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By David Mast, Irwan Halim, Brian Hagan, Kaveh Talebi, Jason Edberg, Amanda Foote

On June 14, 2023 Jay Dee Contractors’ Tunnel Boring Machine (TBM) “Phoenix” holed through and completed mining the second drive of the I-75 Segment 3 Storage and Drainage Tunnel. Completion of the tunnel came only after overcoming several challenges, including a groundwater intrusion event which deposited thousands of cubic yards of wet ground material into the tunnel. This paper will discuss the events which delayed completion of the tunnel by over nine months, the risk management and construction approaches assumed by the Design-Build team during bid, several challenges faced by Design-Build teams when building stormwater resilience tunnels using traditional Department of Transportation standards, and recommendations for improving risk allocation and proposal documents for future similar Design-Build tunnel projects.

Jun 23, 2024

By Tim O’Neil

More than 5,300 mining professionals from around the world attended the SME Annual Meeting and Exhibit, March 1-3 in Denver, CO. Seventy three technical sessions highlighted innovative technologies and applications for the development of mineral resources. And the exhibit featured 421 companies worldwide and 632 exhibit booths. The 1999 SME Annual Meeting had 10% international attendance. Professionals from outside the United States were guests at the first SME International Reception.

Jan 1, 1999

By John W. Barnes

In seeking cost reductions, control methods are a fertile field because they significantly affect labor and other costs. While process control in uranium mills is excellent by the evidence of high recovery, the costs seem high to those familiar with extractive operations for other metals. To some extent this high cost is inevitable, because of exacting quality control-, the technically complicated recovery processes; poor control over grade and nature of mill feed- special problems arising out of the radioactive property of the material. Practices used in uranium mills and the limitations indicated for instrumentation and automation are discussed. It is concluded that any large investment in automatic controls should be preceded by a careful study of their reliability and maintainability, and an estimate of the net income after taxes smaller plants my find it more profitable, or at least less risky, to concentrate their efforts on the possible reduction of some control problems and to development of a stable force of skilled employees. The observed experience does not inspire optimism that ore-dressing plants can be extensively automated although certain unit operations offer a challenge for improvements in instrumentation and machine design.

Jan 1, 1960

By Robert L. Vines

"What is past is prologue" - motto of National Archives The question of past, present, and future safety performance in the coal mining industry is not merely an academic one, or one which arises from soul-searching curiosity. It is a question involving pragmatic ramifications, and the answers, or perhaps the public perception of the answers, will have a strong impact on the public policies which influence the course of meeting the Nation's future energy demands. Those of us in the coal industry are keenly aware of the significant impact of the public reaction -- in the form of the 1969 Health and Safety Act -- to -past performance of the coal industry which it found unacceptable. That Act was revolutionary -- and it was expensive. But in finding the industry's past performance unacceptable, the public also recognized its own contributory role through having enjoyed a "buyer's market" forced on a highly competitive industry. One result was to limit the industry's resources and restrict its ability for self-improvement of its safety performance. In acknowledgement of that role, the public picked up the tab for Black Lung disability incurred prior to that time.

Jan 1, 1985

By Ebrahim Tarshizi, Livernois Ryan, Emily Sarver, Zoe Scopa, Robert Setterlind, Leah Frost

