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By Elisa Comis, David Chastka, Miriam Piemontese, Maria Chastka

The Lower Olentangy Tunnel (LOT) Project involves the construction of a 17,000 ft (5,200 m) long, 12 ft (3.65 m) internal diameter Combined Sewer Overflow (CSO) tunnel. The tunnel is excavated by using an Earth Pressure Balance (EPB) machine designed to cope with soft ground, weak rocks and water pressure. The project is located in the city of Columbus, Ohio and the main geotechnical hazards are related to the heterogenous soils and the low overburden in an urban environment. This paper focuses on the performance of the EPB first drive and the comparison between the design assumptions and the actual TBM performance during construction.

Jun 23, 2024

By John R. Marks

Introduction An engineer is a builder and a problem solver. He uses knowledge of the properties of matter and energy to furnish the needs of society. Engineers form the bridge between scientific researchers and the general public, most of whom are technologically illiterate. Mining, metallurgical, and petroleum engineers extract minerals from the ground and process them into usable forms. Then, other engineers further process them into society's needs. Minerals engineers deal with more uncertainty than other engineers. Each ore deposit has its own personality and each ore is metallurgically unique. Minerals engineers, therefore, must be flexible, often applying larger safety factors and contingencies than other engineers, and frequently functioning as a jack of all trades. A minerals engineer can work in coal, oil, oil shale, base metals, ferrous metals, precious metals, industrial minerals, strategic minerals, or in exploration. Other mining jobs include banking and financing, education and research, marketing and sales, and government. As a minerals engineer, you may be among the first to work on the ocean floor or the moon. College Preparation A difference between college and industry is the type of problems to be solved. A typical college problem has an exact answer derived from given information. An industry problem is more apt to have a solution chosen from a number of alternatives. Information required for the solution is not given. It must be measured, calculated, looked-up, estimated, or otherwise derived. Solutions involve trade-offs, economics, and human factors, as well as application of physical laws and theory. When a college problem is answered, you move on to the next one. In industry, however, the headaches may just be starting with the implementation of the solution. Students often complain that they see little use for the theory they are learning. This is valid. A good professor will link theory and practice. Another difference between college and industry is the price of failure. In college, you can make a half-hearted effort in an assignment and take your C or D. On the job, however, poor engineering results in potentially effective projects being rejected and unsound projects being undertaken. Poor performance results in cost overruns, schedule holdups, oversights, disgruntled employees, irate bosses, unsafe structures, and unreliable systems. The costs are time, money, and possibly lives. The student pays the university for his work - not the other way around. So the rewards for good schoolwork often seem nebulous. But education must be viewed as an investment. Working for good grades will help you think better, learn more, receive better job offers, and perform more effectively on the job. There is no substitute for hard work. Avoid taking the easiest electives. If you desire a more liberal education or dislike rigorous physical sciences, mathematics, or engineering courses, change majors. Remember, you are training to be an engineer, not a computer programmer or market analyst. At least one summer of industry employment is necessary for minerals engineering students. The sooner you gain actual experience, the sooner you will know whether to change majors. Most large companies hire students during summer. It is best to send out applications around Christmas break. First and second year students usually work as laborers. Upper-classmen may work as engineering technicians. Students must sometimes choose between returning to a company at a higher position or trying a different company at a lower position, for more varied experience. Both alternatives have advantages. Do your best on these summer jobs. The company is watching. If you do well, the chances are good you will get a job offer when you graduate. Good references are important when you begin job hunting. Interviewing occurs near the end of your school career. The standard procedure is to send your resume with a cover letter to each company you are interested in. The resume for a graduating engineer with little experience need not exceed one page. The cover letter must be written for the individual company.

