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By W. M. Schafer, C. F. Luckay, D. A. King

Monitoring devices have been installed at several mine sites to assess the potential for the development of acid rock drainage (ARD) in waste rock, spent ore and tailings material. In addition, instrumentation has been designed for monitoring changes in water quality in pit lakes. These devices monitor temperature, oxygen, water movement and water chemistry in the waste rock pile. This information can be used to evaluate the current and future ARD risks and the effectiveness of caps and covers. The information can also be used in the design of other reclamation strategies that limit ARD development. The instrumentation includes nested thermistors and oxygen sensing ports, neutron access tubes, heat dissipation units (HDUs) and lysimeters. Many of the monitoring devices can be linked to a data logger and telemetry systems, enabling monitoring data to be downloaded from the office.

Jan 1, 1999

By Henry Antwi

The decade of the 1990s promises to be one of increasing internationalization for domestic minerals producers as they scramble to enhance relative positions in highly competitive, international minerals markets. This "international mining rush" is fueled by developing countries seeking international investment capital to explore for, develop and exploit sizable mineral endowments in an attempt to support the increasingly popular, but expensive, wave of democracy and selfdetermination sweeping the world. This "fuel" typically takes the form of revised mining codes and, often, lucrative investment incentives. These incentives include favorable tax rates, royalty provisions, relaxation of import/ export constraints, depreciation schedules, profit repatriation and other variables that can positively impact mineral investment decision making. Concomitantly, in their attempts to address real and perceived short- and long-term woes associated with enhancing competitive positions internationally, many domestic explorers and producers are attracted to the prospect of finding high-grade deposits in relatively virgin areas. Combined with the investment incentives provided by foreign governments, these high-grade deposits promise lucrative potential returns from projects having short payback periods. Classic examples of this mutual desire to intensify international mining efforts by domestic producers are illustrated by activity levels in countries like Chile, Bolivia and Venezuela in Latin America and, more recently, in Eastern Europe and select locations in the former Soviet Union. As US corporations scurry to send fact-finding, technical, evaluation and financial teams to these presently popular locations, one area of the world has received little attention - Subsaharan Africa. Specifically, the country of Ghana (formerly the Gold Coast) deserves more attention than it appears to be receiving from North American mining companies.

Jan 1, 1992

By AK Raina

Blasting is used in mining and civil excavations to break the rockmass for ore production or creation of space. One of the disadvantages of the method is that it causes breakage beyond the proposed excavation lines. Pre-split is used to control such breakage in rockmass. This paper introduces the use of digital image analysis technique (DIAT) to measure rock breakage and half cast factor (HCF%). A new factor, undamaged area (AUD%), is introduced to improve the prediction, owing to the shortcomings of the HCF%. A comparison of significant data of AUD% and HCF% showed that HCF% has a lacuna of overpredicting, whereas AUD% can be used effectively to address the issue. Artificial neural networks are used to solve the complexity of multiple variables involved in predictions and to ascertain the importance and sensitivity of such variables in prediction regimes. This method will help users to evolve blast-induced damage objectively. A comprehensive scheme of things for future developments is included, which can be helpful to researchers in defining their research in this area.

By Silas Li, Michael Harris-Gifford, Jason Choi, William H. Hansmire

Twin-bore tunnels with a single track in each tunnel are currently the most common subway tunnel configuration. However, a large diameter single-bore tunnel with two tracks separated by a center wall could replace twin-bore tunnels and introduce potential benefits but require necessary modifications to the subway system. In particular, a nominal 40-foot-diameter single-bore tunnel can be considered in lieu of nominal 20-foot-diameter twin-bore tunnels. This paper discusses the benefits and modifications introduced by replacing twin-bore tunnels with a single-bore tunnel, with respect to various elements of the subway related to the tunnel, stations, track, and tunnel systems.

Dec 1, 2022

By John Newby, Ulf Gwildis, Fred Marquis

From the Brightwater Conveyance System in Seattle to the Second Narrows Water Supply Tunnel in Vancouver, BC, the design and construction of deep-lying tunnels in the Pacific Northwest often require the incorporation of deep portal shafts. Alluvium overlying marine and glacial deposits combined with the high regional seismicity is the common geologic setting. The latest example illustrating the development of shaft design for this scenario is the 40-m-deep shafts of the Annacis Island Wastewater Treatment Plant New Outfall System. The main components of the shafts include the initial lining, providing the excavation support system to be used for launching and receiving a 5-m-diameter TBM; and the final lining, designed to withstand all static and seismic loads and to remain viable for the intended design life. This paper presents design and construction considerations for these shafts against the background of and lessons learned from past project experiences.