"The mines of the future present a host of challenges, which may appear exciting or daunting, depending on one’s perspective. Whether some sectors of the public recognize it or not, the demand for raw resources is not going away any time soon. In fact, it is rising, as the global population grows, urbanizes and attempts to steadily increase quality of life. Yet, at the same time that much of the highly developed world is calling for greener goods, reduced consumption and cleaner production, in other areas there are cries for clean water and sanitation, consistent energy supply, access to health care and education, personal security and support for basic human rights. The balancing act for sustainable development of our global society is, indeed, precarious and the mining community is a key player. Fortunately, many industry members have accepted this role and the responsibility to provide leadership and a solid foundation for progress. Looking ahead, we need new generations of leaders, including many mine engineers who are ready to tackle all sorts of complex problems.There are tremendous needs just for technological innovations. Increasingly tough deposits will require that the industry continues to expand scale toward “mega pits” and “super caves;” fully develop unconventional recovery techniques like in situ leaching and gasification or deep-sea extraction and seriously consider off-earth endeavors. Such work will take entirely autonomous equipment, novel separations, processing and recycling methods, and systems that can withstand extreme physical conditions, just to name a few. It will also take a level of systems integration never-before seen in the mining industry, complete with big data issues, sophisticated predecitve analytics and modeling efforts and cyber-security challenges.Moreover, increasingly complex environmental problems will require creative solutions. Addressing issues like pollution control across multiple media, emerging contaminants, optimal management of wastes, selective mining and shared use of resources between mine operations and surrounding communities and ecosystems are among the top priorities. Really, a complete paradigm shift must occur, such that the focus is on overall improvement of environmental conditions, rather than minimization of impacts. A similar shift will be required in the social realm. How can miners be safer and healthier on-site and off? How can the industry contribute to communities such that they are better off, now and longterm, for having a mine next door? How can artisanal mining practices be transformed to also contribute to sustainable development? How can the industry’s work be a factor in increasing economic and political stability? How can the public understanding of raw resources and the need for mining enterprises be improved?Given the coming challenges, there is no doubt that the mine engineers of the future will need highly diverse skillsets — meshing traditional and contemporary competencies to a degree not previously considered in mining, or most others fields. To be sure, the scope and scale of mining projects make them wholly different than most other engineering work, aside from perhaps the largest civil and urban development projects. While on-the-job experience will continue to be essential, formal education programs (i.e., at post-secondary institutions) must lay critical groundwork."

Jan 6, 2017

By Florian Festge

It has been said that good things come in threes. In the case of screening for mining and quarry operations, profit comes in three distinct phases: layered, basic and sharp screening. But how good they are ? whether they maximize efficiency and improve the potential for success ? depends on having the right screen media on the deck for each of the three phases. A relatively new method for achieving that goal is a blended screen media approach that incorporates the ideal screen media for each phase and the ideal mix of media for the process overall. The goal in implementing a blended solution is to find the optimal combination of open area and durability. If this combination is found, maximum product quality and profits will be realized by increasing efficiency of classification while minimizing downtime and maintenance costs.

Jan 1, 2012

By L. O’Connor, E. Tarshizi

The objective of this work is to provide a detailed review and a list of references in chronological order, comprising 80 recent technical papers, on the use of discrete-event simulation (DES) modeling in mining engineering. In this article, the review papers of published mine simulation projects through 2007 are summarized, and then a comprehensive review of individual articles published from 2008 to 2015 is presented. This survey work also includes analyses of the simulation tools used in the published projects, mining types and applications in order to assess these key features and evaluate the recent state of research in mine DES simulation. In addition, an interactive map visualization for the locations of the simulated projects is made available on a website to benefit current and prospective scholars in the field. The results of this investigation revealed that the most common application of DES in mining had been mining equipment selection and analysis, while ore processing and risk management projects were less frequently reported. The results also showed that modeling surface mines were in the majority, but the trend of publications for underground mine simulations had also increased. According to the results, ARENA was the most popular simulation software package, but several simulation tools that were only used once or twice in the mining projects are also included in this review.

Jan 1, 2018

By L. O’Connor, E. Tarshizi

The objective of this work is to provide a detailed review and a list of references in chronological order, comprising 80 recent technical papers, on the use of discrete-event simulation (DES) modeling in mining engineering. In this article, the review papers of published mine simulation projects through 2007 are summarized, and then a comprehensive review of individual articles published from 2008 to 2015 is presented. This survey work also includes analyses of the simulation tools used in the published projects, mining types and applications in order to assess these key features and evaluate the recent state of research in mine DES simulation. In addition, an interactive map visualization for the locations of the simulated projects is made available on a website to benefit current and prospective scholars in the field. The results of this investigation revealed that the most common application of DES in mining had been mining equipment selection and analysis, while ore processing and risk management projects were less frequently reported. The results also showed that modeling surface mines were in the majority, but the trend of publications for underground mine simulations had also increased. According to the results, ARENA was the most popular simulation software package, but several simulation tools that were only used once or twice in the mining projects are also included in this review.

