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By Samer Sadek, Brian Hagan

We are thrilled to welcome you to the 2025 Rapid Excavation and Tunneling Conference (RETC), which will be held in Dallas, TX. This year’s conference will showcase the continued trend of strong industry interest, as there will be a record setting 115 papers being presented over the course of three days. The set of papers compiled in this book captures the latest and greatest information on a broad array of topics within our fascinating tunneling industry. We hope that the compilation of selected papers in this book will provide a comprehensive recap of the conference while also providing a source of future reference for contractors, engineers, and anyone in general who is a student of our beloved and unique industry. Since its inception in 1972, RETC has been the preeminent tunneling forum to promote ideas, tell stories, share lessons learned, and promote new technologies. RETC prides itself on its focus towards highlighting real-world experiences and practical ideas, with the intent to help the entire industry learn from one another and grow. The need for us all to stay sharp and remain on the cutting edge of technology has never been stronger – the technology and ideas that have been applied in aerospace are now attempting to mix with tunneling, and the advancement of AI continues to permeate all industries. However, no amount of technology or AI can fully replace the human element, and in our tunneling industry, the human element is key and is what sets us apart. In tunneling, every project is different, because the ground is always different. We can only take what the ground will give us, and we must rely on our past experiences to get through present day challenges. Most importantly, we must rely on each other. This is the heart of what RETC is all about. For those of you attending this conference, we encourage you to attend as many sessions as possible and engage with your colleagues to discuss during the breaks in between sessions. This sharing of ideas is what keeps us connected and helps to expand our industry. Please also try to engage with the scholarship students and the newcomers who will be in attendance, as it is the new ideas and fresh energy from the next generation that will continue to make our industry thrive into the future. The program chairs thank and greatly appreciate the efforts made by our session chairs, co-chairs, authors, the members of the RETC Executive Committee, and most importantly the SME staff towards making this RETC possible.

Oct 1, 2025

By Robert W. Yokom

As the search for new sources of energy and minerals leads to more remote areas of the country - and the world - the need to plan for adequate housing and community facilities for the construction and operations workforces and their families takes on an importance equal to the mining and processing facilities themselves. A corollary to the need for planning is the increasingly crucial need for development companies to devise effective strategies for dealing with the local communities impacted by these projects. Experience has amply demonstrated the high price to be paid for failure to learn this lesson, a price measured in lost productivity, confrontation with local communities, labor turnover, mental health and other social and eocnomic problems. In Sweetwater, Wyoming, a new industrial activity caused the population to double from 18,000 to 36,000 between 1970 and 1974. During that period industrial productivity fell 25 to 40 percent, cost overruns on the principal new industrial facility exceeded 33 percent, annual employee turnover rates climbed above 100 percent, the local mental health clinic workload increased nine times and complaints to the local law enforcement agency increased 60 percent.

Jan 1, 1981

By C. Frenzel, N. Blechschmidt

"INTRODUCTION There is no doubt about the time and effort companies put in establishing and maintaining their equipment. However, the question about how these companies can map the benefits comes up. Neither do they have the tools to quantify the benefit of their action, nor do they have the tools to know the actual quality of their current maintenance system. The resources used in the process seem futile to observers. It seems impossible to trace improvements and to get information about the impact of actions in retrospect. Improvements in maintenance performance cannot be recognised by management or shareholders. Thus the necessity for measuring the performance of maintenance systems is given. In this paper ConMoto is systematically showing the strengths and weaknesses of many companies' maintenance management and is providing field-tested proven design elements for measuring maintenance systems and implementing Value Oriented Maintenance. Considering only business assets in production facilities and related machinery out of all investment goods in Europe, you reach a value of around 9.7 trillion euros in 2008. In Germany alone the equipment replacement value amounted to about 1.9 trillion euros [8,10,11,13]. If you calculate a cross sector maintenance costs rate of 4.8 % (corresponding to the average value identified in this study), direct maintenance costs in European production locations add up to over 450 billion euros per year [3]. These figures speak for themselves. Yet maintenance is not only of enormous significance for European enterprises. Our experiences show that maintenance and asset management, particularly sustainability issues, are also increasingly moving to the forefront in the BRIC states, in the Middle East and in many emerging countries. First of all, in order to meet the resulting high quality and cost related requirements of maintenance systems, a comprehensive overview of the issue is needed. This overview is provided by a detailed analysis of 83 companies and production plants from various sectors – with amazing results. SIGNIFICANCE OF MAINTENANCE Current studies show the high financial significance of maintenance and asset management. According to the market study in the Asset Manager [9], in industrialised countries about 10 to 15 per cent of the labour force are employed in maintenance and facility management tasks. In Europe about 40 to50 million people are directly and indirectly involved in retaining the value of machinery, plants, buildings, transport systems and infrastructure facilities. A glance at the costs side also demonstrates the great relevance of maintenance. EU-wide annual direct maintenance costs amount to a total of more than 1,500 billion euros. In Germany alone they are about 250 billion euros. This impressive total is considerably exceeded by indirect maintenance costs caused by technical failures. Indirect costs are estimated to be five times higher (Figure 1). [7,12,14]"