Jan 2, 1985

By T. Qiu

"The purpose of this study is to investigate the effect of the dosage of sodium hypochlorite as activator on the flotations of depressed marmatite and depressed chalcopyrite, with a focus on activation-flotation kinetics. Four flotation kinetic models were applied to test data using 1stOpt statistical analysis software to estimate the relationships between the maximum flotation recovery rates for the depressed marmatite and depressed chalcopyrite, the flotation rate constants and the sodium hypochlorite dosages. Within the range investigated, the highest flotation performances of depressed marmatite and depressed chalcopyrite were obtained at 2.5 mL/L sodium hypochlorite with zinc recovery rate of 93.8 percent and 3 mL/L sodium hypochlorite with copper recovery rate of 94.6 percent, respectively, after four minutes of flotation. A second-order model with rectangular distribution of flotabilities gave the best fit to test data collected at various sodium hypochlorite dosages. For the highest flotation performances of depressed marmatite and depressed chalcopyrite, the respective equations of their flotation models were derived and presented.IntroductionCyanidation tailings are the solid residues generated by gold plants that use cyanide to extract gold (Lv, Ding and Qian, 2015; Zhang, Li and Yu, 2013). Because of increasing demand for gold, the Chinese gold industry has developed rapidly, with production amounting to 451.799 tons in 2014, an increase of 5.5 percent from 2013. Chinese gold production has been the highest in the world for eight consecutive years. As a result, more than 2.45 million tons of cyanidation tailings are estimated to be discharged into tailings ponds every year (Li et al., 2010; Lv, Ding and Qian et al., 2015; Wang et al., 2015; Zhang, Li and Yu, 2013; Zhang, Li and Yu, 2012), and approximately 300 million tons of cyanide tailings are stockpiled in China, with the potential to cause serious environmental pollution as well as death to wildlife (Adams and Lloyd, 2008; Donato et al., 2007; Hewitt, Breuer and Jeffery, 2012; Velasquez-Lopez et al., 2011; Stephen et al., 2009; Zagury, Oudjehani and Deschenes, 2004). Concerns over cyanidation tailings are not exclusively environmental but also economic, as tailings occupy considerable land area, and tailings storage facilities increase the production costs of gold enterprises (Donato et al., 2007). Tailings often contain other valuable metals such as zinc, lead and copper. For example, the cyanidation tailings of Gaoyao Hetai Gold Plant in Guangdong Province contain 2.5 percent copper (Cu), 0.31 percent lead (Pb), 0.23 percent zinc (Zn) and 15.36 percent iron (Fe) (Shi, 2008), and the tailings of Tianshui Gold Plant in Gansu Province contain 1.94 percent Cu, 5.96 percent Pb, 0.27 percent Zn and 24.62 percent Fe. Cyanidation tailings have therefore been increasingly viewed as a secondary resource rather than waste."

Jan 1, 2016

By Gunjan R. Bhattarai, Kumar Bhattarai

Recently, there has been an enormous increase of interest in artificial intelligence (AI), machine learning (ML), and their applications by researchers, government agencies, and the underground construction industry. Ultimately, these tools have the potential to automate the design and construction processes and boost productivity, safety, quality, and operational stability. This paper presents ongoing research and applications of artificial neural networks (ANNs), robotics, and 3D technologies in ground characterization, tunnel ground support prediction, risk projection and reduction, and productivity enhancement in TBM operations. The paper further investigates potential uses of AI, robotics, and 3D technologies in the underground construction industry

Dec 1, 2022

By Robert J. Collins

Computer-aided design drafting systems have been employed in plant design for nearly ten years. Current and future systems will include computer-aided engineering as well. This paper will explore the history and development of such systems including computer and workstation hardware, graphics software, and plant design applications software. The paper will also address future systems and will present both the system vendor and the mine mill designer's view. Specific examples of particularly successful applications will be included.

Jan 1, 1985

By J. J. Renton

The iron disulphide minerals, pyrite and to a lesser extent marcasite, are ubiquitous to coal and coal associated rocks and are the source of nearly all the environmental problems associated with the mining, processing and utilization of coal. The iron disulphides as well as the other minerals in coal exhibit systematic spatial pat- terns of distribution on both regional and local scales and show predictable associations, most of which are determined by the geochemical-sedimentological controls under which they form. It is the purpose of this paper to discuss the geochemical-sedimentological conditions responsible for the formation of coal minerals with special emphasis on the formation of iron disulphides, to illustrate the regional and local patterns of mineral occurrence within coal, to present the microscopic associations of the iron disulphides and finally, to discuss the most important single environmental aspect of the iron disulphide content of coal and coal associated rocks; the production of acid mine drainage.

