonesia through a loan from the Asian Development Bank (ADB). There are 47 public universities

Jan 1, 1991

All aspects of precious metals processing were featured at a symposium held Oct. 3-6, 2007, at Loews Ventana Canyon Resort in Tucson, AZ. Although billed as "Precious Metals Processing: Advances in Primary and Secondary Operations," the symposium also looked at economic, regulatory and environmental issues affecting the precious metals industry. The symposium was sponsored by SME; The Minerals, Metals & Materials Society (TMS); and the International Precious Metals Institute (IPMI). It included workshops, technical presentations, guest speakers and social activities. Mining industry management, process engineers, equipment manufacturers, consultants, metals marketers, academics and others involved in the precious metals industry attended the conference. Needless to say, with gold nearing $25.721g ($800/oz) and platinum pushing $41.801g ($1,300/oz) at the time of the meeting, the mood among the attendees could not have been more positive. The symposium was privileged to have Father Ernest S. Sweeney, professor of Latin American History at Loyola Marymount University, as a guest speaker. Sweeney, a Jesuit priest, provided a colorful account of the history of mining in Arizona and the surrounding region of North America (Fig. 1). He described the importance of the mining industry and said, "To go down into the bowels of the earth to extract its riches for the benefit of all of us is an awesome task deserving our sincere respect and gratitude." However, he warned the industry that: "The ever increasing de¬mands on the mining community for the protection of the environment calls for endless efforts to maintain ethical standards in a business filled with risk, uncertainty and frustrations." Sweeney noted that the Spanish conquest of the Americas was driven by the three fundamental motives of "God, glory and gold." He noted that gold was the basic, most powerful driving force of the conquest and occupation of the Spanish empire. The first European to explore Arizona was the Franciscan missionary Marcos de Niza. He came to Arizona in 1539 in search of the fabled Seven Golden Cities of Cíbola. Sweeny noted that Spanish explorers were consumed, as Cortes himself described it, "with a burning fever that only gold could cure." Sweeney told the story of some of these early explorers, including Francisco Vázquez de Coronado who "mounted an expedition in pursuit of gold and rich empires to conquer." Coronado passed through Arizona and discovered the Grand Canyon. "Coronado returned to Mexico exhausted, bankrupt and disillusioned, but with a wealth of new knowledge of the borderlands of the Spanish empire," said Sweeney. He then described the colorful history of early gold, silver and copper exploration and mining in Arizona, including the famous tale of the Lost Dutchman's Mine. In a luncheon address, David Kanagy, SME's executive director, introduced the attendees to the upcoming OneMine. org Web site. Kanagy told the audience" One-Mine.org will be a collaborative digital library that will

Jan 1, 2008

By Shosei Ph. D Serata

The Stress Control Method of mine design provides enhanced engineering control over the behavior of underground structures in comparison to conventional mine design methods. The same Method can be applied to achieve design control of surface subsidence. The basic mechanism relating undergroued deformation and surface subsidence is disclosed by mine simulations, using the REM (Rheological Element Method) computer code, whose predictions have been validated by field measurements. The key components of the underlying mechanism of surface subsidence have been shown to be the stress envelopes formed in the process of underground excavation. It has also been demonstrated that significant control of surface subsidence can be achieved by designing the geometry and timing of underground excavation to regulate the formation of stress envelopes. A field example is given in this paper to illustrate this application of the Stress Control Method.

Jan 1, 1986

By A. Anani

The need to optimize surface mining operations has led to the use of discrete event simulation (DES) modeling of truck-shovel systems. Often, these models assume truck cycle times are independent and identically distributed (iid) random variables, although, with significant bunching on the haul routes, this may not be valid. The objective of this paper is to present a methodology to (i) account for truck bunching due to slow trucks; and (ii) test for cycle time dependence (i.e. whether truck cycle time data is iid or not). We built a DES model that accounts for bunching due to a slow truck(s) and used the cycle times as data for further analysis. We then tested for cycle time dependence using Pearson correlation coefficients. The results show significant correlation of truck cycle times for different number slow trucks, with variable speeds. Assuming iid in modeling results in over-estimation of productivity and the uncertainty surrounding it. The over-estimation of uncertainty is pronounced when the relative difference in truck speed increases. The confidence interval of the means of truck loads/shift decreases with increasing number of slow operators. This work extends the usefulness of DES in truck-shovel applications.

Feb 27, 2013

By Steve Kral

Despite low commodity prices and mining industry cutbacks throughout the world, Peru remains one of the industry’s bright spots. The country’s remarkable economic turnaround during the 1990s remains a model for other developing nations to follow. And the Peruvian government has not forgotten the industry that was instrumental in that turnaround. True, the country has not been spared the effects of the mining industry’s retrenchment that has occurred in other parts of the world. However, foreign mining companies remain committed to doing business in Peru. And the government remains committed to attracting foreign investment and maintaining a strong mining industry. This commitment was evident in September 1999during the 24th Convention of the Institutos de Ingenieros de Minas del Peru in Arequipa, Peru. More than 3,000 mining industry professionals from around the world attended the convention. And Extemin, the accompanying exhibit, featured more than 450 companies, many from the United States, Canada, Australia, South Africa and other countries.