Jun 13, 2021

By Patricia O. Milley

Two years ago, AlliedSignal embarked on a journey to improve QUALITY. However, the focus of this endeavor was on the CUSTOMER and not the traditional product focus. It wasn't that a focus to improve product quality wasn't fruitful in the past. We've practiced it in the chemical industry for many years with significant results. But our industry today is in a survival mode and yesterday's way of doing business is simply not good enough. In the mining industry, we have to make lug strides in how we do business or face losing our customer base. As you are well aware, other parts of the world are importing our technology at a rapid rate. We must work smarter to stay ahead of our customers ever more demanding need for higher quality at lower prices. With this as a driver, throughout the Corporation we reviewed in depth how we support our customers to keep them competitive and sought to eliminate work which did not help them reach this goal. Our first year of emphasis was on tools: how to hold meetings, gather data, and how to make decisions. This sounds very basic, I know, but you can't begin to imagine how productive meetings can become when you start with an agenda and prework delivered days in advance, and agree at the start of the meeting what should get accomplished. In the second year, we applied these tools to our work processes. We mapped how we do our work, scrutinized each step for value to the customer, and then set to work on how we could do things better. The areas we concentrated on were customer linked commercialization of new products, manufacturing and materials management. Our discussion today will focus on the commercialization of new products.

Jan 1, 1994

By Michael Robert Hodson

I. Introduction The free market cash price of aluminium in the third quarter of 1985 is approximately $1000/tonne, well below the short as well as the long run marginal costs of production. The current disparity between marginal costs and price, as well as the pattern of prices since their high level in 1980, has led many economists to question whether prices are governed by the 'fundamentals'. Prices, some would argue, are the result of speculation; and speculation is irrational, little influenced by the fundamentals of the industry. The object of this paper is first to examine the relation between the fundamentals and price. A number of simple models are formulated and some empirical evidence is given to show that prices are not very different from costs. There are good reasons why costs and prices have fallen since 1980. Second, the connection is drawn between the fundamentals and speculation. To do this the concept of 'rational expectations' is defined and applied to a model of the aluminium industry. Then speculation is introduced into the model and the characteristics of the solution are examined. The object is to discover the new factors that determine prices and the basic change in the nature of the solution that is caused by speculation. 2. Prices and the Simple Supply-Demand Model Consider a simple model of the aluminium industry. Demand, D, is determined by economic activity, A, given exogenously, and inversely by the price, P. Supply, Q, is determined by the inverse of the rnarginal cost curve, and so varies inversely with exogenous factor costs, C, and directly with price. Price is determined by the equality of supply and demand. Given the equilibrium level of demand, price in this model is equal to the rnarginal cost of producing the required level of demand, P = MC (Dl. Algebraically, [ ] How well does this simple model explain the change in prices during the last five years? Table I shows the LME cash price and the estimated marginal cost of producing consumption during the second quarters of 1980 through 1985. The figures in the table show that price and the marginal cost of supplying demand both fell between 1980 and 1982, rose in 1983 and by 1985 had fallen again. Only in 1984 is the direction of change different. And during the 1980 to 1985 period, marginal costs fell by approximately $560/tonne while the LME cash price fell by $678/tonne. There is a correspondence between the fundamentals of cost and price over most of the individual years and the period as a whole.