Jan 1, 2018

By Dean Bray

During the past three years, a new rear-dumping dragline bucket technology has been patented, developed and tested at North Dakota coal mines. Field testing has shown that this new concept in dragline bucket technology can improve strip-mining efficiencies by reducing cycletimes and increasing dumping radius. This article details the process, participants and the results for the development of a rear-dumping dragline bucket. Participants in the process In November 1995, the board of directors of Dakota Coal authorized the execution of a field test and option agreement and a license agreement with the partnership of D.F. Schmidt, electrical/maintenance supervisor, and Bill Lengenfelder, president of Modern Industrial. The board also authorized entering into a dragline bucket field-testing agreement with the Falkirk Mining Co.

Jan 1, 1999

By William G. Fischer

This paper attempts to close the gap between extensive rock testing with field measurements and the mine operator's need for safe mine layouts and alternatives. It was found that many of the variables that influence mine geometry and worker safety are relatively unimportant while others are critical. The development of empirical relationships which tie the critical variables to the "safe useful life" of a trona mine layout and observations made in 140 production areas where the variables were researched over a fifteen year period are discussed. The concepts presented may have applicability in mine design for other bedded deposits.

Jan 1, 1984

By Steve Kral

The domestic mining industry may be in the doldrums but there appears to be hope, at least from a regulatory standpoint. At least one US senator believes that the events of Sept. 11, 2001 made many citizens see the need for the country to become more self-reliant on its growing energy needs. Even before that tragic day, however, the Bush administration was making a strong push to open up more public land for energy and natural resource development.

Jan 1, 2002

By Larry S. Diaz

The paper considers the selection of control instrumentation for a modern flotation plant, as well as the best interpretation and most effective use of the process data obtained. Process control computer availability is considered from the outset. A general philosophy of control is proposed which leads toward a system that is its own reliability monitor. The bulk of the problems are in grinding and classification. Alternative control methods are described that use particle size measuring devices. Flotation controls, based to a large extent upon on-stream X-ray analysis, are reviewed in detail. Reagent control methods are also examined. Methods to analyze the data obtained from the various measurement devices are introduced. These methods would enable an estimate of the validity of the data and require some redundant information. Another objective of these methods is the protection of operating equipment from possible control malfunctions. Although the discussion generally considers some degree of computer usage, this paper attempts to describe instrumentation and data analysis methods that enable control with or without the process control computer.

Jan 1, 1972

By D. J. Pyra, J. Kudelko, Korzekwam W.