Jan 1, 2000

By C. Bazin

The separation of rare earth elements is a complex process that is industrially carried out using liquid/liquid extraction. Detailed flow sheets of solvent extraction plants for the separation of rare earth elements are rarely available in the literature which limits the opportunity to teach and test the application of data reconciliation, process optimization and control to these types of plants. The basis of a simulator for a rare earth elements separation plant is described in this paper. The simulator is used to adjust the organic phase and stripping acid flow rate in a separation circuit of heavy rare earth elements from light one?s.

Feb 27, 2013

Pillars in underground limestone mines are required to support the overburden and provide a safe, stable working environment for mining personnel and equipment. Pillar stability was assessed by the National Institute for Occupational Safety and Health in underground limestone mines in the Eastern and Midwestern United States. It was found that current mine layouts have been successful in providing support to the overburden, while a small number of isolated pillar failures were observed. The stable pillar layouts and failed pillars were plotted on a chart that demonstrates the relationship between pillar width-to-height ratio and pillar stress. The results show that pillar failures occurred at the lower range of width-to-height ratios and can occur at relatively low stress levels. Zones indicating the potential risk of pillar instability are shown on the chart, based on hazards associated with the onset of rib spalling, large angular discontinuities and unconfined pillars. The chart can assist limestone mine planners to evaluate potential instability in current or new pillar layouts that are similar to those included on the stability chart.

Jan 1, 2008

By K. Saikiran, A. R. Nalla

Longwall management, regular shield maintenance, and evaluation of ground control problems can be performed using real-time shield monitoring program. Based on real-time shield pressure data, evaluation of intensity and interval of periodic weighting, estimation of time-dependent pressure increase and the effects of geologic anomalies can be obtained. In this study, full-face shield pressure data of over 457 m (1,500 feet) of face advancement is analyzed to evaluate shield response in the presence of surface lineaments, floor undulations, and multiple main roofs. Shield pressure increase due to web cutting is also correlated with setting pressure during periodic weighting and normal time. In addition, time-dependent pressure increase rate on Sundays and holidays is also correlated with time average pressure and the location of previous periodic weighting.

Jan 1, 2000

By Debasis Deb

The first version of the longwall strata control and maintenance system (LSCMS) has been successfully developed by the Strata Control Re¬search Team at the University of Alabama. The system includes a software package designed to monitor shield leg pressure, interpret the data and predict the forthcoming roof loads and the existence of geological anomalies. It can also detect maintenance problems of the face equipment. The LSCMS was installed underground and connected to the surface terminals at Drummond's Shoal Creek Mine in Alabama. The system has proven to be a useful and practical system for improving safety and efficiency in coal-mining operation. The Shoal Creek Mine is a new, large coal mine operated by Drummond with two longwall panels. The Blue Creek seam is the primary source of coal production. It is located at a depth of 275 to 440 m (900 to 1,450 ft) below the surface with an approximate 2% southwest dip. Typical strata conditions are represented by two stratigraphic columns (Figs. la and b). A fireclay/dark shale parting (called Middleman) 0.2- 0.7-m- (1- to 2.5-ft-) thick exists between the Mary Lee and Blue Creek seams. Mining conditions vary from area to area. This mainly depends on the Blue Creek seam thickness that ranges from 0.9 to 2.9 m (3 to 9.5 ft). The thickness of the Mary Lee and the parting is relatively consistent with a to¬tal of 0.9 m (3 ft). They are mined when the Blue Creek seam becomes thinner. In most of the panels, the immediate roof is composed of sandy shale 1.5-

Jan 1, 1997

By T. H. Chan

As the University of Hong Kong and their advisors planned their new Centennial Campus it became clear that they would have to re-provide existing water reservoirs on an adjacent site with new salt water reservoirs located underground in two new caverns. The existing reservoirs are owned by the Water Supplies Department who provide salt water for sanitary flushing and a separate potable water supply for regular use. Although underground reservoirs had not previously been adopted locally, the planning has been completed to a tight schedule and the construction is well advanced. The need to preserve historic buildings imposed constraints, as did the requirement to minimise potential construction nuisance for the local community and environment. This paper presents the background to the project and the work carried out to develop an innovative, sustainable and environmental acceptable solution. Construction progress to date is also presented.

In 1950, about a third of the world?s population lived in cities. That figure has steadily risen throughout the following decades. Now it is believed that about 60 percent of the estimated 8.1 billion people in 2030 will be living in urban areas. The strain on infrastructure in cities in the developed world is already showing. And the rapid growth in developing nations today is adding to the shortage of materials, equipment and labor needed to keep up with this growth. So, while materials and labor may be in short supply, there is no shortage of work for the underground tunneling and space industry. In June, 718 of those professionals from around the world were in San Francisco, CA for the North American Tunneling (NAT) conference, put on by the Underground Construction Association (UCA) of SME. The attendees spent the three days of technical sessions listening to international authors discuss the state of the industry, new technologies that have become available and updates on major tunneling projects throughout the world. The accompanying exhibit attracted 79 vendors, who displayed the latest in tunneling and underground space equipment and services. In addition to the technical sessions and the exhibit, the NAT featured three short courses ? ?DRB Process Update Workshop,? ?Soft Ground Tunneling Technologies? and ?Underground Blasting Technology and Risk Management.? And the post-meeting field trip to the Devils Slide tunneling project near San Francisco was sold out.