Jan 1, 1986

"The 33rd annual American Mining 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 & Spa on Saturday, Dec. 5, 2015. Each year, one living Hall of Fame inductee, two Medal of Merit recipients, several honorees from Mining’s Past, an Industry Partnership Award and a Special Citation are recognized for their respective contributions to the mining industry.Conrad E. Huss, cofounder of M3 Engineering & Technology Corp. located in Tucson, AZ, will be honored as the 2015 Hall of Fame Inductee and will serve as the keynote speaker at the awards banquet. Huss has served his company as chairman of the board for its entire 30 years and guided M3 to become a full discipline firm. Now M3 offers complete project execution through engineering, procurement and construction management procedure and has become a major engineer of large observatories around the world. The company now has more than 1,000 employees with offices in Arizona, North Carolina, Mexico, Argentina and is incorporated in Guatemala, Peru and Canada.The Medal of Merit will be awarded to Charles Michael (Mick) Lownds, founder of his eponymous consulting firm in Salt Lake City, UT, for his 42 years in commercial explosives following tenure at Sasol and at Orica. Originally from South Africa, Lownds immigrated to the United States in 1998 and has made significant advancement on electronic initiation systems. Lownds has published numerous technical papers, is an inventor with 12 awarded United States patents and was also the recipient of the President’s Award from the International Society of Explosives Engineers in 2000.Medal of Merit for young professionals will be awarded to Fiorella Giana, Freeport- McMoRan Inc.’s (FCX) mine manager at Bagdad. Born in Buenos Aires, Argentina, Giana left the small cattle farm where she was raised in 2001 to pursue higher education in the United States. For the past decade at FCX, as a result of her extraordinary combination of technical skill, leadership and commitment to excellence, she has been given positions of progressively greater responsibility from an entry level engineer to senior mine engineer, to chief engineer and now as mine manager, a position rarely held by woman."

Jan 1, 2015

By CLAIRE STREBINGER, ADITYA JUGANDA, JURGEN F. BRUNE, GREGORY E. BOGIN JR.

Methane gas explosions are a major risk in underground coal mining operations. The severity of such explosions can range from local area damage to massive loss of miners’ lives along with significant damage to mine infrastructure and ventilation controls that may lead to mine closure and loss of the entire operation. This study demonstrates the viability of integrating a computational fluid dynamics (CFD) combustion model into a longwall mine ventilation model to simulate methane gas explosions in the longwall face area. The resulting 3D methane gas explosion simulation can provide better understanding of the fundamental physics and the potential impact of an explosion in an underground longwall coal mine.

Aug 1, 2022

By D. M. Steelman

Digital systems have been employed in industry as an aid in process evaluation and control for about 20 years. The earlier systems were quite simple and did little more than periodically scan a multitude of process variables, perhaps comparing them to alarm limits, and print out the results. As time passed, the needs of industry and the imagination of process engineers became more demanding. Rather than perform only alarm checking and logging, operating guides were generated to help the operator gain optimum performance from the process. Eventually, systems were entrusted with the job of manipulating the set points of the local analog control loops in a (DDAC) digitally directed analog control mode. Today digital systems are used to gather all-the process information, including both analog and digital variables; to make the necessary data manipulations; and to control the process end elements in a (DDC) direct digital control mode. During these years of transition from the very simplest systems to the complex systems of today, the demands upon the system engineer have been every increasing. The process engineer has required, among other things, more computational ability at high speeds, faster input and output rates, greater flexibility, better communication facilities (man-machine interface), (process oriented software), and finally, greater reliability at lower cost.

Jan 1, 1969

By Jim Buckley, Ryan Sibley, Scott G. Giltner, Thomas Pallua, Joe Schrank, Robert Cidlik

Because of variation in rock type and site conditions, it is important to create site-specific prediction models for peak particle velocity (PPV) and understand instrumentation mounting locations to better interpret the readings provided following blasting operations. The Atlanta Airport is expanding the section of underground tunnels for its Plane Train people mover, and drill and blast operations were determined to be the suitable method of excavation for the project. Extensive work was done to begin creating prediction models and determining levels of concern based on readings from various types of instrumentation. This paper analyzes the effect of close quarters construction blast vibrations and observed frequency spectrum on existing structures with data from 22 different seismographs mounted in various locations and ground conditions.

Dec 1, 2022

By J. S. Lewis

Beneficiation and physical and chemical processing of non-terrestrial materials will borrow strongly from terrestrial experience but will also involve the necessity of handling literally unEarthly feedstocks, reagents and environmental conditions. The present state of scientific and engineering understanding of the processing of non-terrestrial minerals, gases and hydrocarbons is reviewed, with the production of rocket propellants, life-support fluids, structural metals and refractories as the goal.