Polkowice region (Lower Silesia, Poland) is an area, where the copper mining activity started about 40 years ago and new technologies were applied. There are 3 underground mines, 3 processing plants, tailings pond (the biggest one in Europe), pipelines for flotation waste transport, railways. Although new technologies were applied during the copper ore exploitation, the environment in this area were polluted mostly by dust containing copper, lead, zinc and arsenic. Estimated values of heavy metals in polluted soils were compared to the natural contents of this metals. The geochemical background for Polkowice area was defined. The pollution zones occur around mining facilities. Copper ore exploitation and processing is planned for the next 20-40 years depending on market situation. After mines and other facilities closing the most important problem will be sustainable development of this area. To evaluate the scope of revitalization activities the analysis of recent soil environment condition will be necessary as well as forecasts for pollution migration. Geostatistic methods used also in mining will be very helpful for this task.

Jan 1, 2005

By F. E. Heuze

This article deals with the effects of high-explosive and nuclear explosions in rock masses. We first highlight the strong influence of geological discontinuities, such as joints and faults, on ground motion characteristics. Then, we briefly introduce the Discrete Element Method, as a new technique for numerical simulations. II is shown to be far superior to continuum-based approaches, when dealing with the dynamics of discontinuous media such as jointed rocks. Finally, we simulate the ground effects from a generic contained nuclear explosion, which bears some similarity to the SHOAL event in granite. This calculation is intended to emphasize the influence of the near-source geology on the distribution of energy, and on the motion at various azimuths in the medium.

Jan 1, 1991

By Robert F. Shurtz

This paper suggests that pre-occupation with the random process model notised by geostatisticians may result in neglect of more promising techniques, especially since the random process model does not appear to be essential to current geostatistical procedures. This point of view is emphasized pictorially. To emphasize the potential of new techniques a simple application of the conventional Brownian function is described. The probabilities estimated in this truly random way are different from those estimated by Kriging

Jan 1, 1980

By F. Maciosek, D. Denton, J. Johnson

Researchers from the Spokane Research Laboratory of the National Institute for Occupational Safety and Health and personnel from Coeur Silver Valley, Wallace, ID, conducted tests using rock strain strips and Split-Set rock bolts instrumented with strain gauges to monitor wall rock strain at the Galena Mine, Osburn, ID. The objective of the test was to identify whether strain on the rock bolts increased prior to a rock burst. Although results were inconclusive, researchers learned that the Split-Set rock bolts yielded in stick-slip fashion in the highly jointed walls of the stope. The bolts were also bent as stress was redistributed following blasting and subsequent movement along joints in the wall rocks.

Jan 1, 2004

By D. Conklin

Annual fish monitoring of the Red River, NM from the town of Red River to downstream of Questa, NM has been conducted since 1997. This long-term dataset, sponsored by the Chevron Mining Inc. Questa Mine provides an opportunity to evaluate the fish community response to natural phenomena, such as landslides and drought. Hydrothermal scars are present on drainages to the Red River, which can contribute large quantities of sediment to the Red River during localized storm events. Sediment inputs from the hydrothermal scars result in decreased habitat and water quality conditions within the Red River. Landslides from the hydrothermal scars contributed large amounts of sediment to the Red River in the summers of 2002 and 2007. Resident trout populations in the Red River after summer 2002 were depressed at sites adjacent to and downstream of the hydrothermal scars. Resident trout populations had begun to recover by 2005 and 2006; however, after the summer 2007 landslide, the resident trout population was again drastically reduced. In fall 2007, 13 resident trout were collected from 11 sites in the approximately 23 km reach of the river, compared to 691 from the same 11 sites in fall 2006. Resident trout density and biomass has gradually increased since fall 2007, and flows have removed sediment from the study reach. A combination of increased sedimentation and decreased water quality were likely responsible for the decreased resident trout populations in the Red River. Drought and the lack of flushing flows appeared to exacerbate the problem of high sedimentation levels from 2001 to 2004. Climate models predict prolonged periods of drought and increased intensity of storm events, potentially resulting in less favorable conditions for the resident trout population of the Red River in this area.