Jan 1, 2017

By Wen Tao Liu, Tong Tian, Fu Sheng Niu, Xiu Man Liang

In order to address the difficulty of accurate segmentation of froth images of different sizes, a method of froth image segmentation based on highlight correction and parameter adaptation is proposed. First, a machine vision system on a single-cell flotation machine is built to collect froth images. Homomorphic filtering is used to improve the uneven brightness and shadow of the images. Fuzzy c-means (FCM) clustering is then utilized to classify similar highlights that belong to the same froth. After Otsu threshold segmentation, a parameter-adaptive morphological operation is used to extract the marker points and edge bands and correct the froth edges in the original image. Finally, the modified image is filtered by morphological reconstruction, and the highlight mark is used as the local minimum point for watershed segmentation. Three sizes of froth images are segmented in comparative experiments. The results show that the proposed method is suitable for the segmentation of froth images of different sizes. The position of the extracted segmentation line is close to reality, with average over-segmentation and under-segmentation rates for froth images of 2.6% and 6.8%, respectively. The froth image segmentation performance is stronger than that of the other methods examined.

By P. James

"INTRODUCTION Control of target stream pH is very important in leach mining and treatment of MIW (mining influenced water). On the production side, solution acidity can impact SX (solvent extraction) effectiveness through PLS (pregnant leach solution) and raffinate pH. Many older operations and legacy mining sites generate ARD (acid rock drainage) that is too weak for profitable metal production by conventional means and faces costly wastewater treatment for mitigation and disposal. For wastewater and environmental treatment, neutralization to precipitate and remove metal contaminants to clean the wastewater is the dominant approach. Traditional lime neutralization and precipitation is most often used but results in large amounts of mixed metal sludge requiring costly disposal. Blue Planet Strategies (BPS); which focuses on improved resource utilization targeting electrolytic treatment and waste conversion into resources, has developed a new “reagentless” neutralization process. Electricity is utilized in its proprietary DEMET™ (Dynamic Electrolytic Metal Effluent Treatment) platform capability to controllably raise target stream pH. The method offers a simple, low-cost approach yielding cleaner treatment chemistry. It can result in less sludge generation and enables possibilities to selectively recover contaminants as potentially saleable products for new revenue generation to offset further offset treatment costs. DEMET Overview BPS’s patented electrolytic DEMET platform leverages solid scientific and chemistry foundations through its advanced design to achieve capabilities and performance not previously realized. DEMET technology combines separated compartment electrolytic cell functionality with proprietary advanced dynamic electrodes and cell configurations to achieve a variety of chemistries and processing targets.[1-6] DEMET‘s unique elements can yield higher processing rates at practical efficiencies, lower energy consumption, plus improved processing stability and lower maintenance requirements due to enhanced resistance to cell fouling and shorting; while also thwarting cross stream (catholyte vs. anolyte) contamination. Consequently, DEMET can provide a superior, extremely versatile, and more cost-effective electrolytic treatment option where a multitude of FEED and PRODUCT stream combinations might be employed in comparison to traditional tankhouse electrolytic cells."

Jan 1, 2015

By J. Fisher, M. Barish

Over the past several years, Somerset International has successfully installed over 20 patented Sub325® Fine Coal Recovery Systems in the United States, Australia, Canada and Russia. These installations recover between 5 TPH and 40 TPH for the host sites. In addition to the increased revenue from the direct recovery of a recirculating load (Screen Bowl “Insurance”, Direct Recovery vs. Indirect Recovery via Recycle, CPSA 2020), host sites have seen benefits ranging from improved operation of refuse equipment to a reduction in the solids content of the refuse streams. As Somerset has improved ultra-fine coal recovery through the introduction of Sub325® Effluent Flotation and, most recently, the Sub325® Effluent Settler™, the amount of coal that has been recovered from these systems has increased by up to as much as 25%. Many host sites have taken a sense of ownership in the Somerset system and consider it to be a critical circuit in the overall optimal performance of the plant. In the past year, Somerset has taken the initiative to expand upon the capabilities of the Sub325® Fine Coal Recovery System, primarily the Sub325® Solid Bowl Centrifuge, to include Refuse Tailings Dewatering to allow for co-mingled refuse disposal. As slurry ponds and boreholes are becoming difficult to impossible to permit and operate, there is a need for a reliable, low-maintenance, continuous operation that can produce a handleable refuse cake. Refuse tailings disposal applications are by no means limited to coal plants and impoundments. Somerset has successfully tested at iron ore and phosphate locations throughout the world and have begun commercial installations. The ability to dewater -325 mesh material, whether it be coal, coal refuse, iron ore tailings, or something else, is a vital piece of processing capability for the continued production of mining operations across the globe. This paper highlights the success that Somerset has had in the coal industry worldwide as well as the initial successes with phosphate, iron ore, and copper tailings (patent pending).