Jan 1, 1994

By Karl Gugel, Dante Garcia, Peter Czel, Eduardo Nunez, Joshua Morales, Boris Sullcahuaman

Real-time operational excellence is achieved through the seamless integration of various components. Key aspects include precise instrumentation, real-time data collection, data analytics, and an efficient optimization platform. Additionally, to ensure success, the real-time optimization platform must be incorporated into the site’s internal process control system (Nunez, 2022). This paper provides an overview of practical lessons and best practices for autogenous (AG), semi-autogenous (SAG), and ball mill (BM) grinding. It highlights the implementation of advanced instrumentation, specifically vibration sensors on the rotating mill shell. The paper also delves into the application of advanced analytics necessary for generating new measurements that accurately represent real-time grinding activity in the mill. These Advanced Analytics Measurements (AAM) are compared with well-known grinding curves to determine the optimal grinding point. The discussion focuses on key industry opportunities using real-time mill shell vibration results to derive new correlations and optimize the grinding process.

Feb 1, 2025

By Kevin Bell

The TRAC™ Program was developed to provide our clients with a mechanism that allows them to better manage site remedia­tion and closure costs. This program provides a fixed-price contract for site remediation and case closure and is well suited for large pro­jects with multiple PRPs, such as Superfund sites. Because Kvaerner is a large engineering/construction firm and not a consult­ing firm, we can offer this type of contracting mechanism that envi­ronmental consulting firms are hesitant or unable to provide. With TRAC™, Kvaerner assumes financial and technical responsibilities for carrying a site through the closure process for a fixed price. Liabilities carried on our client's balance sheet for site closure can be removed when they sign up forTRAC™. In many instances, a profit can be realized as the liability on the balance sheet may exceed our TRAC™ fixed-price cost to close the site. Bonds and other sureties securing the site can be released and set­tlement with other involved parties can be quickly reached. For a project to be considered for this program, it typically meets the following criteria: 1) The project site should be physically separated from other contaminated sites 2) A reasonable quantity of site investigation data must be avail­able including site-usage history with or without a projected fea­sibility study(ies) and/or remediation design 3) Access to perform all necessary work must be available. After a review of all site data, K vaerner develops a "risk menu" to manage financial risks. In this "menu", each compo­nent of the project is assigned a level of probability that the costs will occur. Then the base cost of each activity is "weighted" by multiplying the potential cost growth by the probability. This analysis assures that the financial risks are appropriately defined, weighted, and mitigated and a realistic fixed price is developed. Upon acceptance of our proposal and conclusion of contract negotiations, Kvaerner takes over future responsibility for clos­ing your site. This allows the client to: 4) Release reserves obligated on financial statements for the site (and potentially realize a profit if the TRAC™ fixed-price cost is less than our client's booked obligation) 5) Finalize cost settlement with other responsible parties, insur­ers, etc. 6) Redirect resources involved in the environmental manage­ment of the site 7) Cap legal and administrative costs In addition to performing the site cleanup and closure work, at our client's request we are able to: 8) conclude lease obligations for property 9) dispose of equipment and buildings

Jan 1, 1998

By Yi Luo, Jian Yang, Hua Jiang

Surface subsidence events induced by underground longwall coal-mining operations can cause various disturbances to surface structures, ranging from integrity and stability to functionality problems. Highway bridges, as a kind of special road construction that can only tolerate smaller movements and deformations than road pavements, are particularly susceptible to severe influence caused by subsidence-induced ground movements and deformations. However, based on accurate subsidence prediction and correct influence assessments, efficient and effective mitigation and remediation measures can be designed and implemented to ensure the continuous service of bridges, safety of travelers, and smooth mining operations. In this paper, based on the predicted final and dynamic surface movements and deformations, the techniques to assess subsidence influence on the integrity, stability and functionality of bridge structures (such as decks, beams and abutments) are presented. A number of mitigation measures to protect bridge structures are recommended, along with an actual application case.