Jan 1, 2011

By James Dunn

“The strongest argument of the detractor (of mining)is that the fields are devastated by mining operations ...They argue that the woods and groves are cut down, for there is need of an endless amount of wood for timbers, machines and the smelting of metals. And when the woods and groves are felled, then are exterminated the beasts and birds, very many of which furnish a pleasant and agreeable food for man. Further, when the ores are washed, the water which has been used poisons the brooks and streams, and either destroys the fish or drives them away.” Georgius Agricola, 1556, De Re Metallica, translated by Hoover, 1950. Technical problems associated with the cleanup of historic mines are not new. Nor are they unique to the mining industry or the governmental agencies addressing them. Both face the same issues and challenges of defining the problems, evaluating remediation options and finding the most economic and effective solutions.

Jan 1, 1999

By Florian Häckel, Ulrich Schwarz-Schampera, Benjamin Bühring, Katja Schmidt, Dieter Garbe-Schönberg, KoschinskyM Andrea

"The Vanuatu island arc and its adjacent back-arc basins form part of the southern New Hebrides subduction system in the southwestern Pacific Ocean within a triangle defined by the Solomon Islands, New Caledonia and Fiji (Meffre & Crawford 2001). The back-arc region east of the volcanic front is characterized by three structural depressions namely Vate, Erromango, and Futuna (from N to S), also known as the Coriolis Troughs. Earlier studies of lava compositions reveal the occurrence of highly evolved alkali-rich dacites as well as ankaramite basalts within the individual troughs (McConachy et al. 2005).Here we present the first mineralogical and geochemical analyses of hydrothermal fluids and precipitates (sulfides, sulfates, Fe-oxyhydroxides), sediments, and volcanic rocks, sampled during the "Coriolis Volcanism and Vents" (COVOLVE) cruise SO229 in July 2013 aboard the German R/V Sonne. The samples were retrieved during several ROV Kiel 6000 dives directly from the newly discovered active vent sites at the neovolcanic Nifonea Ridge, and from multiple sites at water depths ranging between 200 to 2800 m within the Vate and Futuna Troughs as well as from the shallow water Epi Caldera NNE of the Coriolis Troughs (Fig. 1)."

Sep 1, 2014

By S. A. Montague

In spite of the many new insulating materials, both synthetic and manufactured, that have been put on the market since the end of World War II, and notwithstanding the many millions of dollars applied to the development of synthetic mica, natural block mica1 is still a most indispensable insulator in various electronic components. It will remain so, barring some spectacular break-through in research that might provide a substitute fully acceptable as a replacement for mica in all of its superior properties. But this is not to say the future for mica is assured, or free from serious problems. Technological advances have created problems requiring a solution to be found if future requirements are to be filled.

Jan 1, 1962

By Frederick A. Mumpton

Recent findings by medical workers on the association of certain zeolite minerals with the high incidence of pleural mesothelioma in two small Turkish villages have caused considerable excitement both in medical circles and in the synthetic and natural zeolite businesses. The 42 cases diagnosed between 1970 and 1977 in one community of 600 population in a region of altered volcanic tuff represent a virtual epidemic of this rare malignancy which normally strikes only about one person in a million. Cancer workers around the world expect that detailed environmental and epidemiological studies of the disease in these areas will shed considerable light on the cause of this particularly lethal form of lung cancer. Scientists and engineers developing uses for zeolite materials in industry and agriculture, however, are justly concerned that the preliminary results available on this situation will be used by environmental and regulatory organizations to label an entire group of miner- als as carcinogens on the basis of what is little more than circumstantial evidence. Although there is no question as to the large number of cases of mesothelioma in these areas of central Anatolia, the work to date has suffered from a lack of sound geological and mineralogical input. Ataman (1) stated that a "correlation" exists between mesothelioma and zeolites in this region; however, the geological data needed to document a direct relationship between the presence of zeolites in the volcanic tuffs surrounding the villages in question and the rate of malignant lung disease in the inhabitants have g been obtained, nor has evidence that suggests a cause-effect relationship between zeolites and cancer been reported. To provide fundamental information on the distribution of zeolite minerals in areas of central Turkey where high incidences of pleural mesothelioma have been reported and to evaluate from first-hand knowledge the published reports and news releases of medical workers engaged in assessing the problem, the following investigation was made.