Mar 2, 2022

By C. Guria

A modeling, simulation and optimization study of a complex industrial fluorspar beneficiation plant (Kadipani, Gujarat, India) with fourteen/ten flotation banks is carried out to find an optimum/near-optimum circuit for the given quality of feed ore. The phenomenological flotation model developed by Mehrotra and Kapur (1974) is used for circuit optimization. Two different optimization problems are formulated and solved. The first optimization problem involves a single objective function, which uses available plant data to estimate the feed-characterizing parameters, i.e., the flotation rate constants, by minimizing the weighted sum-of-square errors between the computed and plant values. The second optimization problem involves two objective functions to obtain several simplified circuits. The number of non-linking streams and the overall recovery of the concentrate, i.e., the acid-grade product, are maximized simultaneously in this problem. The single-objective variant (SGA-II-mJG) of the binary-coded elitist non-dominated sorting genetic algorithm with the jumping gene adaptation, NSGA-II-mJG, is used for the first problem, while NAGA-II-mJG (Guria et al., 2005 a) is used for the second problem. Simplified circuits with a few split streams are proposed on the basis of the present optimization study, which enhance the recovery of the acid-grade product without affecting its quality, for a given total volume of the flotation cell-bank. Even though the optimal solutions have certain drawbacks, they suggest a meaningful direction in using an iterative fitting of parameters to such optimal circuits, followed by re-optimization. Key words: Froth flotation, Mineral processing, Industrial fluorspar beneficiation, Feed identification, Circuit/network optimization, Global optimal, Jumping gene, Genetic algorithm, Multi-objective optimization

Jan 1, 2009

By W. D. Delahaut

Sampling tests performed at the Paradise Peak Mine compared various blasthole samplers and reverse circulation sampling methods. Statistical analysis of the data indicates that be-low-the-deck bag sampling produced a 24 to 29 percent error when compared to bulk sampling methods. Use of a chip pile wedge sampler reduced error to 17 percent. Reverse circulation sampling upgraded over bulk blasthole sampling by 7 percent for gold and 11 percent for silver. These results indicate that bias sampling conditions exist when small volume bag sampling is employed in production blasthole drilling.

Jan 1, 1991

By Andrew S. Prokopovitsh

The Bureau of Mines is concerned with all the approximately 60 industrial minerals, although its research program currently is focused on 10 of them--bauxite, chromite, clay, manganese, phosphate, potash, refractories, sulfur, titanium, and zirconium. To alleviate reliance on imported materials, particular attention is directed to those minerals having a potential for production from domestic resources. Another important consideration is environmental problems associated with the production of industrial minerals, principally in mining and mineral processing operations, The Bureau also is looking at the opportunities to substitute more abundant minerals for scarce raw materials such as rutile, fluorspar, and bauxite. In its overall minerals surveillance, the Bureau's mining and metallurgical research and development are coordinated with its minerals information activities from which reviews, projections, and forecasts identify the potential for critical disruptions and short supply situations.