Jan 1, 1986

By S. K. M. Chao

The increasing demand for large volumes of relatively low-cost cement has resulted in the need for an equally low-cost high-volume means for transporting that cement. It has been estimated that 20% - 25% of the total cost of cement to the buyer represents delivery expenses from the mills. For instance, during the 1972 cement shortage in the Southeastern region of the U. S., bid prices for a ton of cement delivered increased to $45 compared to $20 average at mill price, i. e. , F. O. B. plant. Much of the increase was caused by the anticipated higher cement shipping costs for longer hauling distance. The exceptionally high bid price, of course, was not the price quoted by the successful bidder. Thus, clearly, cement is not a marketable commodity unless it can be economically transported to the consumer.

Jan 1, 1975

By V. F. Hollister

Computer programs developed as part of the PROSPECTOR project at SRI International can indicate where the highest grade hypogene copper occurs in porphyry copper prospects. The programs are useful in selecting drilling targets in untested porphyry deposits. Because of mineralogic, structural and lithologic variations in porphyry-type deposits, three distinct computer programs have been constructed; however, this paper considers only the stockwork type in homogeneous rock (similar to the Lowell and Guilbert model). The programs represent models in the form of inference networks that utilize the mineralogic, alteration, lithologic, structural, geochemical and geophysical data normally collected prior to a drilling decision. One example of an application of the PROSPECTOR program for a stockwork-homogeneous porphyry is given: Island Cooper in British Columbia. Computations based on the surface geologic, geochemical and geophysical data for Island Copper clearly disclose the best hypogene grade of the deposit. Other deposits were tested in the programs as well, and in each case PROSPECTOR programs indicate the region with the highest hypogene grade.

Jan 1, 1983

By J. A. Ehler

Speed and torque control of standard A.C. induction motors can be accomplished using a variety of devices ranging from mechanical, hydraulic, and electrical. Also, the motor can be specified as an A.C. wound rotor or D.C. motor using the associated controls. Normally, any one of these drive types can be adequately used to provide the torque control necessary to accelerate a conveyor belt system. The selection will depend on the economics, experience, and preference of the designer or end user. These drive types will be presented from a functional and performance viewpoint to assist in the understanding of the available technology.

Jan 1, 1998

By Derrick Chambers, George Kevin Chapin, M. Shawn Boltz

Seismic monitoring is one of the few noninvasive technologies with the potential to provide sub-surface geomechanical information to operators of large open-pit mines. Although passive seismic data has been used to refine emerging failure geometries and provide advance indication of surface deformations in the literature, doing so reliably in an operational context is much more difficult. This is due in part to difficulties in estimating and interpreting source locations and parameters in complex, low-stress open-pit environments. Additionally, the high costs associated with implementing, operating, and maintaining deep borehole seismic networks, which are most commonly used to monitor large open pits, can be difficult to justify, especially if monitoring benefits are not readily apparent. In this study, we explore the use of a near-surface nodal seismic deployment, which is commonly used in oil and gas exploration, for monitoring open-pit mining-related seismicity on a short-term basis. A deployment of 18 geophones was conducted on the surface in and around the Bingham Canyon Mine, a large open-pit mine near Salt Lake City, Utah, USA, where we find the small seismic array can detect and locate a variety of mining-related seismic sources, even with an extremely simplified velocity model. We outline the process of creating an idealized velocity model, developing a local magnitude scale, and interpreting the observed seismicity. Of note, we analyze a sequence of mining-induced events associated with a known structure on the south pit wall. We conclude with discussion on how surface-based deployments may be used to augment, or in some cases supplant, borehole seismic networks at large open-pit mines depending on monitoring requirements and objectives.

Apr 26, 2022

The 31st annual American Hall of Fame Awards Banquet and Fundraiser sponsored by the Mining Foundation of the Southwest (MFSW) will be held at the JW Marriott Tucson Starr Pass Resort on Saturday, Dec. 7, 2013. Each year, one living inductee, two Medal of Merit recipients, honorees from mining?s past, an industry partnership award, as well as a special citation, are recognized by the MFSW for their respective contributions to the mining industry. James D. Toole, past president and chief executive officer of Southwest Energy LLC, will be the Hall of Fame inductee, guest of honor, and featured speaker at the awards banquet. Toole founded Southwest Energy LLC in 1973 and is credited with introducing innovative explosive technology, providing even greater value to its mining customers. Medals of Merit will be awarded to Joseph M. Keane, principal metallurgical engineer for SGS Metcon Research/KD Engineering, and Sean D. Dessureault, associate professor at the University of Arizona. Keane is recognized for his metallurgical expertise, especially in design development and pollution abatement. Dessureault is recognized for his advanced mining research, with more than 25 journal publications, and his entrepreneurship as the founder and chief executive officer of two mineral-related companies. To honor mining?s past, the hall of fame will induct Bartolomé de Medina for his invention of the patio process for recovering silver; Ben Williams for his management of the Copper Queen Mine in Bisbee, AZ; Charles E. Mills for his contributions at Morenci and Inspiration Copper and founding Apache Powder Co. and The Valley National Bank; John S. Finlay and Edwin B. Royle for their invention of the mucking machine; and Louis Caryl Graton for his ore deposits research and teaching economic geology at Harvard University.