Jan 1, 1979

By K. Oraee

Zarshuran gold deposit, with the total reserves of some 12.5 million tons of 4.18 g/ton ore, is considered to be an important gold mining project in the area. In this paper the feasibility studies of the whole project is carried out on the basis of several economic variables. Given that mining data are often of uncertain nature, these economic variables have therefore been estimated under the conditions of uncertainty. The resultant Net Present Value is hence also obtained under the same conditions. For this purpose, a model is first devised with the help of Excel and COMFAR software. The model is then developed that considers different scenarios which would result in different expected values for the economic variables. It is concluded that the NPV of the project is most sensitive to gold and silver price and that other variables such as discount rate, operating and capital cost all affect the feasibility of the project with lower degree of severity. Finally, risk analysis is also carried out using Mont Carlo technique, in order to estimate the most probable value of NPV. The average NPV calculated in this way is US$ 49.7 Million, whilst without due consideration of risk, this would be US$ 36.6 Million. The techniques used, together with the procedures adopted in this paper, can be used in feasibility studies of all mining projects. Such decision would result in more accurate Net Present Values than expected from other frequently used methods.

Jan 1, 2011

By Leonard Weixler, Peter Halbach, Michael Jarowinsky, Johannes Post

Germany as an industrial nation is highly dependent on the import of mineral or metal resources. Sources which have not been considered until now are the marine mineral resources (MMR), which in recent times are enjoying more and more increasing interests and which might provide in the future a considerable contribution to the supply security on metal resources not only for the industrial countries. Backed up by the German government’s "National Masterplan Maritime Technologies" (NMMT) and corresponding industrial R&D-activities, the idea and the advantages of deep-sea mining is gaining more and more interests and supporters with respect to industrial and political considerations on strategic raw material resources as well as on the development of deep-sea mining technologies. The NMMT aims to initiate growth and increase the competitiveness of the German maritime industry on international markets and covers about 10 different marine and ocean technology sectors including deep-sea mining.