Jan 1, 1975

By H. Askari-Nasab, B. Osei, K. Awuah-Offei

The U.S. coal mining industry consumes approximately 142 billion kWh/a of energy. The U.S. Department of Energy estimates that the industry’s annual energy consumption could be reduced by 49%. This constitutes nearly $3.7 billion of potential savings on coal production costs at 5.3¢/kWh of energy. Additionally, with climate change regulation on the horizon, any benefits from energy savings in the near future are compounded by associated reductions in CO2 emissions. Research indicates that operating conditions significantly affect energy efficiency. Modeling and simulation have been shown to be a cheap and reliable means of evaluating the effects of process interactions and operating conditions. The goal of this work was to apply stochastic process simulation to model the energy efficiency of a typical truck-and-shovel mining system and use the model to evaluate production strategies to improve energy efficiency. The research team conducted energy audits of truck-and-shovel overburden removal and used the results to develop regression models describing truck and shovel fuel consumption. The team then built a stochastic simulation model of the truck-and-shovel overburden removal operation and used it to assess a variety of improvement measures by simulation experimentation. Valid fuel consumption models for shovel loading and truck haulage have been formulated, based on the energy audit results. Valid stochastic process models of truck-and-shovel operations have been formulated to study energy efficiency. The following strategies, in decreasing order of impact, provide the most energy savings for truck-and-shovel overburden removal at the mine: (1) shorten haul roads, (2) increase shovel capacity and (3) increase shovel utilization through optimal truck matching. Additional data will be required to adequately describe operator effects on energy efficiency.

Jan 1, 2011

By R. Rodgers

The Pinto Valley concentrator of BHP Copper Inc. restarted its sulfide mining operations in September 2007 to produce copper and molybdenum concentrates. During the plant production ramp up, the copper/molybdenum circuit quickly reached the copper grade and recovery targets, but the production and quality of the molybdenum concentrate continued to be a challenge. Even though several improvements in the molybdenum circuit were completed, the final molybdenum concentrate did not meet contractual specifications. After reviewing several options to improve grade and reduce contaminants, the installation of three flotation columns were chosen. The column design and construction were done using in-house craftsmen and engineers. Ten days after commissioning, the columns successfully reached a steady operation and began producing molybdenum concentrate to the required specifications, that is, high molybdenum tenors and low copper and iron content. The Pinto Valley operations, are comprised of the Pinto Valley concentrator, the Pinto Valley dump leaching and a solvent extraction/electrowinning (SX/EW) plant. The concentrator operated from 1972 to 1998 when mining and milling operations were curtailed for economic reasons. The SX/EW plant continued operations for copper cathode production. After a cessation of mining operations of almost 10 years, Pinto Valley operations began a restart project in January 2007, to bring the mine and the concentrator back into production. Copper concentrate production started in October 2007 after refurbishing and upgrading the facilities with a new DCS system and filter plant. The daily targets of the concentrator were to treat 56.7 kt (62,500 st) of ore, produce 762 t (840 st) of copper concentrate containing 27.5 percent copper at recoveries of 86 percent and produce 2.2 t (2.5 st) of molybdenum concentrate containing more than 80 percent MoS2.

Jan 1, 2010

By Eugene F. Casey

An immersed tube tunnel is one which is composed of elements that are prefabricated in a dry dock or on shipways, usually away from the actual tunnel site, floated into position and then lowered into a preexcavated and graded trench below a body of water. The elements or segments are then connected to each other under water, and the entire immersed tube tunnel covered with a protective blanket. Because water is essential, this method of construction offers advantages in a relatively limited field. By the very nature of the method, lowering elements to the bottom of an underwater trench, immersed tube tunnels are primarily used for crossing bodies of water, such as rivers, bays, straits, canals, etc. Although this method of construction was first used for a subaqueous railway crossing under the Detroit River in 1906-1910 and again in 1912-1915, for a four track subway tunnel under the Harlem River in New York, the reason immersed tube tunnels construction has not been used more extensively is simply a matter of economics. Bridges, compressed air tunnels and similar structures could be constructed at a lower cost.