Nov 1, 2013

By Todd Loudin

A majority of the chemical process industry uses lime in either a powder or liquid form. Engineering and maintenance personnel often face a long and potentially expensive trial-and-error period in order to find the best process equipment to handle lime. Limestone is mined from a quarry in the form of calcium carbonate (CaCO3). Then, it is crushed and fed into a kiln at approximately 1,093° C (2,000° F), where the carbon dioxide is burned off (calcining) to make calcium oxide (CaO).

Jan 1, 2010

By Jacques LeBel

After a brief definition of asbestos and a review of regulations, the elements of asbestos dust control are outlined for various asbestos manufacturing industries. To prevent the asbestos dust to become airborne, the general procedure is to control the dust at the source by enclosure and exhaustion. The asbestos dust is collected and removed from the air with bag filter collectors of high efficiency (better than 99%) to ensure that the air emitted to the general environment or returned to the workplace are below the existing asbestos emissions regulations. Dust control systems should be regularly inspected and serviced to maintain at all times the efficiency and reliability of the equipment. Other effective procedures for asbestos dust control are also considered.

Jan 1, 1984

Computerized financial models can be used in all phases of the mineral industry from setting exploration targets to projecting profit plans for producing mines. In this presentation, I will use the example of an exploration company entering a new district to trace the application of financial models through the following intermediate phases. 1. Hypothetical analysis and strategy 2. First encounter of mineralization 3. Preliminary drill results - decision process 4. Feasibility studies 5. Post-feasibility negotiations 6. Producing mine 7. Acquisition of producing mines or mineral properties. I will conclude with a brief discussion of the mechanics of the financial models that we use at Wright Engineers Limited. As we progress through the seven phases, the availability and accuracy of the data will parallel the complexity and application of the financial models. However, the same basic financial models are utilized throughout the seven phases. I will begin by suggesting that the exploration group is somewhat autonomous and has the mandate to explore in Western Canada.

Jan 1, 1979

By F. D. Ayhan

The aim of this study was to investigate desulfurization and de-ashing of a mixture of subbituminous coal and gangue minerals by the agglomeration method. For this purpose, experimental studies were conducted on a mixture containing subbituminous coal, pyrite, quartz and calcite. The effects of some parameters that markedly influence the effectiveness of selective oil agglomeration, such as solid concentration, pH, bridging liquid type and concentration, and depressant type and amount, were investigated. Agglomeration results showed that the usage of various depressants (Na2SiO3, FeCI3, corn starch, wheat starch) in the agglomeration medium has a positive effect on the reduction of ash and total sulfur content of agglomerates. It was found that an agglomerate product containing 3.03% total sulfur and 25.01% ash with a total sulfur reduction of 56.71% was obtained from a feed that contained 7% total sulfur and 43.58% ash when FeCI3 was used in the agglomeration medium. Key words: Desulfurization, De-ashing, Agglomeration, Coal, Gangue minerals

Jan 1, 2009

Information Technology has addressed those problems unique to senior management in the mineral industry. In general, these problems are those concerned with decision-making. Peter Drucker in his discussion of making effective decisions identifies five phases: (1) define the problem, (2) analyze the problem, (3) develop alternate solutions, (4) decide the best solution, and (5) convert the decision into effective action. The scope of the chapter by Guernsey addresses the first three phases which provide input to the decision-maker. The decisions to be made relate, in most instances, to the economics related to a mineral property or process. Computer models have been designed to generate these economic and financial evaluations. No one model is appropriate to the solution of all management's problems. In this chapter several applications are identified and summarized; a model for the economic evaluation of a mineral property is described in greater detail. The implementation of such models is dependent on the unique needs of management.