Sep 1, 2014

Despite limited discussion, Chemistry of Flotation is a good text and reference 1985 by M. C. Fuerstenau, J. D. Miller, and M. C. Kuhn Society of Mining Engineers Caller No. D Littleton, CO 80127 Softcover, $23.50 (member), $18.50 (student member), $28.50 (list) Review by Richard R. Klimpel Chemistry in Flotation, as stated by the authors, is intended as a textbook for students as well as a reference book for practicing flotation engineers. It covers subject matter related to surface phenomena; collectors and collector salts; natural floatability; the flotation of sulfide minerals, insoluble oxide and silicate minerals, semisoluble salts, and soluble salts; and slime coatings. There are no discussions in the book on practical plant implications of flotation chemistry, such as the influence of rate, particle size effects, dosage, flotation equipment, and methods of chemical addition. The book itself is small (only 177 pages), and, as published, is in an easy-to-handle soft cover. Once one accepts the intent of the authors, this book really does represent a very concise and convenient summary of the chemistry of flotation. It is, however, far from complete in its discussion of concepts and implications of data. Very often in the presentation, key prior knowledge (or at least subject matter awareness) not given in the book, is assumed. Thus, depending on one's familiarity with the specific subject matter, some sections can be easily followed while others could be tough going. Some of the discussion is so brief and terse on important subjects that unless the reader already realizes the meaning of the presentation, the conclusions to be drawn are not always clear. Therefore, if one is not expecting a self-contained primer on flotation chemistry, this book is very useful. To this end, the book is recommended to practitioners of flotation chemistry. The presentation of data in figures and tables is good. It helps considerably in the book achieving its conciseness. The authors certainly are qualified and knowledgeable in the subject matter - apparent in the style of presentation. In summary, this reviewer thoroughly enjoyed this book and will use it as a concise review of flotation chemistry. Richard R. Klimpel, member SME, is a scientist with Dow Chemical Co., Discovery Development, 1776 Building, M. E. Pruitt Research Center, Midland, MI 48640. International Symposium on Blast Furnace Ironmaking, 1985, The Indian Institute of Metals, The Tata Iron and Steel Co., Ltd., Jamshedpur 831007, India, 282 pp., papercover, no price given - Papers from this symposium held in Jamshedpur, India, include the following: determination of coal and coke quality; feed to blast furnaces; burden quality and blast furnace performance; operation of blast furnaces on charcoal; review of cast house slag granulation systems; developments in blast furnace engineering and control; process improvements in blast furnace ironmaking; coal injection into the blast furnace; and coke from stamp charged coal. Advances in Materials Technology for the Process Industries, 1985, edited by H.A. Huskins, National Association of Corrosion Engineers, P.O. Box 218340, Houston, TX 77218, 273 pp., softcover, $20-This book is the proceedings of a meeting held in Atlanta, GA in October 1984. It describes innovations in metallurgy, ceramics, glass, composites, and polymeric materials that impact the integrity and economics of operating systems. It covers biotechnical developments, improvements in membrane systems, or beneficiation processes, as well as developments in electrochemical controls, testing procedures, and surveillance techniques. A Reference Guide to Mining Legislation in Canada, 1985, by B. Barton, B. Roulston, and N. Strantz, The Canadian Institute of Resources Law, Room 430, Bio Sciences Building, The University of Calgary, Calgary, Alberta, Canada T2N 1N4, 120 pp., bound, $US28- This guide provides a ready means of finding how the different jurisdictions in Canada regulate mineral activity. It covers the rights required for exploration, development, and production of mineral metallics and industrial minerals. It does not cover placer mining, petroleum and natural gas, bituminuous sands, coal, or structural materials. Dictionary of Geological Terms, 1985, edited by Robert L. Bates and Julia A. Jackson, The American Geological Institute, 4220 King St., Alexandria, VA 22302, papercover, $7.95 plus $1 for postage - This third edition is for geoscience students, teachers, and rockhounds. It defines the core vocabulary of earth sciences, contains 8000 revised definitions, and includes 1000 new terms. It adds recent terms in plate tectonics, hydrology, and permafrost studies. Accurate definitions are given without technical jargon, cross-references are included, and commonly used abbreviations are provided. Processing and Utilization of High Sulfur Coals, 1985, edited by Yosry A. Attia, Elsevier Science Publishing Co. Inc., 52 Vanderbilt Ave., New York, NY 10017, 787 pp., bound, $142.50-These proceedings comprise the majority of the papers presented at the First International conference. Investigators there reported the latest discoveries, developments in commercial practice, and state-of-the-art reviews of scientific principles and applications of various technologies for handling, processing, and use of high sulfur coals. Sessions were held on: characterization of sulfur in coals; environmental problems and impact of high sulfur on coal use; selective mining and blending; coal desulfurization by physical and chemical cleaning techniques; handling of coal fines; sulfur capture during coal combustion; biological desulfurization of coal; and new applications for high sulfur coal. The Economics of Magnesium Metal, 1985, Roskill Information Services Ltd., 2 Clapham Road, London SW9 OJA England, 129 pp., 71 tables, appendices, bound, $750-Despite setbacks in some major magnesium markets in 1985, Roskill's latest forecast for the last half of this decade is for a 4% to 6% annual growth rate in demand. Growth for magnesium metal is expected in the motor industry for use as a possible substitute for aluminum. Some magnesium producers are altering their marketing strategies to cultivate this market. This study also includes a review of the worldwide magnesium industry, its end uses and consumption, and international trade and price trends.

Jan 7, 1986

By Allan E. Koski

Ceveland-Cliffs uses a specialized software package in mine planning at the Empire Mine, an iron ore mine it manages on Michigan’s Marquette Iron Range. The application puts together years of mining experience that began in the early 1960s on the eastern end of the Marquette Range. The Empire Mine is in its 38th year of production. It uses the software to model a complex and highly variable low-grade magnetite ore body, capturing the economics of mining and processing to the final product. With special attention given to geostatistical methods, the software is used for all geologic modeling, ore reserve estimation, ore control, pit design and short- and long-range planning.

Jan 1, 2000