Jan 1, 2008

By Desiree Willis

Disc cutters have determined excavation rates of rock tunneling projects for more than 50 years. First developed in 1956 by James S. Robbins, disc cutters (then 279 mm or 11 in. in diameter) were used to bore limestone of 190 MPa (27,500 psi) unconfined compressive strength (UCS) and were loaded with 7.12 t (15,700 lbs) each. Modern cutters have reached up to 508 mm (20 in.) in diameter and are typically loaded with up to 31.7 t (70,000 lb) to economically bore through the hardest of rock up to plus 400 MPa (60,000 psi) UCS. New developments, such as larger cutter diameters, are geared to increasing the bearing capacity and wear life of the cutting structure. This, in turn, increases cutter life, cutter load and cutter penetration. Disc cutters have also been re-designed on a small scale for use in hard-rock utility installations. Additional variables also affect the three factors, including cutter spacing on the cutterhead, cutterhead diameter and cutter materials.

Jan 1, 2007

By M. Karmis, S. K. Weisiger

The traditional method for training personnel in the mining and other heavy industries has been face-to-face, either via a lecturer in a classroom or through an apprenticeship. With the advent of applications tools such as video, computers, and the Internet, however, a much broader range of training delivery methods is available. Especially exciting are the broad capabilities of multimedia packages that combine the best features of numerous delivery methods. Applying multimedia environments in training holds great potential, especially when there is considerable difficulty in reconstructing real training environments. The authors discuss various delivery methods currently used in training employees, including perceived advantages and disadvantages of those methods. The authors then discuss and evaluate current computer-based training efforts of the mining industry and present an example of a multimedia training tool.

Jan 1, 2001

The theme of the 2012 North American Tunneling conference (NAT) was ?Tunneling: Driving Value.? This theme best reflects where the tunneling and underground construction industry is to-day. Major advances that have been made in technologies have provided tremendous improvements in productivity, which, in turn, have allowed the industry to deliver more cost-effective and less disruptive solutions to the nation?s infrastructure needs. Despite a weak economy, domestically and globally, cities and states continue to spend billions on infrastructure improvements. For the underground construction industry, that means more transportation and water, wastewater, storm water projects and other underground structures. And, for each project completed, underground construction and tunneling technology grows. The NAT conference, put on by the Underground Construction Association (UCA) of SME, provides an outlet for technology transfers among professionals. This year?s conference, held in Indianapolis, IN June 24-27, attracted 918 attendees, up from 803 at the last NAT in 2010. The accompanying exhibit also featured 116 exhibitors occupying 140 booths. That was up from 108 booths in 2010. So, the meeting continues to grow as underground construction professionals throughout the world seek to learn from their peers.

Jan 1, 2012

By P. A. Plunkert, D. E. Morse, L. McCartan, J. F. Papp

The mineral sector is a fundamental part of the U.S. economy. It contributes to the real gross domestic product (GDP) at several stages —basic (mining), intermediate processing, manufacturing of finished goods and construction. The real GDP increased by 3.5 percent from 2004 to 2005. The nominal GDP was $12.5 trillion at the end of 2005. Housing starts were up by more than 5 percent for the year, and the unemployment rate decreased to 5.1 percent in 2005 from 5.5 percent in 2004. The prime interest rate increased from 5.25 percent at the beginning of the year to 7.25 percent at the end of the year. The value of minerals mined in the United States in 2005 rose significantly because of increased unit prices for some metals —particularly molybdenum — and significantly increased production for some industrial minerals, mainly cement, construction sand and gravel, and crushed stone.

Jan 1, 2006

By S. Ersayin

In 1998, the Concentrator Modeling Center was established within the Coleraine Minerals Research Lab to develop models for simulation of iron ore processing plants, and to assist plant operators in improving performance of their aging plants. The short-term objective was to develop necessary models for reliable simulation using conventional techniques, while the long-term objective was set as liberation-based modeling and simulation of these plants. The short-term objective was achieved in 2002, after the development of models for magnetic separators, hydroseparators and fine screens. A project funded the US Department of Energy was carried out to demonstrate the capability in improving iron ore processing at the Mittal plant. As a result of this study, a 10% improvement in throughput at the plant was obtained, and simulation became a desired tool for plant operators. A significant step in the long-term objective was reached in 2005 with the development of a liberation model. This was followed by incorporation of models capable of processing liberation data into the software. By early 2007, the Center had the capability of performing liberation-based simulation of entire plants.

Jan 1, 2008