Jan 1, 1979

By Carlos Kovacs-Figueroa

Because of air pollution control regulations in the early 701s it became necessary to clean effluent gases from the Morenci Reduction Works Smelter. Feasibility studies indicated that this could be accomplished most efficiently by using the smelter gaseous effluent to feed a sulfuric acid plant. Complying with air pollution control regulations thus created the need to dispose of relatively large amounts of concentrated sulfuric acid. Typical Morenci ores contain substantial amounts of oxidized copper minerals which are not recoverable by flotation. In addition, there is low sulfide, high oxide material which can be leached, but is not suitable for flotation concentration. Early in 1971 sufficent data had been accumulated to show that a leaching plant for the Morenci tailings could use a large portion of the sulfuric acid produced by the Smelter. It was determined that for all practical purposes leaching of the available copper was complete in two hours or less. Capital expenditures could not be justified for more than two stages of counter current decantation for recovery of the leached copper, and the plant was designed with these criteria in mind.

Jan 1, 1976

By Goutam H. Shahani

The current economic downturn has been at the center of media attention for several years. Today, the mining and mineral sectors are being impacted by highly fluctuating supply-and-demand conditions, extreme price volatility and tremendous market uncertainty on a world-wide basis. There have been numerous plant closings, project cancellations and employee layoffs. In this gloomy economic environment, it is easy to forget that the world?s gross domestic product (GDP) has more than doubled in real terms during the last 30 years. While current market turbulence may continue for some time, the long-term trend is unmistakably upward. Living standards are rising all over the world, thereby creating demand for food, clothing, transportation and housing. This translates into tremendous demand for the mining and mineral sectors. In the future, new capacity and plant expansions will be necessary to meet this need. These investments, which typically have a life span of 30-plus years, will have to be based on long-term economic considerations rather than current market conditions.

Jan 1, 2011

By William M. Gray

[The products of mites hive historically beet a very large and important segment of total shipment transported by American Railroads. Much as the Mining transportation Executives right have wished for coal and other mineral deposits to be found along navigable rivers, where railroads have for years been competing with the very aggressive Army Corps of Engineers and the inland waterway operators, the mineable reserves are more often that not located in the arid west far from these "free" waterways. The rivers cannot go to the mines but the railroads could, did, and continue to invest it new lines to reach new mines. The mining industry and the railroad industry have good reason to rely upon each other. The former Northern Pacific Railway, the Great Northern Railway, the Chicago, Burlington and Quincy Railroad and the Spokane, Portland and Seattle Railway merged in 1970 to form the Burlington Northern Railroad, with Lou Menk as its first President. As unofficial spokesman for the industry, be had, for years, conducted a tireless effort to educate shippers, lawmakers and the general public of the single most critical problem confronting the railroad industry, the strangle bold of government regulator.]

Jan 1, 1985

By Liliana Rybarska-Rusinek, Aleksandr M. Linkov, Ewa Rejwer-Kosińska

Joined modeling of stressed state and induced seismicity is a means to join geomechanics with seismic observations. When applied to quantifying rockburst hazard, it provides, on one hand, estimations in terms of mechanics, such as stress concentration, and, on the other hand, in statistical terms of the risk analysis developed in mining seismology. The modeling became possible due to progress in computers and numerical methods. However, despite tremendous increase of computational abilities, the joined modeling is still quite time expensive. To make it available for wide use and real time simulations, there is need to reduce the time cost of its key stages: calculation of stresses, caused by mining, and simulation of seismic events, induced by these stresses. The present work aims to decrease the time cost. The stages are time costly because of the same reason, which is a very large number N (up to millions) of elements, representing rock structure, openings and flaws. This leads to immense computational complexity (roughly of order N2) of conventional accounting for pairwise interactions between the elements. The complexity may be notably reduced, when employing the fact that interactions decrease with growing distance between elements. Specifically, the fast multipole methods (FMM) avoid the complexity N2, by employing translations of far-fields from whole collections of sources. This reduces the complexity to the order 22, where p is the number of terms involved in a single translation, is the number of translations, and is the dimension of the quantity translated. Still, for conventional FMM, the complexity remains too high to routinely perform joined modeling of stresses and seismicity.

Apr 26, 2022