By Jouko Suominen

The basic development of various mining equipment has been strongly influenced by two objectives; improving economic results and safety aspects. Both of these factors contribute to increased requirements of mechanization and automation in different parts of mining processes. When we are limiting the discussion the crushing circuits, automation has two dimensions, one being the component automation, or intelligence, the other being automation of complete processes. Both of these subjects are closely tied up, the former being a condition for the latter. The key technologies of crushing automation are transducers, programmable logics and computer software. Also equipment technology continually faces new challenges, which result even in totally new product families. One example of this kind of development area the track-mounted, integrated crushing systems, where design criteria have been simple control, unmanned operation, and flexibility in changing requirements. This crushing system, or philosophy, offers excellent possibilities for new concepts in various underground and open pit applications, connected with automatic process control. Following presentation is a summary of aspects, of haw a crusher manufac¬turer sees the development of automa¬tion as an integral part of equipment technology and development.

Jan 1, 1989

By RICKARD HANSEN

Vehicle fires in underground mines pose a certain risk for which measures to prevent or mitigate the fires are highly important. Fire protection measures can be divided into active and passive measures, where active measures require an external power to work in the event of a fire, and passive measures could include an existing partition preventing fire spread. As passive fire protection does not rely on activation, it is expected to provide high reliability and a robust solution, and should be considered during the design process. This paper investigates passive fire protection measures that could be implemented in the design of mining vehicles. It was found that passive fire protection should include the use of several measures simultaneously to ensure fire protection throughout the different phases of a fire. Threshold distances for fuel components were calculated, and it was found that combining hydraulic hoses and electrical cables resulted in larger threshold distances. A pool fire along the underside of a vehicle will pose a certain risk, and passive measures should be focused on ignition prevention, making high demands on the insulation/shielding along the underside. Any occurring tire fire may pose a challenge, and the priority should be on preventing ignition. Potential measures include shielding the wheelhouse and applying fire-resistant sealings.

By N. R. Hasenmueller, V. Rajaram, R. K. Leininger, D. D. Carr

The content of the paper by V. Rajaram does not fulfill the expectations of the title. But Rajaram submitted the article in October 1983, and he could not have foreseen the numerous developments that would occur before his paper was published more than two years later. Nevertheless, Rajaram failed to mention the interest in oil shale development in southern Indiana beginning in late 1979 and continuing through the present as a result of special financial encouragement of three oil shale projects in May and August 1984 by the Indiana Energy Development Board and the Indiana Corp. for Science and Technology. A session at the 1985 Eastern Oil Shale Symposium in Lexington, KY, Nov. 18-20, 1985, gave the current status of oil shale developments in the eastern United States. Speakers at this session reported on the three Indiana projects. First, Gary D. Aho, Cliffs Engineering Inc., spoke on a feasibility study by Cliffs Engineering and Allis Chalmers for a site-specific pilot plant using the Allis Chalmers process. The plant site is in Clark County, IN, on property of the Midwest Energy Resources Co. The project is funded by $240,908 each from the Indiana Energy Development Board/Corp, for Science and Technology (EDB/CST) and the US Department of Energy (DOE) and $120,454 from the corporate sponsors (total $602,270). Completion is scheduled for mid-1986. Next, Edwin M. Piper, Stone and Webster Engineering Corp., discussed the American Syn-Crude/Indiana Oil Shale Project. This effort followed the completion of two smaller projects funded by the Indiana EDB/ CST: "Testing of Indiana Oil Shale in a Petrosix Pilot Plant" (total funding by EDB/CST at $50,000) and "Assessment of the Petrosix Process for an Indiana Shale Oil Plant" (total funding by EDB/CST at $100,000). The status at the time of the report at the Oil Shale Symposium was that a request for an extension of time for securing nonfederal support had been submitted to the US Synfuels Corp. The proposal included building an 11-m (36-ft) diam retort in south-eastern Indiana to process the New Albany Shale and to produce 366 m3 (2300 bbl) of shale oil per day by the PETROSIX process. The Indiana EDB/CST had contracted with Stone and Webster at $401,100 from EDB/CST and $245,835 from Stone and Webster for activities to advance the project in the negotiations with Synfuels Corp. At the time of the report, this project was the only eastern oil shale proposal that was still on the agenda of the Synfuels Corp. As a result of Congressional action in late December 1985, federal support from the Synfuels Corp. is no longer possible. Finally, Victor H. Carr, Eastern Shale Research Corp., described his firm's project, which is jointly supported by DOE ($227,749) and the Indiana EDB/ CST ($73,850) and is entitled "Feasibility Study to Determine Suitability of an In-Situ Process to Recover Hydrocarbons from Eastern Shale." An area in Scott County, IN, had been chosen, but not a specific 9 x 15-m (30 x 50-ft) site. One burn of a small in situ retort is contemplated as part of the project. Besides these three projects, several reports on shale research were presented. Joseph Damukaitis, American Syn-Crude Corp., reported that a pilot plant using the hydrogenation-extraction (H-E) process (described at the 1984 Eastern Oil Shale Symposium) was 94% built and would go through shakedown with oil shale but would then shift mechanical devices to process coal mine waste. Current status of research on the HYTORT process was then presented by Raymond C. Rex, Jr. Oil shale beneficiation research at the University of Alabama/Minerals Research Institute was reported by R. Bruce Tippin. Scott D. Carter discussed continued research on fluidized-bed retorting of shale at the Kentucky Center for Energy Research Laboratory. Carl E. Roosmagi of DOE, Morgantown, reported on the oil shale research at the Morgantown Energy Technology Center (METC) laboratory. Henry J. Gomberg, Ann Arbor Nuclear Inc., discussed "Radiation Combined with Donor Solvents for Extraction and Up-Grading of Kerogen." Aurora M. Rubel and coauthor Eileen Davis presented results of research at the Kentucky Center for Energy Research Laboratory under the title "The Effect of Shale Particle Size on the Products from the Bench Scale Fixed Bed Steam Pyrolysis of Kentucky Sunbury Shale." Lastly, Maria Rockwell, Technical University of Nova Scotia, presented "Processing and Up-Grading of Low Grade Nova Scotia Oil Shale for Potential Use." A review of shale oil prospects by Gerald Parkinson in Chemical Engineering for Feb. 3, 1986, covers both western and eastern projects and includes a report that the US DOE is funding a few relatively small projects; most of the fiscal 1986 budget of $12 million for shale oil is for fundamental research. Projects include a $3.2 million three-year contract with Hycrude Corp. (Chicago) for development of the HYTORT process and a $1.2 million three-year contract with the University of Alabama's Mineral Resources Institute on beneficiation of eastern oil shale by froth flotation. The report incorrectly states that current projects include a total investment of $466 million in a pair of 18-month technical and economic feasibility studies for proposed projects in southern Indiana. The correct figure is $468,657 [$240,908 for the Cliffs Engineering/