Jan 1, 1970

By Thomas A. Gwynn

"A beautiful America will require the effort of government at every level, of business, and of private groups. Above all it will require the concern and action of individual citizens, alert to danger, determined to improve the quality of their surroundings, resisting blight, demanding and building beauty for themselves and their children." "Improvement of our environment" has become a cause much like "motherhood". The increased awareness of the public concerning this subject makes it most unpopular for anyone to be involved in anything that seemingly is detrimental to our environment. And this awarement goes far beyond our biggest pollution problem in America - the distribution of paper, abandoned automobiles, beer cans and other garbage by our enlightened society along every city, highway, trout stream, river and mountain in America. In fact, the greatest awarement comes because of the "sensational" reporting and writing in our various national communication media, wherein the same voting citizens who so generously distribute their refuse about the countryside are emotionally aroused and duped into transferring what is truly a national problem onto the shoulders of a few industries - notably and particularly the mineral extraction industry. Certainly mankind is more and more stumbling over his own garbage daily, a fact that is easier to sell a citizen of one of our large cities than a resident of the wide open spaces of the west. Yet even in the Rocky Mountain states, the "Land of Sky Blue Waters", the "Big Sky Country", and particularly in Salt Lake valley smog is not unknown. Pollution and littering have become problems that need to be faced squarely. In North Dakota alone it has been estimated that one section of farm land each year flows down the mighty Missouri and the greatest producer of sediment is now reported to be the highway department.

Jan 1, 1969

By I. Dunlop, A. Goulsbra, R. Dunne

Mineral liberation or more aptly the particle size at which cost effect liberation is attained is an important mineral processing parameter. This implies that not all the mineral is liberated as further size reduction is not economically warranted. For ores of low grade minimising both the comminution capital and operating costs are crucial aspect to ensure project visibility. As a consequence the focus of attention for the most part is direct­ed to 'coarsening the grind" ahead of any downstream process­ing treatment. In most cases, recovery will be sacrificed to pro­vide for 'more tonnes' of capacity and in general this is eco­nomically justifiable. Preferential liberation and its measurements is an aspect of mineral processing that has created much attention and contro­versy. It is not the purpose here to discuss this matter in depth other than to state in broad terms that if an ore from the same source is subjected to comminution by two different methods, such that the product particle size distribution is similar, and subsequent downstream treatment demonstrates substantial dif­ferences in recovery, then there is reason to believe that prefer­ential liberation has occurred. Comminution by high pressure grinding rolls (HPGR) is a relatively new technology claimed to have two major advan­tages over conventional comminution. Firstly and more impor­tantly is the ability to improve comminution power efficiency. Power reductions of 10 to 40 percent being claimed. (Pagett et al (1995), Sargent (1995)). A secondary benefit claimed is that preferential liberation can occur. Generally, for HPGR there is a natural tendency of the product to have a skewed particle size distribution to the finer size. This in its own right could manifest itself in improved leaching and preconcentration performance. The question remains that if in using another comminution device, other than a HPGR, to produce a similar product size distribution as the HPGR, will there be any difference in downstream between the products from this and a HPGR.

Jan 1, 1996

By C. S. Caldwell, L. C. Thompson

Mine closure and reclamation issues have evolved over the past several years becoming further complicated by stricter standards and by the cmrent economic climate and price of gold. Many mine permits are calling for more stringent remediation of spent ore heaps and tailings. Leachate solution water quality must meet strict discharge criteria for multiple parameters besides cyanide at mine closure. Closure standards are more difficult to meet and most mines do not have an increased budget at the end of mine life to deal with the falling standards. These issues make additional gold recove1y at the end of mine life a critical problem in financing some closure operations. Another issue is the length of time that must be budgeted for heap rinsing operations. Innovative biological processes developed and applied by Pintail Systems, Inc. at numerous mine closures have indicated that bio-processes can significantly enhance gold recovery dur­ing heap cyanide bio-detox over the recoveries expected from rinse operations. If heap rinsing can be eliminated or reduced and if gold recovery can be improved at the end of mine life, many mine closures may be possible with processes that pay for themselves or generate profit. Additional advantages of the bio­detox technology is that it can be engineered to treat multiple contaminants besides Weak Acid Dissociable (WAD) cyanide. Other contaminants treated in heap process solutions include nitrates, ammonia, heavy metals, thiocyanate and total cyanide. At the Cripple Creek and Victor Mining Company Ironclad Mine near Victor, CO, 5 million tons ofrinsed, heap leached spent ore were biologically detoxified to reduce cyanide content, enhance gold recovery during bio-detox and to reduce dissolved metals in heap leachate solutions. During the bio-detox treatment period a substantial improvement in gold recovery allowed the detox oper­ation to operate as a profit center. Final gold recovery was at least twice what was expected from a normal rinse operation.

Jan 1, 1998