Jan 1, 1987

By Kwangmin Kim, Taehee Lee, Minkyu Kim, JUNHYEOK PARK

Mine tailings storage facilities (TSFs) can be a significant source of fine, respirable dust. About 25 percent of the mass fraction of tailings from a hard-rock mine consists of particles of a respirable size (smaller than 10 μm) [1]. This dust poses concerns, especially for nearby communities, because of its detrimental impact on respiratory health. Respirable tailings dust, primarily composed of quartz or free silica (SiO2), may cause silicosis, chronic pulmonary disease, bronchitis, collagen vascular diseases, and chronic granulomatous infections [2]. 

By T. A. Moss

The installation of equipment and structures at mines often requires the evaluation of unique loading and operating conditions. Consideration of these unusual features is required throughout design and construction and into operation. The necessity for employing sound civil, structural and mechanical engineering techniques to the design of structures and equipment is well understood. However, the influence of geotechnical factors on the overall behavior during construction and operation of these facilities is less appreciated. Mine operators routinely perform exploratory drilling for the purposes of defining ore deposits. These exploration activities can be extensive and often include provisions for assessment of subsurface conditions as they relate to the mining operation, i.e., requirements for ground support. All of these factors are important to the economics of the mine and are well justified. Surface facilities are provided to access and service the mine and they play an important role in the successful development and operation of a project. Headframes, hoist foundations and shaft collars, in particular, are examples of unique installations encountered at underground mine sites. The design and above surface behavior of these facilities can be analyzed with the usual fundamental engineering practices employed throughout the engineering professions. This requirement during the project development is understood and adopted. Unfortunately, near surface exploration for the purposes of assessing soil and rock conditions for foundations are often given a reduced priority and less consideration. This paper is aimed at providing an outline into the benefits and importance of performing such explorations and to provide a brief discussion of the merits of such an approach. References in the paper relate particularly to shaft headframes, hoists and shaft collars but the issues raised apply equally well to other installations of a similar nature, e.g. milling equipment.

Jan 1, 1992